D7net
Home
Console
Upload
information
Create File
Create Folder
About
Tools
:
/
usr
/
share
/
doc
/
python3-docs
/
html
/
library
/
Filename :
asyncio-protocol.html
back
Copy
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="X-UA-Compatible" content="IE=Edge" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>18.5.4. Transports and protocols (callback based API) — Python 3.6.7 documentation</title> <link rel="stylesheet" href="../_static/pydoctheme.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript" id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script> <script type="text/javascript" src="../_static/jquery.js"></script> <script type="text/javascript" src="../_static/underscore.js"></script> <script type="text/javascript" src="../_static/doctools.js"></script> <script type="text/javascript" src="../_static/sidebar.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python 3.6.7 documentation" href="../_static/opensearch.xml"/> <link rel="author" title="About these documents" href="../about.html" /> <link rel="index" title="Index" href="../genindex.html" /> <link rel="search" title="Search" href="../search.html" /> <link rel="copyright" title="Copyright" href="../copyright.html" /> <link rel="next" title="18.5.5. Streams (coroutine based API)" href="asyncio-stream.html" /> <link rel="prev" title="18.5.3. Tasks and coroutines" href="asyncio-task.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> <link rel="canonical" href="https://docs.python.org/3/library/asyncio-protocol.html" /> <script type="text/javascript" src="../_static/copybutton.js"></script> </head><body> <div class="related" role="navigation" aria-label="related navigation"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../genindex.html" title="General Index" accesskey="I">index</a></li> <li class="right" > <a href="../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="asyncio-stream.html" title="18.5.5. Streams (coroutine based API)" accesskey="N">next</a> |</li> <li class="right" > <a href="asyncio-task.html" title="18.5.3. Tasks and coroutines" accesskey="P">previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="https://www.python.org/">Python</a> »</li> <li> <a href="../index.html">3.6.7 Documentation</a> » </li> <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li> <li class="nav-item nav-item-2"><a href="ipc.html" >18. Interprocess Communication and Networking</a> »</li> <li class="nav-item nav-item-3"><a href="asyncio.html" accesskey="U">18.5. <code class="docutils literal notranslate"><span class="pre">asyncio</span></code> — Asynchronous I/O, event loop, coroutines and tasks</a> »</li> <li class="right"> <div class="inline-search" style="display: none" role="search"> <form class="inline-search" action="../search.html" method="get"> <input placeholder="Quick search" type="text" name="q" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> </div> <script type="text/javascript">$('.inline-search').show(0);</script> | </li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body" role="main"> <div class="section" id="transports-and-protocols-callback-based-api"> <h1>18.5.4. Transports and protocols (callback based API)<a class="headerlink" href="#transports-and-protocols-callback-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/transports.py">Lib/asyncio/transports.py</a></p> <p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.6/Lib/asyncio/protocols.py">Lib/asyncio/protocols.py</a></p> <div class="section" id="transports"> <span id="asyncio-transport"></span><h2>18.5.4.1. Transports<a class="headerlink" href="#transports" title="Permalink to this headline">¶</a></h2> <p>Transports are classes provided by <a class="reference internal" href="asyncio.html#module-asyncio" title="asyncio: Asynchronous I/O, event loop, coroutines and tasks."><code class="xref py py-mod docutils literal notranslate"><span class="pre">asyncio</span></code></a> in order to abstract various kinds of communication channels. You generally won’t instantiate a transport yourself; instead, you will call an <a class="reference internal" href="asyncio-eventloop.html#asyncio.AbstractEventLoop" title="asyncio.AbstractEventLoop"><code class="xref py py-class docutils literal notranslate"><span class="pre">AbstractEventLoop</span></code></a> method which will create the transport and try to initiate the underlying communication channel, calling you back when it succeeds.</p> <p>Once the communication channel is established, a transport is always paired with a <a class="reference internal" href="#asyncio-protocol"><span class="std std-ref">protocol</span></a> instance. The protocol can then call the transport’s methods for various purposes.</p> <p><a class="reference internal" href="asyncio.html#module-asyncio" title="asyncio: Asynchronous I/O, event loop, coroutines and tasks."><code class="xref py py-mod docutils literal notranslate"><span class="pre">asyncio</span></code></a> currently implements transports for TCP, UDP, SSL, and subprocess pipes. The methods available on a transport depend on the transport’s kind.</p> <p>The transport classes are <a class="reference internal" href="asyncio-dev.html#asyncio-multithreading"><span class="std std-ref">not thread safe</span></a>.</p> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 3.6: </span>The socket option <code class="docutils literal notranslate"><span class="pre">TCP_NODELAY</span></code> is now set by default.</p> </div> <div class="section" id="basetransport"> <h3>18.5.4.1.1. BaseTransport<a class="headerlink" href="#basetransport" title="Permalink to this headline">¶</a></h3> <dl class="class"> <dt id="asyncio.BaseTransport"> <em class="property">class </em><code class="descclassname">asyncio.</code><code class="descname">BaseTransport</code><a class="headerlink" href="#asyncio.BaseTransport" title="Permalink to this definition">¶</a></dt> <dd><p>Base class for transports.</p> <dl class="method"> <dt id="asyncio.BaseTransport.close"> <code class="descname">close</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.BaseTransport.close" title="Permalink to this definition">¶</a></dt> <dd><p>Close the transport. If the transport has a buffer for outgoing data, buffered data will be flushed asynchronously. No more data will be received. After all buffered data is flushed, the protocol’s <code class="xref py py-meth docutils literal notranslate"><span class="pre">connection_lost()</span></code> method will be called with <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a> as its argument.</p> </dd></dl> <dl class="method"> <dt id="asyncio.BaseTransport.is_closing"> <code class="descname">is_closing</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.BaseTransport.is_closing" title="Permalink to this definition">¶</a></dt> <dd><p>Return <code class="docutils literal notranslate"><span class="pre">True</span></code> if the transport is closing or is closed.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 3.5.1.</span></p> </div> </dd></dl> <dl class="method"> <dt id="asyncio.BaseTransport.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.BaseTransport.get_extra_info" title="Permalink to this definition">¶</a></dt> <dd><p>Return optional transport information. <em>name</em> is a string representing the piece of transport-specific information to get, <em>default</em> is the value to return if the information doesn’t exist.</p> <p>This method allows transport implementations to easily expose channel-specific information.</p> <ul class="simple"> <li>socket:<ul> <li><code class="docutils literal notranslate"><span class="pre">'peername'</span></code>: the remote address to which the socket is connected, result of <a class="reference internal" href="socket.html#socket.socket.getpeername" title="socket.socket.getpeername"><code class="xref py py-meth docutils literal notranslate"><span class="pre">socket.socket.getpeername()</span></code></a> (<code class="docutils literal notranslate"><span class="pre">None</span></code> on error)</li> <li><code class="docutils literal notranslate"><span class="pre">'socket'</span></code>: <a class="reference internal" href="socket.html#socket.socket" title="socket.socket"><code class="xref py py-class docutils literal notranslate"><span class="pre">socket.socket</span></code></a> instance</li> <li><code class="docutils literal notranslate"><span class="pre">'sockname'</span></code>: the socket’s own address, result of <a class="reference internal" href="socket.html#socket.socket.getsockname" title="socket.socket.getsockname"><code class="xref py py-meth docutils literal notranslate"><span class="pre">socket.socket.getsockname()</span></code></a></li> </ul> </li> <li>SSL socket:<ul> <li><code class="docutils literal notranslate"><span class="pre">'compression'</span></code>: the compression algorithm being used as a string, or <code class="docutils literal notranslate"><span class="pre">None</span></code> if the connection isn’t compressed; result of <a class="reference internal" href="ssl.html#ssl.SSLSocket.compression" title="ssl.SSLSocket.compression"><code class="xref py py-meth docutils literal notranslate"><span class="pre">ssl.SSLSocket.compression()</span></code></a></li> <li><code class="docutils literal notranslate"><span class="pre">'cipher'</span></code>: a three-value tuple containing the name of the cipher being used, the version of the SSL protocol that defines its use, and the number of secret bits being used; result of <a class="reference internal" href="ssl.html#ssl.SSLSocket.cipher" title="ssl.SSLSocket.cipher"><code class="xref py py-meth docutils literal notranslate"><span class="pre">ssl.SSLSocket.cipher()</span></code></a></li> <li><code class="docutils literal notranslate"><span class="pre">'peercert'</span></code>: peer certificate; result of <a class="reference internal" href="ssl.html#ssl.SSLSocket.getpeercert" title="ssl.SSLSocket.getpeercert"><code class="xref py py-meth docutils literal notranslate"><span class="pre">ssl.SSLSocket.getpeercert()</span></code></a></li> <li><code class="docutils literal notranslate"><span class="pre">'sslcontext'</span></code>: <a class="reference internal" href="ssl.html#ssl.SSLContext" title="ssl.SSLContext"><code class="xref py py-class docutils literal notranslate"><span class="pre">ssl.SSLContext</span></code></a> instance</li> <li><code class="docutils literal notranslate"><span class="pre">'ssl_object'</span></code>: <a class="reference internal" href="ssl.html#ssl.SSLObject" title="ssl.SSLObject"><code class="xref py py-class docutils literal notranslate"><span class="pre">ssl.SSLObject</span></code></a> or <a class="reference internal" href="ssl.html#ssl.SSLSocket" title="ssl.SSLSocket"><code class="xref py py-class docutils literal notranslate"><span class="pre">ssl.SSLSocket</span></code></a> instance</li> </ul> </li> <li>pipe:<ul> <li><code class="docutils literal notranslate"><span class="pre">'pipe'</span></code>: pipe object</li> </ul> </li> <li>subprocess:<ul> <li><code class="docutils literal notranslate"><span class="pre">'subprocess'</span></code>: <a class="reference internal" href="subprocess.html#subprocess.Popen" title="subprocess.Popen"><code class="xref py py-class docutils literal notranslate"><span class="pre">subprocess.Popen</span></code></a> instance</li> </ul> </li> </ul> </dd></dl> <dl class="method"> <dt id="asyncio.BaseTransport.set_protocol"> <code class="descname">set_protocol</code><span class="sig-paren">(</span><em>protocol</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.BaseTransport.set_protocol" title="Permalink to this definition">¶</a></dt> <dd><p>Set a new protocol. Switching protocol should only be done when both protocols are documented to support the switch.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 3.5.3.</span></p> </div> </dd></dl> <dl class="method"> <dt id="asyncio.BaseTransport.get_protocol"> <code class="descname">get_protocol</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.BaseTransport.get_protocol" title="Permalink to this definition">¶</a></dt> <dd><p>Return the current protocol.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 3.5.3.</span></p> </div> </dd></dl> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 3.5.1: </span><code class="docutils literal notranslate"><span class="pre">'ssl_object'</span></code> info was added to SSL sockets.</p> </div> </dd></dl> </div> <div class="section" id="readtransport"> <h3>18.5.4.1.2. ReadTransport<a class="headerlink" href="#readtransport" title="Permalink to this headline">¶</a></h3> <dl class="class"> <dt id="asyncio.ReadTransport"> <em class="property">class </em><code class="descclassname">asyncio.</code><code class="descname">ReadTransport</code><a class="headerlink" href="#asyncio.ReadTransport" title="Permalink to this definition">¶</a></dt> <dd><p>Interface for read-only transports.</p> <dl class="method"> <dt id="asyncio.ReadTransport.pause_reading"> <code class="descname">pause_reading</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.ReadTransport.pause_reading" title="Permalink to this definition">¶</a></dt> <dd><p>Pause the receiving end of the transport. No data will be passed to the protocol’s <code class="xref py py-meth docutils literal notranslate"><span class="pre">data_received()</span></code> method until <a class="reference internal" href="#asyncio.ReadTransport.resume_reading" title="asyncio.ReadTransport.resume_reading"><code class="xref py py-meth docutils literal notranslate"><span class="pre">resume_reading()</span></code></a> is called.</p> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 3.6.7: </span>The method is idempotent, i.e. it can be called when the transport is already paused or closed.</p> </div> </dd></dl> <dl class="method"> <dt id="asyncio.ReadTransport.resume_reading"> <code class="descname">resume_reading</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.ReadTransport.resume_reading" title="Permalink to this definition">¶</a></dt> <dd><p>Resume the receiving end. The protocol’s <code class="xref py py-meth docutils literal notranslate"><span class="pre">data_received()</span></code> method will be called once again if some data is available for reading.</p> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 3.6.7: </span>The method is idempotent, i.e. it can be called when the transport is already reading.</p> </div> </dd></dl> </dd></dl> </div> <div class="section" id="writetransport"> <h3>18.5.4.1.3. WriteTransport<a class="headerlink" href="#writetransport" title="Permalink to this headline">¶</a></h3> <dl class="class"> <dt id="asyncio.WriteTransport"> <em class="property">class </em><code class="descclassname">asyncio.</code><code class="descname">WriteTransport</code><a class="headerlink" href="#asyncio.WriteTransport" title="Permalink to this definition">¶</a></dt> <dd><p>Interface for write-only transports.</p> <dl class="method"> <dt id="asyncio.WriteTransport.abort"> <code class="descname">abort</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.WriteTransport.abort" title="Permalink to this definition">¶</a></dt> <dd><p>Close the transport immediately, without waiting for pending operations to complete. Buffered data will be lost. No more data will be received. The protocol’s <code class="xref py py-meth docutils literal notranslate"><span class="pre">connection_lost()</span></code> method will eventually be called with <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a> as its argument.</p> </dd></dl> <dl class="method"> <dt id="asyncio.WriteTransport.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.WriteTransport.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.WriteTransport.write_eof" title="asyncio.WriteTransport.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.</p> </dd></dl> <dl class="method"> <dt id="asyncio.WriteTransport.get_write_buffer_size"> <code class="descname">get_write_buffer_size</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.WriteTransport.get_write_buffer_size" title="Permalink to this definition">¶</a></dt> <dd><p>Return the current size of the output buffer used by the transport.</p> </dd></dl> <dl class="method"> <dt id="asyncio.WriteTransport.get_write_buffer_limits"> <code class="descname">get_write_buffer_limits</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.WriteTransport.get_write_buffer_limits" title="Permalink to this definition">¶</a></dt> <dd><p>Get the <em>high</em>- and <em>low</em>-water limits for write flow control. Return a tuple <code class="docutils literal notranslate"><span class="pre">(low,</span> <span class="pre">high)</span></code> where <em>low</em> and <em>high</em> are positive number of bytes.</p> <p>Use <a class="reference internal" href="#asyncio.WriteTransport.set_write_buffer_limits" title="asyncio.WriteTransport.set_write_buffer_limits"><code class="xref py py-meth docutils literal notranslate"><span class="pre">set_write_buffer_limits()</span></code></a> to set the limits.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 3.4.2.</span></p> </div> </dd></dl> <dl class="method"> <dt id="asyncio.WriteTransport.set_write_buffer_limits"> <code class="descname">set_write_buffer_limits</code><span class="sig-paren">(</span><em>high=None</em>, <em>low=None</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.WriteTransport.set_write_buffer_limits" title="Permalink to this definition">¶</a></dt> <dd><p>Set the <em>high</em>- and <em>low</em>-water limits for write flow control.</p> <p>These two values (measured in number of bytes) control when the protocol’s <code class="xref py py-meth docutils literal notranslate"><span class="pre">pause_writing()</span></code> and <code class="xref py py-meth docutils literal notranslate"><span class="pre">resume_writing()</span></code> methods are called. If specified, the low-water limit must be less than or equal to the high-water limit. Neither <em>high</em> nor <em>low</em> can be negative.</p> <p><code class="xref py py-meth docutils literal notranslate"><span class="pre">pause_writing()</span></code> is called when the buffer size becomes greater than or equal to the <em>high</em> value. If writing has been paused, <code class="xref py py-meth docutils literal notranslate"><span class="pre">resume_writing()</span></code> is called when the buffer size becomes less than or equal to the <em>low</em> value.</p> <p>The defaults are implementation-specific. If only the high-water limit is given, the low-water limit defaults to an implementation-specific value less than or equal to the high-water limit. Setting <em>high</em> to zero forces <em>low</em> to zero as well, and causes <code class="xref py py-meth docutils literal notranslate"><span class="pre">pause_writing()</span></code> to be called whenever the buffer becomes non-empty. Setting <em>low</em> to zero causes <code class="xref py py-meth docutils literal notranslate"><span class="pre">resume_writing()</span></code> to be called only once the buffer is empty. Use of zero for either limit is generally sub-optimal as it reduces opportunities for doing I/O and computation concurrently.</p> <p>Use <a class="reference internal" href="#asyncio.WriteTransport.get_write_buffer_limits" title="asyncio.WriteTransport.get_write_buffer_limits"><code class="xref py py-meth docutils literal notranslate"><span class="pre">get_write_buffer_limits()</span></code></a> to get the limits.</p> </dd></dl> <dl class="method"> <dt id="asyncio.WriteTransport.write"> <code class="descname">write</code><span class="sig-paren">(</span><em>data</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.WriteTransport.write" title="Permalink to this definition">¶</a></dt> <dd><p>Write some <em>data</em> bytes to the transport.</p> <p>This method does not block; it buffers the data and arranges for it to be sent out asynchronously.</p> </dd></dl> <dl class="method"> <dt id="asyncio.WriteTransport.writelines"> <code class="descname">writelines</code><span class="sig-paren">(</span><em>list_of_data</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.WriteTransport.writelines" title="Permalink to this definition">¶</a></dt> <dd><p>Write a list (or any iterable) of data bytes to the transport. This is functionally equivalent to calling <a class="reference internal" href="#asyncio.WriteTransport.write" title="asyncio.WriteTransport.write"><code class="xref py py-meth docutils literal notranslate"><span class="pre">write()</span></code></a> on each element yielded by the iterable, but may be implemented more efficiently.</p> </dd></dl> <dl class="method"> <dt id="asyncio.WriteTransport.write_eof"> <code class="descname">write_eof</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.WriteTransport.write_eof" title="Permalink to this definition">¶</a></dt> <dd><p>Close the write end of the transport after flushing buffered data. Data may still be received.</p> <p>This method can raise <a class="reference internal" href="exceptions.html#NotImplementedError" title="NotImplementedError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">NotImplementedError</span></code></a> if the transport (e.g. SSL) doesn’t support half-closes.</p> </dd></dl> </dd></dl> </div> <div class="section" id="datagramtransport"> <h3>18.5.4.1.4. DatagramTransport<a class="headerlink" href="#datagramtransport" title="Permalink to this headline">¶</a></h3> <dl class="method"> <dt id="asyncio.DatagramTransport.sendto"> <code class="descclassname">DatagramTransport.</code><code class="descname">sendto</code><span class="sig-paren">(</span><em>data</em>, <em>addr=None</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.DatagramTransport.sendto" title="Permalink to this definition">¶</a></dt> <dd><p>Send the <em>data</em> bytes to the remote peer given by <em>addr</em> (a transport-dependent target address). If <em>addr</em> is <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a>, the data is sent to the target address given on transport creation.</p> <p>This method does not block; it buffers the data and arranges for it to be sent out asynchronously.</p> </dd></dl> <dl class="method"> <dt id="asyncio.DatagramTransport.abort"> <code class="descclassname">DatagramTransport.</code><code class="descname">abort</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.DatagramTransport.abort" title="Permalink to this definition">¶</a></dt> <dd><p>Close the transport immediately, without waiting for pending operations to complete. Buffered data will be lost. No more data will be received. The protocol’s <code class="xref py py-meth docutils literal notranslate"><span class="pre">connection_lost()</span></code> method will eventually be called with <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a> as its argument.</p> </dd></dl> </div> <div class="section" id="basesubprocesstransport"> <h3>18.5.4.1.5. BaseSubprocessTransport<a class="headerlink" href="#basesubprocesstransport" title="Permalink to this headline">¶</a></h3> <dl class="class"> <dt id="asyncio.BaseSubprocessTransport"> <em class="property">class </em><code class="descclassname">asyncio.</code><code class="descname">BaseSubprocessTransport</code><a class="headerlink" href="#asyncio.BaseSubprocessTransport" title="Permalink to this definition">¶</a></dt> <dd><dl class="method"> <dt id="asyncio.BaseSubprocessTransport.get_pid"> <code class="descname">get_pid</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.BaseSubprocessTransport.get_pid" title="Permalink to this definition">¶</a></dt> <dd><p>Return the subprocess process id as an integer.</p> </dd></dl> <dl class="method"> <dt id="asyncio.BaseSubprocessTransport.get_pipe_transport"> <code class="descname">get_pipe_transport</code><span class="sig-paren">(</span><em>fd</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.BaseSubprocessTransport.get_pipe_transport" title="Permalink to this definition">¶</a></dt> <dd><p>Return the transport for the communication pipe corresponding to the integer file descriptor <em>fd</em>:</p> <ul class="simple"> <li><code class="docutils literal notranslate"><span class="pre">0</span></code>: readable streaming transport of the standard input (<em>stdin</em>), or <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a> if the subprocess was not created with <code class="docutils literal notranslate"><span class="pre">stdin=PIPE</span></code></li> <li><code class="docutils literal notranslate"><span class="pre">1</span></code>: writable streaming transport of the standard output (<em>stdout</em>), or <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a> if the subprocess was not created with <code class="docutils literal notranslate"><span class="pre">stdout=PIPE</span></code></li> <li><code class="docutils literal notranslate"><span class="pre">2</span></code>: writable streaming transport of the standard error (<em>stderr</em>), or <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a> if the subprocess was not created with <code class="docutils literal notranslate"><span class="pre">stderr=PIPE</span></code></li> <li>other <em>fd</em>: <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a></li> </ul> </dd></dl> <dl class="method"> <dt id="asyncio.BaseSubprocessTransport.get_returncode"> <code class="descname">get_returncode</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.BaseSubprocessTransport.get_returncode" title="Permalink to this definition">¶</a></dt> <dd><p>Return the subprocess returncode as an integer or <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a> if it hasn’t returned, similarly to the <a class="reference internal" href="subprocess.html#subprocess.Popen.returncode" title="subprocess.Popen.returncode"><code class="xref py py-attr docutils literal notranslate"><span class="pre">subprocess.Popen.returncode</span></code></a> attribute.</p> </dd></dl> <dl class="method"> <dt id="asyncio.BaseSubprocessTransport.kill"> <code class="descname">kill</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.BaseSubprocessTransport.kill" title="Permalink to this definition">¶</a></dt> <dd><p>Kill the subprocess, as in <a class="reference internal" href="subprocess.html#subprocess.Popen.kill" title="subprocess.Popen.kill"><code class="xref py py-meth docutils literal notranslate"><span class="pre">subprocess.Popen.kill()</span></code></a>.</p> <p>On POSIX systems, the function sends SIGKILL to the subprocess. On Windows, this method is an alias for <a class="reference internal" href="#asyncio.BaseSubprocessTransport.terminate" title="asyncio.BaseSubprocessTransport.terminate"><code class="xref py py-meth docutils literal notranslate"><span class="pre">terminate()</span></code></a>.</p> </dd></dl> <dl class="method"> <dt id="asyncio.BaseSubprocessTransport.send_signal"> <code class="descname">send_signal</code><span class="sig-paren">(</span><em>signal</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.BaseSubprocessTransport.send_signal" title="Permalink to this definition">¶</a></dt> <dd><p>Send the <em>signal</em> number to the subprocess, as in <a class="reference internal" href="subprocess.html#subprocess.Popen.send_signal" title="subprocess.Popen.send_signal"><code class="xref py py-meth docutils literal notranslate"><span class="pre">subprocess.Popen.send_signal()</span></code></a>.</p> </dd></dl> <dl class="method"> <dt id="asyncio.BaseSubprocessTransport.terminate"> <code class="descname">terminate</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.BaseSubprocessTransport.terminate" title="Permalink to this definition">¶</a></dt> <dd><p>Ask the subprocess to stop, as in <a class="reference internal" href="subprocess.html#subprocess.Popen.terminate" title="subprocess.Popen.terminate"><code class="xref py py-meth docutils literal notranslate"><span class="pre">subprocess.Popen.terminate()</span></code></a>. This method is an alias for the <a class="reference internal" href="#asyncio.BaseSubprocessTransport.close" title="asyncio.BaseSubprocessTransport.close"><code class="xref py py-meth docutils literal notranslate"><span class="pre">close()</span></code></a> method.</p> <p>On POSIX systems, this method sends SIGTERM to the subprocess. On Windows, the Windows API function TerminateProcess() is called to stop the subprocess.</p> </dd></dl> <dl class="method"> <dt id="asyncio.BaseSubprocessTransport.close"> <code class="descname">close</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.BaseSubprocessTransport.close" title="Permalink to this definition">¶</a></dt> <dd><p>Ask the subprocess to stop by calling the <a class="reference internal" href="#asyncio.BaseSubprocessTransport.terminate" title="asyncio.BaseSubprocessTransport.terminate"><code class="xref py py-meth docutils literal notranslate"><span class="pre">terminate()</span></code></a> method if the subprocess hasn’t returned yet, and close transports of all pipes (<em>stdin</em>, <em>stdout</em> and <em>stderr</em>).</p> </dd></dl> </dd></dl> </div> </div> <div class="section" id="protocols"> <span id="asyncio-protocol"></span><h2>18.5.4.2. Protocols<a class="headerlink" href="#protocols" title="Permalink to this headline">¶</a></h2> <p><a class="reference internal" href="asyncio.html#module-asyncio" title="asyncio: Asynchronous I/O, event loop, coroutines and tasks."><code class="xref py py-mod docutils literal notranslate"><span class="pre">asyncio</span></code></a> provides base classes that you can subclass to implement your network protocols. Those classes are used in conjunction with <a class="reference internal" href="#asyncio-transport"><span class="std std-ref">transports</span></a> (see below): the protocol parses incoming data and asks for the writing of outgoing data, while the transport is responsible for the actual I/O and buffering.</p> <p>When subclassing a protocol class, it is recommended you override certain methods. Those methods are callbacks: they will be called by the transport on certain events (for example when some data is received); you shouldn’t call them yourself, unless you are implementing a transport.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">All callbacks have default implementations, which are empty. Therefore, you only need to implement the callbacks for the events in which you are interested.</p> </div> <div class="section" id="protocol-classes"> <h3>18.5.4.2.1. Protocol classes<a class="headerlink" href="#protocol-classes" title="Permalink to this headline">¶</a></h3> <dl class="class"> <dt id="asyncio.Protocol"> <em class="property">class </em><code class="descclassname">asyncio.</code><code class="descname">Protocol</code><a class="headerlink" href="#asyncio.Protocol" title="Permalink to this definition">¶</a></dt> <dd><p>The base class for implementing streaming protocols (for use with e.g. TCP and SSL transports).</p> </dd></dl> <dl class="class"> <dt id="asyncio.DatagramProtocol"> <em class="property">class </em><code class="descclassname">asyncio.</code><code class="descname">DatagramProtocol</code><a class="headerlink" href="#asyncio.DatagramProtocol" title="Permalink to this definition">¶</a></dt> <dd><p>The base class for implementing datagram protocols (for use with e.g. UDP transports).</p> </dd></dl> <dl class="class"> <dt id="asyncio.SubprocessProtocol"> <em class="property">class </em><code class="descclassname">asyncio.</code><code class="descname">SubprocessProtocol</code><a class="headerlink" href="#asyncio.SubprocessProtocol" title="Permalink to this definition">¶</a></dt> <dd><p>The base class for implementing protocols communicating with child processes (through a set of unidirectional pipes).</p> </dd></dl> </div> <div class="section" id="connection-callbacks"> <h3>18.5.4.2.2. Connection callbacks<a class="headerlink" href="#connection-callbacks" title="Permalink to this headline">¶</a></h3> <p>These callbacks may be called on <a class="reference internal" href="#asyncio.Protocol" title="asyncio.Protocol"><code class="xref py py-class docutils literal notranslate"><span class="pre">Protocol</span></code></a>, <a class="reference internal" href="#asyncio.DatagramProtocol" title="asyncio.DatagramProtocol"><code class="xref py py-class docutils literal notranslate"><span class="pre">DatagramProtocol</span></code></a> and <a class="reference internal" href="#asyncio.SubprocessProtocol" title="asyncio.SubprocessProtocol"><code class="xref py py-class docutils literal notranslate"><span class="pre">SubprocessProtocol</span></code></a> instances:</p> <dl class="method"> <dt id="asyncio.BaseProtocol.connection_made"> <code class="descclassname">BaseProtocol.</code><code class="descname">connection_made</code><span class="sig-paren">(</span><em>transport</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.BaseProtocol.connection_made" title="Permalink to this definition">¶</a></dt> <dd><p>Called when a connection is made.</p> <p>The <em>transport</em> argument is the transport representing the connection. You are responsible for storing it somewhere (e.g. as an attribute) if you need to.</p> </dd></dl> <dl class="method"> <dt id="asyncio.BaseProtocol.connection_lost"> <code class="descclassname">BaseProtocol.</code><code class="descname">connection_lost</code><span class="sig-paren">(</span><em>exc</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.BaseProtocol.connection_lost" title="Permalink to this definition">¶</a></dt> <dd><p>Called when the connection is lost or closed.</p> <p>The argument is either an exception object or <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a>. The latter means a regular EOF is received, or the connection was aborted or closed by this side of the connection.</p> </dd></dl> <p><a class="reference internal" href="#asyncio.BaseProtocol.connection_made" title="asyncio.BaseProtocol.connection_made"><code class="xref py py-meth docutils literal notranslate"><span class="pre">connection_made()</span></code></a> and <a class="reference internal" href="#asyncio.BaseProtocol.connection_lost" title="asyncio.BaseProtocol.connection_lost"><code class="xref py py-meth docutils literal notranslate"><span class="pre">connection_lost()</span></code></a> are called exactly once per successful connection. All other callbacks will be called between those two methods, which allows for easier resource management in your protocol implementation.</p> <p>The following callbacks may be called only on <a class="reference internal" href="#asyncio.SubprocessProtocol" title="asyncio.SubprocessProtocol"><code class="xref py py-class docutils literal notranslate"><span class="pre">SubprocessProtocol</span></code></a> instances:</p> <dl class="method"> <dt id="asyncio.SubprocessProtocol.pipe_data_received"> <code class="descclassname">SubprocessProtocol.</code><code class="descname">pipe_data_received</code><span class="sig-paren">(</span><em>fd</em>, <em>data</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.SubprocessProtocol.pipe_data_received" title="Permalink to this definition">¶</a></dt> <dd><p>Called when the child process writes data into its stdout or stderr pipe. <em>fd</em> is the integer file descriptor of the pipe. <em>data</em> is a non-empty bytes object containing the data.</p> </dd></dl> <dl class="method"> <dt id="asyncio.SubprocessProtocol.pipe_connection_lost"> <code class="descclassname">SubprocessProtocol.</code><code class="descname">pipe_connection_lost</code><span class="sig-paren">(</span><em>fd</em>, <em>exc</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.SubprocessProtocol.pipe_connection_lost" title="Permalink to this definition">¶</a></dt> <dd><p>Called when one of the pipes communicating with the child process is closed. <em>fd</em> is the integer file descriptor that was closed.</p> </dd></dl> <dl class="method"> <dt id="asyncio.SubprocessProtocol.process_exited"> <code class="descclassname">SubprocessProtocol.</code><code class="descname">process_exited</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.SubprocessProtocol.process_exited" title="Permalink to this definition">¶</a></dt> <dd><p>Called when the child process has exited.</p> </dd></dl> </div> <div class="section" id="streaming-protocols"> <h3>18.5.4.2.3. Streaming protocols<a class="headerlink" href="#streaming-protocols" title="Permalink to this headline">¶</a></h3> <p>The following callbacks are called on <a class="reference internal" href="#asyncio.Protocol" title="asyncio.Protocol"><code class="xref py py-class docutils literal notranslate"><span class="pre">Protocol</span></code></a> instances:</p> <dl class="method"> <dt id="asyncio.Protocol.data_received"> <code class="descclassname">Protocol.</code><code class="descname">data_received</code><span class="sig-paren">(</span><em>data</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.Protocol.data_received" title="Permalink to this definition">¶</a></dt> <dd><p>Called when some data is received. <em>data</em> is a non-empty bytes object containing the incoming data.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">Whether the data is buffered, chunked or reassembled depends on the transport. In general, you shouldn’t rely on specific semantics and instead make your parsing generic and flexible enough. However, data is always received in the correct order.</p> </div> </dd></dl> <dl class="method"> <dt id="asyncio.Protocol.eof_received"> <code class="descclassname">Protocol.</code><code class="descname">eof_received</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.Protocol.eof_received" title="Permalink to this definition">¶</a></dt> <dd><p>Called when the other end signals it won’t send any more data (for example by calling <code class="xref py py-meth docutils literal notranslate"><span class="pre">write_eof()</span></code>, if the other end also uses asyncio).</p> <p>This method may return a false value (including <code class="docutils literal notranslate"><span class="pre">None</span></code>), in which case the transport will close itself. Conversely, if this method returns a true value, closing the transport is up to the protocol. Since the default implementation returns <code class="docutils literal notranslate"><span class="pre">None</span></code>, it implicitly closes the connection.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">Some transports such as SSL don’t support half-closed connections, in which case returning true from this method will not prevent closing the connection.</p> </div> </dd></dl> <p><code class="xref py py-meth docutils literal notranslate"><span class="pre">data_received()</span></code> can be called an arbitrary number of times during a connection. However, <code class="xref py py-meth docutils literal notranslate"><span class="pre">eof_received()</span></code> is called at most once and, if called, <code class="xref py py-meth docutils literal notranslate"><span class="pre">data_received()</span></code> won’t be called after it.</p> <p>State machine:</p> <blockquote> <div>start -> <a class="reference internal" href="#asyncio.BaseProtocol.connection_made" title="asyncio.BaseProtocol.connection_made"><code class="xref py py-meth docutils literal notranslate"><span class="pre">connection_made()</span></code></a> [-> <a class="reference internal" href="#asyncio.Protocol.data_received" title="asyncio.Protocol.data_received"><code class="xref py py-meth docutils literal notranslate"><span class="pre">data_received()</span></code></a> *] [-> <a class="reference internal" href="#asyncio.Protocol.eof_received" title="asyncio.Protocol.eof_received"><code class="xref py py-meth docutils literal notranslate"><span class="pre">eof_received()</span></code></a> ?] -> <a class="reference internal" href="#asyncio.BaseProtocol.connection_lost" title="asyncio.BaseProtocol.connection_lost"><code class="xref py py-meth docutils literal notranslate"><span class="pre">connection_lost()</span></code></a> -> end</div></blockquote> </div> <div class="section" id="datagram-protocols"> <h3>18.5.4.2.4. Datagram protocols<a class="headerlink" href="#datagram-protocols" title="Permalink to this headline">¶</a></h3> <p>The following callbacks are called on <a class="reference internal" href="#asyncio.DatagramProtocol" title="asyncio.DatagramProtocol"><code class="xref py py-class docutils literal notranslate"><span class="pre">DatagramProtocol</span></code></a> instances.</p> <dl class="method"> <dt id="asyncio.DatagramProtocol.datagram_received"> <code class="descclassname">DatagramProtocol.</code><code class="descname">datagram_received</code><span class="sig-paren">(</span><em>data</em>, <em>addr</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.DatagramProtocol.datagram_received" title="Permalink to this definition">¶</a></dt> <dd><p>Called when a datagram is received. <em>data</em> is a bytes object containing the incoming data. <em>addr</em> is the address of the peer sending the data; the exact format depends on the transport.</p> </dd></dl> <dl class="method"> <dt id="asyncio.DatagramProtocol.error_received"> <code class="descclassname">DatagramProtocol.</code><code class="descname">error_received</code><span class="sig-paren">(</span><em>exc</em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.DatagramProtocol.error_received" title="Permalink to this definition">¶</a></dt> <dd><p>Called when a previous send or receive operation raises an <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-class docutils literal notranslate"><span class="pre">OSError</span></code></a>. <em>exc</em> is the <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-class docutils literal notranslate"><span class="pre">OSError</span></code></a> instance.</p> <p>This method is called in rare conditions, when the transport (e.g. UDP) detects that a datagram couldn’t be delivered to its recipient. In many conditions though, undeliverable datagrams will be silently dropped.</p> </dd></dl> </div> <div class="section" id="flow-control-callbacks"> <h3>18.5.4.2.5. Flow control callbacks<a class="headerlink" href="#flow-control-callbacks" title="Permalink to this headline">¶</a></h3> <p>These callbacks may be called on <a class="reference internal" href="#asyncio.Protocol" title="asyncio.Protocol"><code class="xref py py-class docutils literal notranslate"><span class="pre">Protocol</span></code></a>, <a class="reference internal" href="#asyncio.DatagramProtocol" title="asyncio.DatagramProtocol"><code class="xref py py-class docutils literal notranslate"><span class="pre">DatagramProtocol</span></code></a> and <a class="reference internal" href="#asyncio.SubprocessProtocol" title="asyncio.SubprocessProtocol"><code class="xref py py-class docutils literal notranslate"><span class="pre">SubprocessProtocol</span></code></a> instances:</p> <dl class="method"> <dt id="asyncio.BaseProtocol.pause_writing"> <code class="descclassname">BaseProtocol.</code><code class="descname">pause_writing</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.BaseProtocol.pause_writing" title="Permalink to this definition">¶</a></dt> <dd><p>Called when the transport’s buffer goes over the high-water mark.</p> </dd></dl> <dl class="method"> <dt id="asyncio.BaseProtocol.resume_writing"> <code class="descclassname">BaseProtocol.</code><code class="descname">resume_writing</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.BaseProtocol.resume_writing" title="Permalink to this definition">¶</a></dt> <dd><p>Called when the transport’s buffer drains below the low-water mark.</p> </dd></dl> <p><code class="xref py py-meth docutils literal notranslate"><span class="pre">pause_writing()</span></code> and <code class="xref py py-meth docutils literal notranslate"><span class="pre">resume_writing()</span></code> calls are paired – <code class="xref py py-meth docutils literal notranslate"><span class="pre">pause_writing()</span></code> is called once when the buffer goes strictly over the high-water mark (even if subsequent writes increases the buffer size even more), and eventually <code class="xref py py-meth docutils literal notranslate"><span class="pre">resume_writing()</span></code> is called once when the buffer size reaches the low-water mark.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">If the buffer size equals the high-water mark, <code class="xref py py-meth docutils literal notranslate"><span class="pre">pause_writing()</span></code> is not called – it must go strictly over. Conversely, <code class="xref py py-meth docutils literal notranslate"><span class="pre">resume_writing()</span></code> is called when the buffer size is equal or lower than the low-water mark. These end conditions are important to ensure that things go as expected when either mark is zero.</p> </div> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">On BSD systems (OS X, FreeBSD, etc.) flow control is not supported for <a class="reference internal" href="#asyncio.DatagramProtocol" title="asyncio.DatagramProtocol"><code class="xref py py-class docutils literal notranslate"><span class="pre">DatagramProtocol</span></code></a>, because send failures caused by writing too many packets cannot be detected easily. The socket always appears ‘ready’ and excess packets are dropped; an <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-class docutils literal notranslate"><span class="pre">OSError</span></code></a> with errno set to <a class="reference internal" href="errno.html#errno.ENOBUFS" title="errno.ENOBUFS"><code class="xref py py-const docutils literal notranslate"><span class="pre">errno.ENOBUFS</span></code></a> may or may not be raised; if it is raised, it will be reported to <a class="reference internal" href="#asyncio.DatagramProtocol.error_received" title="asyncio.DatagramProtocol.error_received"><code class="xref py py-meth docutils literal notranslate"><span class="pre">DatagramProtocol.error_received()</span></code></a> but otherwise ignored.</p> </div> </div> <div class="section" id="coroutines-and-protocols"> <h3>18.5.4.2.6. Coroutines and protocols<a class="headerlink" href="#coroutines-and-protocols" title="Permalink to this headline">¶</a></h3> <p>Coroutines can be scheduled in a protocol method using <a class="reference internal" href="asyncio-task.html#asyncio.ensure_future" title="asyncio.ensure_future"><code class="xref py py-func docutils literal notranslate"><span class="pre">ensure_future()</span></code></a>, but there is no guarantee made about the execution order. Protocols are not aware of coroutines created in protocol methods and so will not wait for them.</p> <p>To have a reliable execution order, use <a class="reference internal" href="asyncio-stream.html#asyncio-streams"><span class="std std-ref">stream objects</span></a> in a coroutine with <code class="docutils literal notranslate"><span class="pre">yield</span> <span class="pre">from</span></code>. For example, the <a class="reference internal" href="asyncio-stream.html#asyncio.StreamWriter.drain" title="asyncio.StreamWriter.drain"><code class="xref py py-meth docutils literal notranslate"><span class="pre">StreamWriter.drain()</span></code></a> coroutine can be used to wait until the write buffer is flushed.</p> </div> </div> <div class="section" id="protocol-examples"> <h2>18.5.4.3. Protocol examples<a class="headerlink" href="#protocol-examples" title="Permalink to this headline">¶</a></h2> <div class="section" id="tcp-echo-client-protocol"> <span id="asyncio-tcp-echo-client-protocol"></span><h3>18.5.4.3.1. TCP echo client protocol<a class="headerlink" href="#tcp-echo-client-protocol" title="Permalink to this headline">¶</a></h3> <p>TCP echo client using 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, send data and wait until the connection is closed:</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">class</span> <span class="nc">EchoClientProtocol</span><span class="p">(</span><span class="n">asyncio</span><span class="o">.</span><span class="n">Protocol</span><span class="p">):</span> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</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="bp">self</span><span class="o">.</span><span class="n">message</span> <span class="o">=</span> <span class="n">message</span> <span class="bp">self</span><span class="o">.</span><span class="n">loop</span> <span class="o">=</span> <span class="n">loop</span> <span class="k">def</span> <span class="nf">connection_made</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">transport</span><span class="p">):</span> <span class="n">transport</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">message</span><span class="o">.</span><span class="n">encode</span><span class="p">())</span> <span class="nb">print</span><span class="p">(</span><span class="s1">'Data sent: </span><span class="si">{!r}</span><span class="s1">'</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">message</span><span class="p">))</span> <span class="k">def</span> <span class="nf">data_received</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">data</span><span class="p">):</span> <span class="nb">print</span><span class="p">(</span><span class="s1">'Data received: </span><span class="si">{!r}</span><span class="s1">'</span><span class="o">.</span><span class="n">format</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="k">def</span> <span class="nf">connection_lost</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">exc</span><span class="p">):</span> <span class="nb">print</span><span class="p">(</span><span class="s1">'The server closed the connection'</span><span class="p">)</span> <span class="nb">print</span><span class="p">(</span><span class="s1">'Stop the event loop'</span><span class="p">)</span> <span class="bp">self</span><span class="o">.</span><span class="n">loop</span><span class="o">.</span><span class="n">stop</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">message</span> <span class="o">=</span> <span class="s1">'Hello World!'</span> <span class="n">coro</span> <span class="o">=</span> <span class="n">loop</span><span class="o">.</span><span class="n">create_connection</span><span class="p">(</span><span class="k">lambda</span><span class="p">:</span> <span class="n">EchoClientProtocol</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="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">run_until_complete</span><span class="p">(</span><span class="n">coro</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="n">loop</span><span class="o">.</span><span class="n">close</span><span class="p">()</span> </pre></div> </div> <p>The event loop is running twice. The <a class="reference internal" href="asyncio-eventloop.html#asyncio.AbstractEventLoop.run_until_complete" title="asyncio.AbstractEventLoop.run_until_complete"><code class="xref py py-meth docutils literal notranslate"><span class="pre">run_until_complete()</span></code></a> method is preferred in this short example to raise an exception if the server is not listening, instead of having to write a short coroutine to handle the exception and stop the running loop. At <a class="reference internal" href="asyncio-eventloop.html#asyncio.AbstractEventLoop.run_until_complete" title="asyncio.AbstractEventLoop.run_until_complete"><code class="xref py py-meth docutils literal notranslate"><span class="pre">run_until_complete()</span></code></a> exit, the loop is no longer running, so there is no need to stop the loop in case of an error.</p> <div class="admonition seealso"> <p class="first admonition-title">See also</p> <p class="last">The <a class="reference internal" href="asyncio-stream.html#asyncio-tcp-echo-client-streams"><span class="std std-ref">TCP echo client using streams</span></a> example uses the <a class="reference internal" href="asyncio-stream.html#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> </div> <div class="section" id="tcp-echo-server-protocol"> <span id="asyncio-tcp-echo-server-protocol"></span><h3>18.5.4.3.2. TCP echo server protocol<a class="headerlink" href="#tcp-echo-server-protocol" title="Permalink to this headline">¶</a></h3> <p>TCP echo server using 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, send back received data and close the connection:</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">class</span> <span class="nc">EchoServerClientProtocol</span><span class="p">(</span><span class="n">asyncio</span><span class="o">.</span><span class="n">Protocol</span><span class="p">):</span> <span class="k">def</span> <span class="nf">connection_made</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">transport</span><span class="p">):</span> <span class="n">peername</span> <span class="o">=</span> <span class="n">transport</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="s1">'Connection from </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">peername</span><span class="p">))</span> <span class="bp">self</span><span class="o">.</span><span class="n">transport</span> <span class="o">=</span> <span class="n">transport</span> <span class="k">def</span> <span class="nf">data_received</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">data</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="nb">print</span><span class="p">(</span><span class="s1">'Data received: </span><span class="si">{!r}</span><span class="s1">'</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">message</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">format</span><span class="p">(</span><span class="n">message</span><span class="p">))</span> <span class="bp">self</span><span class="o">.</span><span class="n">transport</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="nb">print</span><span class="p">(</span><span class="s1">'Close the client socket'</span><span class="p">)</span> <span class="bp">self</span><span class="o">.</span><span class="n">transport</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="c1"># Each client connection will create a new protocol instance</span> <span class="n">coro</span> <span class="o">=</span> <span class="n">loop</span><span class="o">.</span><span class="n">create_server</span><span class="p">(</span><span class="n">EchoServerClientProtocol</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">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> <p><code class="xref py py-meth docutils literal notranslate"><span class="pre">Transport.close()</span></code> can be called immediately after <a class="reference internal" href="#asyncio.WriteTransport.write" title="asyncio.WriteTransport.write"><code class="xref py py-meth docutils literal notranslate"><span class="pre">WriteTransport.write()</span></code></a> even if data are not sent yet on the socket: both methods are asynchronous. <code class="docutils literal notranslate"><span class="pre">yield</span> <span class="pre">from</span></code> is not needed because these transport methods are not coroutines.</p> <div class="admonition seealso"> <p class="first admonition-title">See also</p> <p class="last">The <a class="reference internal" href="asyncio-stream.html#asyncio-tcp-echo-server-streams"><span class="std std-ref">TCP echo server using streams</span></a> example uses the <a class="reference internal" href="asyncio-stream.html#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> </div> <div class="section" id="udp-echo-client-protocol"> <span id="asyncio-udp-echo-client-protocol"></span><h3>18.5.4.3.3. UDP echo client protocol<a class="headerlink" href="#udp-echo-client-protocol" title="Permalink to this headline">¶</a></h3> <p>UDP echo client using the <a class="reference internal" href="asyncio-eventloop.html#asyncio.AbstractEventLoop.create_datagram_endpoint" title="asyncio.AbstractEventLoop.create_datagram_endpoint"><code class="xref py py-meth docutils literal notranslate"><span class="pre">AbstractEventLoop.create_datagram_endpoint()</span></code></a> method, send data and close the transport when we received the answer:</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">class</span> <span class="nc">EchoClientProtocol</span><span class="p">:</span> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</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="bp">self</span><span class="o">.</span><span class="n">message</span> <span class="o">=</span> <span class="n">message</span> <span class="bp">self</span><span class="o">.</span><span class="n">loop</span> <span class="o">=</span> <span class="n">loop</span> <span class="bp">self</span><span class="o">.</span><span class="n">transport</span> <span class="o">=</span> <span class="kc">None</span> <span class="k">def</span> <span class="nf">connection_made</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">transport</span><span class="p">):</span> <span class="bp">self</span><span class="o">.</span><span class="n">transport</span> <span class="o">=</span> <span class="n">transport</span> <span class="nb">print</span><span class="p">(</span><span class="s1">'Send:'</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">message</span><span class="p">)</span> <span class="bp">self</span><span class="o">.</span><span class="n">transport</span><span class="o">.</span><span class="n">sendto</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">message</span><span class="o">.</span><span class="n">encode</span><span class="p">())</span> <span class="k">def</span> <span class="nf">datagram_received</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">data</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">"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="nb">print</span><span class="p">(</span><span class="s2">"Close the socket"</span><span class="p">)</span> <span class="bp">self</span><span class="o">.</span><span class="n">transport</span><span class="o">.</span><span class="n">close</span><span class="p">()</span> <span class="k">def</span> <span class="nf">error_received</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">exc</span><span class="p">):</span> <span class="nb">print</span><span class="p">(</span><span class="s1">'Error received:'</span><span class="p">,</span> <span class="n">exc</span><span class="p">)</span> <span class="k">def</span> <span class="nf">connection_lost</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">exc</span><span class="p">):</span> <span class="nb">print</span><span class="p">(</span><span class="s2">"Socket closed, stop the event loop"</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">stop</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">message</span> <span class="o">=</span> <span class="s2">"Hello World!"</span> <span class="n">connect</span> <span class="o">=</span> <span class="n">loop</span><span class="o">.</span><span class="n">create_datagram_endpoint</span><span class="p">(</span> <span class="k">lambda</span><span class="p">:</span> <span class="n">EchoClientProtocol</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">remote_addr</span><span class="o">=</span><span class="p">(</span><span class="s1">'127.0.0.1'</span><span class="p">,</span> <span class="mi">9999</span><span class="p">))</span> <span class="n">transport</span><span class="p">,</span> <span class="n">protocol</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">connect</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="n">transport</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">close</span><span class="p">()</span> </pre></div> </div> </div> <div class="section" id="udp-echo-server-protocol"> <span id="asyncio-udp-echo-server-protocol"></span><h3>18.5.4.3.4. UDP echo server protocol<a class="headerlink" href="#udp-echo-server-protocol" title="Permalink to this headline">¶</a></h3> <p>UDP echo server using the <a class="reference internal" href="asyncio-eventloop.html#asyncio.AbstractEventLoop.create_datagram_endpoint" title="asyncio.AbstractEventLoop.create_datagram_endpoint"><code class="xref py py-meth docutils literal notranslate"><span class="pre">AbstractEventLoop.create_datagram_endpoint()</span></code></a> method, send back received data:</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">class</span> <span class="nc">EchoServerProtocol</span><span class="p">:</span> <span class="k">def</span> <span class="nf">connection_made</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">transport</span><span class="p">):</span> <span class="bp">self</span><span class="o">.</span><span class="n">transport</span> <span class="o">=</span> <span class="n">transport</span> <span class="k">def</span> <span class="nf">datagram_received</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">data</span><span class="p">,</span> <span class="n">addr</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="nb">print</span><span class="p">(</span><span class="s1">'Received </span><span class="si">%r</span><span class="s1"> from </span><span class="si">%s</span><span class="s1">'</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="s1">'Send </span><span class="si">%r</span><span class="s1"> to </span><span class="si">%s</span><span class="s1">'</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="bp">self</span><span class="o">.</span><span class="n">transport</span><span class="o">.</span><span class="n">sendto</span><span class="p">(</span><span class="n">data</span><span class="p">,</span> <span class="n">addr</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="nb">print</span><span class="p">(</span><span class="s2">"Starting UDP server"</span><span class="p">)</span> <span class="c1"># One protocol instance will be created to serve all client requests</span> <span class="n">listen</span> <span class="o">=</span> <span class="n">loop</span><span class="o">.</span><span class="n">create_datagram_endpoint</span><span class="p">(</span> <span class="n">EchoServerProtocol</span><span class="p">,</span> <span class="n">local_addr</span><span class="o">=</span><span class="p">(</span><span class="s1">'127.0.0.1'</span><span class="p">,</span> <span class="mi">9999</span><span class="p">))</span> <span class="n">transport</span><span class="p">,</span> <span class="n">protocol</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">listen</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="n">transport</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">close</span><span class="p">()</span> </pre></div> </div> </div> <div class="section" id="register-an-open-socket-to-wait-for-data-using-a-protocol"> <span id="asyncio-register-socket"></span><h3>18.5.4.3.5. Register an open socket to wait for data using a protocol<a class="headerlink" href="#register-an-open-socket-to-wait-for-data-using-a-protocol" title="Permalink to this headline">¶</a></h3> <p>Wait until a socket receives data using 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 with a protocol, and then close the event loop</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="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="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="k">class</span> <span class="nc">MyProtocol</span><span class="p">(</span><span class="n">asyncio</span><span class="o">.</span><span class="n">Protocol</span><span class="p">):</span> <span class="n">transport</span> <span class="o">=</span> <span class="kc">None</span> <span class="k">def</span> <span class="nf">connection_made</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">transport</span><span class="p">):</span> <span class="bp">self</span><span class="o">.</span><span class="n">transport</span> <span class="o">=</span> <span class="n">transport</span> <span class="k">def</span> <span class="nf">data_received</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">data</span><span class="p">):</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="c1"># We are done: close the transport (it will call connection_lost())</span> <span class="bp">self</span><span class="o">.</span><span class="n">transport</span><span class="o">.</span><span class="n">close</span><span class="p">()</span> <span class="k">def</span> <span class="nf">connection_lost</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">exc</span><span class="p">):</span> <span class="c1"># The socket has been closed, stop the event loop</span> <span class="n">loop</span><span class="o">.</span><span class="n">stop</span><span class="p">()</span> <span class="c1"># Register the socket to wait for data</span> <span class="n">connect_coro</span> <span class="o">=</span> <span class="n">loop</span><span class="o">.</span><span class="n">create_connection</span><span class="p">(</span><span class="n">MyProtocol</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">transport</span><span class="p">,</span> <span class="n">protocol</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">connect_coro</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"># Run the event loop</span> <span class="n">loop</span><span class="o">.</span><span class="n">run_forever</span><span class="p">()</span> <span class="c1"># We are done, close sockets and the event loop</span> <span class="n">rsock</span><span class="o">.</span><span class="n">close</span><span class="p">()</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">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-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> <p class="last">The <a class="reference internal" href="asyncio-stream.html#asyncio-register-socket-streams"><span class="std std-ref">register an open socket to wait for data using streams</span></a> example uses high-level streams created by the <a class="reference internal" href="asyncio-stream.html#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 in a coroutine.</p> </div> </div> </div> </div> </div> </div> </div> <div class="sphinxsidebar" role="navigation" aria-label="main navigation"> <div class="sphinxsidebarwrapper"> <h3><a href="../contents.html">Table Of Contents</a></h3> <ul> <li><a class="reference internal" href="#">18.5.4. Transports and protocols (callback based API)</a><ul> <li><a class="reference internal" href="#transports">18.5.4.1. Transports</a><ul> <li><a class="reference internal" href="#basetransport">18.5.4.1.1. BaseTransport</a></li> <li><a class="reference internal" href="#readtransport">18.5.4.1.2. ReadTransport</a></li> <li><a class="reference internal" href="#writetransport">18.5.4.1.3. WriteTransport</a></li> <li><a class="reference internal" href="#datagramtransport">18.5.4.1.4. DatagramTransport</a></li> <li><a class="reference internal" href="#basesubprocesstransport">18.5.4.1.5. BaseSubprocessTransport</a></li> </ul> </li> <li><a class="reference internal" href="#protocols">18.5.4.2. Protocols</a><ul> <li><a class="reference internal" href="#protocol-classes">18.5.4.2.1. Protocol classes</a></li> <li><a class="reference internal" href="#connection-callbacks">18.5.4.2.2. Connection callbacks</a></li> <li><a class="reference internal" href="#streaming-protocols">18.5.4.2.3. Streaming protocols</a></li> <li><a class="reference internal" href="#datagram-protocols">18.5.4.2.4. Datagram protocols</a></li> <li><a class="reference internal" href="#flow-control-callbacks">18.5.4.2.5. Flow control callbacks</a></li> <li><a class="reference internal" href="#coroutines-and-protocols">18.5.4.2.6. Coroutines and protocols</a></li> </ul> </li> <li><a class="reference internal" href="#protocol-examples">18.5.4.3. Protocol examples</a><ul> <li><a class="reference internal" href="#tcp-echo-client-protocol">18.5.4.3.1. TCP echo client protocol</a></li> <li><a class="reference internal" href="#tcp-echo-server-protocol">18.5.4.3.2. TCP echo server protocol</a></li> <li><a class="reference internal" href="#udp-echo-client-protocol">18.5.4.3.3. UDP echo client protocol</a></li> <li><a class="reference internal" href="#udp-echo-server-protocol">18.5.4.3.4. UDP echo server protocol</a></li> <li><a class="reference internal" href="#register-an-open-socket-to-wait-for-data-using-a-protocol">18.5.4.3.5. Register an open socket to wait for data using a protocol</a></li> </ul> </li> </ul> </li> </ul> <h4>Previous topic</h4> <p class="topless"><a href="asyncio-task.html" title="previous chapter">18.5.3. Tasks and coroutines</a></p> <h4>Next topic</h4> <p class="topless"><a href="asyncio-stream.html" title="next chapter">18.5.5. Streams (coroutine based API)</a></p> <div role="note" aria-label="source link"> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../bugs.html">Report a Bug</a></li> <li> <a href="https://github.com/python/cpython/blob/3.6/Doc/library/asyncio-protocol.rst" rel="nofollow">Show Source </a> </li> </ul> </div> </div> </div> <div class="clearer"></div> </div> <div class="related" role="navigation" aria-label="related navigation"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../genindex.html" title="General Index" >index</a></li> <li class="right" > <a href="../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="asyncio-stream.html" title="18.5.5. Streams (coroutine based API)" >next</a> |</li> <li class="right" > <a href="asyncio-task.html" title="18.5.3. Tasks and coroutines" >previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="https://www.python.org/">Python</a> »</li> <li> <a href="../index.html">3.6.7 Documentation</a> » </li> <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li> <li class="nav-item nav-item-2"><a href="ipc.html" >18. Interprocess Communication and Networking</a> »</li> <li class="nav-item nav-item-3"><a href="asyncio.html" >18.5. <code class="docutils literal notranslate"><span class="pre">asyncio</span></code> — Asynchronous I/O, event loop, coroutines and tasks</a> »</li> <li class="right"> <div class="inline-search" style="display: none" role="search"> <form class="inline-search" action="../search.html" method="get"> <input placeholder="Quick search" type="text" name="q" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> </div> <script type="text/javascript">$('.inline-search').show(0);</script> | </li> </ul> </div> <div class="footer"> © <a href="../copyright.html">Copyright</a> 2001-2021, Python Software Foundation. <br /> The Python Software Foundation is a non-profit corporation. <a href="https://www.python.org/psf/donations/">Please donate.</a> <br /> Last updated on Aug 25, 2021. <a href="../bugs.html">Found a bug</a>? <br /> Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.7.6. </div> </body> </html>