<?xml version="1.0" encoding="latin1" ?>
<!DOCTYPE erlref SYSTEM "erlref.dtd">
<erlref>
<header>
<copyright>
<year>1997</year><year>2009</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
The contents of this file are subject to the Erlang Public License,
Version 1.1, (the "License"); you may not use this file except in
compliance with the License. You should have received a copy of the
Erlang Public License along with this software. If not, it can be
retrieved online at http://www.erlang.org/.
Software distributed under the License is distributed on an "AS IS"
basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
the License for the specific language governing rights and limitations
under the License.
</legalnotice>
<title>httpd</title>
<prepared>Ingela Anderton Andin</prepared>
<docno></docno>
<date>1997-10-14</date>
<rev>2.2</rev>
<file>httpd.sgml</file>
</header>
<module>httpd</module>
<modulesummary>An implementation of an HTTP
1.1 compliant Web server, as defined in RFC 2616.
</modulesummary>
<description>
<p>Documents the HTTP server start options, some administrative
functions and also specifies the Erlang Web server callback
API</p>
</description>
<section>
<title>COMMON DATA TYPES </title>
<p>Type definitions that are used more than once in
this module:</p>
<p><c>boolean() = true | false </c></p>
<p><c>string() = list of ASCII characters</c></p>
<p><c>path() = string() - representing a file or directory path.</c></p>
<p><c> ip_address() = {N1,N2,N3,N4} % IPv4
| {K1,K2,K3,K4,K5,K6,K7,K8} % IPv6</c></p>
<p><c>hostname() = string() - representing a host ex "foo.bar.com"</c></p>
<p><c>property() = atom()</c></p>
</section>
<section>
<title>ERLANG HTTP SERVER SERVICE START/STOP </title>
<p>A web server can be configured to start when starting the inets
application or started dynamically in runtime by calling the
Inets application API <c>inets:start(httpd, ServiceConfig)</c>, or
<c>inets:start(httpd, ServiceConfig, How)</c>,
see <seealso marker="inets">inets(3)</seealso> Below follows a
description of the available configuration options, also called
properties.</p>
<marker id="file_prop"></marker>
<p><em>File properties</em></p>
<p>When the web server is started
at application start time the properties should be fetched from a
configuration file that could consist of a regular erlang property
list, e.i. <c>[{Option, Value}] </c> where <c> Option = property()
</c> and <c>Value = term()</c>, followed by a full stop, or for
backwards compatibility an Apache like configuration file. If the
web server is started dynamically at runtime you may still specify
a file but you could also just specify the complete property
list.</p>
<taglist>
<tag>{proplist_file, path()}</tag>
<item>
If this property is defined inets will expect to find
all other properties defined in this file. Note that the
file must include all properties listed under mandatory
properties. </item>
<tag>{file, path()}</tag>
<item> If this property is defined
inets will expect to find all other properties defined in this
file, that uses Apache like syntax. Note that the file must
include all properties listed under mandatory properties. The
Apache like syntax is the property, written as one word where
each new word begins with a capital, followed by a white-space
followed by the value followed by a new line. Ex:
<code>
{server_root, "/urs/local/www"} -> ServerRoot /usr/local/www
</code>
<p>With a few exceptions, that are documented
for each property that behaves differently,
and the special case {directory, {path(), PropertyList}} and
{security_directory, {Dir, PropertyList}} that are represented
as:</p>
<pre>
<![CDATA[
<Directory Dir>
<Properties handled as described above>
</Directory>
]]>
</pre>
</item>
</taglist>
<note>
<p>The properties proplist_file and file are mutually exclusive.</p>
</note>
<marker id="mand_prop"></marker>
<p><em>Mandatory properties</em></p>
<taglist>
<tag>{port, integer()} </tag>
<item>
The port that the HTTP server shall listen on.
If zero is specified as port, an arbitrary available port
will be picked and you can use the httpd:info/2 function to find
out which port was picked. </item>
<tag>{server_name, string()} </tag>
<item>
The name of your server, normally a fully qualified domain
name.
</item>
<tag>{server_root, path()} </tag>
<item>
Defines the servers home directory where log files etc can
be stored. Relative paths specified in other properties refer
to this directory.</item>
<tag>{document_root, path()}</tag>
<item>
Defines the top directory for the documents that
are available on the HTTP server.</item>
</taglist>
<marker id="comm_prop"></marker>
<p><em>Communication properties</em> </p>
<taglist>
<tag>{bind_address, ip_address() | hostname() | any} </tag>
<item>
Defaults to <c>any</c>. Note that <c>any</c> is denoted <em>*</em>
in the apache like configuration file.
</item>
<tag>{socket_type, ip_comm | ssl}</tag>
<item>
<p>Defaults to <c>ip_comm</c>. </p>
</item>
<tag>{ipfamily, inet | inet6 | inet6fb4}</tag>
<item>
<p>Defaults to <c>inet6fb4. </c> </p>
<p>Note that this option is only used when the option
<c>socket_type</c> has the value <c>ip_comm</c>. </p>
</item>
</taglist>
<p><em>Erlang Web server API modules</em> </p>
<taglist>
<tag>{modules, [atom()]} </tag>
<item>
Defines which modules the HTTP server will use to handle
requests. Defaults to: <c>[mod_alias, mod_auth, mod_esi,
mod_actions, mod_cgi, mod_dir, mod_get, mod_head, mod_log,
mod_disk_log] </c>
Note that some mod-modules are dependent on
others, so the order can not be entirely arbitrary. See the
<seealso marker="http_server"> Inets Web server Modules in the
Users guide</seealso> for more information.
</item>
</taglist>
<marker id="limit_prop"></marker>
<p><em>Limit properties</em> </p>
<taglist>
<tag>{disable_chunked_transfer_encoding_send, boolean()}</tag>
<item>
This property allows you to disable chunked
transfer-encoding when sending a response to a HTTP/1.1
client, by default this is false.</item>
<tag>{keep_alive, boolean()}</tag>
<item>
Instructs the server whether or not to use persistent
connections when the client claims to be HTTP/1.1
compliant, default is true.</item>
<tag>{keep_alive_timeout, integer()}</tag>
<item>
The number of seconds the server will wait for a
subsequent request from the client before closing the
connection. Default is 150.</item>
<tag>{max_body_size, integer()}</tag>
<item>
Limits the size of the message body of HTTP request.
By the default there is no limit.</item>
<tag>{max_clients, integer()}</tag>
<item>
Limits the number of simultaneous requests that can be
supported. Defaults to 150. </item>
<tag>{max_header_size, integer()}</tag>
<item>
Limits the size of the message header of HTTP request.
Defaults to 10240.
</item>
<tag>{max_uri, integer()}</tag>
<item>
Limits the size of the HTTP request URI. By
default there is no limit.</item>
<tag>{max_keep_alive_requests, integer()}</tag>
<item> The number of request that a client can do on one
connection. When the server has responded to the number of
requests defined by max_keep_alive_requests the server close the
connection. The server will close it even if there are queued
request. Defaults to no limit.</item>
</taglist>
<marker id="admin_prop"></marker>
<p><em>Administrative properties</em></p>
<taglist>
<tag>{mime_types, [{MimeType, Extension}] | path()}</tag>
<item>
<p>Where MimeType = string() and Extension = string().
Files delivered to the client are MIME typed according to RFC
1590. File suffixes are mapped to MIME types before file delivery.
The mapping between file suffixes and MIME types can be specified
as an Apache like file as well as directly in the property list. Such
a file may look like:</p>
<pre>
\011 # MIME type\011\011\011Extension
\011 text/html\011\011\011html htm
\011 text/plain\011\011\011asc txt
</pre>
<p>Defaults to [{"html","text/html"},{"htm","text/html"}]</p>
</item>
<tag>{mime_type, string()}</tag>
<item>
When the server is asked to provide a document type which
cannot be determined by the MIME Type Settings, the server will
use this default type. </item>
<tag>{server_admin, string()}</tag>
<item>
ServerAdmin defines the email-address of the server
administrator, to be included in any error messages returned by
the server.</item>
<tag>{log_format, common | combined}</tag>
<item>
<p>Defines if access logs should be written according to the common
log format or to the extended common log format.
The <c>common</c> format is one line that looks like this:
<c>remotehost rfc931 authuser [date] "request" status bytes</c></p>
<pre>remotehost
Remote
rfc931
The client's remote username (RFC 931).
authuser
The username with which the user authenticated himself.
[date]
Date and time of the request (RFC 1123).
"request"
The request line exactly as it came from the client(RFC 1945).
status
The HTTP status code returned to the client (RFC 1945).
bytes
The content-length of the document transferred.
</pre>
<p>The <c>combined</c> format is on line that look like this:
<c>remotehost rfc931 authuser [date] "request" status bytes "referer" "user_agent" </c></p>
<pre>"referer"
The url the client was on before
requesting your url. (If it could not be determined a minus
sign will be placed in this field)
"user_agent"
The software the client claims to be using. (If it
could not be determined a minus sign will be placed in
this field)
</pre>
<p>This affects the access logs written by mod_log and mod_disk_log.
</p>
</item>
<tag>{error_log_format, pretty | compact}</tag>
<item>
<p>Defaults to pretty. If the error log is meant to be read
directly by a human <c>pretty</c> will be the best
option. <c>pretty</c> has the format corresponding to:
</p>
<code>io:format("[~s] ~s, reason: ~n ~p ~n~n", [Date, Msg, Reason]).
</code>
<p><c>compact</c> has the format corresponding to:</p>
<code>io:format("[~s] ~s, reason: ~w ~n", [Date, Msg, Reason]).
</code>
<p>This affects the error logs written by mod_log and mod_disk_log.
</p>
</item>
</taglist>
<marker id="ssl_prop"></marker>
<p><em>ssl properties</em></p>
<taglist>
<tag>{ssl_ca_certificate_file, path()}</tag>
<item>
Used as cacertfile option in ssl:listen/2 see
<seealso marker="ssl:ssl">ssl(3)</seealso> </item>
<tag>{ssl_certificate_file, path()}</tag>
<item>
Used as certfile option in ssl:listen/2 see
<seealso marker="ssl:ssl">ssl(3)</seealso>
</item>
<tag>{ssl_ciphers, list()}</tag>
<item>
Used as ciphers option in ssl:listen/2 see
<seealso marker="ssl:ssl">ssl(3)</seealso>
</item>
<tag>{ssl_verify_client, integer()}</tag>
<item>
Used as verify option in ssl:listen/2 see
<seealso marker="ssl:ssl">ssl(3)</seealso> </item>
<tag>{ssl_verify_depth, integer()}</tag>
<item>
Used as depth option in ssl:listen/2 see
<seealso marker="ssl:ssl">ssl(3)</seealso> </item>
<tag>{ssl_password_callback_function, atom()}</tag>
<item>
Used together with ssl_password_callback_module
to retrieve a value to use as password option to ssl:listen/2
see <seealso marker="ssl:ssl">ssl(3)</seealso>
</item>
<tag>{ssl_password_callback_arguments, list()}</tag>
<item>
Used together with ssl_password_callback_function to supply a
list of arguments to the callback function. If not specified
the callback function will be assumed to have arity 0. </item>
<tag>{ssl_password_callback_module, atom()}</tag>
<item>
Used together with ssl_password_callback_function
to retrieve a value to use as password option to ssl:listen/2
see <seealso marker="ssl:ssl">ssl(3)</seealso></item>
</taglist>
<marker id="alias_prop"></marker>
<p><em>URL aliasing properties - requires mod_alias</em></p>
<taglist>
<tag>{alias, {Alias, RealName}}</tag>
<item> Where Alias = string() and RealName = string().
The Alias property allows documents to be stored in the local file
system instead of the document_root location. URLs with a path that
begins with url-path is mapped to local files that begins with
directory-filename, for example:
<code>{alias, {"/image", "/ftp/pub/image"}</code>
and an access to http://your.server.org/image/foo.gif would refer to
the file /ftp/pub/image/foo.gif.</item>
<tag>{directory_index, [string()]}</tag>
<item>
DirectoryIndex specifies a list of resources to look for
if a client requests a directory using a / at the end of the
directory name. file depicts the name of a file in the
directory. Several files may be given, in which case the server
will return the first it finds, for example:
<code>{directory_index, ["index.hml", "welcome.html"]}</code>
and access to http://your.server.org/docs/ would return
http://your.server.org/docs/index.html or
http://your.server.org/docs/welcome.html if index.html do not
exist.
</item>
</taglist>
<marker id="cgi_prop"></marker>
<p><em>CGI properties - requires mod_cgi</em></p>
<taglist>
<tag>{script_alias, {Alias, RealName}}</tag>
<item> Where Alias = string() and RealName = string().
Has the same behavior as the Alias property, except that
it also marks the target directory as containing CGI
scripts. URLs with a path beginning with url-path are mapped to
scripts beginning with directory-filename, for example:
<code> {script_alias, {"/cgi-bin/", "/web/cgi-bin/"}</code>
and an access to http://your.server.org/cgi-bin/foo would cause
the server to run the script /web/cgi-bin/foo.
</item>
<tag>{script_nocache, boolean()}</tag>
<item>
If ScriptNoCache is set to true the HTTP server will by
default add the header fields necessary to prevent proxies from
caching the page. Generally this is something you want. Defaults
to false.</item>
<tag>{script_timeout, integer()}</tag>
<item>
The time in seconds the web server will wait between each
chunk of data from the script. If the CGI-script not delivers
any data before the timeout the connection to the client will be
closed. Defaults to 15. </item>
<tag>{action, {MimeType, CgiScript}} - requires mod_action</tag>
<item>Where MimeType = string() and CgiScript = string().
Action adds an action, which will activate a cgi-script
whenever a file of a certain mime-type is requested. It
propagates the URL and file path of the requested document using
the standard CGI PATH_INFO and PATH_TRANSLATED environment
variables.
<code> {action, {"text/plain", "/cgi-bin/log_and_deliver_text"}
</code>
</item>
<tag>{script, {Method, CgiScript}} - requires mod_action</tag>
<item>Where Method = string() and CgiScript = string().
Script adds an action, which will activate a cgi-script
whenever a file is requested using a certain HTTP method. The
method is either GET or POST as defined in RFC 1945. It
propagates the URL and file path of the requested document using
the standard CGI PATH_INFO and PATH_TRANSLATED environment
variables.
<code> {script, {"PUT", "/cgi-bin/put"}
</code>
</item>
</taglist>
<marker id="esi_prop"></marker>
<p><em>ESI properties - requires mod_esi</em></p>
<taglist>
<tag>{erl_script_alias, {URLPath, [AllowedModule]}}</tag>
<item>Where URLPath = string() and AllowedModule = atom().
erl_script_alias marks all URLs matching url-path as erl
scheme scripts. A matching URL is mapped into a specific module
and function. For example:
<code>{erl_script_alias, {"/cgi-bin/example" [httpd_example]}
</code>
and a request to
http://your.server.org/cgi-bin/example/httpd_example:yahoo
would refer to httpd_example:yahoo/2 and
http://your.server.org/cgi-bin/example/other:yahoo would
not be allowed to execute.
</item>
<tag>{erl_script_nocache, boolean()}</tag>
<item>
If erl_script_nocache is set to true the server will add
http header fields that prevents proxies from caching the
page. This is generally a good idea for dynamic content, since
the content often vary between each request. Defaults to false.
</item>
<tag>{erl_script_timeout, integer()}</tag>
<item>
If erl_script_timeout sets the time in seconds the server will
wait between each chunk of data to be delivered through
mod_esi:deliver/2. Defaults to 15. This is only relevant
for scripts that uses the erl scheme.
</item>
<tag>{eval_script_alias, {URLPath, [AllowedModule]}}</tag>
<item>Where URLPath = string() and AllowedModule = atom().
Same as erl_script_alias but for scripts
using the eval scheme. Note that this is only supported
for backwards compatibility. The eval scheme is deprecated.</item>
</taglist>
<marker id="log_prop"></marker>
<p><em>Log properties - requires mod_log</em></p>
<taglist>
<tag>{error_log, path()}</tag>
<item>
Defines the filename of the error log file to be used to log
server errors. If the filename does not begin with a slash (/)
it is assumed to be relative to the server_root</item>
<tag>{security_log, path()}</tag>
<item>
Defines the filename of the access log file to be used to
log security events. If the filename does not begin with a slash
(/) it is assumed to be relative to the server_root.
</item>
<tag>{transfer_log, path()}</tag>
<item>
Defines the filename of the access log file to be used to
log incoming requests. If the filename does not begin with a
slash (/) it is assumed to be relative to the server_root.
</item>
</taglist>
<marker id="dlog_prop"></marker>
<p><em>Disk Log properties - requires mod_disk_log</em></p>
<taglist>
<tag>{disk_log_format, internal | external}</tag>
<item>
Defines the file-format of the log files see disk_log for
more information. If the internal file-format is used, the
logfile will be repaired after a crash. When a log file is
repaired data might get lost. When the external file-format is
used httpd will not start if the log file is broken. Defaults to
external.
</item>
<tag>{error_disk_log, internal | external}</tag>
<item>
Defines the filename of the (disk_log(3)) error log file
to be used to log server errors. If the filename does not begin
with a slash (/) it is assumed to be relative to the server_root.
</item>
<tag>{error_disk_log_size, {MaxBytes, MaxFiles}}</tag>
<item>Where MaxBytes = integer() and MaxFiles = integer().
Defines the properties of the (disk_log(3)) error log
file. The disk_log(3) error log file is of type wrap log and
max-bytes will be written to each file and max-files will be
used before the first file is truncated and reused. </item>
<tag>{security_disk_log, path()}</tag>
<item>
Defines the filename of the (disk_log(3)) access log file
which logs incoming security events i.e authenticated
requests. If the filename does not begin with a slash (/) it
is assumed to be relative to the server_root.
</item>
<tag>{security_disk_log_size, {MaxBytes, MaxFiles}}</tag>
<item>Where MaxBytes = integer() and MaxFiles = integer().
Defines the properties of the disk_log(3) access log
file. The disk_log(3) access log file is of type wrap log and
max-bytes will be written to each file and max-files will be
used before the first file is truncated and reused.</item>
<tag>{transfer_disk_log, path()}</tag>
<item>
Defines the filename of the (disk_log(3)) access log file
which logs incoming requests. If the filename does not begin
with a slash (/) it is assumed to be relative to the
server_root.
</item>
<tag>{transfer_disk_log_size, {MaxBytes, MaxFiles}}</tag>
<item>Where MaxBytes = integer() and MaxFiles = integer().
Defines the properties of the disk_log(3) access log
file. The disk_log(3) access log file is of type wrap log and
max-bytes will be written to each file and max-files will be
used before the first file is truncated and reused.</item>
</taglist>
<marker id="auth_prop"></marker>
<p><em>Authentication properties - requires mod_auth</em></p>
<p><em>{directory, {path(), [{property(), term()}]}}</em></p>
<marker id="dir_prop"></marker>
<p>Here follows the valid properties for directories </p>
<taglist>
<tag>{allow_from, all | [RegxpHostString]}</tag>
<item>
Defines a set of hosts which should be granted access to a
given directory.
For example:
<code>{allow_from, ["123.34.56.11", "150.100.23"] </code>
The host 123.34.56.11 and all machines on the 150.100.23
subnet are allowed access.</item>
<tag>{deny_from, all | [RegxpHostString]}</tag>
<item>
Defines a set of hosts
which should be denied access to a given directory.
For example:
<code>{deny_from, ["123.34.56.11", "150.100.23"] </code>
The host 123.34.56.11 and all machines on the 150.100.23
subnet are not allowed access.</item>
<tag>{auth_type, plain | dets | mnesia}</tag>
<item>
Sets the type of authentication database that is used for the
directory.The key difference between the different methods is
that dynamic data can be saved when Mnesia and Dets is used.
This property is called AuthDbType in the Apache like
configuration files.
</item>
<tag>{auth_user_file, path()}</tag>
<item>
Sets the name of a file which contains the list of users and
passwords for user authentication. filename can be either
absolute or relative to the <c>server_root</c>. If using the
plain storage method, this file is a plain text file, where
each line contains a user name followed by a colon, followed
by the non-encrypted password. If user names are duplicated,
the behavior is undefined. For example:
<code> ragnar:s7Xxv7
edward:wwjau8 </code>
If using the dets storage method, the user database is
maintained by dets and should not be edited by hand. Use the
API functions in mod_auth module to create / edit the user
database. This directive is ignored if using the mnesia
storage method. For security reasons, make sure that the
<c>auth_user_file</c> is stored outside the document tree of the Web
server. If it is placed in the directory which it protects,
clients will be able to download it.
</item>
<tag>{auth_group_file, path()}</tag>
<item> Sets the name of a file which contains the list of user
groups for user authentication. Filename can be either
absolute or relative to the <c>server_root</c>. If you use the plain
storage method, the group file is a plain text file, where
each line contains a group name followed by a colon, followed
by the member user names separated by spaces. For example:
<code>group1: bob joe ante</code>
If using the dets storage method, the group database is
maintained by dets and should not be edited by hand. Use the
API for mod_auth module to create / edit the group database.
This directive is ignored if using the mnesia storage method.
For security reasons, make sure that the <c>auth_group_file</c> is
stored outside the document tree of the Web server. If it is
placed in the directory which it protects, clients will be
able to download it.</item>
<tag>{auth_name, string()}</tag>
<item>
Sets the name of the authorization realm (auth-domain) for
a directory. This string informs the client about which user
name and password to use. </item>
<tag>{auth_access_password, string()}</tag>
<item> If set to other than "NoPassword" the password is required
for all API calls. If the password is set to "DummyPassword" the
password must be changed before any other API calls. To secure
the authenticating data the password must be changed after the
web server is started since it otherwise is written in clear
text in the configuration file.</item>
<tag>{require_user, [string()]}</tag>
<item>
Defines users which should be granted access to a given
directory using a secret password.
</item>
<tag>{require_group, [string()]}</tag>
<item>
Defines users which should be granted access to a given
directory using a secret password.
</item>
</taglist>
<marker id="htaccess_prop"></marker>
<p><em>Htaccess authentication properties - requires mod_htaccess</em></p>
<taglist>
<tag>{access_files, [path()]}</tag>
<item> Specify which filenames that are used for
access-files. When a request comes every directory in the path
to the requested asset will be searched after files with the
names specified by this parameter. If such a file is found the
file will be parsed and the restrictions specified in it will
be applied to the request.
</item>
</taglist>
<marker id="sec_prop"></marker>
<p><em>Security properties - requires mod_security </em></p>
<p><em>{security_directory, {path(), [{property(), term()}]}</em></p>
<marker id="sdir_prop"></marker>
<p> Here follows the valid properties for security directories</p>
<taglist>
<tag>{security_data_file, path()}</tag>
<item>
Name of the security data file. The filename can either
absolute or relative to the server_root. This file is used to
store persistent data for the mod_security module. </item>
<tag>{security_max_retries, integer()}</tag>
<item> Specifies the maximum number of tries to authenticate a
user has before the user is blocked out. If a user
successfully authenticates when the user has been blocked, the
user will receive a 403 (Forbidden) response from the
server. If the user makes a failed attempt while blocked the
server will return 401 (Unauthorized), for security
reasons. Defaults to 3 may also be set to infinity.</item>
<tag>{security_block_time, integer()}</tag>
<item> Specifies the number of minutes a user is blocked. After
this amount of time, he automatically regains access.
Defaults to 60</item>
<tag>{security_fail_expire_time, integer()}</tag>
<item>
Specifies the number of minutes a failed user authentication
is remembered. If a user authenticates after this amount of
time, his previous failed authentications are
forgotten. Defaults to 30</item>
<tag>{security_auth_timeout, integer()}</tag>
<item>
Specifies the number of seconds a successful user
authentication is remembered. After this time has passed, the
authentication will no longer be reported. Defaults to 30.
</item>
</taglist>
</section>
<funcs>
<func>
<name>info(Pid) -></name>
<name>info(Pid, Properties) -> [{Option, Value}]</name>
<fsummary>Fetches information about the HTTP server</fsummary>
<type>
<v>Properties = [property()]</v>
<v>Option = property()</v>
<v>Value = term()</v>
</type>
<desc>
<p>Fetches information about the HTTP server. When called
with only the pid all properties are fetched, when called
with a list of specific properties they are fetched.
Available properties are the same as the servers start options.
</p>
<note><p>Pid is the pid returned from inets:start/[2,3].
Can also be retrieved form inets:services/0, inets:services_info/0
see <seealso marker="inets">inets(3)</seealso>
</p></note>
</desc>
</func>
<func>
<name>info(Address, Port) -> </name>
<name>info(Address, Port, Properties) -> [{Option, Value}] </name>
<fsummary>Fetches information about the HTTP server</fsummary>
<type>
<v>Address = ip_address()</v>
<v>Port = integer()</v>
<v>Properties = [property()]</v>
<v>Option = property()</v>
<v>Value = term()</v>
</type>
<desc>
<p>Fetches information about the HTTP server. When called with
only the Address and Port all properties are fetched, when
called with a list of specific properties they are fetched.
Available properties are the same as the servers start
options.
</p>
<note><p> Address has to be the ip-address and can not be
the hostname.
</p></note>
</desc>
</func>
<func>
<name>reload_config(Config, Mode) -> ok | {error, Reason}</name>
<fsummary>Reloads the HTTP server configuration without
restarting the server.</fsummary>
<type>
<v>Config = path() | [{Option, Value}]</v>
<v>Option = property()</v>
<v>Value = term()</v>
<v>Mode = non_disturbing | disturbing</v>
</type>
<desc>
<p>Reloads the HTTP server configuration without restarting the
server. Incoming requests will be answered with a temporary
down message during the time the it takes to reload.</p>
<note><p>Available properties are the same as the servers
start options, although the properties bind_address and
port can not be changed.</p></note>
<p>If mode is disturbing, the server is blocked forcefully and
all ongoing requests are terminated and the reload will
start immediately. If mode is non-disturbing, no new
connections are accepted, but the ongoing requests are
allowed to complete before the reload is done.</p>
</desc>
</func>
</funcs>
<section>
<title>ERLANG WEB SERVER API DATA TYPES </title>
<code type="none">
ModData = #mod{}
-record(mod, {
\011\011data = [],
\011\011socket_type = ip_comm,
\011\011socket,
\011\011config_db,
\011\011method,
\011\011absolute_uri,
\011\011request_uri,
\011\011http_version,
\011\011request_line,
\011\011parsed_header = [],
\011\011entity_body,
\011\011connection
\011 }).
</code>
<p>The fields of the <c>mod</c> record has the following meaning:
</p>
<taglist>
<tag><c>data</c></tag>
<item>Type <c>[{InteractionKey,InteractionValue}]</c> is used to
propagate data between modules. Depicted
<c>interaction_data()</c> in function type declarations.
</item>
<tag><c>socket_type</c></tag>
<item><c>socket_type()</c>,
Indicates whether it is an ip socket or a ssl socket.
</item>
<tag><c>socket</c></tag>
<item>The actual socket in <c>ip_comm</c> or <c>ssl</c> format
depending on the <c>socket_type</c>.
</item>
<tag><c>config_db</c></tag>
<item>The config file directives stored as key-value tuples in
an ETS-table. Depicted <c>config_db()</c> in function type
declarations.
</item>
<tag><c>method</c></tag>
<item>Type <c>"GET" | "POST" | "HEAD" | "TRACE"</c>, that is the
HTTP method.
</item>
<tag><c>absolute_uri</c></tag>
<item>If the request is a HTTP/1.1
request the URI might be in the absolute URI format. In that
case httpd will save the absolute URI in this field. An Example
of an absolute URI could
be<c>"http://ServerName:Part/cgi-bin/find.pl?person=jocke"</c></item>
<tag><c>request_uri</c></tag>
<item>The <c>Request-URI</c> as defined
in RFC 1945, for example <c>"/cgi-bin/find.pl?person=jocke"</c></item>
<tag><c>http_version</c></tag>
<item>The <c>HTTP</c> version of the
request, that is "HTTP/0.9", "HTTP/1.0", or "HTTP/1.1".
</item>
<tag><c>request_line</c></tag>
<item>The <c>Request-Line</c> as
defined in RFC 1945, for example <c>"GET /cgi-bin/find.pl?person=jocke HTTP/1.0"</c>.
</item>
<tag><c>parsed_header</c></tag>
<item>Type <c>[{HeaderKey,HeaderValue}]</c>,
<c>parsed_header</c> contains all HTTP header fields from the
HTTP-request stored in a list as key-value tuples. See RFC 2616
for a listing of all header fields. For example the date field
would be stored as: <c>{"date","Wed, 15 Oct 1997 14:35:17 GMT"}.
RFC 2616 defines that HTTP is a case insensitive protocol and
the header fields may be in lower case or upper case. Httpd will
ensure that all header field names are in lower case. </c>.
</item>
<tag><c>entity_body</c></tag>
<item>The <c>Entity-Body</c> as defined
in RFC 2616, for example data sent from a CGI-script using the
POST method.
</item>
<tag><c>connection</c></tag>
<item><c>true | false</c> If set to true the connection to the
client is a persistent connection and will not be closed when
the request is served.</item>
</taglist>
</section>
<section>
<title>ERLANG WEB SERVER API CALLBACK FUNCTIONS</title>
</section>
<funcs>
<func>
<name>Module:do(ModData)-> {proceed, OldData} | {proceed, NewData} | {break, NewData} | done</name>
<fsummary>Called for each request to the Web server.</fsummary>
<type>
<v>OldData = list()</v>
<v>NewData = [{response,{StatusCode,Body}}] | [{response,{response,Head,Body}}] | [{response,{already_sent,Statuscode,Size}] </v>
<v>StausCode = integer()</v>
<v>Body = io_list() | nobody | {Fun, Arg}</v>
<v>Head = [HeaderOption]</v>
<v>HeaderOption = {Option, Value} | {code, StatusCode}</v>
<v>Option = accept_ranges | allow | cache_control | content_MD5 | content_encoding | content_language | content_length | content_location | content_range | content_type | date | etag | expires | last_modified | location | pragma | retry_after | server | trailer | transfer_encoding</v>
<v>Value = string()</v>
<v>Fun = fun( Arg ) -> sent| close | Body </v>
<v>Arg = [term()]</v>
</type>
<desc>
<p>When a valid request reaches httpd it calls <c>do/1</c> in
each module defined by the Modules configuration
option. The function may generate data for other modules
or a response that can be sent back to the client.</p>
<p>The field <c>data</c> in ModData is a list. This list will be
the list returned from the last call to
<c>do/1</c>.</p>
<p><c>Body</c> is the body of the http-response that will be
sent back to the client an appropriate header will be
appended to the message. <c>StatusCode</c> will be the
status code of the response see RFC2616 for the appropriate
values.</p>
<p><c>Head</c> is a key value list of HTTP header fields. The
server will construct a HTTP header from this data. See RFC
2616 for the appropriate value for each header field. If the
client is a HTTP/1.0 client then the server will filter the
list so that only HTTP/1.0 header fields will be sent back
to the client.</p>
<p>If <c>Body</c> is returned and equal to <c>{Fun,Arg}</c>,
the Web server will try <c>apply/2</c> on <c>Fun</c> with
<c>Arg</c> as argument and expect that the fun either
returns a list <c>(Body)</c> that is a HTTP-repsonse or the
atom sent if the HTTP-response is sent back to the
client. If close is returned from the fun something has gone
wrong and the server will signal this to the client by
closing the connection.</p>
</desc>
</func>
<func>
<name>Module:load(Line, AccIn)-> eof | ok | {ok, AccOut} | {ok, AccOut, {Option, Value}} | {ok, AccOut, [{Option, Value}]} | {error, Reason} </name>
<fsummary>Load is used to convert a line in a Apache like config
file to a <c>{Option, Value}</c> tuple.</fsummary>
<type>
<v>Line = string()</v>
<v>AccIn = [{Option, Value}]</v>
<v>AccOut = [{Option, Value}]</v>
<v>Option = property()</v>
<v>Value = term() </v>
<v>Reason = term()</v>
</type>
<desc>
<p>Load is used to convert a line in a Apache like
configuration file to a <c>{Option, Value}</c> tuple. Some
more complex configuration options such as <c>directory</c>
and <c>security_directory</c> will create an
accumulator.This function does only need clauses for the
options implemented by this particular callback module.
</p>
</desc>
</func>
<func>
<name>Module:store({Option, Value}, Config)-> {ok, {Option, NewValue}} | {error, Reason} </name>
<fsummary></fsummary>
<type>
<v>Line = string()</v>
<v>Option = property()</v>
<v>Config = [{Option, Value}]</v>
<v>Value = term() </v>
<v>Reason = term()</v>
</type>
<desc>
<p>This function is used to check the validity of the
configuration options before saving them in the internal
database. This function may also have a side effect
e.i. setup necessary extra resources implied by the
configuration option. It can also
resolve possible dependencies among
configuration options by changing the value of the option.
This function does only need clauses for the options
implemented by this particular callback module.</p>
</desc>
</func>
<func>
<name>Module:remove(ConfigDB) -> ok | {error, Reason} </name>
<fsummary>Callback function that is called when the Web server is closed.</fsummary>
<type>
<v>ConfigDB = ets_table()</v>
<v>Reason = term()</v>
</type>
<desc>
<p>When httpd is shutdown it will try to execute
<c>remove/1</c> in each Erlang web server callback module. The
programmer may use this function to clean up resources
that may have been created in the store function.</p>
</desc>
</func>
</funcs>
<section>
<title>ERLANG WEB SERVER API HELP FUNCTIONS</title>
</section>
<funcs>
<func>
<name>parse_query(QueryString) -> [{Key,Value}]</name>
<fsummary>Parse incoming data to <c>erl </c>and <c>eval </c>scripts.</fsummary>
<type>
<v>QueryString = string()</v>
<v>Key = string()</v>
<v>Value = string()</v>
</type>
<desc>
<marker id="parse_query"></marker>
<p><c>parse_query/1</c> parses incoming data to <c>erl</c> and
<c>eval</c> scripts (See <seealso marker="mod_esi">mod_esi(3)</seealso>) as defined in the standard
URL format, that is '+' becomes 'space' and decoding of
hexadecimal characters (<c>%xx</c>).</p>
</desc>
</func>
</funcs>
<section>
<title>SEE ALSO</title>
<p>RFC 2616, <seealso marker="inets">inets(3)</seealso>,
<seealso marker="ssl:ssl">ssl(3)</seealso>
</p>
</section>
</erlref>
