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<div class="section" id="streams-coroutine-based-api">
<span id="asyncio-streams"></span><h1>18.5.5. Streams (coroutine based API)<a class="headerlink" href="#streams-coroutine-based-api" title="Permalink to this headline">¶</a></h1>
<p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.6/Lib/asyncio/streams.py">Lib/asyncio/streams.py</a></p>
<div class="section" id="stream-functions">
<h2>18.5.5.1. Stream functions<a class="headerlink" href="#stream-functions" title="Permalink to this headline">¶</a></h2>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">The top-level functions in this module are meant as convenience wrappers
only; there’s really nothing special there, and if they don’t do
exactly what you want, feel free to copy their code.</p>
</div>
<dl class="function">
<dt id="asyncio.open_connection">
<em class="property">coroutine </em><code class="descclassname">asyncio.</code><code class="descname">open_connection</code><span class="sig-paren">(</span><em>host=None</em>, <em>port=None</em>, <em>*</em>, <em>loop=None</em>, <em>limit=None</em>, <em>**kwds</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.open_connection" title="Permalink to this definition">¶</a></dt>
<dd><p>A wrapper for <a class="reference internal" href="asyncio-eventloop.html#asyncio.AbstractEventLoop.create_connection" title="asyncio.AbstractEventLoop.create_connection"><code class="xref py py-meth docutils literal notranslate"><span class="pre">create_connection()</span></code></a> returning a (reader,
writer) pair.</p>
<p>The reader returned is a <a class="reference internal" href="#asyncio.StreamReader" title="asyncio.StreamReader"><code class="xref py py-class docutils literal notranslate"><span class="pre">StreamReader</span></code></a> instance; the writer is
a <a class="reference internal" href="#asyncio.StreamWriter" title="asyncio.StreamWriter"><code class="xref py py-class docutils literal notranslate"><span class="pre">StreamWriter</span></code></a> instance.</p>
<p>The arguments are all the usual arguments to
<a class="reference internal" href="asyncio-eventloop.html#asyncio.AbstractEventLoop.create_connection" title="asyncio.AbstractEventLoop.create_connection"><code class="xref py py-meth docutils literal notranslate"><span class="pre">AbstractEventLoop.create_connection()</span></code></a> except <em>protocol_factory</em>; most
common are positional host and port, with various optional keyword arguments
following.</p>
<p>Additional optional keyword arguments are <em>loop</em> (to set the event loop
instance to use) and <em>limit</em> (to set the buffer limit passed to the
<a class="reference internal" href="#asyncio.StreamReader" title="asyncio.StreamReader"><code class="xref py py-class docutils literal notranslate"><span class="pre">StreamReader</span></code></a>).</p>
<p>This function is a <a class="reference internal" href="asyncio-task.html#coroutine"><span class="std std-ref">coroutine</span></a>.</p>
</dd></dl>
<dl class="function">
<dt id="asyncio.start_server">
<em class="property">coroutine </em><code class="descclassname">asyncio.</code><code class="descname">start_server</code><span class="sig-paren">(</span><em>client_connected_cb</em>, <em>host=None</em>, <em>port=None</em>, <em>*</em>, <em>loop=None</em>, <em>limit=None</em>, <em>**kwds</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.start_server" title="Permalink to this definition">¶</a></dt>
<dd><p>Start a socket server, with a callback for each client connected. The return
value is the same as <a class="reference internal" href="asyncio-eventloop.html#asyncio.AbstractEventLoop.create_server" title="asyncio.AbstractEventLoop.create_server"><code class="xref py py-meth docutils literal notranslate"><span class="pre">create_server()</span></code></a>.</p>
<p>The <em>client_connected_cb</em> parameter is called with two parameters:
<em>client_reader</em>, <em>client_writer</em>. <em>client_reader</em> is a
<a class="reference internal" href="#asyncio.StreamReader" title="asyncio.StreamReader"><code class="xref py py-class docutils literal notranslate"><span class="pre">StreamReader</span></code></a> object, while <em>client_writer</em> is a
<a class="reference internal" href="#asyncio.StreamWriter" title="asyncio.StreamWriter"><code class="xref py py-class docutils literal notranslate"><span class="pre">StreamWriter</span></code></a> object. The <em>client_connected_cb</em> parameter can
either be a plain callback function or a <a class="reference internal" href="asyncio-task.html#coroutine"><span class="std std-ref">coroutine function</span></a>; if it is a coroutine function, it will be automatically
converted into a <a class="reference internal" href="asyncio-task.html#asyncio.Task" title="asyncio.Task"><code class="xref py py-class docutils literal notranslate"><span class="pre">Task</span></code></a>.</p>
<p>The rest of the arguments are all the usual arguments to
<a class="reference internal" href="asyncio-eventloop.html#asyncio.AbstractEventLoop.create_server" title="asyncio.AbstractEventLoop.create_server"><code class="xref py py-meth docutils literal notranslate"><span class="pre">create_server()</span></code></a> except <em>protocol_factory</em>; most
common are positional <em>host</em> and <em>port</em>, with various optional keyword
arguments following.</p>
<p>Additional optional keyword arguments are <em>loop</em> (to set the event loop
instance to use) and <em>limit</em> (to set the buffer limit passed to the
<a class="reference internal" href="#asyncio.StreamReader" title="asyncio.StreamReader"><code class="xref py py-class docutils literal notranslate"><span class="pre">StreamReader</span></code></a>).</p>
<p>This function is a <a class="reference internal" href="asyncio-task.html#coroutine"><span class="std std-ref">coroutine</span></a>.</p>
</dd></dl>
<dl class="function">
<dt id="asyncio.open_unix_connection">
<em class="property">coroutine </em><code class="descclassname">asyncio.</code><code class="descname">open_unix_connection</code><span class="sig-paren">(</span><em>path=None</em>, <em>*</em>, <em>loop=None</em>, <em>limit=None</em>, <em>**kwds</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.open_unix_connection" title="Permalink to this definition">¶</a></dt>
<dd><p>A wrapper for <a class="reference internal" href="asyncio-eventloop.html#asyncio.AbstractEventLoop.create_unix_connection" title="asyncio.AbstractEventLoop.create_unix_connection"><code class="xref py py-meth docutils literal notranslate"><span class="pre">create_unix_connection()</span></code></a> returning
a (reader, writer) pair.</p>
<p>See <a class="reference internal" href="#asyncio.open_connection" title="asyncio.open_connection"><code class="xref py py-func docutils literal notranslate"><span class="pre">open_connection()</span></code></a> for information about return value and other
details.</p>
<p>This function is a <a class="reference internal" href="asyncio-task.html#coroutine"><span class="std std-ref">coroutine</span></a>.</p>
<p>Availability: UNIX.</p>
</dd></dl>
<dl class="function">
<dt id="asyncio.start_unix_server">
<em class="property">coroutine </em><code class="descclassname">asyncio.</code><code class="descname">start_unix_server</code><span class="sig-paren">(</span><em>client_connected_cb</em>, <em>path=None</em>, <em>*</em>, <em>loop=None</em>, <em>limit=None</em>, <em>**kwds</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.start_unix_server" title="Permalink to this definition">¶</a></dt>
<dd><p>Start a UNIX Domain Socket server, with a callback for each client connected.</p>
<p>See <a class="reference internal" href="#asyncio.start_server" title="asyncio.start_server"><code class="xref py py-func docutils literal notranslate"><span class="pre">start_server()</span></code></a> for information about return value and other
details.</p>
<p>This function is a <a class="reference internal" href="asyncio-task.html#coroutine"><span class="std std-ref">coroutine</span></a>.</p>
<p>Availability: UNIX.</p>
</dd></dl>
</div>
<div class="section" id="streamreader">
<h2>18.5.5.2. StreamReader<a class="headerlink" href="#streamreader" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt id="asyncio.StreamReader">
<em class="property">class </em><code class="descclassname">asyncio.</code><code class="descname">StreamReader</code><span class="sig-paren">(</span><em>limit=_DEFAULT_LIMIT</em>, <em>loop=None</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader" title="Permalink to this definition">¶</a></dt>
<dd><p>This class is <a class="reference internal" href="asyncio-dev.html#asyncio-multithreading"><span class="std std-ref">not thread safe</span></a>.</p>
<p>The <em>limit</em> argument’s default value is set to _DEFAULT_LIMIT which is 2**16 (64 KiB)</p>
<dl class="method">
<dt id="asyncio.StreamReader.exception">
<code class="descname">exception</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader.exception" title="Permalink to this definition">¶</a></dt>
<dd><p>Get the exception.</p>
</dd></dl>
<dl class="method">
<dt id="asyncio.StreamReader.feed_eof">
<code class="descname">feed_eof</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader.feed_eof" title="Permalink to this definition">¶</a></dt>
<dd><p>Acknowledge the EOF.</p>
</dd></dl>
<dl class="method">
<dt id="asyncio.StreamReader.feed_data">
<code class="descname">feed_data</code><span class="sig-paren">(</span><em>data</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader.feed_data" title="Permalink to this definition">¶</a></dt>
<dd><p>Feed <em>data</em> bytes in the internal buffer. Any operations waiting
for the data will be resumed.</p>
</dd></dl>
<dl class="method">
<dt id="asyncio.StreamReader.set_exception">
<code class="descname">set_exception</code><span class="sig-paren">(</span><em>exc</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader.set_exception" title="Permalink to this definition">¶</a></dt>
<dd><p>Set the exception.</p>
</dd></dl>
<dl class="method">
<dt id="asyncio.StreamReader.set_transport">
<code class="descname">set_transport</code><span class="sig-paren">(</span><em>transport</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader.set_transport" title="Permalink to this definition">¶</a></dt>
<dd><p>Set the transport.</p>
</dd></dl>
<dl class="method">
<dt id="asyncio.StreamReader.read">
<em class="property">coroutine </em><code class="descname">read</code><span class="sig-paren">(</span><em>n=-1</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader.read" title="Permalink to this definition">¶</a></dt>
<dd><p>Read up to <em>n</em> bytes. If <em>n</em> is not provided, or set to <code class="docutils literal notranslate"><span class="pre">-1</span></code>,
read until EOF and return all read bytes.</p>
<p>If the EOF was received and the internal buffer is empty,
return an empty <code class="docutils literal notranslate"><span class="pre">bytes</span></code> object.</p>
<p>This method is a <a class="reference internal" href="asyncio-task.html#coroutine"><span class="std std-ref">coroutine</span></a>.</p>
</dd></dl>
<dl class="method">
<dt id="asyncio.StreamReader.readline">
<em class="property">coroutine </em><code class="descname">readline</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader.readline" title="Permalink to this definition">¶</a></dt>
<dd><p>Read one line, where “line” is a sequence of bytes ending with <code class="docutils literal notranslate"><span class="pre">\n</span></code>.</p>
<p>If EOF is received, and <code class="docutils literal notranslate"><span class="pre">\n</span></code> was not found, the method will
return the partial read bytes.</p>
<p>If the EOF was received and the internal buffer is empty,
return an empty <code class="docutils literal notranslate"><span class="pre">bytes</span></code> object.</p>
<p>This method is a <a class="reference internal" href="asyncio-task.html#coroutine"><span class="std std-ref">coroutine</span></a>.</p>
</dd></dl>
<dl class="method">
<dt id="asyncio.StreamReader.readexactly">
<em class="property">coroutine </em><code class="descname">readexactly</code><span class="sig-paren">(</span><em>n</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader.readexactly" title="Permalink to this definition">¶</a></dt>
<dd><p>Read exactly <em>n</em> bytes. Raise an <a class="reference internal" href="#asyncio.IncompleteReadError" title="asyncio.IncompleteReadError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">IncompleteReadError</span></code></a> if the end of
the stream is reached before <em>n</em> can be read, the
<a class="reference internal" href="#asyncio.IncompleteReadError.partial" title="asyncio.IncompleteReadError.partial"><code class="xref py py-attr docutils literal notranslate"><span class="pre">IncompleteReadError.partial</span></code></a> attribute of the exception contains
the partial read bytes.</p>
<p>This method is a <a class="reference internal" href="asyncio-task.html#coroutine"><span class="std std-ref">coroutine</span></a>.</p>
</dd></dl>
<dl class="method">
<dt id="asyncio.StreamReader.readuntil">
<em class="property">coroutine </em><code class="descname">readuntil</code><span class="sig-paren">(</span><em>separator=b'\n'</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader.readuntil" title="Permalink to this definition">¶</a></dt>
<dd><p>Read data from the stream until <code class="docutils literal notranslate"><span class="pre">separator</span></code> is found.</p>
<p>On success, the data and separator will be removed from the
internal buffer (consumed). Returned data will include the
separator at the end.</p>
<p>Configured stream limit is used to check result. Limit sets the
maximal length of data that can be returned, not counting the
separator.</p>
<p>If an EOF occurs and the complete separator is still not found,
an <a class="reference internal" href="#asyncio.IncompleteReadError" title="asyncio.IncompleteReadError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">IncompleteReadError</span></code></a> exception will be
raised, and the internal buffer will be reset. The
<a class="reference internal" href="#asyncio.IncompleteReadError.partial" title="asyncio.IncompleteReadError.partial"><code class="xref py py-attr docutils literal notranslate"><span class="pre">IncompleteReadError.partial</span></code></a> attribute may contain the
separator partially.</p>
<p>If the data cannot be read because of over limit, a
<a class="reference internal" href="#asyncio.LimitOverrunError" title="asyncio.LimitOverrunError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">LimitOverrunError</span></code></a> exception will be raised, and the data
will be left in the internal buffer, so it can be read again.</p>
<div class="versionadded">
<p><span class="versionmodified">New in version 3.5.2.</span></p>
</div>
</dd></dl>
<dl class="method">
<dt id="asyncio.StreamReader.at_eof">
<code class="descname">at_eof</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader.at_eof" title="Permalink to this definition">¶</a></dt>
<dd><p>Return <code class="docutils literal notranslate"><span class="pre">True</span></code> if the buffer is empty and <a class="reference internal" href="#asyncio.StreamReader.feed_eof" title="asyncio.StreamReader.feed_eof"><code class="xref py py-meth docutils literal notranslate"><span class="pre">feed_eof()</span></code></a> was called.</p>
</dd></dl>
</dd></dl>
</div>
<div class="section" id="streamwriter">
<h2>18.5.5.3. StreamWriter<a class="headerlink" href="#streamwriter" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt id="asyncio.StreamWriter">
<em class="property">class </em><code class="descclassname">asyncio.</code><code class="descname">StreamWriter</code><span class="sig-paren">(</span><em>transport</em>, <em>protocol</em>, <em>reader</em>, <em>loop</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter" title="Permalink to this definition">¶</a></dt>
<dd><p>Wraps a Transport.</p>
<p>This exposes <a class="reference internal" href="#asyncio.StreamWriter.write" title="asyncio.StreamWriter.write"><code class="xref py py-meth docutils literal notranslate"><span class="pre">write()</span></code></a>, <a class="reference internal" href="#asyncio.StreamWriter.writelines" title="asyncio.StreamWriter.writelines"><code class="xref py py-meth docutils literal notranslate"><span class="pre">writelines()</span></code></a>, <a class="reference internal" href="#asyncio.StreamWriter.can_write_eof" title="asyncio.StreamWriter.can_write_eof"><code class="xref py py-meth docutils literal notranslate"><span class="pre">can_write_eof()</span></code></a>,
<a class="reference internal" href="#asyncio.StreamWriter.write_eof" title="asyncio.StreamWriter.write_eof"><code class="xref py py-meth docutils literal notranslate"><span class="pre">write_eof()</span></code></a>, <a class="reference internal" href="#asyncio.StreamWriter.get_extra_info" title="asyncio.StreamWriter.get_extra_info"><code class="xref py py-meth docutils literal notranslate"><span class="pre">get_extra_info()</span></code></a> and <a class="reference internal" href="#asyncio.StreamWriter.close" title="asyncio.StreamWriter.close"><code class="xref py py-meth docutils literal notranslate"><span class="pre">close()</span></code></a>. It adds
<a class="reference internal" href="#asyncio.StreamWriter.drain" title="asyncio.StreamWriter.drain"><code class="xref py py-meth docutils literal notranslate"><span class="pre">drain()</span></code></a> which returns an optional <a class="reference internal" href="asyncio-task.html#asyncio.Future" title="asyncio.Future"><code class="xref py py-class docutils literal notranslate"><span class="pre">Future</span></code></a> on which you can
wait for flow control. It also adds a transport attribute which references
the <code class="xref py py-class docutils literal notranslate"><span class="pre">Transport</span></code> directly.</p>
<p>This class is <a class="reference internal" href="asyncio-dev.html#asyncio-multithreading"><span class="std std-ref">not thread safe</span></a>.</p>
<dl class="attribute">
<dt id="asyncio.StreamWriter.transport">
<code class="descname">transport</code><a class="headerlink" href="#asyncio.StreamWriter.transport" title="Permalink to this definition">¶</a></dt>
<dd><p>Transport.</p>
</dd></dl>
<dl class="method">
<dt id="asyncio.StreamWriter.can_write_eof">
<code class="descname">can_write_eof</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.can_write_eof" title="Permalink to this definition">¶</a></dt>
<dd><p>Return <a class="reference internal" href="constants.html#True" title="True"><code class="xref py py-const docutils literal notranslate"><span class="pre">True</span></code></a> if the transport supports <a class="reference internal" href="#asyncio.StreamWriter.write_eof" title="asyncio.StreamWriter.write_eof"><code class="xref py py-meth docutils literal notranslate"><span class="pre">write_eof()</span></code></a>,
<a class="reference internal" href="constants.html#False" title="False"><code class="xref py py-const docutils literal notranslate"><span class="pre">False</span></code></a> if not. See <a class="reference internal" href="asyncio-protocol.html#asyncio.WriteTransport.can_write_eof" title="asyncio.WriteTransport.can_write_eof"><code class="xref py py-meth docutils literal notranslate"><span class="pre">WriteTransport.can_write_eof()</span></code></a>.</p>
</dd></dl>
<dl class="method">
<dt id="asyncio.StreamWriter.close">
<code class="descname">close</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.close" title="Permalink to this definition">¶</a></dt>
<dd><p>Close the transport: see <a class="reference internal" href="asyncio-protocol.html#asyncio.BaseTransport.close" title="asyncio.BaseTransport.close"><code class="xref py py-meth docutils literal notranslate"><span class="pre">BaseTransport.close()</span></code></a>.</p>
</dd></dl>
<dl class="method">
<dt id="asyncio.StreamWriter.drain">
<em class="property">coroutine </em><code class="descname">drain</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.drain" title="Permalink to this definition">¶</a></dt>
<dd><p>Let the write buffer of the underlying transport a chance to be flushed.</p>
<p>The intended use is to write:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">w</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="n">data</span><span class="p">)</span>
<span class="k">yield from</span> <span class="n">w</span><span class="o">.</span><span class="n">drain</span><span class="p">()</span>
</pre></div>
</div>
<p>When the size of the transport buffer reaches the high-water limit (the
protocol is paused), block until the size of the buffer is drained down
to the low-water limit and the protocol is resumed. When there is nothing
to wait for, the yield-from continues immediately.</p>
<p>Yielding from <a class="reference internal" href="#asyncio.StreamWriter.drain" title="asyncio.StreamWriter.drain"><code class="xref py py-meth docutils literal notranslate"><span class="pre">drain()</span></code></a> gives the opportunity for the loop to
schedule the write operation and flush the buffer. It should especially
be used when a possibly large amount of data is written to the transport,
and the coroutine does not yield-from between calls to <a class="reference internal" href="#asyncio.StreamWriter.write" title="asyncio.StreamWriter.write"><code class="xref py py-meth docutils literal notranslate"><span class="pre">write()</span></code></a>.</p>
<p>This method is a <a class="reference internal" href="asyncio-task.html#coroutine"><span class="std std-ref">coroutine</span></a>.</p>
</dd></dl>
<dl class="method">
<dt id="asyncio.StreamWriter.get_extra_info">
<code class="descname">get_extra_info</code><span class="sig-paren">(</span><em>name</em>, <em>default=None</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.get_extra_info" title="Permalink to this definition">¶</a></dt>
<dd><p>Return optional transport information: see
<a class="reference internal" href="asyncio-protocol.html#asyncio.BaseTransport.get_extra_info" title="asyncio.BaseTransport.get_extra_info"><code class="xref py py-meth docutils literal notranslate"><span class="pre">BaseTransport.get_extra_info()</span></code></a>.</p>
</dd></dl>
<dl class="method">
<dt id="asyncio.StreamWriter.write">
<code class="descname">write</code><span class="sig-paren">(</span><em>data</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.write" title="Permalink to this definition">¶</a></dt>
<dd><p>Write some <em>data</em> bytes to the transport: see
<a class="reference internal" href="asyncio-protocol.html#asyncio.WriteTransport.write" title="asyncio.WriteTransport.write"><code class="xref py py-meth docutils literal notranslate"><span class="pre">WriteTransport.write()</span></code></a>.</p>
</dd></dl>
<dl class="method">
<dt id="asyncio.StreamWriter.writelines">
<code class="descname">writelines</code><span class="sig-paren">(</span><em>data</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.writelines" title="Permalink to this definition">¶</a></dt>
<dd><p>Write a list (or any iterable) of data bytes to the transport:
see <a class="reference internal" href="asyncio-protocol.html#asyncio.WriteTransport.writelines" title="asyncio.WriteTransport.writelines"><code class="xref py py-meth docutils literal notranslate"><span class="pre">WriteTransport.writelines()</span></code></a>.</p>
</dd></dl>
<dl class="method">
<dt id="asyncio.StreamWriter.write_eof">
<code class="descname">write_eof</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.write_eof" title="Permalink to this definition">¶</a></dt>
<dd><p>Close the write end of the transport after flushing buffered data:
see <a class="reference internal" href="asyncio-protocol.html#asyncio.WriteTransport.write_eof" title="asyncio.WriteTransport.write_eof"><code class="xref py py-meth docutils literal notranslate"><span class="pre">WriteTransport.write_eof()</span></code></a>.</p>
</dd></dl>
</dd></dl>
</div>
<div class="section" id="streamreaderprotocol">
<h2>18.5.5.4. StreamReaderProtocol<a class="headerlink" href="#streamreaderprotocol" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt id="asyncio.StreamReaderProtocol">
<em class="property">class </em><code class="descclassname">asyncio.</code><code class="descname">StreamReaderProtocol</code><span class="sig-paren">(</span><em>stream_reader</em>, <em>client_connected_cb=None</em>, <em>loop=None</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReaderProtocol" title="Permalink to this definition">¶</a></dt>
<dd><p>Trivial helper class to adapt between <a class="reference internal" href="asyncio-protocol.html#asyncio.Protocol" title="asyncio.Protocol"><code class="xref py py-class docutils literal notranslate"><span class="pre">Protocol</span></code></a> and
<a class="reference internal" href="#asyncio.StreamReader" title="asyncio.StreamReader"><code class="xref py py-class docutils literal notranslate"><span class="pre">StreamReader</span></code></a>. Subclass of <a class="reference internal" href="asyncio-protocol.html#asyncio.Protocol" title="asyncio.Protocol"><code class="xref py py-class docutils literal notranslate"><span class="pre">Protocol</span></code></a>.</p>
<p><em>stream_reader</em> is a <a class="reference internal" href="#asyncio.StreamReader" title="asyncio.StreamReader"><code class="xref py py-class docutils literal notranslate"><span class="pre">StreamReader</span></code></a> instance, <em>client_connected_cb</em>
is an optional function called with (stream_reader, stream_writer) when a
connection is made, <em>loop</em> is the event loop instance to use.</p>
<p>(This is a helper class instead of making <a class="reference internal" href="#asyncio.StreamReader" title="asyncio.StreamReader"><code class="xref py py-class docutils literal notranslate"><span class="pre">StreamReader</span></code></a> itself a
<a class="reference internal" href="asyncio-protocol.html#asyncio.Protocol" title="asyncio.Protocol"><code class="xref py py-class docutils literal notranslate"><span class="pre">Protocol</span></code></a> subclass, because the <a class="reference internal" href="#asyncio.StreamReader" title="asyncio.StreamReader"><code class="xref py py-class docutils literal notranslate"><span class="pre">StreamReader</span></code></a> has other
potential uses, and to prevent the user of the <a class="reference internal" href="#asyncio.StreamReader" title="asyncio.StreamReader"><code class="xref py py-class docutils literal notranslate"><span class="pre">StreamReader</span></code></a> from
accidentally calling inappropriate methods of the protocol.)</p>
</dd></dl>
</div>
<div class="section" id="incompletereaderror">
<h2>18.5.5.5. IncompleteReadError<a class="headerlink" href="#incompletereaderror" title="Permalink to this headline">¶</a></h2>
<dl class="exception">
<dt id="asyncio.IncompleteReadError">
<em class="property">exception </em><code class="descclassname">asyncio.</code><code class="descname">IncompleteReadError</code><a class="headerlink" href="#asyncio.IncompleteReadError" title="Permalink to this definition">¶</a></dt>
<dd><blockquote>
<div>Incomplete read error, subclass of <a class="reference internal" href="exceptions.html#EOFError" title="EOFError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">EOFError</span></code></a>.</div></blockquote>
<dl class="attribute">
<dt id="asyncio.IncompleteReadError.expected">
<code class="descname">expected</code><a class="headerlink" href="#asyncio.IncompleteReadError.expected" title="Permalink to this definition">¶</a></dt>
<dd><p>Total number of expected bytes (<a class="reference internal" href="functions.html#int" title="int"><code class="xref py py-class docutils literal notranslate"><span class="pre">int</span></code></a>).</p>
</dd></dl>
<dl class="attribute">
<dt id="asyncio.IncompleteReadError.partial">
<code class="descname">partial</code><a class="headerlink" href="#asyncio.IncompleteReadError.partial" title="Permalink to this definition">¶</a></dt>
<dd><p>Read bytes string before the end of stream was reached (<a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>).</p>
</dd></dl>
</dd></dl>
</div>
<div class="section" id="limitoverrunerror">
<h2>18.5.5.6. LimitOverrunError<a class="headerlink" href="#limitoverrunerror" title="Permalink to this headline">¶</a></h2>
<dl class="exception">
<dt id="asyncio.LimitOverrunError">
<em class="property">exception </em><code class="descclassname">asyncio.</code><code class="descname">LimitOverrunError</code><a class="headerlink" href="#asyncio.LimitOverrunError" title="Permalink to this definition">¶</a></dt>
<dd><p>Reached the buffer limit while looking for a separator.</p>
<dl class="attribute">
<dt id="asyncio.LimitOverrunError.consumed">
<code class="descname">consumed</code><a class="headerlink" href="#asyncio.LimitOverrunError.consumed" title="Permalink to this definition">¶</a></dt>
<dd><p>Total number of to be consumed bytes.</p>
</dd></dl>
</dd></dl>
</div>
<div class="section" id="stream-examples">
<h2>18.5.5.7. Stream examples<a class="headerlink" href="#stream-examples" title="Permalink to this headline">¶</a></h2>
<div class="section" id="tcp-echo-client-using-streams">
<span id="asyncio-tcp-echo-client-streams"></span><h3>18.5.5.7.1. TCP echo client using streams<a class="headerlink" href="#tcp-echo-client-using-streams" title="Permalink to this headline">¶</a></h3>
<p>TCP echo client using the <a class="reference internal" href="#asyncio.open_connection" title="asyncio.open_connection"><code class="xref py py-func docutils literal notranslate"><span class="pre">asyncio.open_connection()</span></code></a> function:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">asyncio</span>
<span class="nd">@asyncio</span><span class="o">.</span><span class="n">coroutine</span>
<span class="k">def</span> <span class="nf">tcp_echo_client</span><span class="p">(</span><span class="n">message</span><span class="p">,</span> <span class="n">loop</span><span class="p">):</span>
<span class="n">reader</span><span class="p">,</span> <span class="n">writer</span> <span class="o">=</span> <span class="k">yield from</span> <span class="n">asyncio</span><span class="o">.</span><span class="n">open_connection</span><span class="p">(</span><span class="s1">'127.0.0.1'</span><span class="p">,</span> <span class="mi">8888</span><span class="p">,</span>
<span class="n">loop</span><span class="o">=</span><span class="n">loop</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s1">'Send: </span><span class="si">%r</span><span class="s1">'</span> <span class="o">%</span> <span class="n">message</span><span class="p">)</span>
<span class="n">writer</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="n">message</span><span class="o">.</span><span class="n">encode</span><span class="p">())</span>
<span class="n">data</span> <span class="o">=</span> <span class="k">yield from</span> <span class="n">reader</span><span class="o">.</span><span class="n">read</span><span class="p">(</span><span class="mi">100</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s1">'Received: </span><span class="si">%r</span><span class="s1">'</span> <span class="o">%</span> <span class="n">data</span><span class="o">.</span><span class="n">decode</span><span class="p">())</span>
<span class="nb">print</span><span class="p">(</span><span class="s1">'Close the socket'</span><span class="p">)</span>
<span class="n">writer</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
<span class="n">message</span> <span class="o">=</span> <span class="s1">'Hello World!'</span>
<span class="n">loop</span> <span class="o">=</span> <span class="n">asyncio</span><span class="o">.</span><span class="n">get_event_loop</span><span class="p">()</span>
<span class="n">loop</span><span class="o">.</span><span class="n">run_until_complete</span><span class="p">(</span><span class="n">tcp_echo_client</span><span class="p">(</span><span class="n">message</span><span class="p">,</span> <span class="n">loop</span><span class="p">))</span>
<span class="n">loop</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
</pre></div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last">The <a class="reference internal" href="asyncio-protocol.html#asyncio-tcp-echo-client-protocol"><span class="std std-ref">TCP echo client protocol</span></a>
example uses the <a class="reference internal" href="asyncio-eventloop.html#asyncio.AbstractEventLoop.create_connection" title="asyncio.AbstractEventLoop.create_connection"><code class="xref py py-meth docutils literal notranslate"><span class="pre">AbstractEventLoop.create_connection()</span></code></a> method.</p>
</div>
</div>
<div class="section" id="tcp-echo-server-using-streams">
<span id="asyncio-tcp-echo-server-streams"></span><h3>18.5.5.7.2. TCP echo server using streams<a class="headerlink" href="#tcp-echo-server-using-streams" title="Permalink to this headline">¶</a></h3>
<p>TCP echo server using the <a class="reference internal" href="#asyncio.start_server" title="asyncio.start_server"><code class="xref py py-func docutils literal notranslate"><span class="pre">asyncio.start_server()</span></code></a> function:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">asyncio</span>
<span class="nd">@asyncio</span><span class="o">.</span><span class="n">coroutine</span>
<span class="k">def</span> <span class="nf">handle_echo</span><span class="p">(</span><span class="n">reader</span><span class="p">,</span> <span class="n">writer</span><span class="p">):</span>
<span class="n">data</span> <span class="o">=</span> <span class="k">yield from</span> <span class="n">reader</span><span class="o">.</span><span class="n">read</span><span class="p">(</span><span class="mi">100</span><span class="p">)</span>
<span class="n">message</span> <span class="o">=</span> <span class="n">data</span><span class="o">.</span><span class="n">decode</span><span class="p">()</span>
<span class="n">addr</span> <span class="o">=</span> <span class="n">writer</span><span class="o">.</span><span class="n">get_extra_info</span><span class="p">(</span><span class="s1">'peername'</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"Received </span><span class="si">%r</span><span class="s2"> from </span><span class="si">%r</span><span class="s2">"</span> <span class="o">%</span> <span class="p">(</span><span class="n">message</span><span class="p">,</span> <span class="n">addr</span><span class="p">))</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"Send: </span><span class="si">%r</span><span class="s2">"</span> <span class="o">%</span> <span class="n">message</span><span class="p">)</span>
<span class="n">writer</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="n">data</span><span class="p">)</span>
<span class="k">yield from</span> <span class="n">writer</span><span class="o">.</span><span class="n">drain</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"Close the client socket"</span><span class="p">)</span>
<span class="n">writer</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
<span class="n">loop</span> <span class="o">=</span> <span class="n">asyncio</span><span class="o">.</span><span class="n">get_event_loop</span><span class="p">()</span>
<span class="n">coro</span> <span class="o">=</span> <span class="n">asyncio</span><span class="o">.</span><span class="n">start_server</span><span class="p">(</span><span class="n">handle_echo</span><span class="p">,</span> <span class="s1">'127.0.0.1'</span><span class="p">,</span> <span class="mi">8888</span><span class="p">,</span> <span class="n">loop</span><span class="o">=</span><span class="n">loop</span><span class="p">)</span>
<span class="n">server</span> <span class="o">=</span> <span class="n">loop</span><span class="o">.</span><span class="n">run_until_complete</span><span class="p">(</span><span class="n">coro</span><span class="p">)</span>
<span class="c1"># Serve requests until Ctrl+C is pressed</span>
<span class="nb">print</span><span class="p">(</span><span class="s1">'Serving on </span><span class="si">{}</span><span class="s1">'</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">server</span><span class="o">.</span><span class="n">sockets</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span><span class="o">.</span><span class="n">getsockname</span><span class="p">()))</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">loop</span><span class="o">.</span><span class="n">run_forever</span><span class="p">()</span>
<span class="k">except</span> <span class="ne">KeyboardInterrupt</span><span class="p">:</span>
<span class="k">pass</span>
<span class="c1"># Close the server</span>
<span class="n">server</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
<span class="n">loop</span><span class="o">.</span><span class="n">run_until_complete</span><span class="p">(</span><span class="n">server</span><span class="o">.</span><span class="n">wait_closed</span><span class="p">())</span>
<span class="n">loop</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
</pre></div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last">The <a class="reference internal" href="asyncio-protocol.html#asyncio-tcp-echo-server-protocol"><span class="std std-ref">TCP echo server protocol</span></a>
example uses the <a class="reference internal" href="asyncio-eventloop.html#asyncio.AbstractEventLoop.create_server" title="asyncio.AbstractEventLoop.create_server"><code class="xref py py-meth docutils literal notranslate"><span class="pre">AbstractEventLoop.create_server()</span></code></a> method.</p>
</div>
</div>
<div class="section" id="get-http-headers">
<h3>18.5.5.7.3. Get HTTP headers<a class="headerlink" href="#get-http-headers" title="Permalink to this headline">¶</a></h3>
<p>Simple example querying HTTP headers of the URL passed on the command line:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">asyncio</span>
<span class="kn">import</span> <span class="nn">urllib.parse</span>
<span class="kn">import</span> <span class="nn">sys</span>
<span class="nd">@asyncio</span><span class="o">.</span><span class="n">coroutine</span>
<span class="k">def</span> <span class="nf">print_http_headers</span><span class="p">(</span><span class="n">url</span><span class="p">):</span>
<span class="n">url</span> <span class="o">=</span> <span class="n">urllib</span><span class="o">.</span><span class="n">parse</span><span class="o">.</span><span class="n">urlsplit</span><span class="p">(</span><span class="n">url</span><span class="p">)</span>
<span class="k">if</span> <span class="n">url</span><span class="o">.</span><span class="n">scheme</span> <span class="o">==</span> <span class="s1">'https'</span><span class="p">:</span>
<span class="n">connect</span> <span class="o">=</span> <span class="n">asyncio</span><span class="o">.</span><span class="n">open_connection</span><span class="p">(</span><span class="n">url</span><span class="o">.</span><span class="n">hostname</span><span class="p">,</span> <span class="mi">443</span><span class="p">,</span> <span class="n">ssl</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">connect</span> <span class="o">=</span> <span class="n">asyncio</span><span class="o">.</span><span class="n">open_connection</span><span class="p">(</span><span class="n">url</span><span class="o">.</span><span class="n">hostname</span><span class="p">,</span> <span class="mi">80</span><span class="p">)</span>
<span class="n">reader</span><span class="p">,</span> <span class="n">writer</span> <span class="o">=</span> <span class="k">yield from</span> <span class="n">connect</span>
<span class="n">query</span> <span class="o">=</span> <span class="p">(</span><span class="s1">'HEAD </span><span class="si">{path}</span><span class="s1"> HTTP/1.0</span><span class="se">\r\n</span><span class="s1">'</span>
<span class="s1">'Host: </span><span class="si">{hostname}</span><span class="se">\r\n</span><span class="s1">'</span>
<span class="s1">'</span><span class="se">\r\n</span><span class="s1">'</span><span class="p">)</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">path</span><span class="o">=</span><span class="n">url</span><span class="o">.</span><span class="n">path</span> <span class="ow">or</span> <span class="s1">'/'</span><span class="p">,</span> <span class="n">hostname</span><span class="o">=</span><span class="n">url</span><span class="o">.</span><span class="n">hostname</span><span class="p">)</span>
<span class="n">writer</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="n">query</span><span class="o">.</span><span class="n">encode</span><span class="p">(</span><span class="s1">'latin-1'</span><span class="p">))</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="n">line</span> <span class="o">=</span> <span class="k">yield from</span> <span class="n">reader</span><span class="o">.</span><span class="n">readline</span><span class="p">()</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">line</span><span class="p">:</span>
<span class="k">break</span>
<span class="n">line</span> <span class="o">=</span> <span class="n">line</span><span class="o">.</span><span class="n">decode</span><span class="p">(</span><span class="s1">'latin1'</span><span class="p">)</span><span class="o">.</span><span class="n">rstrip</span><span class="p">()</span>
<span class="k">if</span> <span class="n">line</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s1">'HTTP header> </span><span class="si">%s</span><span class="s1">'</span> <span class="o">%</span> <span class="n">line</span><span class="p">)</span>
<span class="c1"># Ignore the body, close the socket</span>
<span class="n">writer</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
<span class="n">url</span> <span class="o">=</span> <span class="n">sys</span><span class="o">.</span><span class="n">argv</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span>
<span class="n">loop</span> <span class="o">=</span> <span class="n">asyncio</span><span class="o">.</span><span class="n">get_event_loop</span><span class="p">()</span>
<span class="n">task</span> <span class="o">=</span> <span class="n">asyncio</span><span class="o">.</span><span class="n">ensure_future</span><span class="p">(</span><span class="n">print_http_headers</span><span class="p">(</span><span class="n">url</span><span class="p">))</span>
<span class="n">loop</span><span class="o">.</span><span class="n">run_until_complete</span><span class="p">(</span><span class="n">task</span><span class="p">)</span>
<span class="n">loop</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
</pre></div>
</div>
<p>Usage:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">python</span> <span class="n">example</span><span class="o">.</span><span class="n">py</span> <span class="n">http</span><span class="p">:</span><span class="o">//</span><span class="n">example</span><span class="o">.</span><span class="n">com</span><span class="o">/</span><span class="n">path</span><span class="o">/</span><span class="n">page</span><span class="o">.</span><span class="n">html</span>
</pre></div>
</div>
<p>or with HTTPS:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">python</span> <span class="n">example</span><span class="o">.</span><span class="n">py</span> <span class="n">https</span><span class="p">:</span><span class="o">//</span><span class="n">example</span><span class="o">.</span><span class="n">com</span><span class="o">/</span><span class="n">path</span><span class="o">/</span><span class="n">page</span><span class="o">.</span><span class="n">html</span>
</pre></div>
</div>
</div>
<div class="section" id="register-an-open-socket-to-wait-for-data-using-streams">
<span id="asyncio-register-socket-streams"></span><h3>18.5.5.7.4. Register an open socket to wait for data using streams<a class="headerlink" href="#register-an-open-socket-to-wait-for-data-using-streams" title="Permalink to this headline">¶</a></h3>
<p>Coroutine waiting until a socket receives data using the
<a class="reference internal" href="#asyncio.open_connection" title="asyncio.open_connection"><code class="xref py py-func docutils literal notranslate"><span class="pre">open_connection()</span></code></a> function:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">asyncio</span>
<span class="k">try</span><span class="p">:</span>
<span class="kn">from</span> <span class="nn">socket</span> <span class="k">import</span> <span class="n">socketpair</span>
<span class="k">except</span> <span class="ne">ImportError</span><span class="p">:</span>
<span class="kn">from</span> <span class="nn">asyncio.windows_utils</span> <span class="k">import</span> <span class="n">socketpair</span>
<span class="nd">@asyncio</span><span class="o">.</span><span class="n">coroutine</span>
<span class="k">def</span> <span class="nf">wait_for_data</span><span class="p">(</span><span class="n">loop</span><span class="p">):</span>
<span class="c1"># Create a pair of connected sockets</span>
<span class="n">rsock</span><span class="p">,</span> <span class="n">wsock</span> <span class="o">=</span> <span class="n">socketpair</span><span class="p">()</span>
<span class="c1"># Register the open socket to wait for data</span>
<span class="n">reader</span><span class="p">,</span> <span class="n">writer</span> <span class="o">=</span> <span class="k">yield from</span> <span class="n">asyncio</span><span class="o">.</span><span class="n">open_connection</span><span class="p">(</span><span class="n">sock</span><span class="o">=</span><span class="n">rsock</span><span class="p">,</span> <span class="n">loop</span><span class="o">=</span><span class="n">loop</span><span class="p">)</span>
<span class="c1"># Simulate the reception of data from the network</span>
<span class="n">loop</span><span class="o">.</span><span class="n">call_soon</span><span class="p">(</span><span class="n">wsock</span><span class="o">.</span><span class="n">send</span><span class="p">,</span> <span class="s1">'abc'</span><span class="o">.</span><span class="n">encode</span><span class="p">())</span>
<span class="c1"># Wait for data</span>
<span class="n">data</span> <span class="o">=</span> <span class="k">yield from</span> <span class="n">reader</span><span class="o">.</span><span class="n">read</span><span class="p">(</span><span class="mi">100</span><span class="p">)</span>
<span class="c1"># Got data, we are done: close the socket</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"Received:"</span><span class="p">,</span> <span class="n">data</span><span class="o">.</span><span class="n">decode</span><span class="p">())</span>
<span class="n">writer</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
<span class="c1"># Close the second socket</span>
<span class="n">wsock</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
<span class="n">loop</span> <span class="o">=</span> <span class="n">asyncio</span><span class="o">.</span><span class="n">get_event_loop</span><span class="p">()</span>
<span class="n">loop</span><span class="o">.</span><span class="n">run_until_complete</span><span class="p">(</span><span class="n">wait_for_data</span><span class="p">(</span><span class="n">loop</span><span class="p">))</span>
<span class="n">loop</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
</pre></div>
</div>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p>The <a class="reference internal" href="asyncio-protocol.html#asyncio-register-socket"><span class="std std-ref">register an open socket to wait for data using a protocol</span></a> example uses a low-level protocol created by the
<a class="reference internal" href="asyncio-eventloop.html#asyncio.AbstractEventLoop.create_connection" title="asyncio.AbstractEventLoop.create_connection"><code class="xref py py-meth docutils literal notranslate"><span class="pre">AbstractEventLoop.create_connection()</span></code></a> method.</p>
<p class="last">The <a class="reference internal" href="asyncio-eventloop.html#asyncio-watch-read-event"><span class="std std-ref">watch a file descriptor for read events</span></a> example uses the low-level
<a class="reference internal" href="asyncio-eventloop.html#asyncio.AbstractEventLoop.add_reader" title="asyncio.AbstractEventLoop.add_reader"><code class="xref py py-meth docutils literal notranslate"><span class="pre">AbstractEventLoop.add_reader()</span></code></a> method to register the file descriptor of a
socket.</p>
</div>
</div>
</div>
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<h3><a href="../contents.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">18.5.5. Streams (coroutine based API)</a><ul>
<li><a class="reference internal" href="#stream-functions">18.5.5.1. Stream functions</a></li>
<li><a class="reference internal" href="#streamreader">18.5.5.2. StreamReader</a></li>
<li><a class="reference internal" href="#streamwriter">18.5.5.3. StreamWriter</a></li>
<li><a class="reference internal" href="#streamreaderprotocol">18.5.5.4. StreamReaderProtocol</a></li>
<li><a class="reference internal" href="#incompletereaderror">18.5.5.5. IncompleteReadError</a></li>
<li><a class="reference internal" href="#limitoverrunerror">18.5.5.6. LimitOverrunError</a></li>
<li><a class="reference internal" href="#stream-examples">18.5.5.7. Stream examples</a><ul>
<li><a class="reference internal" href="#tcp-echo-client-using-streams">18.5.5.7.1. TCP echo client using streams</a></li>
<li><a class="reference internal" href="#tcp-echo-server-using-streams">18.5.5.7.2. TCP echo server using streams</a></li>
<li><a class="reference internal" href="#get-http-headers">18.5.5.7.3. Get HTTP headers</a></li>
<li><a class="reference internal" href="#register-an-open-socket-to-wait-for-data-using-streams">18.5.5.7.4. Register an open socket to wait for data using streams</a></li>
</ul>
</li>
</ul>
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