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| author | Loïc Hoguin <[email protected]> | 2016-03-28 15:36:42 +0200 |
|---|---|---|
| committer | Loïc Hoguin <[email protected]> | 2016-03-28 15:36:42 +0200 |
| commit | fe3492a98de29942477b061cd02c92246f4bf85a (patch) | |
| tree | 2255b796a657e6e4dfb72beec1141258d17f1220 /docs/en/cowboy/2.0/guide/constraints/index.html | |
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Initial commit, new website system
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diff --git a/docs/en/cowboy/2.0/guide/constraints/index.html b/docs/en/cowboy/2.0/guide/constraints/index.html new file mode 100644 index 00000000..f9c072b6 --- /dev/null +++ b/docs/en/cowboy/2.0/guide/constraints/index.html @@ -0,0 +1,211 @@ +<!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 0.15" /> + + <title>Nine Nines: Constraints</title> + + <link href='http://fonts.googleapis.com/css?family=Open+Sans:400,700,400italic' rel='stylesheet' type='text/css'> + + <link href="/css/bootstrap.min.css" rel="stylesheet"> + <link href="/css/99s.css" 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>Constraints</span></h1> + +<div class="paragraph"><p>Cowboy provides an optional constraints based validation feature
+when interacting with user input.</p></div>
+<div class="paragraph"><p>Constraints are first used during routing. The router uses
+constraints to more accurately match bound values, allowing
+to create routes where a segment is an integer for example,
+and rejecting the others.</p></div>
+<div class="paragraph"><p>Constraints are also used when performing a match operation
+on input data, like the query string or cookies. There, a
+default value can also be provided for optional values.</p></div>
+<div class="paragraph"><p>Finally, constraints can be used to not only validate input,
+but also convert said input into proper Erlang terms, all in
+one step.</p></div>
+<div class="sect1">
+<h2 id="_structure">Structure</h2>
+<div class="sectionbody">
+<div class="paragraph"><p>Constraints are provided as a list of fields and for each
+field a list of constraints for that field can be provided.</p></div>
+<div class="paragraph"><p>Fields are either the name of the field; the name and
+one or more constraints; or the name, one or more constraints
+and a default value.</p></div>
+<div class="paragraph"><p>When no default value is provided then the field is required.
+Otherwise the default value is used.</p></div>
+<div class="paragraph"><p>All constraints for a field will be used to match its value
+in the order they are given. If the value is modified by a
+constraint, the next constraint receives the updated value.</p></div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_built_in_constraints">Built-in constraints</h2>
+<div class="sectionbody">
+<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"> Constraint </th>
+<th align="left" valign="top"> Description</th>
+</tr>
+</thead>
+<tbody>
+<tr>
+<td align="left" valign="top"><p class="table">int</p></td>
+<td align="left" valign="top"><p class="table">Convert binary value to integer.</p></td>
+</tr>
+<tr>
+<td align="left" valign="top"><p class="table">nonempty</p></td>
+<td align="left" valign="top"><p class="table">Ensures the binary value is non-empty.</p></td>
+</tr>
+</tbody>
+</table>
+</div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_custom_constraint">Custom constraint</h2>
+<div class="sectionbody">
+<div class="paragraph"><p>In addition to the predefined constraints, Cowboy will accept
+a fun. This fun must accept one argument and return one of
+<code>true</code>, <code>{true, NewValue}</code> or <code>false</code>. The result indicates
+whether the value matches the constraint, and if it does it
+can optionally be modified. This allows converting the value
+to a more appropriate Erlang term.</p></div>
+<div class="paragraph"><p>Note that constraint functions SHOULD be pure and MUST NOT crash.</p></div>
+</div>
+</div>
+ + + +</div> + +<div class="span3 sidecol"> + + +<h3> + Cowboy + 2.0 + + User Guide +</h3> + +<ul> + + <li><a href="/docs/en/cowboy/2.0/guide">User Guide</a></li> + + + <li><a href="/docs/en/cowboy/2.0/manual">Function Reference</a></li> + + +</ul> + +<h4 id="docs-nav">Navigation</h4> + +<h4>Version select</h4> +<ul> + + + + <li><a href="/docs/en/cowboy/1.0/guide">1.0</a></li> + + <li><a href="/docs/en/cowboy/2.0/guide">2.0</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="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script> + <script src="/js/bootstrap-carousel.js"></script> + <script src="/js/bootstrap-dropdown.js"></script> + <script src="/js/custom.js"></script> + </body> +</html> + + |