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-rw-r--r--doc/src/guide/architecture.asciidoc (renamed from doc/src/guide/architecture.ezdoc)11
-rw-r--r--doc/src/guide/book.asciidoc72
-rw-r--r--doc/src/guide/broken_clients.asciidoc (renamed from doc/src/guide/broken_clients.ezdoc)17
-rw-r--r--doc/src/guide/constraints.asciidoc (renamed from doc/src/guide/constraints.ezdoc)19
-rw-r--r--doc/src/guide/cookies.asciidoc (renamed from doc/src/guide/cookies.ezdoc)49
-rw-r--r--doc/src/guide/erlang_beginners.asciidoc (renamed from doc/src/guide/erlang_beginners.ezdoc)11
-rw-r--r--doc/src/guide/erlang_web.asciidoc (renamed from doc/src/guide/erlang_web.ezdoc)13
-rw-r--r--doc/src/guide/getting_started.asciidoc (renamed from doc/src/guide/getting_started.ezdoc)99
-rw-r--r--doc/src/guide/handlers.asciidoc (renamed from doc/src/guide/handlers.ezdoc)44
-rw-r--r--doc/src/guide/hooks.asciidoc (renamed from doc/src/guide/hooks.ezdoc)15
-rw-r--r--doc/src/guide/index.ezdoc58
-rw-r--r--doc/src/guide/introduction.asciidoc (renamed from doc/src/guide/introduction.ezdoc)13
-rw-r--r--doc/src/guide/loop_handlers.asciidoc (renamed from doc/src/guide/loop_handlers.ezdoc)37
-rw-r--r--doc/src/guide/middlewares.asciidoc (renamed from doc/src/guide/middlewares.ezdoc)11
-rw-r--r--doc/src/guide/modern_web.asciidoc (renamed from doc/src/guide/modern_web.ezdoc)25
-rw-r--r--doc/src/guide/multipart.asciidoc (renamed from doc/src/guide/multipart.ezdoc)33
-rw-r--r--doc/src/guide/overview.asciidoc (renamed from doc/src/guide/overview.ezdoc)25
-rw-r--r--doc/src/guide/req.asciidoc (renamed from doc/src/guide/req.ezdoc)98
-rw-r--r--doc/src/guide/req_body.asciidoc (renamed from doc/src/guide/req_body.ezdoc)54
-rw-r--r--doc/src/guide/resource_design.asciidoc (renamed from doc/src/guide/resource_design.ezdoc)27
-rw-r--r--doc/src/guide/resp.asciidoc (renamed from doc/src/guide/resp.ezdoc)76
-rw-r--r--doc/src/guide/rest_flowcharts.asciidoc (renamed from doc/src/guide/rest_flowcharts.ezdoc)31
-rw-r--r--doc/src/guide/rest_handlers.asciidoc (renamed from doc/src/guide/rest_handlers.ezdoc)110
-rw-r--r--doc/src/guide/rest_principles.asciidoc (renamed from doc/src/guide/rest_principles.ezdoc)15
-rw-r--r--doc/src/guide/routing.asciidoc (renamed from doc/src/guide/routing.ezdoc)79
-rw-r--r--doc/src/guide/static_files.asciidoc (renamed from doc/src/guide/static_files.ezdoc)57
-rw-r--r--doc/src/guide/sub_protocols.asciidoc (renamed from doc/src/guide/sub_protocols.ezdoc)22
-rw-r--r--doc/src/guide/ws_handlers.asciidoc (renamed from doc/src/guide/ws_handlers.ezdoc)54
-rw-r--r--doc/src/guide/ws_protocol.asciidoc (renamed from doc/src/guide/ws_protocol.ezdoc)7
29 files changed, 591 insertions, 591 deletions
diff --git a/doc/src/guide/architecture.ezdoc b/doc/src/guide/architecture.asciidoc
index 745505a..416ef36 100644
--- a/doc/src/guide/architecture.ezdoc
+++ b/doc/src/guide/architecture.asciidoc
@@ -1,11 +1,12 @@
-::: Architecture
+[[architecture]]
+== Architecture
Cowboy is a lightweight HTTP server.
It is built on top of Ranch. Please see the Ranch guide for more
information.
-:: One process per connection
+=== One process per connection
It uses only one process per connection. The process where your
code runs is the process controlling the socket. Using one process
@@ -20,7 +21,7 @@ up before terminating the handling of the current request. This may
include cleaning up the process dictionary, timers, monitoring and
more.
-:: Binaries
+=== Binaries
It uses binaries. Binaries are more efficient than lists for
representing strings because they take less memory space. Processing
@@ -28,14 +29,14 @@ 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.
-:: Date header
+=== Date header
Because querying for the current date and time can be expensive,
Cowboy generates one `Date` 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.
-:: Max connections
+=== Max connections
By default the maximum number of active connections is set to a
generally accepted big enough number. This is meant to prevent having
diff --git a/doc/src/guide/book.asciidoc b/doc/src/guide/book.asciidoc
new file mode 100644
index 0000000..15aa42b
--- /dev/null
+++ b/doc/src/guide/book.asciidoc
@@ -0,0 +1,72 @@
+// a2x: --dblatex-opts "-P latex.output.revhistory=0 -P doc.publisher.show=0 -P index.numbered=0"
+// a2x: -d book --attribute tabsize=4
+
+= Cowboy User Guide
+
+= Rationale
+
+include::modern_web.asciidoc[The modern Web]
+
+include::erlang_web.asciidoc[Erlang and the Web]
+
+= Introduction
+
+include::introduction.asciidoc[Introduction]
+
+include::getting_started.asciidoc[Getting started]
+
+include::overview.asciidoc[Request overview]
+
+include::erlang_beginners.asciidoc[Erlang for beginners]
+
+= Configuration
+
+include::routing.asciidoc[routing]
+
+include::constraints.asciidoc[Constraints]
+
+include::static_files.asciidoc[Static files]
+
+= Request and response
+
+include::handlers.asciidoc[Handlers]
+
+include::loop_handlers.asciidoc[Loop handlers]
+
+include::req.asciidoc[The Req object]
+
+include::req_body.asciidoc[Reading the request body]
+
+include::resp.asciidoc[Sending a response]
+
+include::cookies.asciidoc[Using cookies]
+
+include::multipart.asciidoc[Multipart]
+
+= REST
+
+include::rest_principles.asciidoc[REST principles]
+
+include::rest_handlers.asciidoc[Handling REST requests]
+
+include::rest_flowcharts.asciidoc[REST flowcharts]
+
+include::resource_design.asciidoc[Designing a resource handler]
+
+= Websocket
+
+include::ws_protocol.asciidoc[The Websocket protocol]
+
+include::ws_handlers.asciidoc[Handling Websocket connections]
+
+= Internals
+
+include::architecture.asciidoc[Architecture]
+
+include::broken_clients.asciidoc[Dealing with broken clients]
+
+include::middlewares.asciidoc[Middlewares]
+
+include::sub_protocols.asciidoc[Sub protocols]
+
+include::hooks.asciidoc[Hooks]
diff --git a/doc/src/guide/broken_clients.ezdoc b/doc/src/guide/broken_clients.asciidoc
index c508358..e91e9a2 100644
--- a/doc/src/guide/broken_clients.ezdoc
+++ b/doc/src/guide/broken_clients.asciidoc
@@ -1,4 +1,5 @@
-::: Dealing with broken clients
+[[broken_clients]]
+== Dealing with broken clients
There exists a very large number of implementations for the
HTTP protocol. Most widely used clients, like browsers,
@@ -15,7 +16,7 @@ That means clients that ignore the HTTP standard completely
may fail to understand Cowboy's responses. There are of
course workarounds. This chapter aims to cover them.
-:: Lowercase headers
+=== Lowercase headers
Cowboy converts all headers it receives to lowercase, and
similarly sends back headers all in lowercase. Some broken
@@ -24,19 +25,20 @@ HTTP clients have issues with that.
A simple way to solve this is to create an `onresponse` hook
that will format the header names with the expected case.
-``` erlang
+[source,erlang]
+----
capitalize_hook(Status, Headers, Body, Req) ->
Headers2 = [{cowboy_bstr:capitalize_token(N), V}
|| {N, V} <- Headers],
cowboy_req:reply(Status, Headers2, Body, Req).
-```
+----
Note that SPDY 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.
-:: Camel-case headers
+=== Camel-case headers
Sometimes it is desirable to keep the actual case used by
clients, for example when acting as a proxy between two broken
@@ -44,7 +46,7 @@ implementations. There is no easy solution for this other than
forking the project and editing the `cowboy_protocol` file
directly.
-:: Chunked transfer-encoding
+=== Chunked transfer-encoding
Sometimes an HTTP client advertises itself as HTTP/1.1 but
does not support chunked transfer-encoding. This is invalid
@@ -55,6 +57,5 @@ Req object response state to `waiting_stream`, Cowboy will
understand that it must use the identity transfer-encoding
when replying, just like if it was an HTTP/1.0 client.
-``` erlang
+[source,erlang]
Req2 = cowboy_req:set(resp_state, waiting_stream).
-```
diff --git a/doc/src/guide/constraints.ezdoc b/doc/src/guide/constraints.asciidoc
index a05f489..0ae01d5 100644
--- a/doc/src/guide/constraints.ezdoc
+++ b/doc/src/guide/constraints.asciidoc
@@ -1,4 +1,5 @@
-::: Constraints
+[[constraints]]
+== Constraints
Cowboy provides an optional constraints based validation feature
when interacting with user input.
@@ -16,7 +17,7 @@ Finally, constraints can be used to not only validate input,
but also convert said input into proper Erlang terms, all in
one step.
-:: Structure
+=== Structure
Constraints are provided as a list of fields and for each
field a list of constraints for that field can be provided.
@@ -32,14 +33,16 @@ 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.
-:: Built-in constraints
+=== Built-in constraints
-|| Constraint Description
-|
-| int Convert binary value to integer
-| nonempty Ensures the binary value is non-empty
+[cols="<,<",options="header"]
+|===
+| Constraint | Description
+| int | Convert binary value to integer.
+| nonempty | Ensures the binary value is non-empty.
+|===
-:: Custom constraint
+=== Custom constraint
In addition to the predefined constraints, Cowboy will accept
a fun. This fun must accept one argument and return one of
diff --git a/doc/src/guide/cookies.ezdoc b/doc/src/guide/cookies.asciidoc
index e6d1aeb..6068db3 100644
--- a/doc/src/guide/cookies.ezdoc
+++ b/doc/src/guide/cookies.asciidoc
@@ -1,4 +1,5 @@
-::: Using cookies
+[[cookies]]
+== Using cookies
Cookies are a mechanism allowing applications to maintain
state on top of the stateless HTTP protocol.
@@ -48,69 +49,73 @@ that run from HTTPS webpages.
Finally, cookies can be restricted to HTTP and HTTPS requests,
essentially disabling their access from client-side scripts.
-:: Setting cookies
+=== Setting cookies
By default, cookies you set are defined for the session.
-``` erlang
+[source,erlang]
SessionID = generate_session_id(),
Req2 = cowboy_req:set_resp_cookie(<<"sessionid">>, SessionID, [], Req).
-```
You can also make them expire at a specific point in the
future.
-``` erlang
+[source,erlang]
+----
SessionID = generate_session_id(),
Req2 = cowboy_req:set_resp_cookie(<<"sessionid">>, SessionID, [
{max_age, 3600}
], Req).
-```
+----
You can delete cookies that have already been set. The value
is ignored.
-``` erlang
+[source,erlang]
+----
Req2 = cowboy_req:set_resp_cookie(<<"sessionid">>, <<>>, [
{max_age, 0}
], Req).
-```
+----
You can restrict them to a specific domain and path.
For example, the following cookie will be set for the domain
`my.example.org` and all its subdomains, but only on the path
`/account` and all its subdirectories.
-``` erlang
+[source,erlang]
+----
Req2 = cowboy_req:set_resp_cookie(<<"inaccount">>, <<"1">>, [
{domain, "my.example.org"},
{path, "/account"}
], Req).
-```
+----
You can restrict the cookie to secure channels, typically HTTPS.
-``` erlang
+[source,erlang]
+----
SessionID = generate_session_id(),
Req2 = cowboy_req:set_resp_cookie(<<"sessionid">>, SessionID, [
{secure, true}
], Req).
-```
+----
You can restrict the cookie to client-server communication
only. Such a cookie will not be available to client-side scripts.
-``` erlang
+[source,erlang]
+----
SessionID = generate_session_id(),
Req2 = cowboy_req:set_resp_cookie(<<"sessionid">>, SessionID, [
{http_only, true}
], Req).
-```
+----
Cookies may also be set client-side, for example using
Javascript.
-:: Reading cookies
+=== Reading cookies
As we said, the client sends cookies with every request.
But unlike the server, the client only sends the cookie
@@ -124,16 +129,14 @@ to the values or providing a default if they are missing.
You can parse the cookies and then use standard library
functions to access individual values.
-``` erlang
+[source,erlang]
Cookies = cowboy_req:parse_cookies(Req),
{_, Lang} = lists:keyfind(<<"lang">>, 1, Cookies).
-```
You can match the cookies into a map.
-``` erlang
+[source,erlang]
#{id := ID, lang := Lang} = cowboy_req:match_cookies([id, lang], Req).
-```
You can use constraints to validate the values while matching
them. The following snippet will crash if the `id` cookie is
@@ -141,22 +144,20 @@ not an integer number or if the `lang` cookie is empty. Additionally
the `id` cookie value will be converted to an integer term, saving
you a conversion step.
-``` erlang
+[source,erlang]
CookiesMap = cowboy_req:match_cookies([{id, int}, {lang, nonempty}], Req).
-```
Note that if two cookies share the same name, then the map value
will be a list of the two cookie values.
-Read more about ^constraints^.
+Read more about xref:constraints[constraints].
A default value can be provided. The default will be used
if the `lang` cookie is not found. It will not be used if
the cookie is found but has an empty value.
-``` erlang
+[source,erlang]
#{lang := Lang} = cowboy_req:match_cookies([{lang, [], <<"en-US">>}], Req).
-```
If no default is provided and the value is missing, the
query string is deemed invalid and the process will crash.
diff --git a/doc/src/guide/erlang_beginners.ezdoc b/doc/src/guide/erlang_beginners.asciidoc
index 74d3470..b9a6c65 100644
--- a/doc/src/guide/erlang_beginners.ezdoc
+++ b/doc/src/guide/erlang_beginners.asciidoc
@@ -1,4 +1,5 @@
-::: Erlang for beginners
+[[erlang_beginners]]
+== Erlang for beginners
Chances are you are interested in using Cowboy, but have
no idea how to write an Erlang program. Fear not! This
@@ -8,10 +9,10 @@ We recommend two books for beginners. You should read them
both at some point, as they cover Erlang from two entirely
different perspectives.
-:: Learn You Some Erlang for Great Good!
+=== Learn You Some Erlang for Great Good!
The quickest way to get started with Erlang is by reading
-a book with the funny name of ^"LYSE^http://learnyousomeerlang.com^,
+a book with the funny name of http://learnyousomeerlang.com[LYSE],
as we affectionately call it.
It will get right into the syntax and quickly answer the questions
@@ -22,12 +23,12 @@ You can read an early version of the book online for free,
but you really should buy the much more refined paper and
ebook versions.
-:: Programming Erlang
+=== Programming Erlang
After writing some code, you will probably want to understand
the very concepts that make Erlang what it is today. These
are best explained by Joe Armstrong, the godfather of Erlang,
-in his book ^"Programming Erlang^http://pragprog.com/book/jaerlang2/programming-erlang^.
+in his book http://pragprog.com/book/jaerlang2/programming-erlang[Programming Erlang].
Instead of going into every single details of the language,
Joe focuses on the central concepts behind Erlang, and shows
diff --git a/doc/src/guide/erlang_web.ezdoc b/doc/src/guide/erlang_web.asciidoc
index 42fcd34..91a9eca 100644
--- a/doc/src/guide/erlang_web.ezdoc
+++ b/doc/src/guide/erlang_web.asciidoc
@@ -1,6 +1,7 @@
-::: Erlang and the Web
+[[erlang_web]]
+== Erlang and the Web
-:: The Web is concurrent
+=== The Web is concurrent
When you access a website there is little concurrency
involved. A few connections are opened and requests
@@ -53,7 +54,7 @@ will also connect to various applications on the Internet.
Only Erlang is prepared to deal with what's coming.
-:: The Web is soft real time
+=== The Web is soft real time
What does soft real time mean, you ask? It means we want the
operations done as quickly as possible, and in the case of
@@ -82,7 +83,7 @@ can guarantee stable low latency of operations.
Erlang provides the guarantees that the soft real time Web
requires.
-:: The Web is asynchronous
+=== The Web is asynchronous
Long ago, the Web was synchronous because HTTP was synchronous.
You fired a request, and then waited for a response. Not anymore.
@@ -114,7 +115,7 @@ Erlang is by nature asynchronous and really good at it thanks to the
great engineering that has been done in the VM over the years. It's
only natural that it's so good at dealing with the asynchronous Web.
-:: The Web is omnipresent
+=== The Web is omnipresent
The Web has taken a very important part of our lives. We're
connected at all times, when we're on our phone, using our computer,
@@ -167,7 +168,7 @@ down, or even a data center entirely.
Fault tolerance and distribution are important today, and will be
vital in the future of the Web. Erlang is ready.
-:: Erlang is the ideal platform for the Web
+=== Erlang is the ideal platform for the Web
Erlang provides all the important features that the Web requires
or will require in the near future. Erlang is a perfect match
diff --git a/doc/src/guide/getting_started.ezdoc b/doc/src/guide/getting_started.asciidoc
index deb7bf2..5d72f0a 100644
--- a/doc/src/guide/getting_started.ezdoc
+++ b/doc/src/guide/getting_started.asciidoc
@@ -1,4 +1,5 @@
-::: Getting started
+[[getting_started]]
+== Getting started
Erlang is more than a language, it is also an operating system
for your applications. Erlang developers rarely write standalone
@@ -12,44 +13,40 @@ Cowboy, writing your first application and generating your first
release. At the end of this chapter you should know everything
you need to push your first Cowboy application to production.
-:: Bootstrap
+=== Bootstrap
-We are going to use the ^"erlang.mk^https://github.com/ninenines/erlang.mk
+We are going to use the https://github.com/ninenines/erlang.mk[Erlang.mk]
build system. It also offers bootstrap features allowing us to
quickly get started without having to deal with minute details.
First, let's create the directory for our application.
-``` bash
+[source,bash]
$ mkdir hello_erlang
$ cd hello_erlang
-```
-Then we need to download `erlang.mk`. Either use the following
+Then we need to download Erlang.mk. Either use the following
command or download it manually.
-``` bash
+[source,bash]
$ wget https://raw.githubusercontent.com/ninenines/erlang.mk/master/erlang.mk
-```
We can now bootstrap our application. Since we are going to generate
a release, we will also bootstrap it at the same time.
-``` bash
+[source,bash]
$ make -f erlang.mk bootstrap bootstrap-rel
-```
This creates a Makefile, a base application, and the release files
necessary for creating the release. We can already build and start
this release.
-``` bash
-$ make
-...
-$ ./_rel/hello_erlang_release/bin/hello_erlang_release console
+[source,bash]
+----
+$ make run
...
-```
+----
Entering the command `i().` will show the running processes, including
one called `hello_erlang_sup`. This is the supervisor for our
@@ -59,64 +56,34 @@ The release currently does nothing. In the rest of this chapter we
will add Cowboy as a dependency and write a simple "Hello world!"
handler.
-:: Cowboy setup
-
-To add Cowboy as a dependency to your application, you need to modify
-two files: the Makefile and the application resource file.
+=== Cowboy setup
-Modifying the Makefile allows the build system to know it needs to
+Modifying the 'Makefile' allows the build system to know it needs to
fetch and compile Cowboy. To do that we simply need to add one line
to our Makefile to make it look like this:
-``` Makefile
+[source,make]
PROJECT = hello_erlang
DEPS = cowboy
include erlang.mk
-```
-
-Modifying the application resource file, `src/hello_erlang.app.src`,
-allows the build system to know it needs to include Cowboy in the
-release and start it automatically. This is a different step because
-some dependencies are only needed during development.
-
-We are simply going to add `cowboy` to the list of `applications`,
-right after `stdlib`. Don't forget the comma separator.
-
-``` erlang
-{application, hello_erlang, [
- {description, "Hello Erlang!"},
- {vsn, "0.1.0"},
- {modules, []},
- {registered, []},
- {applications, [
- kernel,
- stdlib,
- cowboy
- ]},
- {mod, {hello_erlang_app, []}},
- {env, []}
-]}.
-```
-
-You may want to set a description for the application while you
-are editing the file.
-
-If you run `make` now and start the release, Cowboy will be included
+
+If you run `make run` now, Cowboy will be included in the release
and started automatically. This is not enough however, as Cowboy
doesn't do anything by default. We still need to tell Cowboy to
listen for connections.
-:: Listening for connections
+=== Listening for connections
We will do this when our application starts. It's a two step process.
First we need to define and compile the dispatch list, a list of
routes that Cowboy will use to map requests to handler modules.
Then we tell Cowboy to listen for connections.
-Open the `src/hello_erlang_app.erl` file and add the necessary
+Open the 'src/hello_erlang_app.erl' file and add the necessary
code to the `start/2` function to make it look like this:
-``` erlang
+[source,erlang]
+----
start(_Type, _Args) ->
Dispatch = cowboy_router:compile([
{'_', [{"/", hello_handler, []}]}
@@ -125,19 +92,19 @@ start(_Type, _Args) ->
[{env, [{dispatch, Dispatch}]}]
),
hello_erlang_sup:start_link().
-```
+----
The dispatch list is explained in great details in the
-^"Routing^routing^ chapter. For this tutorial we map the
+xref:routing[Routing] chapter. For this tutorial we map the
path `/` to the handler module `hello_handler`. This module
doesn't exist yet, we still have to write it.
-If you build the release, start it and open ^http://localhost:8080
-now, you will get an error because the module is missing. Any
-other URL, like ^http://localhost:8080/test^, will result in a
+If you build and start the release, then open http://localhost:8080
+in your browser, you will get an error because the module is missing.
+Any other URL, like http://localhost:8080/test, will result in a
404 error.
-:: Handling requests
+=== Handling requests
Cowboy features different kinds of handlers, including REST
and Websocket handlers. For this tutorial we will use a plain
@@ -145,25 +112,25 @@ HTTP handler.
First, let's generate a handler from a template.
-``` bash
+[source,bash]
$ make new t=cowboy_http n=hello_handler
-```
-You can then open the `src/hello_handler.erl` file and modify
+You can then open the 'src/hello_handler.erl' file and modify
the `init/2` function like this to send a reply.
-``` erlang
+[source,erlang]
+----
init(Req, Opts) ->
Req2 = cowboy_req:reply(200,
[{<<"content-type">>, <<"text/plain">>}],
<<"Hello Erlang!">>,
Req),
{ok, Req2, Opts}.
-```
+----
What the above code does is send a `200 OK` reply, with the
`content-type` header set to `text/plain` and the response
body set to `Hello Erlang!`.
-If you build the release, start it and open ^http://localhost:8080
+If you run the release and open http://localhost:8080
in your browser, you should get a nice `Hello Erlang!` displayed!
diff --git a/doc/src/guide/handlers.ezdoc b/doc/src/guide/handlers.asciidoc
index 9336488..b6cefdd 100644
--- a/doc/src/guide/handlers.ezdoc
+++ b/doc/src/guide/handlers.asciidoc
@@ -1,22 +1,24 @@
-::: Handlers
+[[handlers]]
+== Handlers
Handlers are Erlang modules that handle HTTP requests.
-:: Plain HTTP handlers
+=== Plain HTTP handlers
The most basic handler in Cowboy implements the mandatory
`init/2` callback, manipulates the request, optionally
sends a response and then returns.
-This callback receives the ^"Req object^req and the options
-defined during the ^"router configuration^routing^.
+This callback receives the xref:req[Req object] and the options
+defined during the xref:routing[router configuration].
A handler that does nothing would look like this:
-``` erlang
+[source,erlang]
+----
init(Req, _Opts) ->
{ok, Req, #state{}}.
-```
+----
Despite sending no reply, a `204 No Content` reply will be
sent to the client, as Cowboy makes sure that a reply is
@@ -24,13 +26,14 @@ sent for every request.
We need to use the Req object for sending a reply.
-``` erlang
+[source,erlang]
+----
init(Req, _Opts) ->
Req2 = cowboy_req:reply(200, [
{<<"content-type">>, <<"text/plain">>}
], <<"Hello World!">>, Req),
{ok, Req2, #state{}}.
-```
+----
As you can see we return a 3-tuple. `ok` means that the
handler ran successfully. The Req object is returned as
@@ -43,7 +46,7 @@ in every subsequent callbacks to this handler. Plain HTTP
handlers only have one additional callback, the optional
`terminate/3`.
-:: Other handlers
+=== Other handlers
The `init/2` callback can also be used to inform Cowboy
that this is a different kind of handler and that Cowboy
@@ -51,38 +54,41 @@ should switch to it. To do this you simply need to return
the module name of the handler type you want to switch to.
Cowboy comes with three handler types you can switch to:
-^"cowboy_rest^rest_handlers^, ^"cowboy_websocket^ws_handlers^
-and ^"cowboy_loop^loop_handlers^. In addition to those you
+xref:rest_handlers[cowboy_rest], xref:ws_handlers[cowboy_websocket]
+and xref:loop_handlers[cowboy_loop]. In addition to those you
can define your own handler types.
Switching is simple. Instead of returning `ok`, you simply
return the name of the handler type you want to use. The
following snippet switches to a Websocket handler:
-``` erlang
+[source,erlang]
+----
init(Req, _Opts) ->
{cowboy_websocket, Req, #state{}}.
-```
+----
You can also switch to your own custom handler type:
-``` erlang
+[source,erlang]
+----
init(Req, _Opts) ->
{my_handler_type, Req, #state{}}.
-```
+----
How to implement a custom handler type is described in the
-^"Sub protocols^sub_protocols chapter.
+xref:sub_protocols[Sub protocols] chapter.
-:: Cleaning up
+=== Cleaning up
All handlers coming with Cowboy allow the use of the optional
`terminate/3` callback.
-``` erlang
+[source,erlang]
+----
terminate(_Reason, Req, State) ->
ok.
-```
+----
This callback is strictly reserved for any required cleanup.
You cannot send a response from this function. There is no
diff --git a/doc/src/guide/hooks.ezdoc b/doc/src/guide/hooks.asciidoc
index 1c19648..fc79f8a 100644
--- a/doc/src/guide/hooks.ezdoc
+++ b/doc/src/guide/hooks.asciidoc
@@ -1,9 +1,10 @@
-::: Hooks
+[[hooks]]
+== Hooks
Hooks allow the user to customize Cowboy's behavior during specific
operations.
-:: Onresponse
+=== Onresponse
The `onresponse` hook is called right before sending the response
to the socket. It can be used for the purposes of logging responses,
@@ -16,7 +17,8 @@ explicitly provide all headers that are needed.
You can specify the `onresponse` hook when creating the listener.
-``` erlang
+[source,erlang]
+----
cowboy:start_http(my_http_listener, 100,
[{port, 8080}],
[
@@ -24,13 +26,14 @@ cowboy:start_http(my_http_listener, 100,
{onresponse, fun ?MODULE:custom_404_hook/4}
]
).
-```
+----
The following hook function will provide a custom body for 404 errors
when it has not been provided before, and will let Cowboy proceed with
the default response otherwise.
-``` erlang
+[source,erlang]
+----
custom_404_hook(404, Headers, <<>>, Req) ->
Body = <<"404 Not Found.">>,
Headers2 = lists:keyreplace(<<"content-length">>, 1, Headers,
@@ -38,6 +41,6 @@ custom_404_hook(404, Headers, <<>>, Req) ->
cowboy_req:reply(404, Headers2, Body, Req);
custom_404_hook(_, _, _, Req) ->
Req.
-```
+----
Again, make sure to always return the last request object obtained.
diff --git a/doc/src/guide/index.ezdoc b/doc/src/guide/index.ezdoc
deleted file mode 100644
index dbe75ff..0000000
--- a/doc/src/guide/index.ezdoc
+++ /dev/null
@@ -1,58 +0,0 @@
-::: Cowboy User Guide
-
-The Cowboy User Guide explores the modern Web and how to make
-best use of Cowboy for writing powerful Web applications.
-
-:: Rationale
-
-* ^"The modern Web^modern_web
-* ^"Erlang and the Web^erlang_web
-
-:: Introduction
-
-* ^"Introduction^introduction
-* ^"Getting started^getting_started
-* ^"Request overview^overview
-* ^"Erlang for beginners^erlang_beginners
-
-:: Configuration
-
-* ^"Routing^routing
-* ^"Constraints^constraints
-* ^"Static files^static_files
-
-:: Request and response
-
-* ^"Handlers^handlers
-* ^"The Req object^req
-* ^"Reading the request body^req_body
-* ^"Sending a response^resp
-* ^"Using cookies^cookies
-* ^"Multipart^multipart
-
-:: REST
-
-* ^"REST principles^rest_principles
-* ^"Handling REST requests^rest_handlers
-* ^"REST flowcharts^rest_flowcharts
-* ^"Designing a resource handler^resource_design
-
-:: Websocket
-
-* ^"The Websocket protocol^ws_protocol
-* ^"Handling Websocket connections^ws_handlers
-
-:: Push technology
-
-* ^"Loop handlers^loop_handlers
-
-:: Extensions
-
-* ^"Middlewares^middlewares
-* ^"Sub protocols^sub_protocols
-* ^"Hooks^hooks
-
-:: Internals
-
-* ^"Architecture^architecture
-* ^"Dealing with broken clients^broken_clients
diff --git a/doc/src/guide/introduction.ezdoc b/doc/src/guide/introduction.asciidoc
index e1d2e60..0ffeb91 100644
--- a/doc/src/guide/introduction.ezdoc
+++ b/doc/src/guide/introduction.asciidoc
@@ -1,4 +1,5 @@
-::: Introduction
+[[introduction]]
+== Introduction
Cowboy is a small, fast and modular HTTP server written in Erlang.
@@ -14,14 +15,14 @@ Cowboy is clean Erlang code. It includes hundreds of tests and its code
is fully compliant with the Dialyzer. It is also well documented and
features both a Function Reference and a User Guide.
-:: Prerequisites
+=== Prerequisites
Beginner Erlang knowledge is recommended for reading this guide.
Knowledge of the HTTP protocol is recommended but not required, as it
will be detailed throughout the guide.
-:: Supported platforms
+=== Supported platforms
Cowboy is tested and supported on Linux.
@@ -39,11 +40,11 @@ modifications but there is no guarantee that it will work as expected.
Cowboy uses the maps data type which was introduced in Erlang 17.0.
-:: Versioning
+=== Versioning
-Cowboy uses ^"Semantic Versioning 2.0.0^http://semver.org/^.
+Cowboy uses http://semver.org/[Semantic Versioning 2.0.0].
-:: Conventions
+=== Conventions
In the HTTP protocol, the method name is case sensitive. All standard
method names are uppercase.
diff --git a/doc/src/guide/loop_handlers.ezdoc b/doc/src/guide/loop_handlers.asciidoc
index 47893a9..58c4223 100644
--- a/doc/src/guide/loop_handlers.ezdoc
+++ b/doc/src/guide/loop_handlers.asciidoc
@@ -1,4 +1,5 @@
-::: Loop handlers
+[[loop_handlers]]
+== Loop handlers
Loop handlers are a special kind of HTTP handlers used when the
response can not be sent right away. The handler enters instead
@@ -24,7 +25,7 @@ and feed these messages to the `info/3` callback. It also features
the `init/2` and `terminate/3` callbacks which work the same as
for plain HTTP handlers.
-:: Initialization
+=== Initialization
The `init/2` function must return a `cowboy_loop` tuple to enable
loop handler behavior. This tuple may optionally contain
@@ -33,21 +34,23 @@ process enter hibernation until a message is received.
This snippet enables the loop handler.
-``` erlang
+[source,erlang]
+----
init(Req, _Opts) ->
{cowboy_loop, Req, #state{}}.
-```
+----
However it is largely recommended that you set a timeout
value. The next example sets a timeout value of 30s and
also makes the process hibernate.
-``` erlang
+[source,erlang]
+----
init(Req, _Opts) ->
{cowboy_loop, Req, #state{}, 30000, hibernate}.
-```
+----
-:: Receive loop
+=== Receive loop
Once initialized, Cowboy will wait for messages to arrive
in the process' mailbox. When a message arrives, Cowboy
@@ -58,13 +61,14 @@ The following snippet sends a reply when it receives a
`reply` message from another process, or waits for another
message otherwise.
-``` erlang
+[source,erlang]
+----
info({reply, Body}, Req, State) ->
Req2 = cowboy_req:reply(200, [], Body, Req),
{stop, Req2, State};
info(_Msg, Req, State) ->
{ok, Req, State, hibernate}.
-```
+----
Do note that the `reply` tuple here may be any message
and is simply an example.
@@ -81,7 +85,7 @@ This will instruct Cowboy to end the request.
Otherwise an `ok` tuple should be returned.
-:: Streaming loop
+=== Streaming loop
Another common case well suited for loop handlers is
streaming data received in the form of Erlang messages.
@@ -93,7 +97,8 @@ The following snippet does exactly that. As you can see
a chunk is sent every time a `chunk` message is received,
and the loop is stopped by sending an `eof` message.
-``` erlang
+[source,erlang]
+----
init(Req, _Opts) ->
Req2 = cowboy_req:chunked_reply(200, [], Req),
{cowboy_loop, Req2, #state{}}.
@@ -105,18 +110,18 @@ info({chunk, Chunk}, Req, State) ->
{ok, Req, State};
info(_Msg, Req, State) ->
{ok, Req, State}.
-```
+----
-:: Cleaning up
+==== Cleaning up
It is recommended that you set the connection header to
`close` when replying, as this process may be reused for
a subsequent request.
-Please refer to the ^"Handlers chapter^handlers
+Please refer to the xref:handlers[Handlers chapter]
for general instructions about cleaning up.
-:: Timeout
+=== Timeout
By default Cowboy will not attempt to close the connection
if there is no activity from the client. This is not always
@@ -132,7 +137,7 @@ so there is a configurable limit for it. The default buffer
size is of 5000 bytes, but it may be changed by setting the
`loop_max_buffer` middleware environment value.
-:: Hibernate
+=== Hibernate
To save memory, you may hibernate the process in between
messages received. This is done by returning the atom
diff --git a/doc/src/guide/middlewares.ezdoc b/doc/src/guide/middlewares.asciidoc
index 8b047d7..e6be30d 100644
--- a/doc/src/guide/middlewares.ezdoc
+++ b/doc/src/guide/middlewares.asciidoc
@@ -1,4 +1,5 @@
-::: Middlewares
+[[middlewares]]
+== Middlewares
Cowboy delegates the request processing to middleware components.
By default, two middlewares are defined, for the routing and handling
@@ -11,7 +12,7 @@ change the chain of middlewares as needed.
Cowboy will execute all middlewares in the given order, unless one
of them decides to stop processing.
-:: Usage
+=== Usage
Middlewares only need to implement a single callback: `execute/2`.
It is defined in the `cowboy_middleware` behavior.
@@ -34,7 +35,7 @@ to send an error back to the socket, the process will just crash. It
is up to the middleware to make sure that a reply is sent if something
goes wrong.
-:: Configuration
+=== Configuration
The middleware environment is defined as the `env` protocol option.
In the previous chapters we saw it briefly when we needed to pass
@@ -56,13 +57,13 @@ environment values to perform.
You can update the environment by calling the `cowboy:set_env/3`
convenience function, adding or replacing a value in the environment.
-:: Routing middleware
+=== Routing middleware
The routing middleware requires the `dispatch` value. If routing
succeeds, it will put the handler name and options in the `handler`
and `handler_opts` values of the environment, respectively.
-:: Handler middleware
+=== Handler middleware
The handler middleware requires the `handler` and `handler_opts`
values. It puts the result of the request handling into `result`.
diff --git a/doc/src/guide/modern_web.ezdoc b/doc/src/guide/modern_web.asciidoc
index 1c2c342..7dc812b 100644
--- a/doc/src/guide/modern_web.ezdoc
+++ b/doc/src/guide/modern_web.asciidoc
@@ -1,4 +1,5 @@
-::: The modern Web
+[[modern_web]]
+== The modern Web
Let's take a look at various technologies from the beginnings
of the Web up to this day, and get a preview of what's
@@ -8,7 +9,7 @@ Cowboy is compatible with all the technology cited in this
chapter except of course HTTP/2.0 which has no implementation
in the wild at the time of writing.
-:: The prehistoric Web
+=== The prehistoric Web
HTTP was initially created to serve HTML pages and only
had the GET method for retrieving them. This initial
@@ -29,7 +30,7 @@ this.
Most improvements done in recent years focused on reducing
this load time and reducing the latency of the requests.
-:: HTTP/1.1
+=== HTTP/1.1
HTTP/1.1 quickly followed and added a keep-alive mechanism
to allow using the same connection for many requests, as
@@ -47,7 +48,7 @@ clients to perform what is called as pipelining: sending many
requests in a row, and then processing the responses which will
be received in the same order as the requests.
-:: REST
+=== REST
The design of HTTP/1.1 was influenced by the REST architectural
style. REST, or REpresentational State Transfer, is a style of
@@ -72,7 +73,7 @@ to implement RESTful systems.
REST is most often used when designing web application APIs
which are generally meant to be used by executable code directly.
-:: XmlHttpRequest
+=== XmlHttpRequest
Also know as AJAX, this technology allows Javascript code running
on a web page to perform asynchronous requests to the server.
@@ -88,7 +89,7 @@ This is of course still requests initiated by the client,
the server still had no way of pushing data to the client
on its own, so new technology appeared to allow that.
-:: Long-polling
+=== Long-polling
Polling was a technique used to overcome the fact that the server
cannot push data directly to the client. Therefore the client had
@@ -116,7 +117,7 @@ You probably guessed by now that long-polling is a hack, and
like most hacks it can suffer from unforeseen issues, in this
case it doesn't always play well with proxies.
-:: HTML5
+=== HTML5
HTML5 is, of course, the HTML version after HTML4. But HTML5
emerged to solve a specific problem: dynamic web applications.
@@ -140,7 +141,7 @@ events from the server.
The solution went on to become HTML5. At the time of writing
it is being standardized.
-:: EventSource
+=== EventSource
EventSource, sometimes also called Server-Sent Events, is a
technology allowing servers to push data to HTML5 applications.
@@ -159,7 +160,7 @@ UTF-8 encoded text data. Binary data and text data encoded
differently are not allowed by the protocol. A heavier but
more generic approach can be found in Websocket.
-:: Websocket
+=== Websocket
Websocket is a protocol built on top of HTTP/1.1 that provides
a two-ways communication channel between the client and the
@@ -179,7 +180,7 @@ A Websocket connection can be used to transfer any kind of data,
small or big, text or binary. Because of this Websocket is
sometimes used for communication between systems.
-:: SPDY
+=== SPDY
SPDY is an attempt to reduce page loading time by opening a
single connection per server, keeping it open for subsequent
@@ -203,7 +204,7 @@ to a SPDY connection seamlessly if the protocol supports it.
The protocol itself has a few shortcomings which are being
fixed in HTTP/2.0.
-:: HTTP/2.0
+=== HTTP/2.0
HTTP/2.0 is the long-awaited update to the HTTP/1.1 protocol.
It is based on SPDY although a lot has been improved at the
@@ -211,5 +212,3 @@ time of writing.
HTTP/2.0 is an asynchronous two-ways communication channel
between two endpoints.
-
-It is planned to be ready late 2014.
diff --git a/doc/src/guide/multipart.ezdoc b/doc/src/guide/multipart.asciidoc
index d0b2e40..20d53d5 100644
--- a/doc/src/guide/multipart.ezdoc
+++ b/doc/src/guide/multipart.asciidoc
@@ -1,4 +1,5 @@
-::: Multipart requests
+[[multipart]]
+== Multipart requests
Multipart originates from MIME, an Internet standard that
extends the format of emails. Multipart messages are a
@@ -24,7 +25,7 @@ Req object directly.
Cowboy defines two functions that allows you to get
information about each part and read their contents.
-:: Structure
+=== Structure
A multipart message is a list of parts. Parts may
contain either a multipart message or a non-multipart
@@ -32,7 +33,7 @@ content-type. This allows parts to be arranged in a
tree structure, although this is a rare case as far
as the Web is concerned.
-:: Form-data
+=== Form-data
In the normal case, when a form is submitted, the
browser will use the `application/x-www-form-urlencoded`
@@ -55,7 +56,7 @@ of the files it sends this way, but you should not
rely on it for determining the contents of the file.
Proper investigation of the contents is recommended.
-:: Checking the content-type
+=== Checking the content-type
While there is a variety of multipart messages, the
most common on the Web is `multipart/form-data`. It's
@@ -65,18 +66,20 @@ allows uploading files.
You can quickly figure out if a multipart message
has been sent by parsing the `content-type` header.
-``` erlang
+[source,erlang]
+----
{<<"multipart">>, <<"form-data">>, _}
= cowboy_req:parse_header(<<"content-type">>, Req).
-```
+----
-:: Reading a multipart message
+=== Reading a multipart message
To read a message you have to iterate over all its
parts. Then, for each part, you can inspect its headers
and read its body.
-``` erlang
+[source,erlang]
+----
multipart(Req) ->
case cowboy_req:part(Req) of
{ok, _Headers, Req2} ->
@@ -85,7 +88,7 @@ multipart(Req) ->
{done, Req2} ->
Req2
end.
-```
+----
Parts do not have a size limit. When a part body is
too big, Cowboy will return what it read so far and
@@ -100,7 +103,8 @@ is a file being uploaded.
This can be used for example to allow large part bodies
for files but crash when a normal field is too large.
-``` erlang
+[source,erlang]
+----
multipart(Req) ->
case cowboy_req:part(Req) of
{ok, Headers, Req2} ->
@@ -123,14 +127,14 @@ stream_file(Req) ->
{more, _Body, Req2} ->
stream_file(Req2)
end.
-```
+----
By default the body chunk Cowboy will return is limited
to 8MB. This can of course be overriden. Both functions
can take a second argument, the same list of options that
will be passed to `cowboy_req:body/2` function.
-:: Skipping unwanted parts
+=== Skipping unwanted parts
If you do not want to read a part's body, you can skip it.
Skipping is easy. If you do not call the function to read
@@ -140,7 +144,8 @@ you request the next part.
The following snippet reads all part headers and skips
all bodies:
-``` erlang
+[source,erlang]
+----
multipart(Req) ->
case cowboy_req:part(Req) of
{ok, _Headers, Req2} ->
@@ -148,7 +153,7 @@ multipart(Req) ->
{done, Req2} ->
Req2
end.
-```
+----
Similarly, if you start reading the body and it ends up
being too big, you can simply continue with the next part,
diff --git a/doc/src/guide/overview.ezdoc b/doc/src/guide/overview.asciidoc
index 725ae4e..b337e3d 100644
--- a/doc/src/guide/overview.ezdoc
+++ b/doc/src/guide/overview.asciidoc
@@ -1,10 +1,11 @@
-::: Request overview
+[[overview]]
+== Request overview
This chapter explains the different steps a request
goes through until a response is sent, along with
details of the Cowboy implementation.
-:: Request/response
+=== Request/response
As you already know, HTTP clients connect to the server and
send a request for a resource; the server then sends a
@@ -18,7 +19,7 @@ add like writing logs.
Requests take the following route in Cowboy:
-^"HTTP request/response flowchart^!http_req_resp.png
+image::http_req_resp.png[HTTP request/response flowchart]
This shows the default middlewares, but they may be
configured differently in your setup. The dark green
@@ -42,7 +43,7 @@ When a response is sent, you can optionally modify it
or act upon it by enabling the `onresponse` hook. By
default the response is sent directly to the client.
-:: And then?
+=== And then?
Behavior depends on what protocol is in use.
@@ -59,7 +60,7 @@ asynchronously on the same connection. Details on what
this means for your application is described in this
chapter.
-:: Keep-alive (HTTP/1.1)
+=== Keep-alive (HTTP/1.1)
With HTTP/1.1, the connection may be left open for
subsequent requests to come. This mechanism is called
@@ -79,11 +80,12 @@ as the reply is sent.
This snippet will force Cowboy to close the connection.
-``` erlang
+[source,erlang]
+----
Req2 = cowboy_req:reply(200, [
{<<"connection">>, <<"close">>},
], <<"Closing the socket in 3.. 2.. 1..">>, Req).
-```
+----
Cowboy will only accept a certain number of new requests
on the same connection. By default it will run up to 100
@@ -91,12 +93,13 @@ requests. This number can be changed by setting the
`max_keepalive` configuration value when starting an
HTTP listener.
-``` erlang
+[source,erlang]
+----
cowboy:start_http(my_http_listener, 100, [{port, 8080}], [
{env, [{dispatch, Dispatch}]},
{max_keepalive, 5}
]).
-```
+----
Cowboy implements the keep-alive mechanism by reusing
the same process for all requests. This allows Cowboy
@@ -106,7 +109,7 @@ But it also means you need to clean up if you do have
code with side effects. The `terminate/3` function can
be used for this purpose.
-:: Pipelining (HTTP/1.1)
+=== Pipelining (HTTP/1.1)
While HTTP is designed as a sequential protocol, with
the client sending a request and then waiting for the
@@ -123,7 +126,7 @@ static files for example.
This is handled automatically by the server.
-:: Asynchronous requests (SPDY)
+=== Asynchronous requests (SPDY)
In SPDY, the client can send a request at any time.
And the server can send a response at any time too.
diff --git a/doc/src/guide/req.ezdoc b/doc/src/guide/req.asciidoc
index add6166..09d442a 100644
--- a/doc/src/guide/req.ezdoc
+++ b/doc/src/guide/req.asciidoc
@@ -1,10 +1,11 @@
-::: The Req object
+[[req]]
+== The Req object
The Req object is this variable that you will use to obtain
information about a request, read the body of the request
and send a response.
-:: A special variable
+=== A special variable
While we call it an "object", it is not an object in the
OOP sense of the term. In fact it is completely opaque
@@ -27,7 +28,7 @@ For example, when streaming the request body, the
function will return the body by chunks, one at a
time, until there is none left.
-:: Overview of the cowboy_req interface
+=== Overview of the cowboy_req interface
With the exception of functions manipulating the request
body, all functions return a single value. Depending on
@@ -44,7 +45,7 @@ This chapter covers the access functions mainly. Cookies,
request body and response functions are covered in their
own chapters.
-:: Request
+=== Request
When a client performs a request, it first sends a few required
values. They are sent differently depending on the protocol
@@ -56,31 +57,28 @@ The method identifies the action. Standard methods include
GET, HEAD, OPTIONS, PATCH, POST, PUT, DELETE. Method names
are case sensitive.
-``` erlang
+[source,erlang]
Method = cowboy_req:method(Req).
-```
The host, port and path parts of the URL identify the resource
being accessed. The host and port information may not be
available if the client uses HTTP/1.0.
-``` erlang
+[source,erlang]
Host = cowboy_req:host(Req),
Port = cowboy_req:port(Req),
Path = cowboy_req:path(Req).
-```
The version used by the client can of course also be obtained.
-``` erlang
+[source,erlang]
Version = cowboy_req:version(Req).
-```
Do note however that clients claiming to implement one version
of the protocol does not mean they implement it fully, or even
properly.
-:: Bindings
+=== Bindings
After routing the request, bindings are available. Bindings
are these parts of the host or path that you chose to extract
@@ -89,61 +87,53 @@ when defining the routes of your application.
You can fetch a single binding. The value will be `undefined`
if the binding doesn't exist.
-``` erlang
+[source,erlang]
Binding = cowboy_req:binding(my_binding, Req).
-```
If you need a different value when the binding doesn't exist,
you can change the default.
-``` erlang
+[source,erlang]
Binding = cowboy_req:binding(my_binding, Req, 42).
-```
You can also obtain all bindings in one call. They will be
returned as a list of key/value tuples.
-``` erlang
+[source,erlang]
AllBindings = cowboy_req:bindings(Req).
-```
If you used `...` at the beginning of the route's pattern
for the host, you can retrieve the matched part of the host.
The value will be `undefined` otherwise.
-``` erlang
+[source,erlang]
HostInfo = cowboy_req:host_info(Req).
-```
Similarly, if you used `...` at the end of the route's
pattern for the path, you can retrieve the matched part,
or get `undefined` otherwise.
-``` erlang
+[source,erlang]
PathInfo = cowboy_req:path_info(Req).
-```
-:: Query string
+=== Query string
The raw query string can be obtained directly.
-``` erlang
+[source,erlang]
Qs = cowboy_req:qs(Req).
-```
You can parse the query string and then use standard library
functions to access individual values.
-``` erlang
+[source,erlang]
QsVals = cowboy_req:parse_qs(Req),
{_, Lang} = lists:keyfind(<<"lang">>, 1, QsVals).
-```
You can match the query string into a map.
-``` erlang
+[source,erlang]
#{id := ID, lang := Lang} = cowboy_req:match_qs([id, lang], Req).
-```
You can use constraints to validate the values while matching
them. The following snippet will crash if the `id` value is
@@ -151,9 +141,8 @@ not an integer number or if the `lang` value is empty. Additionally
the `id` value will be converted to an integer term, saving
you a conversion step.
-``` erlang
+[source,erlang]
QsMap = cowboy_req:match_qs([{id, int}, {lang, nonempty}], Req).
-```
Note that in the case of duplicate query string keys, the map
value will become a list of the different values.
@@ -164,58 +153,50 @@ A default value can be provided. The default will be used
if the `lang` key is not found. It will not be used if
the key is found but has an empty value.
-``` erlang
+[source,erlang]
#{lang := Lang} = cowboy_req:match_qs([{lang, [], <<"en-US">>}], Req).
-```
If no default is provided and the value is missing, the
query string is deemed invalid and the process will crash.
-:: Request URL
+=== Request URL
You can reconstruct the full URL of the resource.
-``` erlang
+[source,erlang]
URL = cowboy_req:url(Req).
-```
You can also obtain only the base of the URL, excluding the
path and query string.
-``` erlang
+[source,erlang]
BaseURL = cowboy_req:host_url(Req).
-```
-:: Headers
+=== Headers
Cowboy allows you to obtain the header values as string,
or parsed into a more meaningful representation.
This will get the string value of a header.
-``` erlang
+[source,erlang]
HeaderVal = cowboy_req:header(<<"content-type">>, Req).
-```
You can of course set a default in case the header is missing.
-``` erlang
-HeaderVal
- = cowboy_req:header(<<"content-type">>, Req, <<"text/plain">>).
-```
+[source,erlang]
+HeaderVal = cowboy_req:header(<<"content-type">>, Req, <<"text/plain">>).
And also obtain all headers.
-``` erlang
+[source,erlang]
AllHeaders = cowboy_req:headers(Req).
-```
To parse the previous header, simply call `parse_header/{2,3}`
where you would call `header/{2,3}` otherwise.
-``` erlang
+[source,erlang]
ParsedVal = cowboy_req:parse_header(<<"content-type">>, Req).
-```
Cowboy will crash if it doesn't know how to parse the given
header, or if the value is invalid.
@@ -224,15 +205,16 @@ You can of course define a default value. Note that the default
value you specify here is the parsed value you'd like to get
by default.
-``` erlang
+[source,erlang]
+----
ParsedVal = cowboy_req:parse_header(<<"content-type">>, Req,
{<<"text">>, <<"plain">>, []}).
-```
+----
The list of known headers and default values is defined in the
manual.
-:: Meta
+=== Meta
Cowboy will sometimes associate some meta information with
the request. Built-in meta values are listed in the manual
@@ -241,29 +223,25 @@ for their respective modules.
This will get a meta value. The returned value will be `undefined`
if it isn't defined.
-``` erlang
+[source,erlang]
MetaVal = cowboy_req:meta(websocket_version, Req).
-```
You can change the default value if needed.
-``` erlang
+[source,erlang]
MetaVal = cowboy_req:meta(websocket_version, Req, 13).
-```
You can also define your own meta values. The name must be
an `atom()`.
-``` erlang
+[source,erlang]
Req2 = cowboy_req:set_meta(the_answer, 42, Req).
-```
-:: Peer
+=== Peer
You can obtain the peer address and port number. This is
not necessarily the actual IP and port of the client, but
rather the one of the machine that connected to the server.
-``` erlang
+[source,erlang]
{IP, Port} = cowboy_req:peer(Req).
-```
diff --git a/doc/src/guide/req_body.ezdoc b/doc/src/guide/req_body.asciidoc
index 8864035..d2a43d2 100644
--- a/doc/src/guide/req_body.ezdoc
+++ b/doc/src/guide/req_body.asciidoc
@@ -1,4 +1,5 @@
-::: Reading the request body
+[[req_body]]
+== Reading the request body
The Req object also allows you to read the request body.
@@ -16,13 +17,12 @@ parse in a single call for form urlencoded formats or
multipart. All of these except multipart are covered in
this chapter. Multipart is covered later on in the guide.
-:: Check for request body
+=== Check for request body
You can check whether a body was sent with the request.
-``` erlang
+[source,erlang]
cowboy_req:has_body(Req).
-```
It will return `true` if there is a request body, and
`false` otherwise.
@@ -31,14 +31,13 @@ Note that it is generally safe to assume that a body is
sent for `POST`, `PUT` and `PATCH` requests, without
having to explicitly check for it.
-:: Request body length
+=== Request body length
You can obtain the body length if it was sent with the
request.
-``` erlang
+[source,erlang]
Length = cowboy_req:body_length(Req).
-```
The value returned will be `undefined` if the length
couldn't be figured out from the request headers. If
@@ -46,26 +45,23 @@ there's a body but no length is given, this means that
the chunked transfer-encoding was used. You can read
chunked bodies by using the stream functions.
-:: Reading the body
+=== Reading the body
You can read the whole body directly in one call.
-``` erlang
+[source,erlang]
{ok, Body, Req2} = cowboy_req:body(Req).
-```
By default, Cowboy will attempt to read up to a
size of 8MB. You can override this limit as needed.
-``` erlang
+[source,erlang]
{ok, Body, Req2} = cowboy_req:body(Req, [{length, 100000000}]).
-```
You can also disable it.
-``` erlang
+[source,erlang]
{ok, Body, Req2} = cowboy_req:body(Req, [{length, infinity}]).
-```
It is recommended that you do not disable it for public
facing websites.
@@ -74,7 +70,7 @@ If the body is larger than the limit, then Cowboy will return
a `more` tuple instead, allowing you to stream it if you
would like to.
-:: Streaming the body
+=== Streaming the body
You can stream the request body by chunks.
@@ -82,7 +78,8 @@ Cowboy returns a `more` tuple when there is more body to
be read, and an `ok` tuple for the last chunk. This allows
you to loop over all chunks.
-``` erlang
+[source,erlang]
+----
body_to_console(Req) ->
case cowboy_req:body(Req) of
{ok, Data, Req2} ->
@@ -92,12 +89,12 @@ body_to_console(Req) ->
io:format("~s", [Data]),
body_to_console(Req2)
end.
-```
+----
You can of course set the `length` option to configure the
size of chunks.
-:: Rate of data transmission
+=== Rate of data transmission
You can control the rate of data transmission by setting
options when calling body functions. This applies not only
@@ -110,7 +107,7 @@ to be received from the socket at once, in bytes.
The `read_timeout` option defines the time Cowboy waits
before that amount is received, in milliseconds.
-:: Transfer and content decoding
+=== Transfer and content decoding
Cowboy will by default decode the chunked transfer-encoding
if any. It will not decode any content-encoding by default.
@@ -122,28 +119,27 @@ ignored.
The following example shows how to set both options.
-``` erlang
+[source,erlang]
+----
{ok, Data, Req2} = cowboy_req:body(Req, [
{transfer_decode, fun transfer_decode/2, TransferState},
{content_decode, fun content_decode/1}
]).
-```
+----
-:: Reading a form urlencoded body
+=== Reading a form urlencoded body
You can directly obtain a list of key/value pairs if the
body was sent using the application/x-www-form-urlencoded
content-type.
-``` erlang
+[source,erlang]
{ok, KeyValues, Req2} = cowboy_req:body_qs(Req).
-```
You can then retrieve an individual value from that list.
-``` erlang
+[source,erlang]
{_, Lang} = lists:keyfind(lang, 1, KeyValues).
-```
You should not attempt to match on the list as the order
of the values is undefined.
@@ -152,7 +148,5 @@ By default Cowboy will reject bodies with a size above
64KB when using this function. You can override this limit
by setting the `length` option.
-``` erlang
-{ok, KeyValues, Req2} = cowboy_req:body_qs(Req,
- [{length, 2000000}]).
-```
+[source,erlang]
+{ok, KeyValues, Req2} = cowboy_req:body_qs(Req, [{length, 2000000}]).
diff --git a/doc/src/guide/resource_design.ezdoc b/doc/src/guide/resource_design.asciidoc
index 67cb09b..a8a6648 100644
--- a/doc/src/guide/resource_design.ezdoc
+++ b/doc/src/guide/resource_design.asciidoc
@@ -1,10 +1,11 @@
-::: Designing a resource handler
+[[resource_design]]
+== Designing a resource handler
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.
-:: The service
+=== The service
Can the service become unavailable, and when it does, can
we detect it? For example database connectivity problems
@@ -17,7 +18,7 @@ more than the standard OPTIONS, HEAD, GET, PUT, POST,
PATCH and DELETE? Are we not using one of those at all?
Implement the `known_methods` callback.
-:: Type of resource handler
+=== Type of resource handler
Am I writing a handler for a collection of resources,
or for a single resource?
@@ -26,7 +27,7 @@ The semantics for each of these are quite different.
You should not mix collection and single resource in
the same handler.
-:: Collection handler
+=== Collection handler
Skip this section if you are not doing a collection.
@@ -70,7 +71,7 @@ operation is atomic. The PATCH operation may
be used for such things as reordering; adding,
modifying or deleting parts of the collection.
-:: Single resource handler
+=== Single resource handler
Skip this section if you are doing a collection.
@@ -98,7 +99,7 @@ operation is atomic. The PATCH operation may
be used for adding, removing or modifying specific
values in the resource.
-:: The resource
+=== The resource
Following the above discussion, implement the
`allowed_methods` callback.
@@ -125,7 +126,7 @@ Is 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 `uri_too_long`.
-:: Representations
+=== Representations
What media types do I provide? If text based, what charsets
are provided? What languages do I provide?
@@ -149,7 +150,7 @@ representation available? Send a list of available
representations in the response body and implement
the `multiple_choices` callback.
-:: Redirections
+=== Redirections
Do I need to keep track of what resources were deleted?
For example you may have a mechanism where moving a
@@ -161,7 +162,7 @@ it is explicitly temporary, for example due to maintenance,
implement the `moved_temporarily` callback. Otherwise,
implement the `moved_permanently` callback.
-:: The request
+=== The request
Do we need to perform extra checks to make sure the request
is valid? Cowboy will do many checks when receiving the
@@ -176,20 +177,20 @@ to accept? Implement `valid_entity_length`.
Finally, take a look at the sections corresponding to the
methods you are implementing.
-:: OPTIONS method
+=== OPTIONS method
Cowboy by default will send back a list of allowed methods.
Do I need to add more information to the response? Implement
the `options` method.
-:: GET and HEAD methods
+=== GET and HEAD methods
If you implement the methods GET and/or HEAD, you must
implement one `ProvideResource` callback for each
content-type returned by the `content_types_provided`
callback.
-:: PUT, POST and PATCH methods
+=== PUT, POST and PATCH methods
If you implement the methods PUT, POST and/or PATCH,
you must implement the `content_types_accepted` callback,
@@ -208,7 +209,7 @@ a resource? Do we want to make sure that two updates around
the same time are not cancelling one another? Implement the
`is_conflict` callback.
-:: DELETE methods
+=== DELETE methods
If you implement the method DELETE, you must implement
the `delete_resource` callback.
diff --git a/doc/src/guide/resp.ezdoc b/doc/src/guide/resp.asciidoc
index 009756a..1ffdfbd 100644
--- a/doc/src/guide/resp.ezdoc
+++ b/doc/src/guide/resp.asciidoc
@@ -1,4 +1,5 @@
-::: Sending a response
+[[resp]]
+== Sending a response
The Req object also allows you to send a response.
@@ -9,36 +10,37 @@ with its body streamed by chunks of arbitrary size.
You can also set headers or the response body in advance
and Cowboy will use them when you finally do reply.
-:: Reply
+=== Reply
You can send a reply with no particular headers or body.
Cowboy will make sure to send the mandatory headers with
the response.
-``` erlang
+[source,erlang]
Req2 = cowboy_req:reply(200, Req).
-```
You can define headers to be sent with the response. Note
that header names must be lowercase. Again, Cowboy will
make sure to send the mandatory headers with the response.
-``` erlang
+[source,erlang]
+----
Req2 = cowboy_req:reply(303, [
{<<"location">>, <<"http://ninenines.eu">>}
], Req).
-```
+----
You can override headers that Cowboy would send otherwise.
Any header set by the user will be used over the ones set
by Cowboy. For example, you can advertise yourself as a
different server.
-``` erlang
+[source,erlang]
+----
Req2 = cowboy_req:reply(200, [
{<<"server">>, <<"yaws">>}
], Req).
-```
+----
We also saw earlier how to force close the connection by
overriding the connection header.
@@ -48,34 +50,35 @@ will automatically set the content-length header if you do.
We recommend that you set the content-type header so the
client may know how to read the body.
-``` erlang
+[source,erlang]
+----
Req2 = cowboy_req:reply(200, [
{<<"content-type">>, <<"text/plain">>}
], "Hello world!", Req).
-```
+----
Here is the same example but sending HTML this time.
-``` erlang
+[source,erlang]
+----
Req2 = cowboy_req:reply(200, [
{<<"content-type">>, <<"text/html">>}
], "<html><head>Hello world!</head><body><p>Hats off!</p></body></html>", Req).
-```
+----
Note that the reply is sent immediately.
-:: Chunked reply
+=== Chunked reply
You can also stream the response body. First, you need to
initiate the reply by sending the response status code.
Then you can send the body in chunks of arbitrary size.
-``` erlang
+[source,erlang]
Req2 = cowboy_req:chunked_reply(200, Req),
cowboy_req:chunk("Hello...", Req2),
cowboy_req:chunk("chunked...", Req2),
cowboy_req:chunk("world!!", Req2).
-```
You should make sure to match on `ok` as an error may be
returned.
@@ -84,36 +87,35 @@ While it is possible to send a chunked response without
a content-type header, it is still recommended. You can
set this header or any other just like for normal replies.
-``` erlang
+[source,erlang]
+----
Req2 = cowboy_req:chunked_reply(200, [
{<<"content-type">>, <<"text/html">>}
], Req),
cowboy_req:chunk("<html><head>Hello world!</head>", Req2),
cowboy_req:chunk("<body><p>Hats off!</p></body></html>", Req2).
-```
+----
Note that the reply and each chunk following it are sent
immediately.
-:: Preset response headers
+=== Preset response headers
You can define response headers in advance. They will be
merged into the headers given in the reply call. Headers
in the reply call override preset response headers which
override the default Cowboy headers.
-``` erlang
+[source,erlang]
Req2 = cowboy_req:set_resp_header(<<"allow">>, "GET", Req).
-```
You can check if a response header has already been set.
This will only check the response headers that you set,
and not the ones Cowboy will add when actually sending
the reply.
-``` erlang
+[source,erlang]
cowboy_req:has_resp_header(<<"allow">>, Req).
-```
It will return `true` if the header is defined, and `false`
otherwise.
@@ -121,19 +123,17 @@ otherwise.
Finally, you can also delete a preset response header if
needed. If you do, it will not be sent.
-``` erlang
+[source,erlang]
Req2 = cowboy_req:delete_resp_header(<<"allow">>, Req).
-```
-:: Preset response body
+=== Preset response body
You can set the response body in advance. Note that this
body will be ignored if you then choose to send a chunked
reply, or if you send a reply with an explicit body.
-``` erlang
+[source,erlang]
Req2 = cowboy_req:set_resp_body("Hello world!", Req).
-```
You can also set a fun that will be called when it is time
to send the body. There are three different ways of doing
@@ -144,38 +144,41 @@ you should specify it, as it will help clients determine
the remaining download time and allow them to inform the
user.
-``` erlang
+[source,erlang]
+----
F = fun (Socket, Transport) ->
Transport:send(Socket, "Hello world!")
end,
Req2 = cowboy_req:set_resp_body_fun(12, F, Req).
-```
+----
If you do not know the length of the body, you should use
a chunked response body fun instead.
-``` erlang
+[source,erlang]
+----
F = fun (SendChunk) ->
Body = lists:duplicate(random:uniform(1024, $a)),
SendChunk(Body)
end,
Req2 = cowboy_req:set_resp_body_fun(chunked, F, Req).
-```
+----
Finally, you can also send data on the socket directly,
without knowing the length in advance. Cowboy may be
forced to close the connection at the end of the response
though depending on the protocol capabilities.
-``` erlang
+[source,erlang]
+----
F = fun (Socket, Transport) ->
Body = lists:duplicate(random:uniform(1024, $a)),
Transport:send(Socket, Body)
end,
Req2 = cowboy_req:set_resp_body_fun(F, Req).
-```
+----
-:: Sending files
+=== Sending files
You can send files directly from disk without having to
read them. Cowboy will use the `sendfile` syscall when
@@ -186,12 +189,13 @@ than doing it from userland.
Again, it is recommended to set the size of the file if it
can be known in advance.
-``` erlang
+[source,erlang]
+----
F = fun (Socket, Transport) ->
Transport:sendfile(Socket, "priv/styles.css")
end,
Req2 = cowboy_req:set_resp_body_fun(FileSize, F, Req).
-```
+----
Please see the Ranch guide for more information about
sending files.
diff --git a/doc/src/guide/rest_flowcharts.ezdoc b/doc/src/guide/rest_flowcharts.asciidoc
index cee9cf0..b569782 100644
--- a/doc/src/guide/rest_flowcharts.ezdoc
+++ b/doc/src/guide/rest_flowcharts.asciidoc
@@ -1,4 +1,5 @@
-::: REST flowcharts
+[[rest_flowcharts]]
+== REST flowcharts
This chapter will explain the REST handler state machine through
a number of different diagrams.
@@ -17,11 +18,11 @@ indicate a response. Other squares may be either a callback or a
question answered by Cowboy itself. Green arrows tend to indicate
the default behavior if the callback is undefined.
-:: Start
+=== Start
All requests start from here.
-^"REST starting flowchart^!rest_start.png
+image::rest_start.png[REST starting flowchart]
A series of callbacks are called in succession to perform
a general checkup of the service, the request line and
@@ -48,11 +49,11 @@ This diagram is immediately followed by either the
"OPTIONS method" diagram when the request method is
OPTIONS, or the "Content negotiation" diagram otherwise.
-:: OPTIONS method
+=== OPTIONS method
This diagram only applies to OPTIONS requests.
-^"REST OPTIONS method flowchart^!rest_options.png
+image::rest_options.png[REST OPTIONS method flowchart]
The `options` callback may be used to add information
about the resource, such as media types or languages
@@ -64,13 +65,13 @@ If the `options` callback is not defined, Cowboy will
send a response containing the list of allowed methods
by default.
-:: Content negotiation
+=== Content negotiation
This diagram applies to all request methods other than
OPTIONS. It is executed right after the "Start" diagram
is completed.
-^"REST content negotiation flowchart^!rest_conneg.png
+image::rest_conneg.png[REST content negotiation flowchart]
The purpose of these steps is to determine an appropriate
representation to be sent back to the client.
@@ -105,14 +106,14 @@ the "PUT, POST and PATCH methods" diagram,
or the "DELETE method" diagram, depending on the
method.
-:: GET and HEAD methods
+=== GET and HEAD methods
This diagram only applies to GET and HEAD requests.
For a description of the `cond` step, please see
the "Conditional requests" diagram.
-^"REST GET/HEAD methods flowchart^!rest_get_head.png
+image::rest_get_head.png[REST GET/HEAD methods flowchart]
When the resource exists, and the conditional steps
succeed, the resource can be retrieved.
@@ -134,14 +135,14 @@ The `moved_permanently` and `moved_temporarily` callbacks
must return the new location of the resource if it was in
fact moved.
-:: PUT, POST and PATCH methods
+=== PUT, POST and PATCH methods
This diagram only applies to PUT, POST and PATCH requests.
For a description of the `cond` step, please see
the "Conditional requests" diagram.
-^"REST PUT/POST/PATCH methods flowchart^!rest_put_post_patch.png
+image::rest_put_post_patch.png[REST PUT/POST/PATCH methods flowchart]
When the resource exists, first the conditional steps
are executed. When that succeeds, and the method is PUT,
@@ -188,14 +189,14 @@ on whether a resource has been created, rather than
modified, and on the availability of a location header
or a body in the response.
-:: DELETE method
+=== DELETE method
This diagram only applies to DELETE requests.
For a description of the `cond` step, please see
the "Conditional requests" diagram.
-^"REST DELETE method flowchart^!rest_delete.png
+image::rest_delete.png[REST DELETE method flowchart]
When the resource exists, and the conditional steps
succeed, the resource can be deleted.
@@ -227,13 +228,13 @@ The `moved_permanently` and `moved_temporarily` callbacks
must return the new location of the resource if it was in
fact moved.
-:: Conditional requests
+=== Conditional requests
This diagram applies to all request methods other than
OPTIONS. It is executed right after the `resource_exists`
callback, when the resource exists.
-^"REST conditional requests flowchart^!rest_cond.png
+image::rest_cond.png[REST conditional requests flowchart]
A request becomes conditional when it includes either of
the if-match header; the if-unmodified-since header; the
diff --git a/doc/src/guide/rest_handlers.ezdoc b/doc/src/guide/rest_handlers.asciidoc
index e6bb092..6bff18d 100644
--- a/doc/src/guide/rest_handlers.ezdoc
+++ b/doc/src/guide/rest_handlers.asciidoc
@@ -1,4 +1,5 @@
-::: REST handlers
+[[rest_handlers]]
+== REST handlers
REST is implemented in Cowboy as a sub protocol. The request
is handled as a state machine with many optional callbacks
@@ -6,16 +7,17 @@ describing the resource and modifying the machine's behavior.
The REST handler is the recommended way to handle HTTP requests.
-:: Initialization
+=== Initialization
First, the `init/2` callback is called. This callback is common
to all handlers. To use REST for the current request, this function
must return a `cowboy_rest` tuple.
-``` erlang
+[source,erlang]
+----
init(Req, _Opts) ->
{cowboy_rest, Req, #state{}}.
-```
+----
Cowboy will then switch to the REST protocol and start executing
the state machine.
@@ -23,7 +25,7 @@ the state machine.
After reaching the end of the flowchart, the `terminate/3` callback
will be called if it is defined.
-:: Methods
+=== Methods
The REST component has code for handling the following HTTP methods:
HEAD, GET, POST, PATCH, PUT, DELETE and OPTIONS.
@@ -31,7 +33,7 @@ HEAD, GET, POST, PATCH, PUT, DELETE and OPTIONS.
Other methods can be accepted, however they have no specific callback
defined for them at this time.
-:: Callbacks
+=== Callbacks
All callbacks are optional. Some may become mandatory depending
on what other defined callbacks return. The various flowcharts
@@ -53,35 +55,37 @@ In the following table, "skip" means the callback is entirely skipped
if it is undefined, moving directly to the next step. Similarly,
"none" means there is no default value for this callback.
-|| Callback name Default value
-|
-| allowed_methods `[<<"GET">>, <<"HEAD">>, <<"OPTIONS">>]`
-| allow_missing_post `true`
-| charsets_provided skip
-| content_types_accepted none
-| content_types_provided `[{{<<"text">>, <<"html">>, '*'}, to_html}] `
-| delete_completed `true`
-| delete_resource `false`
-| expires `undefined`
-| forbidden `false`
-| generate_etag `undefined`
-| is_authorized `true`
-| is_conflict `false`
-| known_methods `[<<"GET">>, <<"HEAD">>, <<"POST">>, <<"PUT">>, <<"PATCH">>, <<"DELETE">>, <<"OPTIONS">>]`
-| languages_provided skip
-| last_modified `undefined`
-| malformed_request `false`
-| moved_permanently `false`
-| moved_temporarily `false`
-| multiple_choices `false`
-| options `ok`
-| previously_existed `false`
-| resource_exists `true`
-| service_available `true`
-| uri_too_long `false`
-| valid_content_headers `true`
-| valid_entity_length `true`
-| variances `[]`
+[cols="<,^",options="header"]
+|===
+| Callback name | Default value
+| allowed_methods | `[<<"GET">>, <<"HEAD">>, <<"OPTIONS">>]`
+| allow_missing_post | `true`
+| charsets_provided | skip
+| content_types_accepted | none
+| content_types_provided | `$$[{{<<"text">>, <<"html">>, '*'}, to_html}]$$`
+| delete_completed | `true`
+| delete_resource | `false`
+| expires | `undefined`
+| forbidden | `false`
+| generate_etag | `undefined`
+| is_authorized | `true`
+| is_conflict | `false`
+| known_methods | `[<<"GET">>, <<"HEAD">>, <<"POST">>, <<"PUT">>, <<"PATCH">>, <<"DELETE">>, <<"OPTIONS">>]`
+| languages_provided | skip
+| last_modified | `undefined`
+| malformed_request | `false`
+| moved_permanently | `false`
+| moved_temporarily | `false`
+| multiple_choices | `false`
+| options | `ok`
+| previously_existed | `false`
+| resource_exists | `true`
+| service_available | `true`
+| uri_too_long | `false`
+| valid_content_headers | `true`
+| valid_entity_length | `true`
+| variances | `[]`
+|===
As you can see, Cowboy tries to move on with the request whenever
possible by using well thought out default values.
@@ -94,32 +98,36 @@ each function. For example, `from_html` and `to_html` indicate
in the first case that we're accepting a resource given as HTML,
and in the second case that we send one as HTML.
-:: Meta data
+=== Meta data
Cowboy will set informative meta values at various points of the
execution. You can retrieve them using `cowboy_req:meta/{2,3}`.
The values are defined in the following table.
-|| Meta key Details
-|
-| media_type The content-type negotiated for the response entity.
-| language The language negotiated for the response entity.
-| charset The charset negotiated for the response entity.
+[cols="<,<",options="header"]
+|===
+| Meta key | Details
+| media_type | The content-type negotiated for the response entity.
+| language | The language negotiated for the response entity.
+| charset | The charset negotiated for the response entity.
+|===
They can be used to send a proper body with the response to a
request that used a method other than HEAD or GET.
-:: Response headers
+=== Response headers
Cowboy will set response headers automatically over the execution
of the REST code. They are listed in the following table.
-|| Header name Details
-|
-| content-language Language used in the response body
-| content-type Media type and charset of the response body
-| etag Etag of the resource
-| expires Expiration date of the resource
-| last-modified Last modification date for the resource
-| location Relative or absolute URI to the requested resource
-| vary List of headers that may change the representation of the resource
+[cols="<,<",options="header"]
+|===
+| Header name | Details
+| content-language | Language used in the response body
+| content-type | Media type and charset of the response body
+| etag | Etag of the resource
+| expires | Expiration date of the resource
+| last-modified | Last modification date for the resource
+| location | Relative or absolute URI to the requested resource
+| vary | List of headers that may change the representation of the resource
+|===
diff --git a/doc/src/guide/rest_principles.ezdoc b/doc/src/guide/rest_principles.asciidoc
index 1d54594..6ae2063 100644
--- a/doc/src/guide/rest_principles.ezdoc
+++ b/doc/src/guide/rest_principles.asciidoc
@@ -1,4 +1,5 @@
-::: REST principles
+[[rest_principles]]
+== REST principles
This chapter will attempt to define the concepts behind REST
and explain what makes a service RESTful.
@@ -10,11 +11,11 @@ and POST methods. That's highly misguided at best.
We will first attempt to define REST and will look at what
it means in the context of HTTP and the Web.
For a more in-depth explanation of REST, you can read
-^"Roy T. Fielding's dissertation^http://www.ics.uci.edu/~fielding/pubs/dissertation/top.htm
+http://www.ics.uci.edu/~fielding/pubs/dissertation/top.htm[Roy T. Fielding's dissertation]
as it does a great job explaining where it comes from and
what it achieves.
-:: REST architecture
+=== REST architecture
REST is a *client-server* architecture. The client and the server
both have a different set of concerns. The server stores and/or
@@ -54,7 +55,7 @@ to extend client functionality. This is optional however because
the client may not be able to download or run this code, and so
a REST component cannot rely on it being executed.
-:: Resources and resource identifiers
+=== Resources and resource identifiers
A resource is an abstract concept. In a REST system, any information
that can be named may be a resource. This includes documents, images,
@@ -79,7 +80,7 @@ resources map to a set of one element, for example "user Joe".
Collection of resources map to a set of 0 to N elements,
for example "all users".
-:: Resource representations
+=== Resource representations
The representation of a resource is a sequence of bytes associated
with metadata.
@@ -111,7 +112,7 @@ type. Some media types are intended for direct rendering to the
user, while others are intended for automated processing. The
media type is a key component of the REST architecture.
-:: Self-descriptive messages
+=== Self-descriptive messages
Messages must be self-descriptive. That means that the data
format of a representation must always come with its media
@@ -132,7 +133,7 @@ This means that you can create your own media types, like
specifications for it and that both endpoints agree about
it then the constraint is respected.
-:: Hypermedia as the engine of application state
+=== Hypermedia as the engine of application state
The last constraint is generally where services that claim
to be RESTful fail. Interactions with a server must be
diff --git a/doc/src/guide/routing.ezdoc b/doc/src/guide/routing.asciidoc
index 2482c12..6ac2ebd 100644
--- a/doc/src/guide/routing.ezdoc
+++ b/doc/src/guide/routing.asciidoc
@@ -1,4 +1,5 @@
-::: Routing
+[[routing]]
+== Routing
Cowboy does nothing by default.
@@ -14,42 +15,38 @@ and then try to find a matching path.
Routes need to be compiled before they can be used by Cowboy.
-:: Structure
+=== Structure
The general structure for the routes is defined as follow.
-``` erlang
+[source,erlang]
Routes = [Host1, Host2, ... HostN].
-```
Each host contains matching rules for the host along with optional
constraints, and a list of routes for the path component.
-``` erlang
+[source,erlang]
Host1 = {HostMatch, PathsList}.
Host2 = {HostMatch, Constraints, PathsList}.
-```
The list of routes for the path component is defined similar to the
list of hosts.
-``` erlang
+[source,erlang]
PathsList = [Path1, Path2, ... PathN].
-```
Finally, each path contains matching rules for the path along with
optional constraints, and gives us the handler module to be used
along with options that will be given to it on initialization.
-``` erlang
+[source,erlang]
Path1 = {PathMatch, Handler, Opts}.
Path2 = {PathMatch, Constraints, Handler, Opts}.
-```
Continue reading to learn more about the match syntax and the optional
constraints.
-:: Match syntax
+=== Match syntax
The match syntax is used to associate host names and paths with their
respective handlers.
@@ -64,30 +61,29 @@ Excluding special values that we will explain at the end of this section,
the simplest match value is a host or a path. It can be given as either
a `string()` or a `binary()`.
-``` erlang
+[source,erlang]
+----
PathMatch1 = "/".
PathMatch2 = "/path/to/resource".
HostMatch1 = "cowboy.example.org".
-```
+----
As you can see, all paths defined this way must start with a slash
character. Note that these two paths are identical as far as routing
is concerned.
-``` erlang
+[source,erlang]
PathMatch2 = "/path/to/resource".
PathMatch3 = "/path/to/resource/".
-```
Hosts with and without a trailing dot are equivalent for routing.
Similarly, hosts with and without a leading dot are also equivalent.
-``` erlang
+[source,erlang]
HostMatch1 = "cowboy.example.org".
HostMatch2 = "cowboy.example.org.".
HostMatch3 = ".cowboy.example.org".
-```
It is possible to extract segments of the host and path and to store
the values in the `Req` object for later use. We call these kind of
@@ -97,10 +93,9 @@ The syntax for bindings is very simple. A segment that begins with
the `:` character means that what follows until the end of the segment
is the name of the binding in which the segment value will be stored.
-``` erlang
+[source,erlang]
PathMatch = "/hats/:name/prices".
HostMatch = ":subdomain.example.org".
-```
If these two end up matching when routing, you will end up with two
bindings defined, `subdomain` and `name`, each containing the
@@ -116,23 +111,20 @@ variable in Erlang. Any match against the `_` binding will succeed
but the data will be discarded. This is especially useful for
matching against many domain names in one go.
-``` erlang
+[source,erlang]
HostMatch = "ninenines.:_".
-```
Similarly, it is possible to have optional segments. Anything
between brackets is optional.
-``` erlang
+[source,erlang]
PathMatch = "/hats/[page/:number]".
HostMatch = "[www.]ninenines.eu".
-```
You can also have imbricated optional segments.
-``` erlang
+[source,erlang]
PathMatch = "/hats/[page/[:number]]".
-```
You can retrieve the rest of the host or path using `[...]`.
In the case of hosts it will match anything before, in the case
@@ -142,51 +134,45 @@ zero, one or many segments. You can then find the segments using
`cowboy_req:host_info/1` and `cowboy_req:path_info/1` respectively.
They will be represented as a list of segments.
-``` erlang
+[source,erlang]
PathMatch = "/hats/[...]".
HostMatch = "[...]ninenines.eu".
-```
If a binding appears twice in the routing rules, then the match
will succeed only if they share the same value. This copies the
Erlang pattern matching behavior.
-``` erlang
+[source,erlang]
PathMatch = "/hats/:name/:name".
-```
This is also true when an optional segment is present. In this
case the two values must be identical only if the segment is
available.
-``` erlang
+[source,erlang]
PathMatch = "/hats/:name/[:name]".
-```
If a binding is defined in both the host and path, then they must
also share the same value.
-``` erlang
+[source,erlang]
PathMatch = "/:user/[...]".
HostMatch = ":user.github.com".
-```
Finally, there are two special match values that can be used. The
first is the atom `'_'` which will match any host or path.
-``` erlang
+[source,erlang]
PathMatch = '_'.
HostMatch = '_'.
-```
The second is the special host match `"*"` which will match the
wildcard path, generally used alongside the `OPTIONS` method.
-``` erlang
+[source,erlang]
HostMatch = "*".
-```
-:: Constraints
+=== Constraints
After the matching has completed, the resulting bindings can be tested
against a set of constraints. Constraints are only tested when the
@@ -200,9 +186,9 @@ one or more constraints. While the router accepts the same format,
it will skip fields with no constraints and will also ignore default
values, if any.
-Read more about ^constraints^.
+Read more about xref:constraints[constraints].
-:: Compilation
+=== Compilation
The structure defined in this chapter needs to be compiled before it is
passed to Cowboy. This allows Cowboy to efficiently lookup the correct
@@ -210,7 +196,8 @@ handler to run instead of having to parse the routes repeatedly.
This can be done with a simple call to `cowboy_router:compile/1`.
-``` erlang
+[source,erlang]
+----
Dispatch = cowboy_router:compile([
%% {HostMatch, list({PathMatch, Handler, Opts})}
{'_', [{'_', my_handler, []}]}
@@ -220,20 +207,18 @@ cowboy:start_http(my_http_listener, 100,
[{port, 8080}],
[{env, [{dispatch, Dispatch}]}]
).
-```
+----
Note that this function will return `{error, badarg}` if the structure
given is incorrect.
-:: Live update
+=== Live update
You can use the `cowboy:set_env/3` function for updating the dispatch
list used by routing. This will apply to all new connections accepted
by the listener.
-``` erlang
-cowboy:set_env(my_http_listener, dispatch,
- cowboy_router:compile(Dispatch)).
-```
+[source,erlang]
+cowboy:set_env(my_http_listener, dispatch, cowboy_router:compile(Dispatch)).
Note that you need to compile the routes before updating.
diff --git a/doc/src/guide/static_files.ezdoc b/doc/src/guide/static_files.asciidoc
index 5a289d0..39197a8 100644
--- a/doc/src/guide/static_files.ezdoc
+++ b/doc/src/guide/static_files.asciidoc
@@ -1,4 +1,5 @@
-::: Static files
+[[static_files]]
+== Static files
Cowboy comes with a special handler built as a REST handler
and designed specifically for serving static files. It is
@@ -20,30 +21,28 @@ client-side caching.
To use the static file handler, simply add routes for it
with the appropriate options.
-:: Serve one file
+=== Serve one file
You can use the static handler to serve one specific file
from an application's private directory. This is particularly
-useful to serve an `index.html` file when the client requests
+useful to serve an 'index.html' file when the client requests
the `/` path, for example. The path configured is relative
to the given application's private directory.
-The following rule will serve the file `static/index.html`
+The following rule will serve the file 'static/index.html'
from the application `my_app`'s priv directory whenever the
path `/` is accessed.
-``` erlang
+[source,erlang]
{"/", cowboy_static, {priv_file, my_app, "static/index.html"}}
-```
You can also specify the absolute path to a file, or the
path to the file relative to the current directory.
-``` erlang
+[source,erlang]
{"/", cowboy_static, {file, "/var/www/index.html"}}
-```
-:: Serve all files from a directory
+=== Serve all files from a directory
You can also use the static handler to serve all files that
can be found in the configured directory. The handler will
@@ -59,18 +58,16 @@ The following rule will serve any file found in the application
`my_app`'s priv directory inside the `static/assets` folder
whenever the requested path begins with `/assets/`.
-``` erlang
+[source,erlang]
{"/assets/[...]", cowboy_static, {priv_dir, my_app, "static/assets"}}
-```
You can also specify the absolute path to the directory or
set it relative to the current directory.
-``` erlang
+[source,erlang]
{"/assets/[...]", cowboy_static, {dir, "/var/www/assets"}}
-```
-:: Customize the mimetype detection
+=== Customize the mimetype detection
By default, Cowboy will attempt to recognize the mimetype
of your static files by looking at the extension.
@@ -91,10 +88,11 @@ To use the default function, you should not have to configure
anything, as it is the default. If you insist, though, the
following will do the job.
-``` erlang
+[source,erlang]
+----
{"/assets/[...]", cowboy_static, {priv_dir, my_app, "static/assets",
[{mimetypes, cow_mimetypes, web}]}}
-```
+----
As you can see, there is an optional field that may contain
a list of less used options, like mimetypes or etag. All option
@@ -103,19 +101,21 @@ types have this optional field.
To use the function that will detect almost any mimetype,
the following configuration will do.
-``` erlang
+[source,erlang]
+----
{"/assets/[...]", cowboy_static, {priv_dir, my_app, "static/assets",
[{mimetypes, cow_mimetypes, all}]}}
-```
+----
You probably noticed the pattern by now. The configuration
expects a module and a function name, so you can use any
of your own functions instead.
-``` erlang
+[source,erlang]
+----
{"/assets/[...]", cowboy_static, {priv_dir, my_app, "static/assets",
[{mimetypes, Module, Function}]}}
-```
+----
The function that performs the mimetype detection receives
a single argument that is the path to the file on disk. It
@@ -133,12 +133,13 @@ Finally, the mimetype can be hard-coded for all files.
This is especially useful in combination with the `file`
and `priv_file` options as it avoids needless computation.
-``` erlang
+[source,erlang]
+----
{"/", cowboy_static, {priv_file, my_app, "static/index.html",
[{mimetypes, {<<"text">>, <<"html">>, []}}]}}
-```
+----
-:: Generate an etag
+=== Generate an etag
By default, the static handler will generate an etag header
value based on the size and modified time. This solution
@@ -149,10 +150,11 @@ different etag on each server.
You can however change the way the etag is calculated.
-``` erlang
+[source,erlang]
+----
{"/assets/[...]", cowboy_static, {priv_dir, my_app, "static/assets",
[{etag, Module, Function}]}}
-```
+----
This function will receive three arguments: the path to the
file on disk, the size of the file and the last modification
@@ -162,7 +164,8 @@ all your servers.
You can also completely disable etag handling.
-``` erlang
+[source,erlang]
+----
{"/assets/[...]", cowboy_static, {priv_dir, my_app, "static/assets",
[{etag, false}]}}
-```
+----
diff --git a/doc/src/guide/sub_protocols.ezdoc b/doc/src/guide/sub_protocols.asciidoc
index 54e57aa..63fd52b 100644
--- a/doc/src/guide/sub_protocols.ezdoc
+++ b/doc/src/guide/sub_protocols.asciidoc
@@ -1,4 +1,5 @@
-::: Sub protocols
+[[sub_protocols]]
+== Sub protocols
Sub protocols are used for creating new types of handlers that
provide extra functionality in a reusable way. Cowboy uses this
@@ -7,16 +8,17 @@ mechanism to provide its loop, REST and Websocket handlers.
This chapter will explain how to create your own sub protocols
and handler types.
-:: Usage
+=== Usage
To switch to a sub protocol, the `init/2` callback must return
the name of the sub protocol module. Everything past this point
is handled by the sub protocol.
-``` erlang
+[source,erlang]
+----
init(Req, _Opts) ->
{cowboy_websocket, Req, #state{}}.
-```
+----
The return value may also have a `Timeout` value and/or the
atom `hibernate`. These options are useful for long living
@@ -27,15 +29,16 @@ The following snippet switches to the `my_protocol` sub
protocol, sets the timeout value to 5 seconds and enables
hibernation:
-``` erlang
+[source,erlang]
+----
init(Req, _Opts) ->
{my_protocol, Req, #state{}, 5000, hibernate}.
-```
+----
If a sub protocol does not make use of these options, it should
crash if it receives anything other than the default values.
-:: Upgrade
+=== Upgrade
After the `init/2` function returns, Cowboy will then call the
`upgrade/6` function. This is the only callback defined by the
@@ -51,10 +54,11 @@ The upgrade callback receives the Req object, the middleware
environment, the handler and its options, and the aforementioned
timeout and hibernate values.
-``` erlang
+[source,erlang]
+----
upgrade(Req, Env, Handler, HandlerOpts, Timeout, Hibernate) ->
%% Sub protocol code here.
-```
+----
This callback is expected to behave like a middleware and to
return an updated environment and Req object.
diff --git a/doc/src/guide/ws_handlers.ezdoc b/doc/src/guide/ws_handlers.asciidoc
index a0cfc29..9ddddf4 100644
--- a/doc/src/guide/ws_handlers.ezdoc
+++ b/doc/src/guide/ws_handlers.asciidoc
@@ -1,4 +1,5 @@
-::: Handling Websocket connections
+[[ws_handlers]]
+== Handling Websocket connections
A special handler is required for handling Websocket connections.
Websocket handlers allow you to initialize the connection,
@@ -9,16 +10,17 @@ Websocket handlers essentially act as a bridge between the client
and the Erlang system. They will typically do little more than
socket communication and decoding/encoding of frames.
-:: Initialization
+=== Initialization
First, the `init/2` callback is called. This callback is common
to all handlers. To establish a Websocket connection, this function
must return a `ws` tuple.
-``` erlang
+[source,erlang]
+----
init(Req, _Opts) ->
{cowboy_websocket, Req, #state{}}.
-```
+----
Upon receiving this tuple, Cowboy will switch to the code
that handles Websocket connections and perform the handshake
@@ -30,7 +32,8 @@ handler *must* select one of these subprotocol and send it
back to the client, otherwise the client might decide to close
the connection, assuming no correct subprotocol was found.
-``` erlang
+[source,erlang]
+----
init(Req, _Opts) ->
case cowboy_req:parse_header(<<"sec-websocket-protocol">>, Req) of
undefined ->
@@ -45,7 +48,7 @@ init(Req, _Opts) ->
{stop, Req, undefined}
end
end.
-```
+----
It is not recommended to wait too long inside the `init/2`
function. Any extra initialization may be done after returning by
@@ -57,7 +60,8 @@ It is also very easy to ensure that this message arrives before
any message from other processes by sending it before registering
or enabling timers.
-``` erlang
+[source,erlang]
+----
init(Req, _Opts) ->
self() ! post_init,
%% Register process here...
@@ -66,9 +70,9 @@ init(Req, _Opts) ->
websocket_info(post_init, Req, State) ->
%% Perform post_init initialization here...
{ok, Req, State}.
-```
+----
-:: Handling frames from the client
+=== Handling frames from the client
Cowboy will call `websocket_handle/3` whenever a text, binary,
ping or pong frame arrives from the client. Note that in the
@@ -81,14 +85,15 @@ or just continue without sending anything.
The following snippet echoes back any text frame received and
ignores all others.
-``` erlang
+[source,erlang]
+----
websocket_handle(Frame = {text, _}, Req, State) ->
{reply, Frame, Req, State};
websocket_handle(_Frame, Req, State) ->
{ok, Req, State}.
-```
+----
-:: Handling Erlang messages
+=== Handling Erlang messages
Cowboy will call `websocket_info/3` whenever an Erlang message
arrives.
@@ -99,14 +104,15 @@ or just continue without sending anything.
The following snippet forwards any `log` message to the socket
and ignores all others.
-``` erlang
+[source,erlang]
+----
websocket_info({log, Text}, Req, State) ->
{reply, {text, Text}, Req, State};
websocket_info(_Info, Req, State) ->
{ok, Req, State}.
-```
+----
-:: Sending frames to the socket
+=== Sending frames to the socket
Cowboy allows sending either a single frame or a list of
frames to the socket, in which case the frames are sent
@@ -116,7 +122,8 @@ pong or close frames.
The following example sends three frames using a single `reply`
tuple.
-``` erlang
+[source,erlang]
+----
websocket_info(hello_world, Req, State) ->
{reply, [
{text, "Hello"},
@@ -124,7 +131,7 @@ websocket_info(hello_world, Req, State) ->
{binary, <<0:8000>>}
], Req, State};
%% More websocket_info/3 clauses here...
-```
+----
Note that the payload for text and binary frames is of type
`iodata()`, meaning it can be either a `binary()` or an
@@ -137,7 +144,7 @@ be received will not be processed. Also note that when replying
a list of frames that includes close, any frame found after the
close frame will not be sent.
-:: Ping and timeout
+=== Ping and timeout
The biggest performance improvement you can do when dealing
with a huge number of Websocket connections is to reduce the
@@ -160,15 +167,16 @@ leave the process alive forever.
A good timeout value is 60 seconds.
-``` erlang
+[source,erlang]
+----
init(Req, _Opts) ->
{cowboy_websocket, Req, #state{}, 60000}.
-```
+----
This value cannot be changed once it is set. It defaults to
`infinity`.
-:: Hibernate
+=== Hibernate
Most tuples returned from handler callbacks can include an
extra value `hibernate`. After doing any necessary operations
@@ -180,9 +188,9 @@ handle much traffic. It is a good idea to hibernate all
connections by default and investigate only when you start
noticing increased CPU usage.
-:: Supporting older browsers
+=== Supporting older browsers
Unfortunately Websocket is a relatively recent technology,
which means that not all browsers support it. A library like
-^"Bullet^https://github.com/extend/bullet^ can be used to
+https://github.com/ninenines/bullet[Bullet] can be used to
emulate Websocket connections on older browsers.
diff --git a/doc/src/guide/ws_protocol.ezdoc b/doc/src/guide/ws_protocol.asciidoc
index d283ae3..67b2cdf 100644
--- a/doc/src/guide/ws_protocol.ezdoc
+++ b/doc/src/guide/ws_protocol.asciidoc
@@ -1,9 +1,10 @@
-::: The Websocket protocol
+[[ws_protocol]]
+== The Websocket protocol
This chapter explains what Websocket is and why it is
a vital component of soft realtime Web applications.
-:: Description
+=== Description
Websocket is an extension to HTTP that emulates plain TCP
connections between the client, typically a Web browser,
@@ -22,7 +23,7 @@ and all drafts that were previously implemented by browsers,
excluding the initial flawed draft sometimes known as
"version 0".
-:: Implementation
+=== Implementation
Cowboy implements Websocket as a protocol upgrade. Once the
upgrade is performed from the `init/2` callback, Cowboy