<?xml version="1.0" encoding="utf-8" ?> <!DOCTYPE erlref SYSTEM "erlref.dtd"> <erlref> <header> <copyright> <year>2004</year><year>2013</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 do not explicitly use a profile will access 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. When https links needs to go through a proxy the CONNECT method extension to HTTP-1.1 is used to establish a tunnel and then the connection is upgraded to TLS, however "TLS upgrade" according to RFC 2817 is not supported.</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() | {fun(accumulator()) -> body_processing_result(), accumulator()} | {chunkify, fun(accumulator()) -> body_processing_result(), accumulator()} body_processing_result() = eof | {ok, iolist(), accumulator()} accumulator() = term() filename() = string() ]]></code> </section> <section> <title>SSL DATA TYPES </title> <p>See <seealso marker="ssl:ssl">ssl(3)</seealso> for information about ssl options (<c>ssloptions()</c>). </p> </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 <c>inets:stop(httpc, Pid)</c> or <c>inets:stop(httpc, Profile)</c>.</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>Body = string() | binary()</v> <v>Profile = profile() | pid() (when started <c>stand_alone</c>)</v> <v>Reason = term() </v> </type> <desc> <p>Equivalent to <c>httpc:request(get, {Url, []}, [], [])</c>.</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, ssloptions()} | {essl, ssloptions()} | {autoredirect, boolean()} | {proxy_auth, {userstring(), passwordstring()}} | {version, http_version()} | {relaxed, boolean()} | {url_encode, 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()}, {ipv6_host_with_brackets, boolean()}}</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>Body = string() | binary()</v> <v>Profile = profile() | pid() (when started <c>stand_alone</c>)</v> <v>Reason = {connect_failed, term()} | {send_failed, term()} | 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 <c>{ok, RequestId}</c> 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> <marker id="request2_http_options"></marker> <taglist> <tag><c><![CDATA[timeout]]></c></tag> <item> <p>Timeout time for the request. </p> <p>The clock starts 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>This is the default ssl config option, currently defaults to <c>essl</c>, see below. </p> <p>Defaults to <c>[]</c>. </p> </item> <tag><c><![CDATA[essl]]></c></tag> <item> <p>If using the Erlang based implementation of 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 retrieve 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 string <c>"HTTP/1.1"</c>. </p> </item> <tag><c><![CDATA[relaxed]]></c></tag> <item> <p>If set to <c>true</c> workarounds for known server deviations from the HTTP-standard are enabled. </p> <p>Defaults to <c>false</c>. </p> </item> <tag><c><![CDATA[url_encode]]></c></tag> <item> <p>Will apply Percent-encoding, also known as URL encoding on the URL.</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 following stream messages will be sent to that process: <c>{http, {RequestId, stream_start, Headers}}, {http, {RequestId, stream, BinBodyPart}}, {http, {RequestId, stream_end, Headers}}</c>. When streaming to to the calling processes using the option <c>{self, once}</c> the first message will have an additional element e.i. <c>{http, {RequestId, stream_start, Headers, Pid}}</c>, this is the process id that should be used as an argument to <c>http:stream_next/1</c> 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 <c>stream_end</c> message than in the <c>stream_start</c>. When streaming to a file and the request is asynchronous the message <c>{http, {RequestId, saved_to_file}}</c> 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 have 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="kernel:inet#setopts/2">inet:setopts/2</seealso>) for an already existing one, and therefore an already connected request handler. </p> <p>By default the socket options set by the <seealso marker="#set_options">set_options/1,2</seealso> function are used when establishing a connection. </p> </item> <tag><c><![CDATA[receiver]]></c></tag> <item> <p>Defines how the client will deliver the result of an 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, Function, 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 of the above cases, <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> <marker id="ipv6_host_with_brackets"></marker> </item> <tag><c><![CDATA[ipv6_host_with_brackets]]></c></tag> <item> <p>When parsing the Host-Port part of an URI with a IPv6 address with brackets, shall we retain those brackets (<c>true</c>) or strip them (<c>false</c>). </p> <p>Defaults to <c>false</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() | pid() (when started <c>stand_alone</c>)</v> </type> <desc> <p>Cancels an asynchronous HTTP-request. Note this does not guarantee that the request response will not be delivered, as it is asynchronous the the request may already have been completed when the cancellation arrives. </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}} | {https_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>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> <d>proxy defaults to {undefined, []} e.i. no proxy is configured and https_proxy defaults to the value of proxy.</d> <v>MaxSessions = integer() </v> <d>Default is <c>2</c>. Maximum number of persistent connections to a host.</d> <v>MaxKeepAlive = integer() </v> <d>Default is <c>5</c>. Maximum number of outstanding requests on the same connection to a host.</d> <v>KeepAliveTimeout = integer() </v> <d>Default is <c>120000</c> (= 2 min). If a persistent connection is idle longer than the <c>keep_alive_timeout</c> in milliseconds, the client will close the connection. The server may also have such a time out but you should not count on it!</d> <v>MaxPipeline = integer() </v> <d>Default is <c>2</c>. Maximum number of outstanding requests on a pipelined connection to a host.</d> <v>PipelineTimeout = integer() </v> <d>Default is <c>0</c>, which will result in pipelining not being used. If a persistent connection is idle longer than the <c>pipeline_timeout</c> in milliseconds, the client will close the connection. </d> <v>CookieMode = enabled | disabled | verify </v> <d>Default is <c>disabled</c>. If Cookies are enabled all valid cookies will automatically be saved in the client manager's cookie database. If the option <c>verify</c> is used the function <c>store_cookies/2</c> has to be called for the cookies to be saved.</d> <v>IpFamily = inet | inet6 | inet6fb4 </v> <d>By default <c>inet</c>. 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 <seealso marker="kernel:gen_tcp#connect">gen_tcp:connect/3,4</seealso> for more info. </d> <v>Port = integer() </v> <d>Specify which local port number to use. See <seealso marker="kernel:gen_tcp#connect">gen_tcp:connect/3,4</seealso> for more info. </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>VerboseMode = false | verbose | debug | trace </v> <d>Default is <c>false</c>. 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() | pid() (when started <c>stand_alone</c>)</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 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 delay as earlier requests 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 <c>max_sessions</c> option. </p> </note> <marker id="get_options"></marker> </desc> </func> <func> <name>get_options(OptionItems) -> {ok, Values} | {error, Reason}</name> <name>get_options(OptionItems, Profile) -> {ok, Values} | {error, Reason}</name> <fsummary>Gets the currently used options.</fsummary> <type> <v>OptionItems = all | [option_item()]</v> <v>option_item() = proxy | https_proxy max_sessions | keep_alive_timeout | max_keep_alive_length | pipeline_timeout | max_pipeline_length | cookies | ipfamily | ip | port | socket_opts | verbose</v> <v>Profile = profile() | pid() (when started <c>stand_alone</c>)</v> <v>Values = [{option_item(), term()}]</v> <v>Reason = term() </v> </type> <desc> <p>Retrieves the options currently used by the client.</p> <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_cookies"></marker> <marker id="store_cookies"></marker> </desc> </func> <func> <name>store_cookies(SetCookieHeaders, Url) -> </name> <name>store_cookies(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() | pid() (when started <c>stand_alone</c>)</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 have set the option <c>cookies</c> 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 | Opts) -> header() | {error, Reason}</name> <name>cookie_header(Url, Opts, Profile) -> header() | {error, Reason}</name> <fsummary>Returns the cookie header that would be sent when making a request to Url using the profile <c>Profile</c>.</fsummary> <type> <v>Url = url()</v> <v>Opts = [cookie_header_opt()]</v> <v>Profile = profile() | pid() (when started <c>stand_alone</c>)</v> <v>cookie_header_opt() = {ipv6_host_with_brackets, boolean()}</v> </type> <desc> <p>Returns the cookie header that would be sent when making a request to <c>Url</c> using the profile <c>Profile</c>. If no profile is specified the default profile will be used. </p> <p>The option <c>ipv6_host_with_bracket</c> deals with how to parse IPv6 addresses. See the <c>Options</c> argument of the <seealso marker="#request2">request/4,5</seealso> for more info. </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() | pid() (when started <c>stand_alone</c>)</v> </type> <desc> <p>Resets (clears) the cookie database for the specified <c>Profile</c>. If no profile is specified the default profile will be used. </p> <marker id="which_cookies"></marker> </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() | pid() (when started <c>stand_alone</c>)</v> <v>cookies() = [cookie_stores()]</v> <v>cookie_stores() = {cookies, cookies()} | {session_cookies, cookies()}</v> <v>cookies() = [cookie()]</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> <marker id="which_sessions"></marker> </desc> </func> <func> <name>which_sessions() -> session_info()</name> <name>which_sessions(Profile) -> session_info()</name> <fsummary>Produces a slightly processed dump of the sessions database.</fsummary> <type> <v>Profile = profile() | pid() (when started <c>stand_alone</c>)</v> <v>session_info() = {GoodSessions, BadSessions, NonSessions}</v> <v>GoodSessions = session()</v> <v>BadSessions = tuple()</v> <v>NonSessions = term()</v> </type> <desc> <p>This function produces a slightly processed dump of the session database. It is intended for debugging. If no profile is specified the default profile will be used. </p> <marker id="info"></marker> </desc> </func> <func> <name>info() -> list()</name> <name>info(Profile) -> list()</name> <fsummary>Produces a list of miscelleneous info</fsummary> <type> <v>Profile = profile() | pid() (when started <c>stand_alone</c>)</v> </type> <desc> <p>This function produces a list of miscelleneous info. It is intended for debugging. 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>