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<h1 class="lined-header"><span>cowboy_router</span></h1>
<p>The <code>cowboy_router</code> middleware maps the requested host and path to the handler to be used for processing the request. It uses the dispatch rules compiled from the routes given to the <code>compile/1</code> function for this purpose. It adds the handler name and options to the environment as the values <code>handler</code> and <code>handler_opts</code> respectively.</p>
<p>Environment input:</p>
<ul>
<li>dispatch = dispatch_rules()</li>
</ul>
<p>Environment output:</p>
<ul>
<li>handler = module()</li>
<li>handler_opts = any()</li>
</ul>
<h2 id="types">Types</h2>
<h3 id="bindings">bindings() = [{atom(), binary()}]</h3>
<p>List of bindings found during routing.</p>
<h3 id="constraints">constraints() = [IntConstraint | FunConstraint]</h3>
<p>Types:</p>
<ul>
<li>IntConstraint = {atom(), int}</li>
<li>FunConstraint = {atom(), function, Fun}</li>
<li>Fun = fun((binary()) -> true | {true, any()} | false)</li>
</ul>
<p>List of constraints to apply to the bindings.</p>
<p>The int constraint will convert the binding to an integer. The fun constraint allows writing custom code for checking the bindings. Returning a new value from that fun allows replacing the current binding with a new value.</p>
<h3 id="dispatch_rules">dispatch_rules() - opaque to the user</h3>
<p>Rules for dispatching request used by Cowboy.</p>
<h3 id="routes">routes() = [{Host, Paths} | {Host, constraints(), Paths}]</h3>
<p>Types:</p>
<ul>
<li>Host = Path = '_' | iodata()</li>
<li>Paths = [{Path, Handler, Opts} | {Path, constraints(), Handler, Opts}]</li>
<li>Handler = module()</li>
<li>Opts = any()</li>
</ul>
<p>Human readable list of routes mapping hosts and paths to handlers.</p>
<p>The syntax for routes is defined in the user guide.</p>
<h3 id="tokens">tokens() = [binary()]</h3>
<p>List of host_info and path_info tokens found during routing.</p>
<h2 id="exports">Exports</h2>
<h3 id="compile">compile(Routes) -> Dispatch</h3>
<p>Types:</p>
<ul>
<li>Routes = routes()</li>
<li>Dispatch = dispatch_rules()</li>
</ul>
<p>Compile the routes for use by Cowboy.</p>
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<h3>See also</h3><ul><li><a href="/docs/en/cowboy/1.0/guide/">User Guide</a></li><li><a href="/docs/en/cowboy/1.0/index.html">README</a></li></ul>
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<li><a href="/docs/en/cowboy/1.0/manual/"><strong>1.0</strong></a></li>
<li><a href="/docs/en/cowboy/HEAD/manual/"><strong>HEAD</strong></a></li>
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