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    <title>Docs on Nine Nines</title>
    <link>http://ninenines.eu/docs/</link>
    <description>Recent content in Docs on Nine Nines</description>
    <generator>Hugo -- gohugo.io</generator>
    <language>en-us</language>
    <atom:link href="http://ninenines.eu/docs/index.xml" rel="self" type="application/rss+xml" />
    
    <item>
      <title>Architecture</title>
      <link>http://ninenines.eu/docs/en/cowboy/2.0/guide/architecture/</link>
      <pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate>
      
      <guid>http://ninenines.eu/docs/en/cowboy/2.0/guide/architecture/</guid>
      <description>&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Cowboy is a lightweight HTTP server.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;It is built on top of Ranch. Please see the Ranch guide for more
information.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_one_process_per_connection&#34;&gt;One process per connection&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;It uses only one process per connection. The process where your
code runs is the process controlling the socket. Using one process
instead of two allows for lower memory usage.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Because there can be more than one request per connection with the
keepalive feature of HTTP/1.1, that means the same process will be
used to handle many requests.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Because of this, you are expected to make sure your process cleans
up before terminating the handling of the current request. This may
include cleaning up the process dictionary, timers, monitoring and
more.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_binaries&#34;&gt;Binaries&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;It uses binaries. Binaries are more efficient than lists for
representing strings because they take less memory space. Processing
performance can vary depending on the operation. Binaries are known
for generally getting a great boost if the code is compiled natively.
Please see the HiPE documentation for more details.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_date_header&#34;&gt;Date header&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Because querying for the current date and time can be expensive,
Cowboy generates one &lt;code&gt;Date&lt;/code&gt; header value every second, shares it
to all other processes, which then simply copy it in the response.
This allows compliance with HTTP/1.1 with no actual performance loss.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_max_connections&#34;&gt;Max connections&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;By default the maximum number of active connections is set to a
generally accepted big enough number. This is meant to prevent having
too many processes performing potentially heavy work and slowing
everything else down, or taking up all the memory.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Disabling this feature, by setting the &lt;code&gt;{max_connections, infinity}&lt;/code&gt;
protocol option, would give you greater performance when you are
only processing short-lived requests.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
</description>
    </item>
    
    <item>
      <title>AsciiDoc documentation</title>
      <link>http://ninenines.eu/docs/en/erlang.mk/1/guide/asciidoc/</link>
      <pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate>
      
      <guid>http://ninenines.eu/docs/en/erlang.mk/1/guide/asciidoc/</guid>
      <description>&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk provides rules for generating documentation from
AsciiDoc files. It can automatically build a user guide PDF,
chunked HTML documentation and Unix manual pages.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_requirements&#34;&gt;Requirements&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;It is necessary to have &lt;a href=&#34;http://asciidoc.org/&#34;&gt;AsciiDoc&lt;/a&gt;,
&lt;a href=&#34;http://xmlsoft.org/XSLT/xsltproc2.html&#34;&gt;xsltproc&lt;/a&gt; and
&lt;a href=&#34;http://dblatex.sourceforge.net/&#34;&gt;dblatex&lt;/a&gt; installed on your
system for Erlang.mk to generate documentation from AsciiDoc sources.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_writing_asciidoc_documentation&#34;&gt;Writing AsciiDoc documentation&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;&lt;a href=&#34;http://asciidoc.org/&#34;&gt;AsciiDoc&lt;/a&gt; is a text document format for
writing notes, documentation, articles, books, ebooks, slideshows,
web pages, man pages and blogs. AsciiDoc files can be translated
to many formats including HTML, PDF, EPUB, man page.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The &lt;a href=&#34;http://asciidoc.org/userguide.html&#34;&gt;AsciiDoc user guide&lt;/a&gt;
describes the AsciiDoc syntax.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The &lt;a href=&#34;https://github.com/ninenines/erlang.mk/tree/master/doc/src/guide&#34;&gt;Erlang.mk user guide&lt;/a&gt;
is written in AsciiDoc and can be used as an example. The entry
file is &lt;a href=&#34;https://github.com/ninenines/erlang.mk/blob/master/doc/src/guide/book.asciidoc&#34;&gt;book.asciidoc&lt;/a&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk expects you to put your documentation in a specific
location. This is &lt;em&gt;doc/src/guide/&lt;/em&gt; for the user guide, and
&lt;em&gt;doc/src/manual/&lt;/em&gt; for the function reference. In the case of
the user guide, the entry point is always &lt;em&gt;doc/src/guide/book.asciidoc&lt;/em&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;For manual pages, it is good practice to use section 3 for
modules, and section 7 for the application itself.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_configuration&#34;&gt;Configuration&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;All of the AsciiDoc related configuration can be done directly
inside the files themselves.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_usage&#34;&gt;Usage&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To build all documentation:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make docs&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To build only the AsciiDoc documentation:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make asciidoc&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To build only the user guide:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make asciidoc-guide&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To build only the manual:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make asciidoc-manual&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To install man pages on Unix:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make install-docs&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk allows customizing the installation path and sections
of the man pages to be installed. The &lt;code&gt;MAN_INSTALL_PATH&lt;/code&gt; variable
defines where man pages will be installed. It defaults to
&lt;em&gt;/usr/local/share/man&lt;/em&gt;. The &lt;code&gt;MAN_SECTIONS&lt;/code&gt; variable defines
which manual sections are to be installed. It defaults to &lt;code&gt;3 7&lt;/code&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To install man pages to a custom location:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make install-docs &lt;span style=&#34;color: #009900&#34;&gt;MAN_INSTALL_PATH&lt;/span&gt;&lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt;/opt/share/man&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Note that you may need to run the install commands using
&lt;code&gt;sudo&lt;/code&gt; or equivalent if the location is not writeable by
your user.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
</description>
    </item>
    
    <item>
      <title>Building</title>
      <link>http://ninenines.eu/docs/en/erlang.mk/1/guide/app/</link>
      <pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate>
      
      <guid>http://ninenines.eu/docs/en/erlang.mk/1/guide/app/</guid>
      <description>&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk can do a lot of things, but it is, first and
foremost, a build tool. In this chapter we will cover
the basics of building a project with Erlang.mk.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;For most of this chapter, we will assume that you are
using a project &lt;a href=&#34;../getting_started&#34;&gt;generated by Erlang.mk&lt;/a&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_how_to_build&#34;&gt;How to build&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To build a project, all you have to do is type &lt;code&gt;make&lt;/code&gt;:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;It will work regardless of your project: OTP applications,
library applications, NIFs, port drivers or even releases.
Erlang.mk also automatically downloads and compiles the
dependencies for your project.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;All this is possible thanks to a combination of configuration
and conventions. Most of the conventions come from Erlang/OTP
itself so any seasoned Erlang developers should feel right at
home.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_what_to_build&#34;&gt;What to build&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk gives you control over three steps of the build
process, allowing you to do a partial build if needed.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;A build has three phases: first any dependency is fetched
and built, then the project itself is built and finally a
release may be generated when applicable. A release is only
generated for projects specifically configured to do so.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk handles those three phases automatically when you
type &lt;code&gt;make&lt;/code&gt;. But sometimes you just want to repeat one or
two of them.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The commands detailed in this section are most useful after
you have a successful build as they allow you to quickly
redo a step instead of going through everything. This is
especially useful for large projects or projects that end
up generating releases.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;sect3&#34;&gt;
&lt;h4 id=&#34;_application&#34;&gt;Application&lt;/h4&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;You can build your application and dependencies without
generating a release by running the following command:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make app&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To build your application without touching dependencies
at all, you can use the &lt;code&gt;SKIP_DEPS&lt;/code&gt; variable:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make app &lt;span style=&#34;color: #009900&#34;&gt;SKIP_DEPS&lt;/span&gt;&lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt;&lt;span style=&#34;color: #993399&#34;&gt;1&lt;/span&gt;&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;This command is very useful if you have a lot of dependencies
and develop on a machine with slow file access, like the
Raspberry Pi and many other embedded devices.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Note that this command may fail if a required dependency
is missing.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect3&#34;&gt;
&lt;h4 id=&#34;_dependencies&#34;&gt;Dependencies&lt;/h4&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;You can build all dependencies, and nothing else, by
running the following command:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make deps&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;This will fetch and compile all dependencies and their
dependencies, recursively.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;&lt;a href=&#34;../deps&#34;&gt;Packages and dependencies&lt;/a&gt; are covered
in the next chapter.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect3&#34;&gt;
&lt;h4 id=&#34;_release&#34;&gt;Release&lt;/h4&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;It is not possible to build the release without at least
building the application itself, unless of course if there&amp;#8217;s
no application to begin with.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To generate the release, &lt;code&gt;make&lt;/code&gt; will generally suffice with
a normal Erlang.mk. A separate target is however available,
and will take care of building the release, after building
the application and all dependencies:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make rel&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Consult the &lt;a href=&#34;../relx&#34;&gt;Releases&lt;/a&gt; chapter for more
information about what releases are and how they are generated.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_application_resource_file&#34;&gt;Application resource file&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;When building your application, Erlang.mk will generate the
&lt;a href=&#34;http://www.erlang.org/doc/man/app.html&#34;&gt;application resource file&lt;/a&gt;.
This file is mandatory for all Erlang applications and is
found in &lt;em&gt;ebin/$(PROJECT).app&lt;/em&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;&lt;code&gt;PROJECT&lt;/code&gt; is a variable defined in your Makefile and taken
from the name of the directory when Erlang.mk bootstraps
your project.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk can build the &lt;em&gt;ebin/$(PROJECT).app&lt;/em&gt; in two different
ways: from the configuration found in the Makefile, or from
the &lt;em&gt;src/$(PROJECT).app.src&lt;/em&gt; file.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;sect3&#34;&gt;
&lt;h4 id=&#34;_application_configuration&#34;&gt;Application configuration&lt;/h4&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk automatically fills the &lt;code&gt;PROJECT&lt;/code&gt; variable when
bootstrapping a new project, but everything else is up to
you. None of the values are required to build your project,
although it is recommended to fill everything relevant to
your situation.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;dlist&#34;&gt;&lt;dl&gt;
&lt;dt class=&#34;hdlist1&#34;&gt;
&lt;code&gt;PROJECT&lt;/code&gt;
&lt;/dt&gt;
&lt;dd&gt;
&lt;p&gt;
        The name of the OTP application or library.
&lt;/p&gt;
&lt;/dd&gt;
&lt;dt class=&#34;hdlist1&#34;&gt;
&lt;code&gt;PROJECT_DESCRIPTION&lt;/code&gt;
&lt;/dt&gt;
&lt;dd&gt;
&lt;p&gt;
        Short description of the project.
&lt;/p&gt;
&lt;/dd&gt;
&lt;dt class=&#34;hdlist1&#34;&gt;
&lt;code&gt;PROJECT_VERSION&lt;/code&gt;
&lt;/dt&gt;
&lt;dd&gt;
&lt;p&gt;
        Current version of the project.
&lt;/p&gt;
&lt;/dd&gt;
&lt;dt class=&#34;hdlist1&#34;&gt;
&lt;code&gt;PROJECT_REGISTERED&lt;/code&gt;
&lt;/dt&gt;
&lt;dd&gt;
&lt;p&gt;
        List of the names of all registered processes.
&lt;/p&gt;
&lt;/dd&gt;
&lt;dt class=&#34;hdlist1&#34;&gt;
&lt;code&gt;LOCAL_DEPS&lt;/code&gt;
&lt;/dt&gt;
&lt;dd&gt;
&lt;p&gt;
        List of Erlang/OTP applications this project depends on,
        excluding &lt;code&gt;erts&lt;/code&gt;, &lt;code&gt;kernel&lt;/code&gt; and &lt;code&gt;stdlib&lt;/code&gt;, or list of
        dependencies local to this repository (in &lt;code&gt;APPS_DIR&lt;/code&gt;).
&lt;/p&gt;
&lt;/dd&gt;
&lt;dt class=&#34;hdlist1&#34;&gt;
&lt;code&gt;DEPS&lt;/code&gt;
&lt;/dt&gt;
&lt;dd&gt;
&lt;p&gt;
        List of applications this project depends on that need
        to be fetched by Erlang.mk.
&lt;/p&gt;
&lt;/dd&gt;
&lt;/dl&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;There&amp;#8217;s no need for quotes or anything. The relevant part of
the Cowboy Makefile follows, if you need an example:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;&lt;span style=&#34;color: #009900&#34;&gt;PROJECT =&lt;/span&gt; cowboy
&lt;span style=&#34;color: #009900&#34;&gt;PROJECT_DESCRIPTION =&lt;/span&gt; Small&lt;span style=&#34;color: #990000&#34;&gt;,&lt;/span&gt; fast&lt;span style=&#34;color: #990000&#34;&gt;,&lt;/span&gt; modular HTTP server&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;
&lt;span style=&#34;color: #009900&#34;&gt;PROJECT_VERSION =&lt;/span&gt; 2.0.0-pre.2
&lt;span style=&#34;color: #009900&#34;&gt;PROJECT_REGISTERED =&lt;/span&gt; cowboy_clock

&lt;span style=&#34;color: #009900&#34;&gt;LOCAL_DEPS =&lt;/span&gt; crypto
&lt;span style=&#34;color: #009900&#34;&gt;DEPS =&lt;/span&gt; cowlib ranch&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Any space before and after the value is dropped.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;&lt;a href=&#34;../deps&#34;&gt;Dependencies&lt;/a&gt; are covered in details in
the next chapter.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect3&#34;&gt;
&lt;h4 id=&#34;_legacy_method&#34;&gt;Legacy method&lt;/h4&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The &lt;em&gt;src/$(PROJECT).app.src&lt;/em&gt; file is a legacy method of
building Erlang applications. It was introduced by the original
&lt;code&gt;rebar&lt;/code&gt; build tool, of which Erlang.mk owes a great deal as it
is its main inspiration.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The &lt;em&gt;.app.src&lt;/em&gt; file serves as a template to generate the &lt;em&gt;.app&lt;/em&gt;
file. Erlang.mk will take it, fill in the &lt;code&gt;modules&lt;/code&gt; value
dynamically, and save the result in &lt;em&gt;ebin/$(PROJECT).app&lt;/em&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;When using this method, Erlang.mk cannot fill the &lt;code&gt;applications&lt;/code&gt;
key from dependencies automatically, which means you need to
add them to Erlang.mk and to the &lt;em&gt;.app.src&lt;/em&gt; at the same time,
duplicating the work.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you really can&amp;#8217;t live without the legacy method, for one
reason or another, worry not; Erlang.mk will support it. And
if you need to create a new project that uses this method, you
just have to say so when bootstrapping:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make -f erlang&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;mk bootstrap-lib &lt;span style=&#34;color: #009900&#34;&gt;LEGACY&lt;/span&gt;&lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt;&lt;span style=&#34;color: #993399&#34;&gt;1&lt;/span&gt;&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_automatic_application_resource_file_values&#34;&gt;Automatic application resource file values&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;When building the application resource file, Erlang.mk may
automatically add an &lt;code&gt;id&lt;/code&gt; key with information about the
Git commit (if using Git), or an empty string otherwise.
It will only do this under specific conditions:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;ulist&#34;&gt;&lt;ul&gt;
&lt;li&gt;
&lt;p&gt;
The application was built as a dependency of another, or
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
The legacy method was used, and the &lt;em&gt;.app.src&lt;/em&gt; file contained &lt;code&gt;{id, &#34;git&#34;}&lt;/code&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;/ul&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;This value is most useful when you need to help your users,
as it allows you to know which version they run exactly by
asking them to look in the file, or by running a simple
command on their production server:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;&lt;span style=&#34;color: #993399&#34;&gt;1&lt;/span&gt;&lt;span style=&#34;color: #990000&#34;&gt;&amp;gt;&lt;/span&gt; &lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000000&#34;&gt;application:get_all_key&lt;/span&gt;&lt;/span&gt;(&lt;span style=&#34;color: #FF6600&#34;&gt;cowboy&lt;/span&gt;)&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;
{&lt;span style=&#34;color: #FF6600&#34;&gt;ok&lt;/span&gt;,[{&lt;span style=&#34;color: #FF6600&#34;&gt;description&lt;/span&gt;,&lt;span style=&#34;color: #FF0000&#34;&gt;&#34;Small, fast, modular HTTP server.&#34;&lt;/span&gt;},
     {&lt;span style=&#34;color: #FF6600&#34;&gt;id&lt;/span&gt;,&lt;span style=&#34;color: #FF0000&#34;&gt;&#34;2.0.0-pre.2-25-g0ffde50-dirty&#34;&lt;/span&gt;},&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_file_formats&#34;&gt;File formats&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk supports a variety of different source file formats.
The following formats are supported natively:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;tableblock&#34;&gt;
&lt;table rules=&#34;all&#34;
width=&#34;100%&#34;
frame=&#34;border&#34;
cellspacing=&#34;0&#34; cellpadding=&#34;4&#34;&gt;
&lt;col width=&#34;25%&#34; /&gt;
&lt;col width=&#34;25%&#34; /&gt;
&lt;col width=&#34;25%&#34; /&gt;
&lt;col width=&#34;25%&#34; /&gt;
&lt;thead&gt;
&lt;tr&gt;
&lt;th align=&#34;left&#34; valign=&#34;top&#34;&gt; Extension &lt;/th&gt;
&lt;th align=&#34;center&#34; valign=&#34;top&#34;&gt; Location &lt;/th&gt;
&lt;th align=&#34;center&#34; valign=&#34;top&#34;&gt; Description        &lt;/th&gt;
&lt;th align=&#34;center&#34; valign=&#34;top&#34;&gt; Output&lt;/th&gt;
&lt;/tr&gt;
&lt;/thead&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td align=&#34;left&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;.erl&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;src/&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;Erlang source&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;ebin/*.beam&lt;/p&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td align=&#34;left&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;.core&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;src/&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;Core Erlang source&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;ebin/*.beam&lt;/p&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td align=&#34;left&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;.xrl&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;src/&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;Leex source&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;src/*.erl&lt;/p&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td align=&#34;left&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;.yrl&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;src/&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;Yecc source&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;src/*.erl&lt;/p&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td align=&#34;left&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;.asn1&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;asn1/&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;ASN.1 files&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;include/&lt;strong&gt;.hrl include/&lt;/strong&gt;.asn1db src/*.erl&lt;/p&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td align=&#34;left&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;.mib&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;mibs/&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;SNMP MIB files&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;include/&lt;strong&gt;.hrl priv/mibs/&lt;/strong&gt;.bin&lt;/p&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Files are always searched recursively.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The build is ordered, so that files that generate Erlang source
files are run before, and the resulting Erlang source files are
then built normally.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;In addition, Erlang.mk keeps track of header files (&lt;code&gt;.hrl&lt;/code&gt;)
as described at the end of this chapter. It can also compile
C code, as described in the &lt;a href=&#34;../ports&#34;&gt;NIFs and port drivers&lt;/a&gt;
chapter.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk also comes with plugins for the following formats:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;tableblock&#34;&gt;
&lt;table rules=&#34;all&#34;
width=&#34;100%&#34;
frame=&#34;border&#34;
cellspacing=&#34;0&#34; cellpadding=&#34;4&#34;&gt;
&lt;col width=&#34;25%&#34; /&gt;
&lt;col width=&#34;25%&#34; /&gt;
&lt;col width=&#34;25%&#34; /&gt;
&lt;col width=&#34;25%&#34; /&gt;
&lt;thead&gt;
&lt;tr&gt;
&lt;th align=&#34;left&#34; valign=&#34;top&#34;&gt; Extension &lt;/th&gt;
&lt;th align=&#34;center&#34; valign=&#34;top&#34;&gt; Location   &lt;/th&gt;
&lt;th align=&#34;center&#34; valign=&#34;top&#34;&gt; Description      &lt;/th&gt;
&lt;th align=&#34;center&#34; valign=&#34;top&#34;&gt; Output&lt;/th&gt;
&lt;/tr&gt;
&lt;/thead&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td align=&#34;left&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;.dtl&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;templates/&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;Django templates&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;ebin/*.beam&lt;/p&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td align=&#34;left&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;.proto&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;src/&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;Protocol buffers&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;center&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;ebin/*.beam&lt;/p&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_compilation_options&#34;&gt;Compilation options&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk provides a few variables that you can use to customize
the build process and the resulting files.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;sect3&#34;&gt;
&lt;h4 id=&#34;_erlc_opts&#34;&gt;ERLC_OPTS&lt;/h4&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;&lt;code&gt;ERLC_OPTS&lt;/code&gt; can be used to pass some options to &lt;code&gt;erlc&lt;/code&gt;, the Erlang
compiler. Erlang.mk does not restrict any option. Please refer to
the &lt;a href=&#34;http://www.erlang.org/doc/man/erlc.html&#34;&gt;erlc Manual&lt;/a&gt; for the
full list.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;By default, Erlang.mk will set the following options:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;&lt;span style=&#34;color: #009900&#34;&gt;ERLC_OPTS =&lt;/span&gt; -Werror &lt;span style=&#34;color: #990000&#34;&gt;+&lt;/span&gt;debug_info &lt;span style=&#34;color: #990000&#34;&gt;+&lt;/span&gt;warn_export_vars &lt;span style=&#34;color: #990000&#34;&gt;+&lt;/span&gt;warn_shadow_vars &lt;span style=&#34;color: #990000&#34;&gt;+&lt;/span&gt;warn_obsolete_guard&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;In other words: warnings as errors, debug info (recommended) and
enable warnings for exported variables, shadow variables and
obsolete guard functions.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;You can redefine this variable in your Makefile to change it
completely, either before or after including Erlang.mk:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;&lt;span style=&#34;color: #009900&#34;&gt;ERLC_OPTS =&lt;/span&gt; &lt;span style=&#34;color: #990000&#34;&gt;+&lt;/span&gt;debug_info&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;You can also filter out some options from the defaults Erlang.mk
sets, by defining ERLC_OPTS after including Erlang.mk using the
&lt;code&gt;:=&lt;/code&gt; operator.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;include erlang.mk

&lt;span style=&#34;color: #990000&#34;&gt;ERLC_OPTS :=&lt;/span&gt; &lt;span style=&#34;color: #009900&#34;&gt;$(&lt;/span&gt;filter-out -Werror&lt;span style=&#34;color: #990000&#34;&gt;,&lt;/span&gt;&lt;span style=&#34;color: #009900&#34;&gt;$(ERLC_OPTS))&lt;/span&gt;&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect3&#34;&gt;
&lt;h4 id=&#34;_erlc_exclude&#34;&gt;ERLC_EXCLUDE&lt;/h4&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;&lt;code&gt;ERLC_EXCLUDE&lt;/code&gt; can be used to exclude some modules from the
compilation. It&amp;#8217;s there for handling special cases, you should
not normally need it.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To exclude a module, simply list it in the variable, either
before or after including Erlang.mk:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;&lt;span style=&#34;color: #009900&#34;&gt;ERLC_EXCLUDE =&lt;/span&gt; cowboy_http2&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_cold_and_hot_builds&#34;&gt;Cold and hot builds&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The first time you run &lt;code&gt;make&lt;/code&gt;, Erlang.mk will build everything.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The second time you run &lt;code&gt;make&lt;/code&gt;, and all subsequent times, Erlang.mk
will only rebuild what changed. Erlang.mk has been optimized for
this use case, as it is the most common during development.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk figures out what changed by using the dependency tracking
feature of Make. Make automatically rebuilds a target if one of its
dependency has changed (for example if a header file has changed,
all the source files that include it will be rebuilt), and Erlang.mk
leverages this feature to cut down on rebuild times.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Note that this applies only to building; some other features of
Erlang.mk will run every time they are called regardless of files
changed.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_dependency_tracking&#34;&gt;Dependency tracking&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;admonitionblock&#34;&gt;
&lt;table&gt;&lt;tr&gt;
&lt;td class=&#34;icon&#34;&gt;
&lt;div class=&#34;title&#34;&gt;Note&lt;/div&gt;
&lt;/td&gt;
&lt;td class=&#34;content&#34;&gt;This section is about the dependency tracking between files
inside your project, not application dependencies.&lt;/td&gt;
&lt;/tr&gt;&lt;/table&gt;
&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk keeps track of the dependencies between the different
files in your project. This information is kept in the &lt;em&gt;$(PROJECT).d&lt;/em&gt;
file in your directory. It is generated if missing, and will be
generated again after every file change, by default.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Dependency tracking is what allows Erlang.mk to know when to
rebuild Erlang files when header files, behaviors or parse
transforms have changed. Erlang.mk also automatically keeps
track of which files should be compiled first, for example
when you have behaviors used by other modules in your project.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If your project is stable, you may want to disable generating
the dependency tracking file every time you compile. You can
do this by adding the following line to your &lt;em&gt;Makefile&lt;/em&gt;:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;NO_MAKEDEP &lt;span style=&#34;color: #990000&#34;&gt;?=&lt;/span&gt; &lt;span style=&#34;color: #993399&#34;&gt;1&lt;/span&gt;&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;As you can see, the snippet above uses &lt;code&gt;?=&lt;/code&gt; instead of a
simple equal sign. This is to allow you to temporarily override
this value when you do make substantial changes to your project
(including a new header file, new module with dependencies, etc.)
and want to rebuild the dependency tracking file. You&amp;#8217;ll be
able to use the following command:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ &lt;span style=&#34;color: #009900&#34;&gt;NO_MAKEDEP&lt;/span&gt;&lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt; make&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Otherwise, &lt;code&gt;make clean app&lt;/code&gt; will of course force the
recompilation of your project.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk can also keep track of the source files generated
by other means, for example if you generate code from a data
file in your repository.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_generating_erlang_source&#34;&gt;Generating Erlang source&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk provides hooks at different stages of the build process.
When your goal is to generate Erlang source files, you can
add your own rules before or after the dependency tracking
file is generated. To do this, you would add your hook before
or after including the &lt;em&gt;erlang.mk&lt;/em&gt; file.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The easiest way is after:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;&lt;span style=&#34;color: #009900&#34;&gt;PROJECT =&lt;/span&gt; example

include erlang.mk

&lt;span style=&#34;color: #009900&#34;&gt;$(PROJECT)&lt;/span&gt;.d&lt;span style=&#34;color: #990000&#34;&gt;::&lt;/span&gt; src/generated_mod.erl

src/generated_mod.erl&lt;span style=&#34;color: #990000&#34;&gt;::&lt;/span&gt; gen-mod.sh
        &lt;span style=&#34;color: #009900&#34;&gt;$(gen_verbose)&lt;/span&gt; &lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;/gen-mod.sh &lt;span style=&#34;color: #009900&#34;&gt;$@&lt;/span&gt;&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;In this case we use &lt;code&gt;$(gen_verbose)&lt;/code&gt; to hide the details of
the build by default. Erlang.mk will simply say what file
is it currently generating.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;When using an external script to generate the Erlang source
file, it is recommended to depend on that script, so that
the source file gets generated again when the script gets
modified.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If for whatever reason you prefer to hook before including
Erlang.mk, don&amp;#8217;t forget to set the &lt;code&gt;.DEFAULT_GOAL&lt;/code&gt; variable,
otherwise nothing will get built:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;&lt;span style=&#34;color: #009900&#34;&gt;PROJECT =&lt;/span&gt; example

.DEFAULT_GOAL &lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt; all

&lt;span style=&#34;color: #009900&#34;&gt;$(PROJECT)&lt;/span&gt;.d&lt;span style=&#34;color: #990000&#34;&gt;::&lt;/span&gt; src/generated_mod.erl

include erlang.mk

src/generated_mod.erl&lt;span style=&#34;color: #990000&#34;&gt;::&lt;/span&gt; gen-mod.sh
        &lt;span style=&#34;color: #009900&#34;&gt;$(gen_verbose)&lt;/span&gt; &lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;/gen-mod.sh &lt;span style=&#34;color: #009900&#34;&gt;$@&lt;/span&gt;&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_cleaning&#34;&gt;Cleaning&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Building typically involves creating a lot of new files. Some
are reused in rebuilds, some are simply replaced. All can be
removed safely.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk provides two commands to remove them: &lt;code&gt;clean&lt;/code&gt; and
&lt;code&gt;distclean&lt;/code&gt;. &lt;code&gt;clean&lt;/code&gt; removes all the intermediate files that
were created as a result of building, including the BEAM files,
the dependency tracking file and the generated documentation.
&lt;code&gt;distclean&lt;/code&gt; removes these and more, including the downloaded
dependencies, Dialyzer&amp;#8217;s PLT file and the generated release,
putting your directory back to the state it was before you
started working on it.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To clean:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make clean&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Or distclean:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make distclean&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;That is the question.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Note that Erlang.mk will automatically clean some files as
part of other targets, but it will never run &lt;code&gt;distclean&lt;/code&gt; if
you don&amp;#8217;t explicitly use it.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
</description>
    </item>
    
    <item>
      <title>Code coverage</title>
      <link>http://ninenines.eu/docs/en/erlang.mk/1/guide/coverage/</link>
      <pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate>
      
      <guid>http://ninenines.eu/docs/en/erlang.mk/1/guide/coverage/</guid>
      <description>&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Placeholder chapter.&lt;/p&gt;&lt;/div&gt;
</description>
    </item>
    
    <item>
      <title>Common Test</title>
      <link>http://ninenines.eu/docs/en/erlang.mk/1/guide/common_test/</link>
      <pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate>
      
      <guid>http://ninenines.eu/docs/en/erlang.mk/1/guide/common_test/</guid>
      <description>&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Common Test is Erlang&amp;#8217;s functional testing framework.
Erlang.mk automates the discovery and running of Common
Test suites.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_writing_tests&#34;&gt;Writing tests&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The &lt;a href=&#34;http://www.erlang.org/doc/apps/common_test/write_test_chapter.html&#34;&gt;Common Test user guide&lt;/a&gt;
is the best place to learn how to write tests. Erlang.mk
requires that file names for test suites end with &lt;em&gt;_SUITE.erl&lt;/em&gt;
and that the files be located in the &lt;em&gt;$(TEST_DIR)&lt;/em&gt; directory.
This defaults to &lt;em&gt;test/&lt;/em&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_configuration&#34;&gt;Configuration&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The &lt;code&gt;CT_OPTS&lt;/code&gt; variable allows you to set extra Common Test
options. Options are documented in the
&lt;a href=&#34;http://www.erlang.org/doc/apps/common_test/run_test_chapter.html&#34;&gt;Common Test user guide&lt;/a&gt;.
You can use it to set Common Test hooks, for example:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;&lt;span style=&#34;color: #009900&#34;&gt;CT_OPTS =&lt;/span&gt; -ct_hooks cowboy_ct_hook&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The &lt;code&gt;CT_SUITES&lt;/code&gt; variable can be used to override what
Common Test suites Erlang.mk will be aware of. It does
not normally need to be set as Erlang.mk will find the
test suites automatically.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The name of the suite is the part before &lt;code&gt;_SUITE.erl&lt;/code&gt;.
If the file is named &lt;em&gt;http_SUITE.erl&lt;/em&gt;, the test suite
is &lt;code&gt;http&lt;/code&gt;:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;&lt;span style=&#34;color: #009900&#34;&gt;CT_SUITES =&lt;/span&gt; http ws&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_usage&#34;&gt;Usage&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To run all tests (including Common Test):&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make tests&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To run all tests and static checks (including Common Test):&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make check&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;You can also run Common Test separately:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make ct&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk will create targets for all test suites it finds.
If you have a file named &lt;em&gt;test/http_SUITE.erl&lt;/em&gt;, then the
target &lt;code&gt;ct-http&lt;/code&gt; will run that specific test suite:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make ct-http&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk provides a convenient way to run a specific
group or a specific test case within a specific group,
using the variable &lt;code&gt;t&lt;/code&gt;. Note that this only applies to
suite-specific targets, like the &lt;code&gt;ct-http&lt;/code&gt; example above.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To run all tests from the &lt;code&gt;http_compress&lt;/code&gt; group in the
&lt;code&gt;http_SUITE&lt;/code&gt; test suite, write:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make ct-http &lt;span style=&#34;color: #009900&#34;&gt;t&lt;/span&gt;&lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt;http_compress&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Similarly, to run a specific test case in that group:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make ct-http &lt;span style=&#34;color: #009900&#34;&gt;t&lt;/span&gt;&lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt;http_compress&lt;span style=&#34;color: #990000&#34;&gt;:&lt;/span&gt;headers_dupe&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To do the same against a multi-application repository,
you can use the &lt;code&gt;-C&lt;/code&gt; option:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make -C apps/my_app ct-http &lt;span style=&#34;color: #009900&#34;&gt;t&lt;/span&gt;&lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt;my_group&lt;span style=&#34;color: #990000&#34;&gt;:&lt;/span&gt;my_case&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Note that this also applies to dependencies. When using Cowboy
as a dependency, you can run the following directly:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make -C deps/cowboy ct-http &lt;span style=&#34;color: #009900&#34;&gt;t&lt;/span&gt;&lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt;http_compress&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Finally, &lt;a href=&#34;../coverage&#34;&gt;code coverage&lt;/a&gt; is available,
but covered in its own chapter.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
</description>
    </item>
    
    <item>
      <title>Compatibility with other build tools</title>
      <link>http://ninenines.eu/docs/en/erlang.mk/1/guide/compat/</link>
      <pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate>
      
      <guid>http://ninenines.eu/docs/en/erlang.mk/1/guide/compat/</guid>
      <description>&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk tries its best to be compatible with the other Erlang
build tools. It can use dependencies written with other build
tools in mind, and can also make your projects usable by those
build tools as well. Erlang.mk is like the cool kid that gets
along with everybody.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;In this chapter I will use the term &lt;em&gt;Rebar project&lt;/em&gt; to refer
to a project built using Rebar 2, Rebar 3 or Mad. These three
build tools are very similar and share the same configuration
file.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_rebar_projects_as_erlang_mk_dependencies&#34;&gt;Rebar projects as Erlang.mk dependencies&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk comes with a feature called &lt;em&gt;Autoload&lt;/em&gt; which will
use Rebar 2 to patch any Rebar project and make it compatible
with Erlang.mk. This feature essentially patches Rebar out
and adds a Makefile to the project that Erlang.mk can then
use for building:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;&lt;em&gt;Autoload&lt;/em&gt; is documented in more details in the
&lt;a href=&#34;../deps&#34;&gt;Packages and dependencies&lt;/a&gt; chapter.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_erlang_mk_projects_as_rebar_dependencies&#34;&gt;Erlang.mk projects as Rebar dependencies&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk projects can be made compatible with the Rebar family
of build tools pretty easily, as Erlang.mk will generate
all the files they require for building.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The Rebar family requires two files: a &lt;em&gt;rebar.config&lt;/em&gt; file
containing compilation options and the list of dependencies,
and the application resource file, found either at
&lt;em&gt;ebin/$(PROJECT).app&lt;/em&gt; or at &lt;em&gt;src/$(PROJECT).app.src&lt;/em&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;sect3&#34;&gt;
&lt;h4 id=&#34;_rebar_configuration&#34;&gt;Rebar configuration&lt;/h4&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk comes with a target that generates a &lt;em&gt;rebar.config&lt;/em&gt;
file when invoked:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make rebar&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;config&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Careful! This will build the file even if it already existed
before.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To build this file, Erlang.mk uses information it finds in
the &lt;code&gt;DEPS&lt;/code&gt; and &lt;code&gt;ERLC_OPTS&lt;/code&gt; variables, among others. This
means that the Rebar family builds your project much the
same way as Erlang.mk.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Careful though! Different build tools have different fetching
strategies. If some applications provide differing dependencies,
they might be fetched differently by other build tools. Check
the upcoming Sanity check chapter to find out how to detect such
issues.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;You can automatically generate this file when you build
your application, by making it a dependency of the &lt;code&gt;app&lt;/code&gt;
target:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;&lt;span style=&#34;color: #990000&#34;&gt;app::&lt;/span&gt; rebar.config&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Don&amp;#8217;t forget to commit the file when it changes!&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you run into other issues, it&amp;#8217;s probably because you use a
feature specific to Erlang.mk, like the &lt;code&gt;cp&lt;/code&gt; fetch method.
It could also be that we forgot to handle something! Sorry.
We are of course interested to hear about any compatibility
problems you may have, just open a ticket!&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect3&#34;&gt;
&lt;h4 id=&#34;_application_resource_file&#34;&gt;Application resource file&lt;/h4&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk has two ways to generate an application resource
file: from the information found in the Makefile, or from
the information found in the &lt;em&gt;src/$(PROJECT).app.src&lt;/em&gt; file.
Needless to say, if you have this file in your repository,
then you don&amp;#8217;t need to worry about compatibility with other
build tools.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you don&amp;#8217;t, however, it&amp;#8217;s not much harder. Every time
Erlang.mk will compile your application, it will produce
a new &lt;em&gt;ebin/$(PROJECT).app&lt;/em&gt; file. Simply commit this file
when it changes. It will only change when you modify the
configuration, add or remove modules.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
</description>
    </item>
    
    <item>
      <title>Connection</title>
      <link>http://ninenines.eu/docs/en/gun/1.0/guide/connect/</link>
      <pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate>
      
      <guid>http://ninenines.eu/docs/en/gun/1.0/guide/connect/</guid>
      <description>&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;This chapter describes how to open, monitor and close
a connection using the Gun client.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_gun_connections&#34;&gt;Gun connections&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Gun is designed with the SPDY and Websocket protocols in mind.
They are built for long-running connections that allow concurrent
exchange of data, either in the form of request/responses for
SPDY or in the form of messages for Websocket.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;A Gun connection is an Erlang process that manages a socket to
a remote endpoint. This Gun connection is owned by a user
process that is called the &lt;em&gt;owner&lt;/em&gt; of the connection, and is
managed by the supervision tree of the &lt;code&gt;gun&lt;/code&gt; application.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The owner process communicates with the Gun connection
by calling functions from the module &lt;code&gt;gun&lt;/code&gt;. All functions
perform their respective operations asynchronously. The Gun
connection will send Erlang messages to the owner process
whenever needed.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;When the remote endpoint closes the connection, Gun attempts
to reconnect automatically.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_opening_a_new_connection&#34;&gt;Opening a new connection&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The &lt;code&gt;gun:open/{2,3}&lt;/code&gt; function must be used to open a connection.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;title&#34;&gt;Opening a connection to example.org on port 443&lt;/div&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;{&lt;span style=&#34;color: #FF6600&#34;&gt;ok&lt;/span&gt;, &lt;span style=&#34;color: #009900&#34;&gt;ConnPid&lt;/span&gt;} &lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt; &lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000000&#34;&gt;gun:open&lt;/span&gt;&lt;/span&gt;(&lt;span style=&#34;color: #FF0000&#34;&gt;&#34;example.org&#34;&lt;/span&gt;, &lt;span style=&#34;color: #993399&#34;&gt;443&lt;/span&gt;)&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If the port given is 443, Gun will attempt to connect using
SSL. The protocol will be selected automatically using the
NPN extension for TLS. By default Gun supports SPDY/3.1,
SPDY/3 and HTTP/1.1 when connecting using SSL.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;For any other port, Gun will attempt to connect using TCP
and will use the HTTP/1.1 protocol.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The transport and protocol used can be overriden using
options. The manual documents all available options.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Options can be provided as a third argument, and take the
form of a map.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;title&#34;&gt;Opening an SSL connection to example.org on port 8443&lt;/div&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;{&lt;span style=&#34;color: #FF6600&#34;&gt;ok&lt;/span&gt;, &lt;span style=&#34;color: #009900&#34;&gt;ConnPid&lt;/span&gt;} &lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt; &lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000000&#34;&gt;gun:open&lt;/span&gt;&lt;/span&gt;(&lt;span style=&#34;color: #FF0000&#34;&gt;&#34;example.org&#34;&lt;/span&gt;, &lt;span style=&#34;color: #993399&#34;&gt;8443&lt;/span&gt;, #{&lt;span style=&#34;color: #0000FF&#34;&gt;transport&lt;/span&gt;&lt;span style=&#34;color: #990000&#34;&gt;=&amp;gt;&lt;/span&gt;&lt;span style=&#34;color: #FF6600&#34;&gt;ssl&lt;/span&gt;})&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_waiting_for_the_connection_to_be_established&#34;&gt;Waiting for the connection to be established&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;When Gun successfully connects to the server, it sends a
&lt;code&gt;gun_up&lt;/code&gt; message with the protocol that has been selected
for the connection.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Gun provides the functions &lt;code&gt;gun:await_up/{1,2,3}&lt;/code&gt; that wait
for the &lt;code&gt;gun_up&lt;/code&gt; message. They can optionally take a monitor
reference and/or timeout value. If no monitor is provided,
one will be created for the duration of the function call.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;title&#34;&gt;Synchronous opening of a connection&lt;/div&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;{&lt;span style=&#34;color: #FF6600&#34;&gt;ok&lt;/span&gt;, &lt;span style=&#34;color: #009900&#34;&gt;ConnPid&lt;/span&gt;} &lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt; &lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000000&#34;&gt;gun:open&lt;/span&gt;&lt;/span&gt;(&lt;span style=&#34;color: #FF0000&#34;&gt;&#34;example.org&#34;&lt;/span&gt;, &lt;span style=&#34;color: #993399&#34;&gt;443&lt;/span&gt;),
{&lt;span style=&#34;color: #FF6600&#34;&gt;ok&lt;/span&gt;, &lt;span style=&#34;color: #009900&#34;&gt;Protocol&lt;/span&gt;} &lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt; &lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000000&#34;&gt;gun:await_up&lt;/span&gt;&lt;/span&gt;(&lt;span style=&#34;color: #009900&#34;&gt;ConnPid&lt;/span&gt;)&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_handling_connection_loss&#34;&gt;Handling connection loss&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;When the connection is lost, Gun will send a &lt;code&gt;gun_down&lt;/code&gt;
message indicating the current protocol, the reason the
connection was lost and two list of stream references.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The first list indicates open streams that &lt;em&gt;may&lt;/em&gt; have been
processed by the server. The second list indicates open
streams that the server did not process.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_monitoring_the_connection_process&#34;&gt;Monitoring the connection process&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;@todo Gun should detect the owner process being killed&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Because software errors are unavoidable, it is important to
detect when the Gun process crashes. It is also important
to detect when it exits normally. Erlang provides two ways
to do that: links and monitors.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Gun leaves you the choice as to which one will be used.
However, if you use the &lt;code&gt;gun:await/{2,3}&lt;/code&gt; or &lt;code&gt;gun:await_body/{2,3}&lt;/code&gt;
functions, a monitor may be used for you to avoid getting
stuck waiting for a message that will never come.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you choose to monitor yourself you can do it on a permanent
basis rather than on every message you will receive, saving
resources. Indeed, the &lt;code&gt;gun:await/{3,4}&lt;/code&gt; and &lt;code&gt;gun:await_body/{3,4}&lt;/code&gt;
functions both accept a monitor argument if you have one already.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;title&#34;&gt;Monitoring the connection process&lt;/div&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;{&lt;span style=&#34;color: #FF6600&#34;&gt;ok&lt;/span&gt;, &lt;span style=&#34;color: #009900&#34;&gt;ConnPid&lt;/span&gt;} &lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt; &lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000000&#34;&gt;gun:open&lt;/span&gt;&lt;/span&gt;(&lt;span style=&#34;color: #FF0000&#34;&gt;&#34;example.org&#34;&lt;/span&gt;, &lt;span style=&#34;color: #993399&#34;&gt;443&lt;/span&gt;)&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;
&lt;span style=&#34;color: #009900&#34;&gt;MRef&lt;/span&gt; &lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt; &lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000000&#34;&gt;monitor&lt;/span&gt;&lt;/span&gt;(&lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000080&#34;&gt;process&lt;/span&gt;&lt;/span&gt;, &lt;span style=&#34;color: #009900&#34;&gt;ConnPid&lt;/span&gt;)&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;This monitor reference can be kept and used until the connection
process exits.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;title&#34;&gt;Handling &lt;code&gt;DOWN&lt;/code&gt; messages&lt;/div&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;&lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #0000FF&#34;&gt;receive&lt;/span&gt;&lt;/span&gt;
        &lt;span style=&#34;font-style: italic&#34;&gt;&lt;span style=&#34;color: #9A1900&#34;&gt;%% Receive Gun messages here...&lt;/span&gt;&lt;/span&gt;
        {&lt;span style=&#34;color: #FF6600&#34;&gt;&#39;DOWN&#39;&lt;/span&gt;, &lt;span style=&#34;color: #009900&#34;&gt;Mref&lt;/span&gt;, &lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000080&#34;&gt;process&lt;/span&gt;&lt;/span&gt;, &lt;span style=&#34;color: #009900&#34;&gt;ConnPid&lt;/span&gt;, &lt;span style=&#34;color: #009900&#34;&gt;Reason&lt;/span&gt;} &lt;span style=&#34;color: #990000&#34;&gt;-&amp;gt;&lt;/span&gt;
                &lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000000&#34;&gt;error_logger:error_msg&lt;/span&gt;&lt;/span&gt;(&lt;span style=&#34;color: #FF0000&#34;&gt;&#34;Oops!&#34;&lt;/span&gt;),
                &lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000080&#34;&gt;exit&lt;/span&gt;&lt;/span&gt;(&lt;span style=&#34;color: #009900&#34;&gt;Reason&lt;/span&gt;);
&lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #0000FF&#34;&gt;end&lt;/span&gt;&lt;/span&gt;&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;What to do when you receive a &lt;code&gt;DOWN&lt;/code&gt; message is entirely up to you.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_closing_the_connection_abruptly&#34;&gt;Closing the connection abruptly&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The connection can be stopped abruptly at any time by calling
the &lt;code&gt;gun:close/1&lt;/code&gt; function.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;title&#34;&gt;Immediate closing of the connection&lt;/div&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;&lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000000&#34;&gt;gun:close&lt;/span&gt;&lt;/span&gt;(&lt;span style=&#34;color: #009900&#34;&gt;ConnPid&lt;/span&gt;)&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The process is stopped immediately without having a chance to
perform the protocol&amp;#8217;s closing handshake, if any.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_closing_the_connection_gracefully&#34;&gt;Closing the connection gracefully&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The connection can also be stopped gracefully by calling the
&lt;code&gt;gun:shutdown/1&lt;/code&gt; function.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;title&#34;&gt;Graceful shutdown of the connection&lt;/div&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;&lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000000&#34;&gt;gun:shutdown&lt;/span&gt;&lt;/span&gt;(&lt;span style=&#34;color: #009900&#34;&gt;ConnPid&lt;/span&gt;)&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Gun will refuse any new requests or messages after you call
this function. It will however continue to send you messages
for existing streams until they are all completed.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;For example if you performed a GET request just before calling
&lt;code&gt;gun:shutdown/1&lt;/code&gt;, you will still receive the response before
Gun closes the connection.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you set a monitor beforehand, you will receive a message
when the connection has been closed.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
</description>
    </item>
    
    <item>
      <title>Constraints</title>
      <link>http://ninenines.eu/docs/en/cowboy/2.0/guide/constraints/</link>
      <pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate>
      
      <guid>http://ninenines.eu/docs/en/cowboy/2.0/guide/constraints/</guid>
      <description>&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Cowboy provides an optional constraints based validation feature
when interacting with user input.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Constraints are first used during routing. The router uses
constraints to more accurately match bound values, allowing
to create routes where a segment is an integer for example,
and rejecting the others.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Constraints are also used when performing a match operation
on input data, like the query string or cookies. There, a
default value can also be provided for optional values.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Finally, constraints can be used to not only validate input,
but also convert said input into proper Erlang terms, all in
one step.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_structure&#34;&gt;Structure&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Constraints are provided as a list of fields and for each
field a list of constraints for that field can be provided.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Fields are either the name of the field; the name and
one or more constraints; or the name, one or more constraints
and a default value.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;When no default value is provided then the field is required.
Otherwise the default value is used.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;All constraints for a field will be used to match its value
in the order they are given. If the value is modified by a
constraint, the next constraint receives the updated value.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_built_in_constraints&#34;&gt;Built-in constraints&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;tableblock&#34;&gt;
&lt;table rules=&#34;all&#34;
width=&#34;100%&#34;
frame=&#34;border&#34;
cellspacing=&#34;0&#34; cellpadding=&#34;4&#34;&gt;
&lt;col width=&#34;50%&#34; /&gt;
&lt;col width=&#34;50%&#34; /&gt;
&lt;thead&gt;
&lt;tr&gt;
&lt;th align=&#34;left&#34; valign=&#34;top&#34;&gt; Constraint &lt;/th&gt;
&lt;th align=&#34;left&#34; valign=&#34;top&#34;&gt; Description&lt;/th&gt;
&lt;/tr&gt;
&lt;/thead&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td align=&#34;left&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;int&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;left&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;Convert binary value to integer.&lt;/p&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td align=&#34;left&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;nonempty&lt;/p&gt;&lt;/td&gt;
&lt;td align=&#34;left&#34; valign=&#34;top&#34;&gt;&lt;p class=&#34;table&#34;&gt;Ensures the binary value is non-empty.&lt;/p&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_custom_constraint&#34;&gt;Custom constraint&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;In addition to the predefined constraints, Cowboy will accept
a fun. This fun must accept one argument and return one of
&lt;code&gt;true&lt;/code&gt;, &lt;code&gt;{true, NewValue}&lt;/code&gt; or &lt;code&gt;false&lt;/code&gt;. The result indicates
whether the value matches the constraint, and if it does it
can optionally be modified. This allows converting the value
to a more appropriate Erlang term.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Note that constraint functions SHOULD be pure and MUST NOT crash.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
</description>
    </item>
    
    <item>
      <title>Continuous integration</title>
      <link>http://ninenines.eu/docs/en/erlang.mk/1/guide/ci/</link>
      <pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate>
      
      <guid>http://ninenines.eu/docs/en/erlang.mk/1/guide/ci/</guid>
      <description>&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Placeholder chapter.&lt;/p&gt;&lt;/div&gt;
</description>
    </item>
    
    <item>
      <title>Contributing</title>
      <link>http://ninenines.eu/docs/en/erlang.mk/1/guide/contributing/</link>
      <pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate>
      
      <guid>http://ninenines.eu/docs/en/erlang.mk/1/guide/contributing/</guid>
      <description>&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;You are welcome and encouraged to contribute.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;This is how.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_priorities&#34;&gt;Priorities&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;From the most important to the least important:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;ulist&#34;&gt;&lt;ul&gt;
&lt;li&gt;
&lt;p&gt;
Bugs
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
Package issues/additions
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
Refactoring
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
Features
&lt;/p&gt;
&lt;/li&gt;
&lt;/ul&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_bugs&#34;&gt;Bugs&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you have found a bug, you should open a ticket. Include
everything relevant including the command you used, output,
a link to the code that triggers the issue, why you think
this is a bug, etc.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you think you have found a bug but you are not sure, you
should open a ticket as previously explained.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you have found a bug and you need it to be solved RIGHT
NOW, open a ticket as previously explained.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Once you have opened a ticket, be patient, try to answer
questions in a timely manner and confirm that the bug was
indeed fixed when it is.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you can&amp;#8217;t be patient, either try to solve the bug and
contribute the fix back or become a paying customer.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_code&#34;&gt;Code&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The code is located in the &lt;em&gt;core/*.mk&lt;/em&gt; and &lt;em&gt;plugins/*.mk&lt;/em&gt; files.
The tests are located in the &lt;em&gt;test/Makefile&lt;/em&gt; and &lt;em&gt;test/*.mk&lt;/em&gt; files.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you have a fix or a hack for a bug, you should open a
pull request. Any fix should include a test case that fails
before the fix and is working after.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you have a test case that reproduces a bug, but no fix for
it, you should open a pull request.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Changes need to be tested with at least the &lt;code&gt;make check&lt;/code&gt;
command. A specific test case can be tested using &lt;code&gt;make check c=CASE&lt;/code&gt;
with &lt;code&gt;CASE&lt;/code&gt; the name of the target to run. Output can be
modulated using the &lt;code&gt;V&lt;/code&gt; variable, which is an integer
from 0 to 4. A typical use would be &lt;code&gt;make check c=dialyzer V=3&lt;/code&gt;.
The value 4 is particular and shows expanded commands right
before they are executed.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To run tests in parallel, use the &lt;code&gt;-j&lt;/code&gt; option. It is generally
a good idea to also use the &lt;code&gt;-k&lt;/code&gt; option to run all tests even
if one fails. For example: &lt;code&gt;make check -j 32 -k&lt;/code&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Some changes should be tested against all packages. Continue
reading for more details on testing them.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_packages&#34;&gt;Packages&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;You can search existing packages using the &lt;code&gt;make search q=STRING&lt;/code&gt;
command. This can be done both from an Erlang.mk project or
directly from the Erlang.mk repository.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Packages can be added to the index using the &lt;code&gt;pkg_add.sh&lt;/code&gt; script.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ git clone https&lt;span style=&#34;color: #990000&#34;&gt;:&lt;/span&gt;//github&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;com&lt;span style=&#34;color: #990000&#34;&gt;/&lt;/span&gt;&lt;span style=&#34;color: #009900&#34;&gt;$YOURUSERNAME&lt;/span&gt;/erlang&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;mk
$ cd erlang&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;mk
$ &lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;/pkg_add&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;sh cowboy git https&lt;span style=&#34;color: #990000&#34;&gt;:&lt;/span&gt;//github&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;com/ninenines/cowboy &lt;span style=&#34;color: #993399&#34;&gt;1.0&lt;/span&gt;&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;&lt;span style=&#34;color: #993399&#34;&gt;0&lt;/span&gt;
  http&lt;span style=&#34;color: #990000&#34;&gt;:&lt;/span&gt;//ninenines&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;eu &lt;span style=&#34;color: #FF0000&#34;&gt;&#34;Small, fast and modular HTTP server.&#34;&lt;/span&gt;
$ git push origin master&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Before sending a pull request, you should test your package.
You can use the following command: &lt;code&gt;make check p=PACKAGE&lt;/code&gt;,
where &lt;code&gt;PACKAGE&lt;/code&gt; is the name of the package, for example
&lt;code&gt;cowboy&lt;/code&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To test all packages, the &lt;code&gt;make packages&lt;/code&gt; command can be used.
This can take a long time. Some packages will fail with certain
versions of Erlang, or if a prerequisite is missing from your system.
You can of course speed things up using the &lt;code&gt;-j&lt;/code&gt; and &lt;code&gt;-k&lt;/code&gt; flags.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;After all packages have been tested, you can run the command
&lt;code&gt;make summary&lt;/code&gt; to know what changed since the previous run.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_documentation&#34;&gt;Documentation&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The documentation is always right.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you think you have found a mistake in the documentation,
this is a bug. You can either open a ticket or send a pull
request.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To make sure that the documentation changes work, install
the listed &lt;a href=&#34;../asciidoc&#34;&gt;Requirements&lt;/a&gt; on your system and
run &lt;code&gt;make docs&lt;/code&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_feature_requests&#34;&gt;Feature requests&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you have an awesome idea or need something that Erlang.mk
doesn&amp;#8217;t provide yet, open a ticket. Provide as much detail as
possible.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you have code, great! Open a pull request as previously
explained.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If not, you can still improve your feature request by writing
the related documentation.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
</description>
    </item>
    
    <item>
      <title>Cowboy Function Reference</title>
      <link>http://ninenines.eu/docs/en/cowboy/2.0/manual/</link>
      <pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate>
      
      <guid>http://ninenines.eu/docs/en/cowboy/2.0/manual/</guid>
      <description>&lt;div class=&#34;ulist&#34;&gt;&lt;ul&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;cowboy_app&#34;&gt;cowboy(7)&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;cowboy&#34;&gt;cowboy(3)&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;cowboy_handler&#34;&gt;cowboy_handler(3)&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;cowboy_loop&#34;&gt;cowboy_loop(3)&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;cowboy_middleware&#34;&gt;cowboy_middleware(3)&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;cowboy_protocol&#34;&gt;cowboy_protocol(3)&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;cowboy_req&#34;&gt;cowboy_req(3)&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;cowboy_rest&#34;&gt;cowboy_rest(3)&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;cowboy_router&#34;&gt;cowboy_router(3)&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;cowboy_static&#34;&gt;cowboy_static(3)&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;cowboy_sub_protocol&#34;&gt;cowboy_sub_protocol(3)&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;cowboy_websocket&#34;&gt;cowboy_websocket(3)&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;http_status_codes&#34;&gt;HTTP status codes(7)&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;/ul&gt;&lt;/div&gt;
</description>
    </item>
    
    <item>
      <title>Cowboy User Guide</title>
      <link>http://ninenines.eu/docs/en/cowboy/2.0/guide/</link>
      <pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate>
      
      <guid>http://ninenines.eu/docs/en/cowboy/2.0/guide/</guid>
      <description>&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_rationale&#34;&gt;Rationale&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;ulist&#34;&gt;&lt;ul&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;modern_web/&#34;&gt;The modern Web&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;erlang_web/&#34;&gt;Erlang and the Web&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;/ul&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_introduction&#34;&gt;Introduction&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;ulist&#34;&gt;&lt;ul&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;introduction/&#34;&gt;Introduction&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;getting_started/&#34;&gt;Getting started&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;overview/&#34;&gt;Request overview&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;erlang_beginners/&#34;&gt;Erlang for beginners&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;/ul&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_configuration&#34;&gt;Configuration&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;ulist&#34;&gt;&lt;ul&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;routing/&#34;&gt;routing&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;constraints/&#34;&gt;Constraints&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;static_files/&#34;&gt;Static files&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;/ul&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_request_and_response&#34;&gt;Request and response&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;ulist&#34;&gt;&lt;ul&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;handlers/&#34;&gt;Handlers&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;loop_handlers/&#34;&gt;Loop handlers&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;req/&#34;&gt;The Req object&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;req_body/&#34;&gt;Reading the request body&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;resp/&#34;&gt;Sending a response&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;cookies/&#34;&gt;Using cookies&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;multipart/&#34;&gt;Multipart&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;/ul&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_rest&#34;&gt;REST&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;ulist&#34;&gt;&lt;ul&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;rest_principles/&#34;&gt;REST principles&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;rest_handlers/&#34;&gt;Handling REST requests&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;rest_flowcharts/&#34;&gt;REST flowcharts&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;resource_design/&#34;&gt;Designing a resource handler&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;/ul&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_websocket&#34;&gt;Websocket&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;ulist&#34;&gt;&lt;ul&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;ws_protocol/&#34;&gt;The Websocket protocol&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;ws_handlers/&#34;&gt;Handling Websocket connections&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;/ul&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_internals&#34;&gt;Internals&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;ulist&#34;&gt;&lt;ul&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;architecture/&#34;&gt;Architecture&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;broken_clients/&#34;&gt;Dealing with broken clients&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;middlewares/&#34;&gt;Middlewares&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;sub_protocols/&#34;&gt;Sub protocols&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;li&gt;
&lt;p&gt;
&lt;a href=&#34;hooks/&#34;&gt;Hooks&lt;/a&gt;
&lt;/p&gt;
&lt;/li&gt;
&lt;/ul&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
</description>
    </item>
    
    <item>
      <title>Dealing with broken clients</title>
      <link>http://ninenines.eu/docs/en/cowboy/2.0/guide/broken_clients/</link>
      <pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate>
      
      <guid>http://ninenines.eu/docs/en/cowboy/2.0/guide/broken_clients/</guid>
      <description>&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;There exists a very large number of implementations for the
HTTP protocol. Most widely used clients, like browsers,
follow the standard quite well, but others may not. In
particular custom enterprise clients tend to be very badly
written.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Cowboy tries to follow the standard as much as possible,
but is not trying to handle every possible special cases.
Instead Cowboy focuses on the cases reported in the wild,
on the public Web.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;That means clients that ignore the HTTP standard completely
may fail to understand Cowboy&amp;#8217;s responses. There are of
course workarounds. This chapter aims to cover them.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_lowercase_headers&#34;&gt;Lowercase headers&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Cowboy converts all headers it receives to lowercase, and
similarly sends back headers all in lowercase. Some broken
HTTP clients have issues with that.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;A simple way to solve this is to create an &lt;code&gt;onresponse&lt;/code&gt; hook
that will format the header names with the expected case.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;&lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000000&#34;&gt;capitalize_hook&lt;/span&gt;&lt;/span&gt;(&lt;span style=&#34;color: #009900&#34;&gt;Status&lt;/span&gt;, &lt;span style=&#34;color: #009900&#34;&gt;Headers&lt;/span&gt;, &lt;span style=&#34;color: #009900&#34;&gt;Body&lt;/span&gt;, &lt;span style=&#34;color: #009900&#34;&gt;Req&lt;/span&gt;) &lt;span style=&#34;color: #990000&#34;&gt;-&amp;gt;&lt;/span&gt;
    &lt;span style=&#34;color: #009900&#34;&gt;Headers2&lt;/span&gt; &lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt; [{&lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000000&#34;&gt;cowboy_bstr:capitalize_token&lt;/span&gt;&lt;/span&gt;(&lt;span style=&#34;color: #009900&#34;&gt;N&lt;/span&gt;), &lt;span style=&#34;color: #009900&#34;&gt;V&lt;/span&gt;}
        || {&lt;span style=&#34;color: #009900&#34;&gt;N&lt;/span&gt;, &lt;span style=&#34;color: #009900&#34;&gt;V&lt;/span&gt;} &lt;span style=&#34;color: #990000&#34;&gt;&amp;lt;-&lt;/span&gt; &lt;span style=&#34;color: #009900&#34;&gt;Headers&lt;/span&gt;],
    &lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000000&#34;&gt;cowboy_req:reply&lt;/span&gt;&lt;/span&gt;(&lt;span style=&#34;color: #009900&#34;&gt;Status&lt;/span&gt;, &lt;span style=&#34;color: #009900&#34;&gt;Headers2&lt;/span&gt;, &lt;span style=&#34;color: #009900&#34;&gt;Body&lt;/span&gt;, &lt;span style=&#34;color: #009900&#34;&gt;Req&lt;/span&gt;)&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Note that HTTP/2 clients do not have that particular issue
because the specification explicitly says all headers are
lowercase, unlike HTTP which allows any case but treats
them as case insensitive.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_camel_case_headers&#34;&gt;Camel-case headers&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Sometimes it is desirable to keep the actual case used by
clients, for example when acting as a proxy between two broken
implementations. There is no easy solution for this other than
forking the project and editing the &lt;code&gt;cowboy_protocol&lt;/code&gt; file
directly.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_chunked_transfer_encoding&#34;&gt;Chunked transfer-encoding&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Sometimes an HTTP client advertises itself as HTTP/1.1 but
does not support chunked transfer-encoding. This is invalid
behavior, as HTTP/1.1 clients are required to support it.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;A simple workaround exists in these cases. By changing the
Req object response state to &lt;code&gt;waiting_stream&lt;/code&gt;, Cowboy will
understand that it must use the identity transfer-encoding
when replying, just like if it was an HTTP/1.0 client.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;&lt;span style=&#34;color: #009900&#34;&gt;Req2&lt;/span&gt; &lt;span style=&#34;color: #990000&#34;&gt;=&lt;/span&gt; &lt;span style=&#34;font-weight: bold&#34;&gt;&lt;span style=&#34;color: #000000&#34;&gt;cowboy_req:set&lt;/span&gt;&lt;/span&gt;(&lt;span style=&#34;color: #FF6600&#34;&gt;resp_state&lt;/span&gt;, &lt;span style=&#34;color: #FF6600&#34;&gt;waiting_stream&lt;/span&gt;)&lt;span style=&#34;color: #990000&#34;&gt;.&lt;/span&gt;&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
</description>
    </item>
    
    <item>
      <title>Designing a resource handler</title>
      <link>http://ninenines.eu/docs/en/cowboy/2.0/guide/resource_design/</link>
      <pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate>
      
      <guid>http://ninenines.eu/docs/en/cowboy/2.0/guide/resource_design/</guid>
      <description>&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;This chapter aims to provide you with a list of questions
you must answer in order to write a good resource handler.
It is meant to be usable as a step by step guide.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_the_service&#34;&gt;The service&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Can the service become unavailable, and when it does, can
we detect it? For example, database connectivity problems
may be detected early. We may also have planned outages
of all or parts of the system. Implement the
&lt;code&gt;service_available&lt;/code&gt; callback.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;What HTTP methods does the service implement? Do we need
more than the standard OPTIONS, HEAD, GET, PUT, POST,
PATCH and DELETE? Are we not using one of those at all?
Implement the &lt;code&gt;known_methods&lt;/code&gt; callback.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_type_of_resource_handler&#34;&gt;Type of resource handler&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Am I writing a handler for a collection of resources,
or for a single resource?&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The semantics for each of these are quite different.
You should not mix collection and single resource in
the same handler.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_collection_handler&#34;&gt;Collection handler&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Skip this section if you are not doing a collection.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Is the collection hardcoded or dynamic? For example,
if you use the route &lt;code&gt;/users&lt;/code&gt; for the collection of
users then the collection is hardcoded; if you use
&lt;code&gt;/forums/:category&lt;/code&gt; for the collection of threads
then it isn&amp;#8217;t. When the collection is hardcoded you
can safely assume the resource always exists.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;What methods should I implement?&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;OPTIONS is used to get some information about the
collection. It is recommended to allow it even if you
do not implement it, as Cowboy has a default
implementation built-in.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;HEAD and GET are used to retrieve the collection.
If you allow GET, also allow HEAD as there&amp;#8217;s no extra
work required to make it work.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;POST is used to create a new resource inside the
collection. Creating a resource by using POST on
the collection is useful when resources may be
created before knowing their URI, usually because
parts of it are generated dynamically. A common
case is some kind of auto incremented integer
identifier.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The next methods are more rarely allowed.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;PUT is used to create a new collection (when
the collection isn&amp;#8217;t hardcoded), or replace
the entire collection.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;DELETE is used to delete the entire collection.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;PATCH is used to modify the collection using
instructions given in the request body. A PATCH
operation is atomic. The PATCH operation may
be used for such things as reordering; adding,
modifying or deleting parts of the collection.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_single_resource_handler&#34;&gt;Single resource handler&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Skip this section if you are doing a collection.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;What methods should I implement?&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;OPTIONS is used to get some information about the
resource. It is recommended to allow it even if you
do not implement it, as Cowboy has a default
implementation built-in.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;HEAD and GET are used to retrieve the resource.
If you allow GET, also allow HEAD as there&amp;#8217;s no extra
work required to make it work.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;POST is used to update the resource.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;PUT is used to create a new resource (when it doesn&amp;#8217;t
already exist) or replace the resource.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;DELETE is used to delete the resource.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;PATCH is used to modify the resource using
instructions given in the request body. A PATCH
operation is atomic. The PATCH operation may
be used for adding, removing or modifying specific
values in the resource.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_the_resource&#34;&gt;The resource&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Following the above discussion, implement the
&lt;code&gt;allowed_methods&lt;/code&gt; callback.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Does the resource always exist? If it may not, implement
the &lt;code&gt;resource_exists&lt;/code&gt; callback.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Do I need to authenticate the client before they can
access the resource? What authentication mechanisms
should I provide? This may include form-based, token-based
(in the URL or a cookie), HTTP basic, HTTP digest,
SSL certificate or any other form of authentication.
Implement the &lt;code&gt;is_authorized&lt;/code&gt; callback.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Do I need fine-grained access control? How do I determine
that they are authorized access? Handle that in your
&lt;code&gt;is_authorized&lt;/code&gt; callback.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Can access to a resource be forbidden regardless of access
being authorized? A simple example of that is censorship
of a resource. Implement the &lt;code&gt;forbidden&lt;/code&gt; callback.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Are there any constraints on the length of the resource URI?
For example, the URI may be used as a key in storage and may
have a limit in length. Implement &lt;code&gt;uri_too_long&lt;/code&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_representations&#34;&gt;Representations&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;What media types do I provide? If text based, what charsets
are provided? What languages do I provide?&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Implement the mandatory &lt;code&gt;content_types_provided&lt;/code&gt;. Prefix
the callbacks with &lt;code&gt;to_&lt;/code&gt; for clarity. For example, &lt;code&gt;to_html&lt;/code&gt;
or &lt;code&gt;to_text&lt;/code&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Implement the &lt;code&gt;languages_provided&lt;/code&gt; or &lt;code&gt;charsets_provided&lt;/code&gt;
callbacks if applicable.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Is there any other header that may make the representation
of the resource vary? Implement the &lt;code&gt;variances&lt;/code&gt; callback.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Depending on your choices for caching content, you may
want to implement one or more of the &lt;code&gt;generate_etag&lt;/code&gt;,
&lt;code&gt;last_modified&lt;/code&gt; and &lt;code&gt;expires&lt;/code&gt; callbacks.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Do I want the user or user agent to actively choose a
representation available? Send a list of available
representations in the response body and implement
the &lt;code&gt;multiple_choices&lt;/code&gt; callback.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_redirections&#34;&gt;Redirections&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Do I need to keep track of what resources were deleted?
For example, you may have a mechanism where moving a
resource leaves a redirect link to its new location.
Implement the &lt;code&gt;previously_existed&lt;/code&gt; callback.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Was the resource moved, and is the move temporary? If
it is explicitly temporary, for example due to maintenance,
implement the &lt;code&gt;moved_temporarily&lt;/code&gt; callback. Otherwise,
implement the &lt;code&gt;moved_permanently&lt;/code&gt; callback.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_the_request&#34;&gt;The request&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Do we need to perform extra checks to make sure the request
is valid? Cowboy will do many checks when receiving the
request already, do we need more? Note that this only
applies to the request-line and headers of the request,
and not the body. Implement &lt;code&gt;malformed_request&lt;/code&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;May there be a request body? Will I know its size?
What&amp;#8217;s the maximum size of the request body I&amp;#8217;m willing
to accept? Implement &lt;code&gt;valid_entity_length&lt;/code&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Finally, take a look at the sections corresponding to the
methods you are implementing.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_options_method&#34;&gt;OPTIONS method&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Cowboy by default will send back a list of allowed methods.
Do I need to add more information to the response? Implement
the &lt;code&gt;options&lt;/code&gt; method.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_get_and_head_methods&#34;&gt;GET and HEAD methods&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you implement the methods GET and/or HEAD, you must
implement one &lt;code&gt;ProvideResource&lt;/code&gt; callback for each
content-type returned by the &lt;code&gt;content_types_provided&lt;/code&gt;
callback.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_put_post_and_patch_methods&#34;&gt;PUT, POST and PATCH methods&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you implement the methods PUT, POST and/or PATCH,
you must implement the &lt;code&gt;content_types_accepted&lt;/code&gt; callback,
and one &lt;code&gt;AcceptResource&lt;/code&gt; callback for each content-type
it returns. Prefix the &lt;code&gt;AcceptResource&lt;/code&gt; callback names
with &lt;code&gt;from_&lt;/code&gt; for clarity. For example, &lt;code&gt;from_html&lt;/code&gt; or
&lt;code&gt;from_json&lt;/code&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Do we want to allow the POST method to create individual
resources directly through their URI (like PUT)? Implement
the &lt;code&gt;allow_missing_post&lt;/code&gt; callback. It is recommended to
explicitly use PUT in these cases instead.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;May there be conflicts when using PUT to create or replace
a resource? Do we want to make sure that two updates around
the same time are not cancelling one another? Implement the
&lt;code&gt;is_conflict&lt;/code&gt; callback.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_delete_methods&#34;&gt;DELETE methods&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;If you implement the method DELETE, you must implement
the &lt;code&gt;delete_resource&lt;/code&gt; callback.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;When &lt;code&gt;delete_resource&lt;/code&gt; returns, is the resource completely
removed from the server, including from any caching service?
If not, and/or if the deletion is asynchronous and we have
no way of knowing it has been completed yet, implement the
&lt;code&gt;delete_completed&lt;/code&gt; callback.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
</description>
    </item>
    
    <item>
      <title>Dialyzer</title>
      <link>http://ninenines.eu/docs/en/erlang.mk/1/guide/dialyzer/</link>
      <pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate>
      
      <guid>http://ninenines.eu/docs/en/erlang.mk/1/guide/dialyzer/</guid>
      <description>&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Dialyzer is a tool that will detect discrepancies in your
program. It does so using a technique known as success
typing analysis which has the advantage of providing no
false positives. Dialyzer is able to detect type errors,
dead code and more.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk provides a wrapper around Dialyzer.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_how_it_works&#34;&gt;How it works&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Dialyzer requires a PLT file to work. The PLT file contains
the analysis information from all applications which are not
expected to change, or rarely do. These would be all the
dependencies of the application or applications you are
currently working on, including standard applications in
Erlang/OTP itself.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Dialyzer can generate this PLT file. Erlang.mk includes rules
to automatically generate the PLT file when it is missing.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Once the PLT file is generated, Dialyzer can perform the
analysis in record time.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_configuration&#34;&gt;Configuration&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;In a typical usage scenario, no variable needs to be set.
The defaults should be enough. Do note however that the
dependencies need to be set properly using the &lt;code&gt;DEPS&lt;/code&gt; and
&lt;code&gt;LOCAL_DEPS&lt;/code&gt; variables.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The &lt;code&gt;DIALYZER_PLT&lt;/code&gt; file indicates where the PLT file will
be written to (and read from). By default this is
&lt;em&gt;$(PROJECT).plt&lt;/em&gt; in the project&amp;#8217;s directory. Note that
the &lt;code&gt;DIALYZER_PLT&lt;/code&gt; variable is exported and is understood
by Dialyzer directly.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The &lt;code&gt;PLT_APPS&lt;/code&gt; variable can be used to add additional
applications to the PLT. You can either list application
names or paths to these applications.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Erlang.mk defines two variables for specifying options
for the analysis: &lt;code&gt;DIALYZER_DIRS&lt;/code&gt; and &lt;code&gt;DIALYZER_OPTS&lt;/code&gt;.
The former one defines which directories should be part
of the analysis. The latter defines what extra warnings
Dialyzer should report.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;Note that Erlang.mk enables the race condition warnings
by default. As it can take considerably large resources
to run, you may want to disable it on larger projects.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
&lt;div class=&#34;sect1&#34;&gt;
&lt;h2 id=&#34;_usage&#34;&gt;Usage&lt;/h2&gt;
&lt;div class=&#34;sectionbody&#34;&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;To perform an analysis, run the following command:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make dialyze&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;This will create the PLT file if it doesn&amp;#8217;t exist.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The analysis will also be performed when you run the
following command, alongside tests:&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;listingblock&#34;&gt;
&lt;div class=&#34;content&#34;&gt;&lt;!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite --&gt;
&lt;pre&gt;&lt;tt&gt;$ make check&lt;/tt&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;You can use the &lt;code&gt;plt&lt;/code&gt; target to create the PLT file if
it doesn&amp;#8217;t exist. This is normally not necessary as
Dialyzer creates it automatically.&lt;/p&gt;&lt;/div&gt;
&lt;div class=&#34;paragraph&#34;&gt;&lt;p&gt;The PLT file will be removed when you run &lt;code&gt;make distclean&lt;/code&gt;.&lt;/p&gt;&lt;/div&gt;
&lt;/div&gt;
&lt;/div&gt;
</description>
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