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| author | Loïc Hoguin <[email protected]> | 2018-05-02 11:35:26 +0200 |
|---|---|---|
| committer | Loïc Hoguin <[email protected]> | 2018-05-02 11:35:26 +0200 |
| commit | fec98300ec9af6c8b5f3120a60f217983c451076 (patch) | |
| tree | 9772977293124e8b9b5b253e44d8c2695cddfb44 /docs/en/cowboy/2.4/guide/rest_handlers/index.html | |
| parent | bfd2b6e01cbb36b0be0b3c860f5baf8d5b49fe7a (diff) | |
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Cowboy 2.4.0
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diff --git a/docs/en/cowboy/2.4/guide/rest_handlers/index.html b/docs/en/cowboy/2.4/guide/rest_handlers/index.html new file mode 100644 index 00000000..3489faec --- /dev/null +++ b/docs/en/cowboy/2.4/guide/rest_handlers/index.html @@ -0,0 +1,447 @@ +<!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: REST handlers</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="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>REST handlers</span></h1> + +<div class="paragraph"><p>REST is implemented in Cowboy as a sub protocol. The request +is handled as a state machine with many optional callbacks +describing the resource and modifying the machine’s behavior.</p></div> +<div class="paragraph"><p>The REST handler is the recommended way to handle HTTP requests.</p></div> +<div class="sect1"> +<h2 id="_initialization">Initialization</h2> +<div class="sectionbody"> +<div class="paragraph"><p>First, the <code>init/2</code> callback is called. This callback is common +to all handlers. To use REST for the current request, this function +must return a <code>cowboy_rest</code> tuple.</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: #990000">.</span></tt></pre></div></div> +<div class="paragraph"><p>Cowboy will then switch to the REST protocol and start executing +the state machine.</p></div> +<div class="paragraph"><p>After reaching the end of the flowchart, the <code>terminate/3</code> callback +will be called if it is defined.</p></div> +</div> +</div> +<div class="sect1"> +<h2 id="_methods">Methods</h2> +<div class="sectionbody"> +<div class="paragraph"><p>The REST component has code for handling the following HTTP methods: +HEAD, GET, POST, PATCH, PUT, DELETE and OPTIONS.</p></div> +<div class="paragraph"><p>Other methods can be accepted, however they have no specific callback +defined for them at this time.</p></div> +</div> +</div> +<div class="sect1"> +<h2 id="_callbacks">Callbacks</h2> +<div class="sectionbody"> +<div class="paragraph"><p>All callbacks are optional. Some may become mandatory depending +on what other defined callbacks return. The various flowcharts +in the next chapter should be a useful to determine which callbacks +you need.</p></div> +<div class="paragraph"><p>All callbacks take two arguments, the Req object and the State, +and return a three-element tuple of the form <code>{Value, Req, State}</code>.</p></div> +<div class="paragraph"><p>Nearly all callbacks can also return <code>{stop, Req, State}</code> to +stop execution of the request, and +<code>{{switch_handler, Module}, Req, State}</code> or +<code>{{switch_handler, Module, Opts}, Req, State}</code> to switch to +a different handler type. The exceptions are <code>expires</code> +<code>generate_etag</code>, <code>last_modified</code> and <code>variances</code>.</p></div> +<div class="paragraph"><p>The following table summarizes the callbacks and their default values. +If the callback isn’t defined, then the default value will be used. +Please look at the flowcharts to find out the result of each return +value.</p></div> +<div class="paragraph"><p>In the following table, "skip" means the callback is entirely skipped +if it is undefined, moving directly to the next step. Similarly, +"none" means there is no default value for this callback.</p></div> +<div class="tableblock"> +<table rules="all" +width="100%" +frame="border" +cellspacing="0" cellpadding="4"> +<col width="50%" /> +<col width="50%" /> +<thead> +<tr> +<th align="left" valign="top"> Callback name </th> +<th align="center" valign="top"> Default value</th> +</tr> +</thead> +<tbody> +<tr> +<td align="left" valign="top"><p class="table">allowed_methods</p></td> +<td align="center" valign="top"><p class="table"><code>[<<"GET">>, <<"HEAD">>, <<"OPTIONS">>]</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">allow_missing_post</p></td> +<td align="center" valign="top"><p class="table"><code>true</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">charsets_provided</p></td> +<td align="center" valign="top"><p class="table">skip</p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">content_types_accepted</p></td> +<td align="center" valign="top"><p class="table">none</p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">content_types_provided</p></td> +<td align="center" valign="top"><p class="table"><code>[{{ <<"text">>, <<"html">>, '*'}, to_html}]</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">delete_completed</p></td> +<td align="center" valign="top"><p class="table"><code>true</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">delete_resource</p></td> +<td align="center" valign="top"><p class="table"><code>false</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">expires</p></td> +<td align="center" valign="top"><p class="table"><code>undefined</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">forbidden</p></td> +<td align="center" valign="top"><p class="table"><code>false</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">generate_etag</p></td> +<td align="center" valign="top"><p class="table"><code>undefined</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">is_authorized</p></td> +<td align="center" valign="top"><p class="table"><code>true</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">is_conflict</p></td> +<td align="center" valign="top"><p class="table"><code>false</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">known_methods</p></td> +<td align="center" valign="top"><p class="table"><code>[<<"GET">>, <<"HEAD">>, <<"POST">>, <<"PUT">>, <<"PATCH">>, <<"DELETE">>, <<"OPTIONS">>]</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">languages_provided</p></td> +<td align="center" valign="top"><p class="table">skip</p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">last_modified</p></td> +<td align="center" valign="top"><p class="table"><code>undefined</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">malformed_request</p></td> +<td align="center" valign="top"><p class="table"><code>false</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">moved_permanently</p></td> +<td align="center" valign="top"><p class="table"><code>false</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">moved_temporarily</p></td> +<td align="center" valign="top"><p class="table"><code>false</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">multiple_choices</p></td> +<td align="center" valign="top"><p class="table"><code>false</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">options</p></td> +<td align="center" valign="top"><p class="table"><code>ok</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">previously_existed</p></td> +<td align="center" valign="top"><p class="table"><code>false</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">resource_exists</p></td> +<td align="center" valign="top"><p class="table"><code>true</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">service_available</p></td> +<td align="center" valign="top"><p class="table"><code>true</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">uri_too_long</p></td> +<td align="center" valign="top"><p class="table"><code>false</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">valid_content_headers</p></td> +<td align="center" valign="top"><p class="table"><code>true</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">valid_entity_length</p></td> +<td align="center" valign="top"><p class="table"><code>true</code></p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">variances</p></td> +<td align="center" valign="top"><p class="table"><code>[]</code></p></td> +</tr> +</tbody> +</table> +</div> +<div class="paragraph"><p>As you can see, Cowboy tries to move on with the request whenever +possible by using well thought out default values.</p></div> +<div class="paragraph"><p>In addition to these, there can be any number of user-defined +callbacks that are specified through <code>content_types_accepted/2</code> +and <code>content_types_provided/2</code>. They can take any name, however +it is recommended to use a separate prefix for the callbacks of +each function. For example, <code>from_html</code> and <code>to_html</code> indicate +in the first case that we’re accepting a resource given as HTML, +and in the second case that we send one as HTML.</p></div> +</div> +</div> +<div class="sect1"> +<h2 id="_meta_data">Meta data</h2> +<div class="sectionbody"> +<div class="paragraph"><p>Cowboy will set informative values to the Req object at various +points of the execution. You can retrieve them by matching the +Req object directly. The values are defined in the following table:</p></div> +<div class="tableblock"> +<table rules="all" +width="100%" +frame="border" +cellspacing="0" cellpadding="4"> +<col width="50%" /> +<col width="50%" /> +<thead> +<tr> +<th align="left" valign="top"> Key </th> +<th align="left" valign="top"> Details</th> +</tr> +</thead> +<tbody> +<tr> +<td align="left" valign="top"><p class="table">media_type</p></td> +<td align="left" valign="top"><p class="table">The content-type negotiated for the response entity.</p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">language</p></td> +<td align="left" valign="top"><p class="table">The language negotiated for the response entity.</p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">charset</p></td> +<td align="left" valign="top"><p class="table">The charset negotiated for the response entity.</p></td> +</tr> +</tbody> +</table> +</div> +<div class="paragraph"><p>They can be used to send a proper body with the response to a +request that used a method other than HEAD or GET.</p></div> +</div> +</div> +<div class="sect1"> +<h2 id="_response_headers">Response headers</h2> +<div class="sectionbody"> +<div class="paragraph"><p>Cowboy will set response headers automatically over the execution +of the REST code. They are listed in the following table.</p></div> +<div class="tableblock"> +<table rules="all" +width="100%" +frame="border" +cellspacing="0" cellpadding="4"> +<col width="50%" /> +<col width="50%" /> +<thead> +<tr> +<th align="left" valign="top"> Header name </th> +<th align="left" valign="top"> Details</th> +</tr> +</thead> +<tbody> +<tr> +<td align="left" valign="top"><p class="table">content-language</p></td> +<td align="left" valign="top"><p class="table">Language used in the response body</p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">content-type</p></td> +<td align="left" valign="top"><p class="table">Media type and charset of the response body</p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">etag</p></td> +<td align="left" valign="top"><p class="table">Etag of the resource</p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">expires</p></td> +<td align="left" valign="top"><p class="table">Expiration date of the resource</p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">last-modified</p></td> +<td align="left" valign="top"><p class="table">Last modification date for the resource</p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">location</p></td> +<td align="left" valign="top"><p class="table">Relative or absolute URI to the requested resource</p></td> +</tr> +<tr> +<td align="left" valign="top"><p class="table">vary</p></td> +<td align="left" valign="top"><p class="table">List of headers that may change the representation of the resource</p></td> +</tr> +</tbody> +</table> +</div> +</div> +</div> + + + + + + + + + + + <nav style="margin:1em 0"> + + <a style="float:left" href="https://ninenines.eu/docs/en/cowboy/2.4/guide/rest_principles/"> + REST principles + </a> + + + + <a style="float:right" href="https://ninenines.eu/docs/en/cowboy/2.4/guide/rest_flowcharts/"> + REST flowcharts + </a> + + </nav> + + + + +</div> + +<div class="span3 sidecol"> + + +<h3> + Cowboy + 2.4 + + User Guide +</h3> + +<ul> + + <li><a href="/docs/en/cowboy/2.4/guide">User Guide</a></li> + + + <li><a href="/docs/en/cowboy/2.4/manual">Function Reference</a></li> + + +</ul> + +<h4 id="docs-nav">Navigation</h4> + +<h4>Version select</h4> +<ul> + + + + <li><a href="/docs/en/cowboy/2.4/guide">2.4</a></li> + + <li><a href="/docs/en/cowboy/2.3/guide">2.3</a></li> + + <li><a href="/docs/en/cowboy/2.2/guide">2.2</a></li> + + <li><a href="/docs/en/cowboy/2.1/guide">2.1</a></li> + + <li><a href="/docs/en/cowboy/2.0/guide">2.0</a></li> + + <li><a href="/docs/en/cowboy/1.0/guide">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 2012-2018</p> + </div> + </div> + </div> + </footer> + + + <script src="/js/custom.js"></script> + </body> +</html> + + |