<?xml version="1.0" encoding="latin1" ?>
<!DOCTYPE erlref SYSTEM "erlref.dtd">
<erlref>
<header>
<copyright>
<year>2004</year><year>2010</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>httpc</title>
<prepared>Ingela Anderton Andin</prepared>
<responsible></responsible>
<docno></docno>
<date></date>
<rev></rev>
</header>
<module>httpc</module>
<modulesummary>An HTTP/1.1 client </modulesummary>
<description>
<p>This module provides the API to a HTTP/1.1 compatible client according
to RFC 2616, caching is currently not supported.</p>
<note>
<p>When starting the Inets application a manager process for the
default profile will be started. The functions in this API
that does not explicitly use a profile will accesses the
default profile. A profile keeps track of proxy options,
cookies and other options that can be applied to more than one
request. </p>
<p>If the scheme
https is used the ssl application needs to be started.</p>
<p>Also note that pipelining will only be used if the pipeline
timeout is set, otherwise persistent connections without
pipelining will be used e.i. the client always waits for
the previous response before sending the next request.</p>
</note>
<p>There are some usage examples in the <seealso
marker="http_client">Inets User's Guide.</seealso></p>
</description>
<section>
<title>COMMON DATA TYPES </title>
<p>Type definitions that are used more than once in
this module:</p>
<code type="none"><![CDATA[
boolean() = true | false
string() = list of ASCII characters
request_id() = ref()
profile() = atom()
path() = string() representing a file path or directory path
ip_address() = See inet(3)
socket_opt() = See the Options used by gen_tcp(3) and
ssl(3) connect(s)
]]></code>
</section>
<section>
<title>HTTP DATA TYPES </title>
<p>Type definitions that are related to HTTP:</p>
<p>For more information about HTTP see rfc 2616</p>
<code type="none"><![CDATA[
method() = head | get | put | post | trace | options | delete
request() = {url(), headers()} |
{url(), headers(), content_type(), body()}
url() = string() - Syntax according to the URI definition in rfc 2396, ex: "http://www.erlang.org"
status_line() = {http_version(), status_code(), reason_phrase()}
http_version() = string() ex: "HTTP/1.1"
status_code() = integer()
reason_phrase() = string()
content_type() = string()
headers() = [header()]
header() = {field(), value()}
field() = string()
value() = string()
body() = string() | binary()
filename() = string()
]]></code>
</section>
<section>
<title>SSL DATA TYPES </title>
<p>Some type definitions relevant when using https,
for details <seealso marker="ssl:ssl">ssl(3)</seealso>: </p>
<code type="none"><![CDATA[
ssl_options() = {verify, code()} |
{depth, depth()} |
{certfile, path()} |
{keyfile, path()} |
{password, string()} |
{cacertfile, path()} |
{ciphers, string()}
]]></code>
</section>
<section>
<title>HTTP CLIENT SERVICE START/STOP </title>
<p>A HTTP client can be configured to start when starting the inets
application or started dynamically in runtime by calling the
inets application API <c>inets:start(httpc, ServiceConfig)</c>, or
<c>inets:start(httpc, ServiceConfig, How)</c>
see <seealso marker="inets">inets(3)</seealso> Below follows a
description of the available configuration options.</p>
<taglist>
<tag>{profile, profile()}</tag>
<item>Name of the profile, see
common data types below, this option is mandatory.</item>
<tag>{data_dir, path()}</tag>
<item>Directory where the profile
may save persistent data, if omitted all cookies will be treated
as session cookies.</item>
</taglist>
<p>The client can be stopped using inets:stop(httpc, Pid) or
inets:stop(httpc, Profile).</p>
<marker id="request1"></marker>
</section>
<funcs>
<func>
<name>request(Url) -> </name>
<name>request(Url, Profile) -> {ok, Result} | {error, Reason}</name>
<fsummary>Sends a get HTTP-request</fsummary>
<type>
<v>Url = url() </v>
<v>Result = {status_line(), headers(), body()} |
{status_code(), body()} | request_id() </v>
<v>Profile = profile()</v>
<v>Reason = term() </v>
</type>
<desc>
<p>Equivalent to httpc:request(get, {Url, []}, [], []).</p>
<marker id="request2"></marker>
</desc>
</func>
<func>
<name>request(Method, Request, HTTPOptions, Options) -> </name>
<name>request(Method, Request, HTTPOptions, Options, Profile) -> {ok, Result} | {ok, saved_to_file} | {error, Reason}</name>
<fsummary>Sends a HTTP-request</fsummary>
<type>
<v>Method = method() </v>
<v>Request = request()</v>
<v>HTTPOptions = http_options()</v>
<v>http_options() = [http_option()]</v>
<v>http_option() = {timeout, timeout()} |
{connect_timeout, timeout()} |
{ssl, ssl_options()} |
{autoredirect, boolean()} |
{proxy_auth, {userstring(), passwordstring()}} |
{version, http_version()} |
{relaxed, boolean()}</v>
<v>timeout() = integer() >= 0 | infinity</v>
<v>Options = options()</v>
<v>options() = [option()]</v>
<v>option() = {sync, boolean()} |
{stream, stream_to()} |
{body_format, body_format()} |
{full_result, boolean()} |
{headers_as_is, boolean() |
{socket_opts, socket_opts()} |
{receiver, receiver()}}</v>
<v>stream_to() = none | self | {self, once} | filename() </v>
<v>socket_opts() = [socket_opt()]</v>
<v>receiver() = pid() | function()/1 | {Module, Function, Args} </v>
<v>Module = atom() </v>
<v>Function = atom() </v>
<v>Args = list() </v>
<v>body_format() = string | binary </v>
<v>Result = {status_line(), headers(), body()} |
{status_code(), body()} | request_id() </v>
<v>Profile = profile() </v>
<v>Reason = term() </v>
</type>
<desc>
<p>Sends a HTTP-request. The function can be both synchronous
and asynchronous. In the later case the function will return
{ok, RequestId} and later on the information will be delivered
to the <c>receiver</c> depending on that value. </p>
<p>Http option (<c>http_option()</c>) details: </p>
<taglist>
<tag><c><![CDATA[timeout]]></c></tag>
<item>
<p>Timeout time for the request. </p>
<p>The clock start ticking as soon as the request has been
sent. </p>
<p>Time is in milliseconds. </p>
<p>Defaults to <c>infinity</c>. </p>
</item>
<tag><c><![CDATA[connect_timeout]]></c></tag>
<item>
<p>Connection timeout time, used during the initial request,
when the client is <em>connecting</em> to the server. </p>
<p>Time is in milliseconds. </p>
<p>Defaults to the value of the <c>timeout</c> option. </p>
</item>
<tag><c><![CDATA[ssl]]></c></tag>
<item>
<p>If using SSL, these SSL-specific options are used. </p>
<p>Defaults to <c>[]</c>. </p>
</item>
<tag><c><![CDATA[autoredirect]]></c></tag>
<item>
<p>Should the client automatically retreive the information
from the new URI and return that as the result instead
of a 30X-result code. </p>
<p>Note that for some 30X-result codes automatic redirect
is not allowed in these cases the 30X-result will always
be returned. </p>
<p>Defaults to <c>true</c>. </p>
</item>
<tag><c><![CDATA[proxy_auth]]></c></tag>
<item>
<p>A proxy-authorization header using the provided user name and
password will be added to the request. </p>
</item>
<tag><c><![CDATA[version]]></c></tag>
<item>
<p>Can be used to make the client act as an <c>HTTP/1.0</c> or
<c>HTTP/0.9</c> client. By default this is an <c>HTTP/1.1</c>
client. When using <c>HTTP/1.0</c> persistent connections will
not be used. </p>
<p>Defaults to the trsing <c>"HTTP/1.1"</c>. </p>
</item>
<tag><c><![CDATA[relaxed]]></c></tag>
<item>
<p>If set to true workarounds for known server deviations from
the HTTP-standard are enabled. </p>
<p>Defaults to <c>false</c>. </p>
</item>
</taglist>
<p>Option (<c>option()</c>) details: </p>
<taglist>
<tag><c><![CDATA[sync]]></c></tag>
<item>
<p>Shall the request be synchronous or asynchronous. </p>
<p>Defaults to <c>true</c>. </p>
</item>
<tag><c><![CDATA[stream]]></c></tag>
<item>
<p>Streams the body of a 200 or 206 response to the calling
process or to a file. When streaming to the calling process
using the option <c>self</c> the the following stream messages
will be sent to that process: {http, {RequestId,
stream_start, Headers}, {http, {RequestId, stream,
BinBodyPart}, {http, {RequestId, stream_end, Headers}. When
streaming to to the calling processes using the option
<c>{self once}</c> the first message will have an additional
element e.i. {http, {RequestId, stream_start, Headers, Pid},
this is the process id that should be used as an argument to
http:stream_next/1 to trigger the next message to be sent to
the calling process. </p>
<p>Note that it is possible that chunked encoding will add
headers so that there are more headers in the stream_end
message than in the stream_start.
When streaming to a file and the request is asynchronous the
message {http, {RequestId, saved_to_file}} will be sent. </p>
<p>Defaults to <c>none</c>. </p>
</item>
<tag><c><![CDATA[body_format]]></c></tag>
<item>
<p>Defines if the body shall be delivered as a string or as a
binary. This option is only valid for the synchronous
request. </p>
<p>Defaults to <c>string</c>. </p>
</item>
<tag><c><![CDATA[full_result]]></c></tag>
<item>
<p>Should a "full result" be returned to the caller (that is,
the body, the headers and the entire status-line) or not
(the body and the status code). </p>
<p>Defaults to <c>true</c>. </p>
</item>
<tag><c><![CDATA[header_as_is]]></c></tag>
<item>
<p>Shall the headers provided by the user be made
lower case or be regarded as case sensitive. </p>
<p>Note that the http standard requires them to be
case insenstive. This feature should only be used if there is
no other way to communicate with the server or for testing
purpose. Also note that when this option is used no headers
will be automatically added, all necessary headers has to be
provided by the user. </p>
<p>Defaults to <c>false</c>. </p>
</item>
<tag><c><![CDATA[socket_opts]]></c></tag>
<item>
<p>Socket options to be used for this and subsequent
request(s). </p>
<p>Overrides any value set by the
<seealso marker="set_options">set_options</seealso>
function. </p>
<p>Note that the validity of the options are <em>not</em>
checked in any way. </p>
<p>Note that this may change the socket behaviour
(see <seealso marker="inet#setopts">inet:setopts/2</seealso>)
for an already existing, and therefor already connected
request handler. </p>
<p>By defaults the socket options set by the
<seealso marker="#set_options">set_options/1,2</seealso>
function is used when establishing connection. </p>
</item>
<tag><c><![CDATA[receiver]]></c></tag>
<item>
<p>Defines how the client will deliver the result for a
asynchroneous request (<c>sync</c> has the value
<c>false</c>). </p>
<taglist>
<tag><c><![CDATA[pid()]]></c></tag>
<item>
<p>Message(s) will be sent to this process in the format: </p>
<pre>
{http, ReplyInfo}
</pre>
</item>
<tag><c><![CDATA[function/1]]></c></tag>
<item>
<p>Information will be delivered to the receiver via calls
to the provided fun: </p>
<pre>
Receiver(ReplyInfo)
</pre>
</item>
<tag><c><![CDATA[{Module, Funcion, Args}]]></c></tag>
<item>
<p>Information will be delivered to the receiver via calls
to the callback function: </p>
<pre>
apply(Module, Function, [ReplyInfo | Args])
</pre>
</item>
</taglist>
<p>In all cases above, <c>ReplyInfo</c> has the following
structure: </p>
<pre>
{RequestId, saved_to_file}
{RequestId, {error, Reason}}
{RequestId, Result}
{RequestId, stream_start, Headers}
{RequestId, stream_start, Headers, HandlerPid}
{RequestId, stream, BinBodyPart}
{RequestId, stream_end, Headers}
</pre>
<p>Defaults to the <c>pid()</c> of the process calling the request
function (<c>self()</c>). </p>
</item>
</taglist>
<marker id="cancel_request"></marker>
</desc>
</func>
<func>
<name>cancel_request(RequestId) -> </name>
<name>cancel_request(RequestId, Profile) -> ok</name>
<fsummary>Cancels an asynchronous HTTP-request.</fsummary>
<type>
<v>RequestId = request_id() - A unique identifier as returned
by request/4</v>
<v>Profile = profile()</v>
</type>
<desc>
<p>Cancels an asynchronous HTTP-request. </p>
<marker id="set_options"></marker>
</desc>
</func>
<func>
<name>set_options(Options) -> </name>
<name>set_options(Options, Profile) -> ok | {error, Reason}</name>
<fsummary>Sets options to be used for subsequent requests.</fsummary>
<type>
<v>Options = [Option]</v>
<v>Option = {proxy, {Proxy, NoProxy}} |
{max_sessions, MaxSessions} |
{max_keep_alive_length, MaxKeepAlive} |
{keep_alive_timeout, KeepAliveTimeout} |
{max_pipeline_length, MaxPipeline} |
{pipeline_timeout, PipelineTimeout} |
{cookies, CookieMode} |
{ipfamily, IpFamily} |
{ip, IpAddress} |
{port, Port} |
{socket_opts, socket_opts()} |
{verbose, VerboseMode} </v>
<v>Proxy = {Hostname, Port}</v>
<v>Hostname = string() </v>
<d>ex: "localhost" or "foo.bar.se"</d>
<v>Port = integer()</v>
<d>ex: 8080 </d>
<v>socket_opts() = [socket_opt()]</v>
<d>The options are appended to the socket options used by the
client. </d>
<d>These are the default values when a new request handler
is started (for the initial connect). They are passed directly
to the underlying transport (gen_tcp or ssl) <em>without</em>
verification! </d>
<v>NoProxy = [NoProxyDesc]</v>
<v>NoProxyDesc = DomainDesc | HostName | IPDesc</v>
<v>DomainDesc = "*.Domain"</v>
<d>ex: "*.ericsson.se"</d>
<v>IpDesc = string()</v>
<d>ex: "134.138" or "[FEDC:BA98" (all IP-addresses starting with 134.138 or FEDC:BA98), "66.35.250.150" or "[2010:836B:4179::836B:4179]" (a complete IP-address).</d>
<v>MaxSessions = integer() </v>
<d>Default is <em>2</em>.
Maximum number of persistent connections to a host.</d>
<v>MaxKeepAlive = integer() </v>
<d>Default is <em>5</em>.
Maximum number of outstanding requests on the same connection to
a host.</d>
<v>KeepAliveTimeout = integer() </v>
<d>Default is <em>120000</em> (= 2 min).
If a persistent connection is idle longer than the
keep_alive_timeout the client will close the connection.
The server may also have a such a time out but you should
not count on it!</d>
<v>MaxPipeline = integer() </v>
<d>Default is <em>2</em>.
Maximum number of outstanding requests on a pipelined connection to a host.</d>
<v>PipelineTimeout = integer() </v>
<d>Default is <em>0</em>,
which will result in pipelining not being used.
If a persistent connection is idle longer than the
pipeline_timeout the client will close the connection. </d>
<v>CookieMode = enabled | disabled | verify </v>
<d>Default is <em>disabled</em>.
If Cookies are enabled all valid cookies will automatically be
saved in the client manager's cookie database.
If the option verify is used the function http:verify_cookie/2
has to be called for the cookie to be saved.</d>
<v>IpFamily = inet | inet6 | inet6fb4 </v>
<d>By default <em>inet</em>.
When it is set to <c>inet6fb4</c> you can use both ipv4 and ipv6.
It first tries <c>inet6</c> and if that does not works falls back to <c>inet</c>.
The option is here to provide a workaround for buggy ipv6 stacks to ensure that
ipv4 will always work.</d>
<v>IpAddress = ip_address() </v>
<d>If the host has several network interfaces, this option specifies which one to use.
See gen_tcp:connect/3,4 for more info. </d>
<v>Port = integer() </v>
<d>Specify which local port number to use.
See gen_tcp:connect/3,4 for more info. </d>
<v>VerboseMode = false | verbose | debug | trace </v>
<d>Default is <em>false</em>.
This option is used to switch on (or off)
different levels of erlang trace on the client.
It is a debug feature.</d>
<v>Profile = profile()</v>
</type>
<desc>
<p>Sets options to be used for subsequent
requests.</p>
<note>
<p>If possible the client will keep its connections
alive and use persistent connections
with or without pipeline depending on configuration
and current circumstances. The HTTP/1.1 specification does not
provide a guideline for how many requests that would be
ideal to be sent on a persistent connection,
this very much depends on the
application. Note that a very long queue of requests may cause a
user perceived delays as earlier request may take a long time
to complete. The HTTP/1.1 specification does suggest a
limit of 2 persistent connections per server, which is the
default value of the max_sessions option. </p>
</note>
<marker id="stream_next"></marker>
</desc>
</func>
<func>
<name>stream_next(Pid) -> ok</name>
<fsummary> Triggers the next message to be streamed, e.i.
same behavior as active once for sockets.
</fsummary>
<type>
<v>Pid = pid() - as received in the stream_start message</v>
</type>
<desc>
<p>Triggers the next message to be streamed, e.i.
same behavior as active once for sockets.</p>
<marker id="verify_cookie"></marker>
<marker id="store_cookie"></marker>
</desc>
</func>
<func>
<name>store_cookie(SetCookieHeaders, Url) -> </name>
<name>store_cookie(SetCookieHeaders, Url, Profile) -> ok | {error, Reason}</name>
<fsummary>Saves the cookies defined in SetCookieHeaders in the client profile's cookie database.</fsummary>
<type>
<v>SetCookieHeaders = headers() - where field = "set-cookie"</v>
<v>Url = url()</v>
<v>Profile = profile()</v>
</type>
<desc>
<p>Saves the cookies defined in SetCookieHeaders
in the client profile's cookie database. You need to
call this function if you set the option cookies to <c>verify</c>.
If no profile is specified the default profile will be used.
</p>
<marker id="cookie_header"></marker>
</desc>
</func>
<func>
<name>cookie_header(Url) -> </name>
<name>cookie_header(Url, Profile) -> header() | {error, Rason}</name>
<fsummary>Returns the cookie header that would be sent when
making a request to Url using the profile Profile.</fsummary>
<type>
<v>Url = url()</v>
<v>Profile = profile()</v>
</type>
<desc>
<p>Returns the cookie header that would be sent
when making a request to Url using the profile Profile.
If no profile is specified the default profile will be used.
</p>
<marker id="reset_cookies"></marker>
</desc>
</func>
<func>
<name>reset_cookies() -> void()</name>
<name>reset_cookies(Profile) -> void()</name>
<fsummary>Reset the cookie database.</fsummary>
<type>
<v>Profile = profile()</v>
</type>
<desc>
<p>Resets (clears) the cookie database for the specified Profile.
If no profile is specified the default profile will be used.
</p>
</desc>
</func>
<func>
<name>which_cookies() -> cookies()</name>
<name>which_cookies(Profile) -> cookies()</name>
<fsummary>Dumps out the entire cookie database.</fsummary>
<type>
<v>Profile = profile()</v>
<v>cookies() = [cooie_stores()]</v>
<v>cookie_stores() = {cookies, icookies()} | {session_cookies, icookies()}</v>
<v>icookies() = [icookie()]</v>
<v>cookie() = term()</v>
</type>
<desc>
<p>This function produces a list of the entire cookie database.
It is intended for debugging/testing purposes.
If no profile is specified the default profile will be used.
</p>
</desc>
</func>
</funcs>
<section>
<title>SEE ALSO</title>
<p>RFC 2616, <seealso marker="inets">inets(3)</seealso>,
<seealso marker="kernel:gen_tcp">gen_tcp(3)</seealso>,
<seealso marker="ssl:ssl">ssl(3)</seealso>
</p>
</section>
</erlref>
