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<h1 class="lined-header"><span>cowboy_req:stream_events(3)</span></h1>
<h2 id="_name">Name</h2>
<p>cowboy_req:stream_events - Stream events</p>
<h2 id="_description">Description</h2>
<div class="listingblock"><div class="content"><!-- Generator: GNU source-highlight 3.1.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><b><font color="#000000">stream_events</font></b>(<font color="#009900">Events</font>, <font color="#009900">IsFin</font>, <font color="#009900">Req</font> <font color="#990000">::</font> <b><font color="#000000">cowboy_req:req</font></b>()) <font color="#990000">-></font> <font color="#FF6600">ok</font>
<font color="#009900">Events</font> <font color="#990000">::</font> <font color="#009900">Event</font> | [<font color="#009900">Event</font>]
<font color="#009900">IsFin</font> <font color="#990000">::</font> <font color="#FF6600">fin</font> | <font color="#FF6600">nofin</font>
<font color="#009900">Event</font> <font color="#990000">::</font> #{
<font color="#0000FF">comment</font> <font color="#990000">=></font> <b><font color="#000000">iodata</font></b>(),
<font color="#0000FF">data</font> <font color="#990000">=></font> <b><font color="#000000">iodata</font></b>(),
<font color="#0000FF">event</font> <font color="#990000">=></font> <b><font color="#000000">iodata</font></b>() | <b><font color="#000080">atom</font></b>(),
<font color="#0000FF">id</font> <font color="#990000">=></font> <b><font color="#000000">iodata</font></b>(),
<font color="#0000FF">retry</font> <font color="#990000">=></font> <b><font color="#000000">non_neg_integer</font></b>()
}</tt></pre>
</div></div>
<p>Stream events.</p>
<p>This function should only be used for <code>text/event-stream</code> responses when using server-sent events. Cowboy will automatically encode the given events to their text representation.</p>
<p>This function may be called as many times as needed after initiating a response using the <a href="../cowboy_req.stream_reply">cowboy_req:stream_reply(3)</a> function.</p>
<p>The second argument indicates if this call is the final call. Use the <code>nofin</code> value until you know no more data will be sent. The final call should use <code>fin</code> (possibly with an empty data value) or be a call to the <a href="../cowboy_req.stream_trailers">cowboy_req:stream_trailers(3)</a> function.</p>
<p>Note that not using <code>fin</code> for the final call is not an error; Cowboy will take care of it when the request handler terminates if needed. Depending on the resource it may however be more efficient to do it as early as possible.</p>
<p>You do not need to handle HEAD requests specifically as Cowboy will ensure no data is sent when you call this function.</p>
<h2 id="_arguments">Arguments</h2>
<dl><dt>Events</dt>
<dd><p>Events to be sent. All fields are optional.</p>
</dd>
<dt>IsFin</dt>
<dd><p>A flag indicating whether this is the final piece of data to be sent.</p>
</dd>
<dt>Req</dt>
<dd><p>The Req object.</p>
</dd>
</dl>
<h2 id="_return_value">Return value</h2>
<p>The atom <code>ok</code> is always returned. It can be safely ignored.</p>
<h2 id="_changelog">Changelog</h2>
<ul><li><strong>2.5</strong>: Function introduced.
</li>
</ul>
<h2 id="_examples">Examples</h2>
<div class="listingblock"><div class="title">Stream events</div>
<div class="content"><!-- Generator: GNU source-highlight 3.1.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><font color="#009900">Req</font> <font color="#990000">=</font> <b><font color="#000000">cowboy_req:stream_reply</font></b>(<font color="#993399">200</font>, #{
<font color="#990000"><<</font><font color="#FF0000">"content-type"</font><font color="#990000">>></font> <font color="#990000">=></font> <font color="#990000"><<</font><font color="#FF0000">"text/event-stream"</font><font color="#990000">>></font>
}, <font color="#009900">Req0</font>),
<b><font color="#000000">cowboy_req:stream_events</font></b>(#{
<font color="#0000FF">id</font> <font color="#990000">=></font> <font color="#990000"><<</font><font color="#FF0000">"comment-123"</font><font color="#990000">>></font>,
<font color="#0000FF">event</font> <font color="#990000">=></font> <font color="#990000"><<</font><font color="#FF0000">"add_comment"</font><font color="#990000">>></font>,
<font color="#0000FF">data</font> <font color="#990000">=></font> <font color="#990000"><<</font><font color="#FF0000">"Hello,\n\nI noticed something wrong in ..."</font><font color="#990000">>></font>
}, <font color="#FF6600">nofin</font>, <font color="#009900">Req</font>),
<b><font color="#000000">timer:sleep</font></b>(<font color="#993399">1000</font>),
<b><font color="#000000">cowboy_req:stream_events</font></b>(#{
<font color="#0000FF">event</font> <font color="#990000">=></font> <font color="#990000"><<</font><font color="#FF0000">"debug"</font><font color="#990000">>></font>,
<font color="#0000FF">data</font> <font color="#990000">=></font> <b><font color="#000000">io_lib:format</font></b>(<font color="#FF0000">"An error occurred: ~p~n"</font>, [<font color="#009900">Error</font>])
}, <font color="#FF6600">fin</font>, <font color="#009900">Req</font>)<font color="#990000">.</font></tt></pre>
</div></div>
<h2 id="_see_also">See also</h2>
<p><a href="../cowboy_req">cowboy_req(3)</a>, <a href="../cowboy_req.stream_reply">cowboy_req:stream_reply(3)</a>, <a href="../cowboy_req.stream_body">cowboy_req:stream_body(3)</a>, <a href="../cowboy_req.stream_trailers">cowboy_req:stream_trailers(3)</a></p>
</div>
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<h3>
Cowboy
2.5
Function Reference
</h3>
<ul>
<li><a href="/docs/en/cowboy/2.5/guide">User Guide</a></li>
<li><a href="/docs/en/cowboy/2.5/manual">Function Reference</a></li>
</ul>
<h4 id="docs-nav">Navigation</h4>
<h4>Version select</h4>
<ul>
<li><a href="/docs/en/cowboy/2.7/manual">2.7</a></li>
<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>
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