blob: a3dc4c66019516816ca4c9b703df6c09b0ab1a13 (
plain) (
tree)
|
|
<!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">
<title>Nine Nines: cowboy_constraints:nonempty(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=6" 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>cowboy_constraints:nonempty(3)</span></h1>
<h2 id="_name">Name</h2>
<p>cowboy_constraints:nonempty - Non-empty constraint</p>
<h2 id="_description">Description</h2>
<p>Constraint functions implement a number of different operations.</p>
<div class="listingblock"><div class="content"><!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><b><font color="#000000">nonempty</font></b>(<font color="#FF6600">forward</font> | <font color="#FF6600">reverse</font>, <font color="#990000"><<>></font>) <font color="#990000">-></font> {<font color="#FF6600">error</font>, <font color="#FF6600">empty</font>}</tt></pre>
</div></div>
<p>Reject empty values.</p>
<div class="listingblock"><div class="content"><!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><b><font color="#000000">nonempty</font></b>(<font color="#FF6600">forward</font> | <font color="#FF6600">reverse</font>, <font color="#009900">Bin</font>) <font color="#990000">-></font> {<font color="#FF6600">ok</font>, <font color="#009900">Bin</font>}
<font color="#009900">Bin</font> <font color="#990000">::</font> <b><font color="#000080">binary</font></b>()</tt></pre>
</div></div>
<p>Accept any other binary values.</p>
<div class="listingblock"><div class="content"><!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><b><font color="#000000">nonempty</font></b>(<font color="#FF6600">format_error</font>, <font color="#009900">Error</font>) <font color="#990000">-></font> <font color="#009900">HumanReadable</font>
<font color="#009900">Error</font> <font color="#990000">::</font> {<font color="#FF6600">empty</font>, <font color="#009900">Bin</font>}
<font color="#009900">HumanReadable</font> <font color="#990000">::</font> <b><font color="#000000">iolist</font></b>()</tt></pre>
</div></div>
<p>Generate a human-readable error message.</p>
<h2 id="_arguments">Arguments</h2>
<p>Arguments vary depending on the operation. Constraint functions always take the operation type as first argument, and the value as second argument.</p>
<h2 id="_return_value">Return value</h2>
<p>The return value varies depending on the operation.</p>
<h2 id="_changelog">Changelog</h2>
<ul><li><strong>2.0</strong>: Interface modified to allow for a variety of operations.
</li>
<li><strong>1.0</strong>: Constraint introduced.
</li>
</ul>
<h2 id="_examples">Examples</h2>
<p>This function is not meant to be called directly.</p>
<h2 id="_see_also">See also</h2>
<p><a href="../cowboy_constraints">cowboy_constraints(3)</a>, <a href="../cowboy_constraints.int">cowboy_constraints:int(3)</a>, <a href="../cowboy_router">cowboy_router(3)</a>, <a href="../cowboy_req.match_cookies">cowboy_req:match_cookies(3)</a>, <a href="../cowboy_req.match_qs">cowboy_req:match_qs(3)</a></p>
</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/2.6/manual">2.6</a></li>
<li><a href="/docs/en/cowboy/2.5/manual">2.5</a></li>
<li><a href="/docs/en/cowboy/2.4/manual">2.4</a></li>
<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>
</ul>
<h3 id="_like_my_work__donate">Like my work? Donate!</h3>
<p>Donate to Loïc Hoguin because his work on Cowboy, Ranch, Gun and Erlang.mk is fantastic:</p>
<form action="https://www.paypal.com/cgi-bin/webscr" method="post" style="display:inline">
<input type="hidden" name="cmd" value="_donations">
<input type="hidden" name="business" value="[email protected]">
<input type="hidden" name="lc" value="FR">
<input type="hidden" name="item_name" value="Loic Hoguin">
<input type="hidden" name="item_number" value="99s">
<input type="hidden" name="currency_code" value="EUR">
<input type="hidden" name="bn" value="PP-DonationsBF:btn_donate_LG.gif:NonHosted">
<input type="image" src="https://www.paypalobjects.com/en_US/i/btn/btn_donate_LG.gif" border="0" name="submit" alt="PayPal - The safer, easier way to pay online!">
<img alt="" border="0" src="https://www.paypalobjects.com/fr_FR/i/scr/pixel.gif" width="1" height="1">
</form><p>Recurring payment options are also available via <a href="https://salt.bountysource.com/teams/ninenines">BountySource</a>. These funds are used to cover the recurring expenses like dedicated servers or domain names.</p>
</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>
|
