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