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| author | Loïc Hoguin <[email protected]> | 2018-04-04 13:13:37 +0200 |
|---|---|---|
| committer | Loïc Hoguin <[email protected]> | 2018-04-04 13:13:37 +0200 |
| commit | d2a3f2cedd7c00d0933222aed9c06b3149aa4db4 (patch) | |
| tree | 4f1499bac639c782b250af0fbf0dec2064315813 /docs/en/cowboy/2.3/manual/cowboy_rest | |
| parent | 1d654719f5fa6be67d2c95145872068665702cb7 (diff) | |
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Cowboy 2.3.0
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diff --git a/docs/en/cowboy/2.3/manual/cowboy_rest/index.html b/docs/en/cowboy/2.3/manual/cowboy_rest/index.html new file mode 100644 index 00000000..2102f6a9 --- /dev/null +++ b/docs/en/cowboy/2.3/manual/cowboy_rest/index.html @@ -0,0 +1,809 @@ +<!DOCTYPE html> +<html lang="en"> + +<head> + <meta charset="utf-8"> + <meta name="viewport" content="width=device-width, initial-scale=1.0"> + <meta name="description" content=""> + <meta name="author" content="Loïc Hoguin based on a design from (Soft10) Pol Cámara"> + + <meta name="generator" content="Hugo 0.37.1" /> + + <title>Nine Nines: cowboy_rest(3)</title> + + <link href='https://fonts.googleapis.com/css?family=Open+Sans:400,700,400italic' rel='stylesheet' type='text/css'> + <link href="/css/99s.css?r=1" rel="stylesheet"> + + <link rel="shortcut icon" href="/img/ico/favicon.ico"> + <link rel="apple-touch-icon-precomposed" sizes="114x114" href="/img/ico/apple-touch-icon-114.png"> + <link rel="apple-touch-icon-precomposed" sizes="72x72" href="/img/ico/apple-touch-icon-72.png"> + <link rel="apple-touch-icon-precomposed" href="/img/ico/apple-touch-icon-57.png"> + + +</head> + + +<body class=""> + <header id="page-head"> + <div id="topbar" class="container"> + <div class="row"> + <div class="span2"> + <h1 id="logo"><a href="/" title="99s">99s</a></h1> + </div> + <div class="span10"> + + <div id="side-header"> + <nav> + <ul> + <li><a title="Hear my thoughts" href="/articles">Articles</a></li> + <li><a title="Watch my talks" href="/talks">Talks</a></li> + <li class="active"><a title="Read the docs" href="/docs">Documentation</a></li> + <li><a title="Request my services" href="/services">Consulting & Training</a></li> + </ul> + </nav> + <ul id="social"> + <li> + <a href="https://github.com/ninenines" title="Check my Github repositories"><img src="/img/ico_github.png" data-hover="/img/ico_github_alt.png" alt="Github"></a> + </li> + <li> + <a title="Keep in touch!" href="http://twitter.com/lhoguin"><img src="/img/ico_microblog.png" data-hover="/img/ico_microblog_alt.png"></a> + </li> + <li> + <a title="Contact me" href="mailto:[email protected]"><img src="/img/ico_mail.png" data-hover="/img/ico_mail_alt.png"></a> + </li> + </ul> + </div> + </div> + </div> + </div> + + +</header> + +<div id="contents" class="two_col"> +<div class="container"> +<div class="row"> +<div id="docs" class="span9 maincol"> + +<h1 class="lined-header"><span>cowboy_rest(3)</span></h1> + +<div class="sect1"> +<h2 id="_name">Name</h2> +<div class="sectionbody"> +<div class="paragraph"><p>cowboy_rest - REST handlers</p></div> +</div> +</div> +<div class="sect1"> +<h2 id="_description">Description</h2> +<div class="sectionbody"> +<div class="paragraph"><p>The module <code>cowboy_rest</code> implements the HTTP state machine.</p></div> +<div class="paragraph"><p>Implementing REST handlers is not enough to provide a REST +interface; this interface must also follow the REST +constraints including HATEOAS (hypermedia as the engine +of application state).</p></div> +</div> +</div> +<div class="sect1"> +<h2 id="_callbacks">Callbacks</h2> +<div class="sectionbody"> +<div class="paragraph"><p>REST handlers implement the following interface:</p></div> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">init</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) + <span style="color: #990000">-></span> {<span style="color: #FF6600">cowboy_rest</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Callback</span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) + <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + | {<span style="color: #FF6600">stop</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + | {{<span style="color: #FF6600">switch_handler</span>, <span style="color: #009900">Module</span>}, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + | {{<span style="color: #FF6600">switch_handler</span>, <span style="color: #009900">Module</span>, <span style="color: #009900">Opts</span>}, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="font-weight: bold"><span style="color: #000000">terminate</span></span>(<span style="color: #009900">Reason</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> <span style="color: #FF6600">ok</span> <span style="font-style: italic"><span style="color: #9A1900">%% optional</span></span> + +<span style="color: #009900">Req</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">cowboy_req:req</span></span>() +<span style="color: #009900">State</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">any</span></span>() +<span style="color: #009900">Module</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">module</span></span>() +<span style="color: #009900">Opts</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">any</span></span>() +<span style="color: #009900">Reason</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000080">normal</span></span> + | {<span style="color: #FF6600">crash</span>, <span style="color: #FF6600">error</span> | <span style="font-weight: bold"><span style="color: #000080">exit</span></span> | <span style="font-weight: bold"><span style="color: #000080">throw</span></span>, <span style="font-weight: bold"><span style="color: #000000">any</span></span>()} + +<span style="color: #009900">Callback</span> <span style="color: #990000">-</span> <span style="color: #FF6600">see</span> <span style="color: #FF6600">below</span> +<span style="color: #009900">Result</span> <span style="color: #990000">-</span> <span style="color: #FF6600">see</span> <span style="color: #FF6600">below</span> +<span style="color: #009900">Default</span> <span style="color: #990000">-</span> <span style="color: #FF6600">see</span> <span style="color: #FF6600">below</span></tt></pre></div></div> +<div class="paragraph"><p>The <code>init/2</code> callback is common to all handlers. To switch +to the REST handler behavior, it must return <code>cowboy_rest</code> +as the first element of the tuple.</p></div> +<div class="paragraph"><p>The <code>Callback/2</code> above represents all the REST-specific +callbacks. They are described in the following section +of this manual. REST-specific callbacks differ by their +name, semantics, result and default values. The default +value is the one used when the callback has not been +implemented. They otherwise all follow the same interface.</p></div> +<div class="paragraph"><p>The <code>stop</code> tuple can be returned to stop REST processing. +If no response was sent before then, Cowboy will send a +<em>204 No Content</em>. The <code>stop</code> tuple can be returned from +any callback, excluding <code>expires</code>, <code>generate_etag</code>, +<code>last_modified</code> and <code>variances</code>.</p></div> +<div class="paragraph"><p>A <code>switch_handler</code> tuple can be returned from these same +callbacks to stop REST processing and switch to a different +handler type. This is very useful to, for example, to stream +the response body.</p></div> +<div class="paragraph"><p>The optional <code>terminate/3</code> callback will ultimately be called +with the reason for the termination of the handler. +Cowboy will terminate the process right after this. There +is no need to perform any cleanup in this callback.</p></div> +<div class="paragraph"><p>The following terminate reasons are defined for loop handlers:</p></div> +<div class="dlist"><dl> +<dt class="hdlist1"> +normal +</dt> +<dd> +<p> + The handler terminated normally. +</p> +</dd> +<dt class="hdlist1"> +{crash, Class, Reason} +</dt> +<dd> +<p> + A crash occurred in the handler. <code>Class</code> and <code>Reason</code> can be + used to obtain more information about the crash. The function + <code>erlang:get_stacktrace/0</code> can also be called to obtain the + stacktrace of the process when the crash occurred. +</p> +</dd> +</dl></div> +</div> +</div> +<div class="sect1"> +<h2 id="_rest_callbacks">REST callbacks</h2> +<div class="sectionbody"> +<div class="sect2"> +<h3 id="_acceptcallback">AcceptCallback</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="color: #009900">AcceptCallback</span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="color: #000080">true</span> | {<span style="color: #000080">true</span>, <span style="color: #009900">URI</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">iodata</span></span>()} | <span style="color: #000080">false</span>} +<span style="color: #009900">Default</span> <span style="color: #990000">-</span> <span style="color: #FF6600">crash</span></tt></pre></div></div> +<div class="paragraph"><p>Process the request body.</p></div> +<div class="paragraph"><p>This function should create or update the resource using the +request body.</p></div> +<div class="paragraph"><p>For PUT requests, the body is a representation of the resource +that is being created or replaced.</p></div> +<div class="paragraph"><p>For POST requests, the body is typically application-specific +instructions on how to process the request, but it may also +be a representation of the resource. When creating a new +resource with POST at a different location, return <code>{true, URI}</code> +with <code>URI</code> the new location.</p></div> +<div class="paragraph"><p>For PATCH requests, the body is a series of instructions on +how to update the resource. Patch files or JSON Patch are +examples of such media types.</p></div> +<div class="paragraph"><p>A response body may be sent. The appropriate media type, charset +and language for the response can be retrieved from the Req +object using the <code>media_type</code>, <code>charset</code> and <code>language</code> keys, +respectively. The body can be set using +<a href="../cowboy_req.set_resp_body">cowboy_req:set_resp_body(3)</a>.</p></div> +</div> +<div class="sect2"> +<h3 id="_allowed_methods">allowed_methods</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">allowed_methods</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> [<span style="font-weight: bold"><span style="color: #000080">binary</span></span>()] <span style="font-style: italic"><span style="color: #9A1900">%% case sensitive</span></span> +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> [<span style="color: #990000"><<</span><span style="color: #FF0000">"GET"</span><span style="color: #990000">>></span>, <span style="color: #990000"><<</span><span style="color: #FF0000">"HEAD"</span><span style="color: #990000">>></span>, <span style="color: #990000"><<</span><span style="color: #FF0000">"OPTIONS"</span><span style="color: #990000">>></span>]</tt></pre></div></div> +<div class="paragraph"><p>Return the list of allowed methods.</p></div> +</div> +<div class="sect2"> +<h3 id="_allow_missing_post">allow_missing_post</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">allow_missing_post</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">boolean</span></span>() +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> <span style="color: #000080">true</span></tt></pre></div></div> +<div class="paragraph"><p>Return whether POST is allowed when the resource doesn’t exist.</p></div> +<div class="paragraph"><p>Returning <code>true</code> here means that a new resource will be +created. The URI for the newly created resource should be +returned from the <code>AcceptCallback</code> function.</p></div> +</div> +<div class="sect2"> +<h3 id="_charsets_provided">charsets_provided</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">charsets_provided</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> [<span style="font-weight: bold"><span style="color: #000080">binary</span></span>()] <span style="font-style: italic"><span style="color: #9A1900">%% lowercase; case insensitive</span></span> +<span style="color: #009900">Default</span> <span style="color: #990000">-</span> <span style="color: #FF6600">skip</span> <span style="color: #FF6600">this</span> <span style="color: #FF6600">step</span></tt></pre></div></div> +<div class="paragraph"><p>Return the list of charsets the resource provides in order +of preference.</p></div> +<div class="paragraph"><p>During content negotiation Cowboy will pick the most +appropriate charset for the client. The client advertises +charsets it prefers with the accept-charset header. When +that header is missing, Cowboy picks the first charset +from the resource.</p></div> +<div class="paragraph"><p>Cowboy will add the negotiated <code>charset</code> to the Req object +after this step completes:</p></div> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">req</span></span>() <span style="color: #990000">::</span> #{ + <span style="color: #0000FF">charset</span> <span style="color: #990000">=></span> <span style="font-weight: bold"><span style="color: #000080">binary</span></span>() <span style="font-style: italic"><span style="color: #9A1900">%% lowercase; case insensitive</span></span> +}</tt></pre></div></div> +</div> +<div class="sect2"> +<h3 id="_content_types_accepted">content_types_accepted</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">content_types_accepted</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> [{<span style="font-weight: bold"><span style="color: #000080">binary</span></span>() | <span style="color: #009900">ParsedMime</span>, <span style="color: #009900">AcceptCallback</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000080">atom</span></span>()}] +<span style="color: #009900">ParsedMime</span> <span style="color: #990000">::</span> {<span style="color: #009900">Type</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000080">binary</span></span>(), <span style="color: #009900">SubType</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000080">binary</span></span>(), <span style="color: #FF6600">'*'</span> | <span style="color: #009900">Params</span>} +<span style="color: #009900">Params</span> <span style="color: #990000">::</span> [{<span style="color: #009900">Key</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000080">binary</span></span>(), <span style="color: #009900">Value</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000080">binary</span></span>()}] + +<span style="color: #009900">Default</span> <span style="color: #990000">-</span> <span style="color: #FF6600">crash</span></tt></pre></div></div> +<div class="paragraph"><p>Return the list of media types the resource accepts in +order of preference.</p></div> +<div class="paragraph"><p>A media type is made of different parts. The media type +<code>text/html;charset=utf-8</code> is of type <code>text</code>, subtype <code>html</code> +and has a single parameter <code>charset</code> with value <code>utf-8</code>.</p></div> +<div class="paragraph"><p>Cowboy will match the content-type request header against +the media types the server accepts and select the appropriate +callback. When that header is missing, or when the server does not +accept this media type, the request fails and an error response +is returned. Cowboy will execute the callback immediately otherwise.</p></div> +<div class="paragraph"><p>An empty parameters list <code>[]</code> means that no parameters will be +accepted. When any parameter is acceptable, the tuple form +should be used with parameters as the atom <code>'*'</code>.</p></div> +<div class="paragraph"><p>Cowboy treats all parameters as case sensitive, except for the +<code>charset</code> parameter, which is known to be case insensitive. You +should therefore always provide the charset as a lowercase +binary string.</p></div> +</div> +<div class="sect2"> +<h3 id="_content_types_provided">content_types_provided</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">content_types_provided</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> [{<span style="font-weight: bold"><span style="color: #000080">binary</span></span>() | <span style="color: #009900">ParsedMime</span>, <span style="color: #009900">ProvideCallback</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000080">atom</span></span>()}] +<span style="color: #009900">ParsedMime</span> <span style="color: #990000">::</span> {<span style="color: #009900">Type</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000080">binary</span></span>(), <span style="color: #009900">SubType</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000080">binary</span></span>(), <span style="color: #FF6600">'*'</span> | <span style="color: #009900">Params</span>} +<span style="color: #009900">Params</span> <span style="color: #990000">::</span> [{<span style="color: #009900">Key</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000080">binary</span></span>(), <span style="color: #009900">Value</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000080">binary</span></span>()}] + +<span style="color: #009900">Default</span> <span style="color: #990000">-</span> [{{ <span style="color: #990000"><<</span><span style="color: #FF0000">"text"</span><span style="color: #990000">>></span>, <span style="color: #990000"><<</span><span style="color: #FF0000">"html"</span><span style="color: #990000">>></span>, <span style="color: #FF6600">'*'</span>}, <span style="color: #FF6600">to_html</span>}]</tt></pre></div></div> +<div class="paragraph"><p>Return the list of media types the resource provides in +order of preference.</p></div> +<div class="paragraph"><p>A media type is made of different parts. The media type +<code>text/html;charset=utf-8</code> is of type <code>text</code>, subtype <code>html</code> +and has a single parameter <code>charset</code> with value <code>utf-8</code>.</p></div> +<div class="paragraph"><p>During content negotiation Cowboy will pick the most appropriate +media type for the client. The client advertises media types it +prefers with the accept header. When that header is missing, +the content negotiation fails and an error response is returned.</p></div> +<div class="paragraph"><p>The callback given for the selected media type will be called +at the end of the execution of GET and HEAD requests when a +representation must be sent to the client.</p></div> +<div class="paragraph"><p>An empty parameters list <code>[]</code> means that no parameters will be +accepted. When any parameter is acceptable, the tuple form +should be used with parameters as the atom <code>'*'</code>.</p></div> +<div class="paragraph"><p>Cowboy treats all parameters as case sensitive, except for the +<code>charset</code> parameter, which is known to be case insensitive. You +should therefore always provide the charset as a lowercase +binary string.</p></div> +<div class="paragraph"><p>Cowboy will add the negotiated <code>media_type</code> to the Req object +after this step completes:</p></div> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">req</span></span>() <span style="color: #990000">::</span> #{ + <span style="color: #0000FF">media_type</span> <span style="color: #990000">=></span> <span style="color: #009900">ParsedMime</span> +}</tt></pre></div></div> +</div> +<div class="sect2"> +<h3 id="_delete_completed">delete_completed</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">delete_completed</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">boolean</span></span>() +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> <span style="color: #000080">true</span></tt></pre></div></div> +<div class="paragraph"><p>Return whether the resource has been fully deleted from the +system, including from any internal cache.</p></div> +<div class="paragraph"><p>Returning <code>false</code> will result in a <em>202 Accepted</em> response +being sent instead of a <em>200 OK</em> or <em>204 No Content</em>.</p></div> +</div> +<div class="sect2"> +<h3 id="_delete_resource">delete_resource</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">delete_resource</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">boolean</span></span>() +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> <span style="color: #000080">false</span></tt></pre></div></div> +<div class="paragraph"><p>Delete the resource.</p></div> +<div class="paragraph"><p>Cowboy will send an error response when this function +returns <code>false</code>.</p></div> +</div> +<div class="sect2"> +<h3 id="_expires">expires</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">expires</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">calendar:datetime</span></span>() | <span style="font-weight: bold"><span style="color: #000080">binary</span></span>() | <span style="color: #000080">undefined</span> +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> <span style="color: #000080">undefined</span></tt></pre></div></div> +<div class="paragraph"><p>Return the resource’s expiration date.</p></div> +</div> +<div class="sect2"> +<h3 id="_forbidden">forbidden</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">forbidden</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">boolean</span></span>() +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> <span style="color: #000080">false</span></tt></pre></div></div> +<div class="paragraph"><p>Return whether access to the resource is forbidden.</p></div> +<div class="paragraph"><p>A <em>403 Forbidden</em> response will be sent if this +function returns <code>true</code>. This status code means that +access is forbidden regardless of authentication, +and that the request shouldn’t be repeated.</p></div> +</div> +<div class="sect2"> +<h3 id="_generate_etag">generate_etag</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">generate_etag</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000080">binary</span></span>() | {<span style="color: #FF6600">weak</span> | <span style="color: #FF6600">strong</span>, <span style="font-weight: bold"><span style="color: #000080">binary</span></span>()} +<span style="color: #009900">Default</span> <span style="color: #990000">-</span> <span style="color: #FF6600">no</span> <span style="color: #FF6600">etag</span> <span style="color: #FF6600">value</span></tt></pre></div></div> +<div class="paragraph"><p>Return the entity tag of the resource.</p></div> +<div class="paragraph"><p>When a binary is returned, the value is automatically +parsed to a tuple. The binary must be in the same +format as the etag header, including quotes.</p></div> +</div> +<div class="sect2"> +<h3 id="_is_authorized">is_authorized</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">is_authorized</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="color: #000080">true</span> | {<span style="color: #000080">false</span>, <span style="color: #009900">AuthHeader</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">iodata</span></span>()} +<span style="color: #009900">Default</span> <span style="color: #990000">-</span> <span style="color: #000080">true</span></tt></pre></div></div> +<div class="paragraph"><p>Return whether the user is authorized to perform the action.</p></div> +<div class="paragraph"><p>This function should be used to perform any necessary +authentication of the user before attempting to perform +any action on the resource.</p></div> +<div class="paragraph"><p>When authentication fails, the <code>AuthHeader</code> value will +be sent in the www-authenticate header for the +<em>401 Unauthorized</em> response.</p></div> +</div> +<div class="sect2"> +<h3 id="_is_conflict">is_conflict</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">is_conflict</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">boolean</span></span>() +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> <span style="color: #000080">false</span></tt></pre></div></div> +<div class="paragraph"><p>Return whether the PUT request results in a conflict.</p></div> +<div class="paragraph"><p>A <em>409 Conflict</em> response is sent when <code>true</code>.</p></div> +</div> +<div class="sect2"> +<h3 id="_known_methods">known_methods</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">known_methods</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> [<span style="font-weight: bold"><span style="color: #000080">binary</span></span>()] <span style="font-style: italic"><span style="color: #9A1900">%% case sensitive</span></span> +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> [<span style="color: #990000"><<</span><span style="color: #FF0000">"GET"</span><span style="color: #990000">>></span>, <span style="color: #990000"><<</span><span style="color: #FF0000">"HEAD"</span><span style="color: #990000">>></span>, <span style="color: #990000"><<</span><span style="color: #FF0000">"POST"</span><span style="color: #990000">>></span>, <span style="color: #990000"><<</span><span style="color: #FF0000">"PUT"</span><span style="color: #990000">>></span>, + <span style="color: #990000"><<</span><span style="color: #FF0000">"PATCH"</span><span style="color: #990000">>></span>, <span style="color: #990000"><<</span><span style="color: #FF0000">"DELETE"</span><span style="color: #990000">>></span>, <span style="color: #990000"><<</span><span style="color: #FF0000">"OPTIONS"</span><span style="color: #990000">>></span>]</tt></pre></div></div> +<div class="paragraph"><p>Return the list of known methods.</p></div> +<div class="paragraph"><p>The full list of methods known by the server should be +returned, regardless of their use in the resource.</p></div> +<div class="paragraph"><p>The default value lists the methods Cowboy knows and +implement in <code>cowboy_rest</code>.</p></div> +</div> +<div class="sect2"> +<h3 id="_languages_provided">languages_provided</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">languages_provided</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> [<span style="font-weight: bold"><span style="color: #000080">binary</span></span>()] <span style="font-style: italic"><span style="color: #9A1900">%% lowercase; case insensitive</span></span> +<span style="color: #009900">Default</span> <span style="color: #990000">-</span> <span style="color: #FF6600">skip</span> <span style="color: #FF6600">this</span> <span style="color: #FF6600">step</span></tt></pre></div></div> +<div class="paragraph"><p>Return the list of languages the resource provides in order +of preference.</p></div> +<div class="paragraph"><p>During content negotiation Cowboy will pick the most +appropriate language for the client. The client advertises +languages it prefers with the accept-language header. When +that header is missing, Cowboy picks the first language +from the resource.</p></div> +<div class="paragraph"><p>Cowboy will add the negotiated <code>language</code> to the Req object +after this step completes:</p></div> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">req</span></span>() <span style="color: #990000">::</span> #{ + <span style="color: #0000FF">language</span> <span style="color: #990000">=></span> <span style="font-weight: bold"><span style="color: #000080">binary</span></span>() <span style="font-style: italic"><span style="color: #9A1900">%% lowercase; case insensitive</span></span> +}</tt></pre></div></div> +</div> +<div class="sect2"> +<h3 id="_last_modified">last_modified</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">last_modified</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">calendar:datetime</span></span>() +<span style="color: #009900">Default</span> <span style="color: #990000">-</span> <span style="color: #FF6600">no</span> <span style="color: #FF6600">last</span> <span style="color: #FF6600">modified</span> <span style="color: #FF6600">value</span></tt></pre></div></div> +<div class="paragraph"><p>Return the resource’s last modification date.</p></div> +<div class="paragraph"><p>This date will be used to test against the if-modified-since +and if-unmodified-since headers, and sent as the last-modified +header in the response to GET and HEAD requests.</p></div> +</div> +<div class="sect2"> +<h3 id="_malformed_request">malformed_request</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">malformed_request</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">boolean</span></span>() +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> <span style="color: #000080">false</span></tt></pre></div></div> +<div class="paragraph"><p>Return whether the request is malformed.</p></div> +<div class="paragraph"><p>A request is malformed when a component required by the +resource is invalid. This may include the query string +or individual headers. They should be parsed and validated +in this function. The body should not be read at this point.</p></div> +</div> +<div class="sect2"> +<h3 id="_moved_permanently">moved_permanently</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">moved_permanently</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> {<span style="color: #000080">true</span>, <span style="color: #009900">URI</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">iodata</span></span>()} | <span style="color: #000080">false</span> +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> <span style="color: #000080">false</span></tt></pre></div></div> +<div class="paragraph"><p>Return whether the resource was permanently moved, and +what its new location is.</p></div> +</div> +<div class="sect2"> +<h3 id="_moved_temporarily">moved_temporarily</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">moved_temporarily</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> {<span style="color: #000080">true</span>, <span style="color: #009900">URI</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">iodata</span></span>()} | <span style="color: #000080">false</span> +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> <span style="color: #000080">false</span></tt></pre></div></div> +<div class="paragraph"><p>Return whether the resource was temporarily moved, and +what its new location is.</p></div> +</div> +<div class="sect2"> +<h3 id="_multiple_choices">multiple_choices</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">multiple_choices</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">boolean</span></span>() +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> <span style="color: #000080">false</span></tt></pre></div></div> +<div class="paragraph"><p>Return whether the client should engage in reactive +negotiation.</p></div> +<div class="paragraph"><p>Return <code>true</code> when the server has multiple representations +of a resource, each with their specific identifier, but is +unable to determine which is best for the client. For +example an image might have different sizes and the server +is unable to determine the capabilities of the client.</p></div> +<div class="paragraph"><p>When returning <code>true</code> the server should send a body with +links to the different representations. If the server has +a preferred representation it can send its link inside a +location header.</p></div> +</div> +<div class="sect2"> +<h3 id="_options">options</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">options</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #FF6600">ok</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>}</tt></pre></div></div> +<div class="paragraph"><p>Respond to an OPTIONS request.</p></div> +<div class="paragraph"><p>The response should inform the client the communication +options available for this resource. By default Cowboy +will send a <em>200 OK</em> response with the allow header set.</p></div> +</div> +<div class="sect2"> +<h3 id="_previously_existed">previously_existed</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">previously_existed</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">boolean</span></span>() +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> <span style="color: #000080">false</span></tt></pre></div></div> +<div class="paragraph"><p>Return whether the resource existed previously.</p></div> +</div> +<div class="sect2"> +<h3 id="_providecallback">ProvideCallback</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="color: #009900">ProvideCallback</span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">cowboy_req:resp_body</span></span>() +<span style="color: #009900">Default</span> <span style="color: #990000">-</span> <span style="color: #FF6600">crash</span></tt></pre></div></div> +<div class="paragraph"><p>Return the response body.</p></div> +<div class="paragraph"><p>The response body can be provided either as the actual data +to be sent or a tuple indicating which file to send.</p></div> +<div class="paragraph"><p>This function is called for both GET and HEAD requests. For +the latter the body is not sent, however.</p></div> +<div class="paragraph"><p>Note that there used to be a way to stream the response body. +It was temporarily removed and will be added back in a later +release.</p></div> +</div> +<div class="sect2"> +<h3 id="_resource_exists">resource_exists</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">resource_exists</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">boolean</span></span>() +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> <span style="color: #000080">true</span></tt></pre></div></div> +<div class="paragraph"><p>Return whether the resource exists.</p></div> +</div> +<div class="sect2"> +<h3 id="_service_available">service_available</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">service_available</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">boolean</span></span>() +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> <span style="color: #000080">true</span></tt></pre></div></div> +<div class="paragraph"><p>Return whether the service is available.</p></div> +<div class="paragraph"><p>A <em>503 Service Unavailable</em> response will be sent when this +function returns <code>false</code>.</p></div> +</div> +<div class="sect2"> +<h3 id="_uri_too_long">uri_too_long</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">uri_too_long</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">boolean</span></span>() +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> <span style="color: #000080">false</span></tt></pre></div></div> +<div class="paragraph"><p>Return whether the requested URI is too long.</p></div> +<div class="paragraph"><p>This function can be used to further restrict the length +of the URI for this specific resource.</p></div> +</div> +<div class="sect2"> +<h3 id="_valid_content_headers">valid_content_headers</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">valid_content_headers</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">boolean</span></span>() +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> <span style="color: #000080">true</span></tt></pre></div></div> +<div class="paragraph"><p>Return whether the content headers are valid.</p></div> +<div class="paragraph"><p>This callback can be used to reject requests that have +invalid content header values, for example an unsupported +content-encoding.</p></div> +</div> +<div class="sect2"> +<h3 id="_valid_entity_length">valid_entity_length</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">valid_entity_length</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">boolean</span></span>() +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> <span style="color: #000080">true</span></tt></pre></div></div> +<div class="paragraph"><p>Return whether the request body length is within acceptable boundaries.</p></div> +<div class="paragraph"><p>A <em>413 Request Entity Too Large</em> response will be sent if this +function returns <code>false</code>.</p></div> +</div> +<div class="sect2"> +<h3 id="_variances">variances</h3> +<div class="listingblock"> +<div class="content"><!-- Generator: GNU source-highlight +by Lorenzo Bettini +http://www.lorenzobettini.it +http://www.gnu.org/software/src-highlite --> +<pre><tt><span style="font-weight: bold"><span style="color: #000000">variances</span></span>(<span style="color: #009900">Req</span>, <span style="color: #009900">State</span>) <span style="color: #990000">-></span> {<span style="color: #009900">Result</span>, <span style="color: #009900">Req</span>, <span style="color: #009900">State</span>} + +<span style="color: #009900">Result</span> <span style="color: #990000">::</span> [<span style="font-weight: bold"><span style="color: #000080">binary</span></span>()] <span style="font-style: italic"><span style="color: #9A1900">%% case insensitive</span></span> +<span style="color: #009900">Default</span> <span style="color: #990000">::</span> []</tt></pre></div></div> +<div class="paragraph"><p>Return the list of request headers that affect the +representation of the resource.</p></div> +<div class="paragraph"><p>Cowboy automatically adds the accept, accept-charset and +accept-language headers when necessary. It’s also useful +to note that some standard headers also do not need to be +listed here, like the authorization header.</p></div> +</div> +</div> +</div> +<div class="sect1"> +<h2 id="_changelog">Changelog</h2> +<div class="sectionbody"> +<div class="ulist"><ul> +<li> +<p> +<strong>2.1</strong>: The <code>switch_handler</code> return value was added. +</p> +</li> +<li> +<p> +<strong>1.0</strong>: Behavior introduced. +</p> +</li> +</ul></div> +</div> +</div> +<div class="sect1"> +<h2 id="_see_also">See also</h2> +<div class="sectionbody"> +<div class="paragraph"><p><a href="..">cowboy(7)</a>, +<a href="../cowboy_handler">cowboy_handler(3)</a></p></div> +</div> +</div> + + + + + +</div> + +<div class="span3 sidecol"> + + +<h3> + Cowboy + 2.3 + Function Reference + +</h3> + +<ul> + + <li><a href="/docs/en/cowboy/2.3/guide">User Guide</a></li> + + + <li><a href="/docs/en/cowboy/2.3/manual">Function Reference</a></li> + + +</ul> + +<h4 id="docs-nav">Navigation</h4> + +<h4>Version select</h4> +<ul> + + + + <li><a href="/docs/en/cowboy/2.3/manual">2.3</a></li> + + <li><a href="/docs/en/cowboy/2.2/manual">2.2</a></li> + + <li><a href="/docs/en/cowboy/2.1/manual">2.1</a></li> + + <li><a href="/docs/en/cowboy/2.0/manual">2.0</a></li> + + <li><a href="/docs/en/cowboy/1.0/manual">1.0</a></li> + +</ul> + +</div> +</div> +</div> +</div> + + <footer> + <div class="container"> + <div class="row"> + <div class="span6"> + <p id="scroll-top"><a href="#">↑ Scroll to top</a></p> + <nav> + <ul> + <li><a href="mailto:[email protected]" title="Contact us">Contact us</a></li><li><a href="https://github.com/ninenines/ninenines.github.io" title="Github repository">Contribute to this site</a></li> + </ul> + </nav> + </div> + <div class="span6 credits"> + <p><img src="/img/footer_logo.png"></p> + <p>Copyright © Loïc Hoguin 2012-2016</p> + </div> + </div> + </div> + </footer> + + + <script src="/js/custom.js"></script> + </body> +</html> + + |