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<h1 class="lined-header"><span>cowboy:start_clear(3)</span></h1>
<div class="sect1">
<h2 id="_name">Name</h2>
<div class="sectionbody">
<div class="paragraph"><p>cowboy:start_clear - Listen for connections using plain TCP</p></div>
</div>
</div>
<div class="sect1">
<h2 id="_description">Description</h2>
<div class="sectionbody">
<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><span style="font-weight: bold"><span style="color: #000000">start_clear</span></span>(<span style="color: #009900">Name</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">ranch:ref</span></span>(),
<span style="color: #009900">TransportOpts</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">ranch_tcp:opts</span></span>(),
<span style="color: #009900">ProtocolOpts</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000000">opts</span></span>())
<span style="color: #990000">-></span> {<span style="color: #FF6600">ok</span>, <span style="color: #009900">ListenerPid</span> <span style="color: #990000">::</span> <span style="font-weight: bold"><span style="color: #000080">pid</span></span>()}
| {<span style="color: #FF6600">error</span>, <span style="font-weight: bold"><span style="color: #000000">any</span></span>()}</tt></pre></div></div>
<div class="paragraph"><p>Start listening for connections over a clear TCP channel.</p></div>
<div class="paragraph"><p>Both HTTP/1.1 and HTTP/2 are supported on this listener.
HTTP/2 has two methods of establishing a connection over
a clear TCP channel. Both the upgrade and the prior knowledge
methods are supported.</p></div>
</div>
</div>
<div class="sect1">
<h2 id="_arguments">Arguments</h2>
<div class="sectionbody">
<div class="dlist"><dl>
<dt class="hdlist1">
Name
</dt>
<dd>
<p>
The listener name is used to refer to this listener in
future calls, for example when stopping it or when
updating the routes defined.
</p>
<div class="paragraph"><p>It can be any Erlang term. An atom is generally good enough,
for example <code>api</code>, <code>my_app_clear</code> or <code>my_app_tls</code>.</p></div>
</dd>
<dt class="hdlist1">
TransportOpts
</dt>
<dd>
<p>
The transport options are where the TCP options, including
the listener’s port number, are defined. Transport options
are provided as a list of keys and values, for example
<code>[{port, 8080}]</code>.
</p>
<div class="paragraph"><p>The available options are documented in the
<a href="../ranch_tcp">ranch_tcp(3)</a> manual.</p></div>
</dd>
<dt class="hdlist1">
ProtocolOpts
</dt>
<dd>
<p>
The protocol options are in a map containing all the options for
the different protocols that may be involved when connecting
to the listener, including HTTP/1.1 and HTTP/2.
</p>
<div class="paragraph"><p>The HTTP/1.1 options are documented in the
<a href="../cowboy_http">cowboy_http(3)</a> manual;
and the HTTP/2 options in
<a href="../cowboy_http2">cowboy_http2(3)</a>.</p></div>
</dd>
</dl></div>
</div>
</div>
<div class="sect1">
<h2 id="_return_value">Return value</h2>
<div class="sectionbody">
<div class="paragraph"><p>An ok tuple is returned on success. It contains the pid of
the top-level supervisor for the listener.</p></div>
<div class="paragraph"><p>An error tuple is returned on error. The error reason may
be any Erlang term.</p></div>
<div class="paragraph"><p>A common error is <code>eaddrinuse</code>. It indicates that the port
configured for Cowboy is already in use.</p></div>
</div>
</div>
<div class="sect1">
<h2 id="_changelog">Changelog</h2>
<div class="sectionbody">
<div class="ulist"><ul>
<li>
<p>
<strong>2.0</strong>: HTTP/2 support added.
</p>
</li>
<li>
<p>
<strong>2.0</strong>: Function introduced. Replaces <code>cowboy:start_http/4</code>.
</p>
</li>
</ul></div>
</div>
</div>
<div class="sect1">
<h2 id="_examples">Examples</h2>
<div class="sectionbody">
<div class="listingblock">
<div class="title">Start a listener</div>
<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><span style="color: #009900">Dispatch</span> <span style="color: #990000">=</span> <span style="font-weight: bold"><span style="color: #000000">cowboy_router:compile</span></span>([
{<span style="color: #FF6600">'_'</span>, [
{<span style="color: #FF0000">"/"</span>, <span style="color: #FF6600">toppage_h</span>, []}
]}
]),
{<span style="color: #FF6600">ok</span>, <span style="color: #990000">_</span>} <span style="color: #990000">=</span> <span style="font-weight: bold"><span style="color: #000000">cowboy:start_clear</span></span>(<span style="color: #FF6600">example</span>, [{<span style="color: #FF6600">port</span>, <span style="color: #993399">8080</span>}], #{
<span style="color: #0000FF">env</span> <span style="color: #990000">=></span> #{<span style="color: #0000FF">dispatch</span> <span style="color: #990000">=></span> <span style="color: #009900">Dispatch</span>}
})<span style="color: #990000">.</span></tt></pre></div></div>
<div class="listingblock">
<div class="title">Start a listener on a random port</div>
<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><span style="color: #009900">Name</span> <span style="color: #990000">=</span> <span style="color: #FF6600">example</span>,
{<span style="color: #FF6600">ok</span>, <span style="color: #990000">_</span>} <span style="color: #990000">=</span> <span style="font-weight: bold"><span style="color: #000000">cowboy:start_clear</span></span>(<span style="color: #009900">Name</span>, [], #{
<span style="color: #0000FF">env</span> <span style="color: #990000">=></span> #{<span style="color: #0000FF">dispatch</span> <span style="color: #990000">=></span> <span style="color: #009900">Dispatch</span>}
}),
<span style="color: #009900">Port</span> <span style="color: #990000">=</span> <span style="font-weight: bold"><span style="color: #000000">ranch:get_port</span></span>(<span style="color: #009900">Name</span>)<span style="color: #990000">.</span></tt></pre></div></div>
</div>
</div>
<div class="sect1">
<h2 id="_see_also">See also</h2>
<div class="sectionbody">
<div class="paragraph"><p><a href="../cowboy">cowboy(3)</a>,
<a href="../cowboy.start_tls">cowboy:start_tls(3)</a>,
<a href="../cowboy.stop_listener">cowboy:stop_listener(3)</a>,
<a href="../ranch">ranch(3)</a></p></div>
</div>
</div>
</div>
<div class="span3 sidecol">
<h3>
Cowboy
2.0
Function Reference
</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/2.0/manual">2.0</a></li>
<li><a href="/docs/en/cowboy/1.0/manual">1.0</a></li>
</ul>
</div>
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