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| <li><a class="reference internal" href="#">Streams</a><ul> | |
| <li><a class="reference internal" href="#streamreader">StreamReader</a></li> | |
| <li><a class="reference internal" href="#streamwriter">StreamWriter</a></li> | |
| <li><a class="reference internal" href="#examples">Examples</a><ul> | |
| <li><a class="reference internal" href="#tcp-echo-client-using-streams">TCP echo client using streams</a></li> | |
| <li><a class="reference internal" href="#tcp-echo-server-using-streams">TCP echo server using streams</a></li> | |
| <li><a class="reference internal" href="#get-http-headers">Get HTTP headers</a></li> | |
| <li><a class="reference internal" href="#register-an-open-socket-to-wait-for-data-using-streams">Register an open socket to wait for data using streams</a></li> | |
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| <section id="streams"> | |
| <span id="asyncio-streams"></span><h1>Streams<a class="headerlink" href="#streams" title="Link to this heading">¶</a></h1> | |
| <p><strong>Source code:</strong> <a class="extlink-source reference external" href="https://github.com/python/cpython/tree/main/Lib/asyncio/streams.py">Lib/asyncio/streams.py</a></p> | |
| <hr class="docutils" /> | |
| <p>Streams are high-level async/await-ready primitives to work with | |
| network connections. Streams allow sending and receiving data without | |
| using callbacks or low-level protocols and transports.</p> | |
| <p id="asyncio-example-stream">Here is an example of a TCP echo client written using asyncio | |
| streams:</p> | |
| <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">asyncio</span> | |
| <span class="k">async</span> <span class="k">def</span><span class="w"> </span><span class="nf">tcp_echo_client</span><span class="p">(</span><span class="n">message</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">await</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="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s1">'Send: </span><span class="si">{</span><span class="n">message</span><span class="si">!r}</span><span class="s1">'</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="k">await</span> <span class="n">writer</span><span class="o">.</span><span class="n">drain</span><span class="p">()</span> | |
| <span class="n">data</span> <span class="o">=</span> <span class="k">await</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="sa">f</span><span class="s1">'Received: </span><span class="si">{</span><span class="n">data</span><span class="o">.</span><span class="n">decode</span><span class="p">()</span><span class="si">!r}</span><span class="s1">'</span><span class="p">)</span> | |
| <span class="nb">print</span><span class="p">(</span><span class="s1">'Close the connection'</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="k">await</span> <span class="n">writer</span><span class="o">.</span><span class="n">wait_closed</span><span class="p">()</span> | |
| <span class="n">asyncio</span><span class="o">.</span><span class="n">run</span><span class="p">(</span><span class="n">tcp_echo_client</span><span class="p">(</span><span class="s1">'Hello World!'</span><span class="p">))</span> | |
| </pre></div> | |
| </div> | |
| <p>See also the <a class="reference internal" href="#examples">Examples</a> section below.</p> | |
| <p class="rubric">Stream Functions</p> | |
| <p>The following top-level asyncio functions can be used to create | |
| and work with streams:</p> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="asyncio.open_connection"> | |
| <em class="property"><span class="k"><span class="pre">async</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">asyncio.</span></span><span class="sig-name descname"><span class="pre">open_connection</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">host</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">port</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="keyword-only-separator o"><abbr title="Keyword-only parameters separator (PEP 3102)"><span class="pre">*</span></abbr></span></em>, <em class="sig-param"><span class="n"><span class="pre">limit</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ssl</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">family</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">proto</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">sock</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">local_addr</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">server_hostname</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ssl_handshake_timeout</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ssl_shutdown_timeout</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">happy_eyeballs_delay</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">interleave</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.open_connection" title="Link to this definition">¶</a></dt> | |
| <dd><p>Establish a network connection and return a pair of | |
| <code class="docutils literal notranslate"><span class="pre">(reader,</span> <span class="pre">writer)</span></code> objects.</p> | |
| <p>The returned <em>reader</em> and <em>writer</em> objects are instances of | |
| <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> and <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> classes.</p> | |
| <p><em>limit</em> determines the buffer size limit used by the | |
| returned <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. By default the <em>limit</em> | |
| is set to 64 KiB.</p> | |
| <p>The rest of the arguments are passed directly to | |
| <a class="reference internal" href="asyncio-eventloop.html#asyncio.loop.create_connection" title="asyncio.loop.create_connection"><code class="xref py py-meth docutils literal notranslate"><span class="pre">loop.create_connection()</span></code></a>.</p> | |
| <div class="admonition note"> | |
| <p class="admonition-title">Note</p> | |
| <p>The <em>sock</em> argument transfers ownership of the socket to the | |
| <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> created. To close the socket, call its | |
| <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> method.</p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.7: </span>Added the <em>ssl_handshake_timeout</em> parameter.</p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.8: </span>Added the <em>happy_eyeballs_delay</em> and <em>interleave</em> parameters.</p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.10: </span>Removed the <em>loop</em> parameter.</p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.11: </span>Added the <em>ssl_shutdown_timeout</em> parameter.</p> | |
| </div> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="asyncio.start_server"> | |
| <em class="property"><span class="k"><span class="pre">async</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">asyncio.</span></span><span class="sig-name descname"><span class="pre">start_server</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">client_connected_cb</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">host</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">port</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="keyword-only-separator o"><abbr title="Keyword-only parameters separator (PEP 3102)"><span class="pre">*</span></abbr></span></em>, <em class="sig-param"><span class="n"><span class="pre">limit</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">family</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">socket.AF_UNSPEC</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">socket.AI_PASSIVE</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">sock</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">backlog</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">100</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ssl</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">reuse_address</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">reuse_port</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">keep_alive</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ssl_handshake_timeout</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ssl_shutdown_timeout</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">start_serving</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">True</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.start_server" title="Link to this definition">¶</a></dt> | |
| <dd><p>Start a socket server.</p> | |
| <p>The <em>client_connected_cb</em> callback is called whenever a new client | |
| connection is established. It receives a <code class="docutils literal notranslate"><span class="pre">(reader,</span> <span class="pre">writer)</span></code> pair | |
| as two arguments, instances 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> and | |
| <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> classes.</p> | |
| <p><em>client_connected_cb</em> can be a plain callable 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 scheduled as 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><em>limit</em> determines the buffer size limit used by the | |
| returned <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. By default the <em>limit</em> | |
| is set to 64 KiB.</p> | |
| <p>The rest of the arguments are passed directly to | |
| <a class="reference internal" href="asyncio-eventloop.html#asyncio.loop.create_server" title="asyncio.loop.create_server"><code class="xref py py-meth docutils literal notranslate"><span class="pre">loop.create_server()</span></code></a>.</p> | |
| <div class="admonition note"> | |
| <p class="admonition-title">Note</p> | |
| <p>The <em>sock</em> argument transfers ownership of the socket to the | |
| server created. To close the socket, call the server’s | |
| <a class="reference internal" href="asyncio-eventloop.html#asyncio.Server.close" title="asyncio.Server.close"><code class="xref py py-meth docutils literal notranslate"><span class="pre">close()</span></code></a> method.</p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.7: </span>Added the <em>ssl_handshake_timeout</em> and <em>start_serving</em> parameters.</p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.10: </span>Removed the <em>loop</em> parameter.</p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.11: </span>Added the <em>ssl_shutdown_timeout</em> parameter.</p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.13: </span>Added the <em>keep_alive</em> parameter.</p> | |
| </div> | |
| </dd></dl> | |
| <p class="rubric">Unix Sockets</p> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="asyncio.open_unix_connection"> | |
| <em class="property"><span class="k"><span class="pre">async</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">asyncio.</span></span><span class="sig-name descname"><span class="pre">open_unix_connection</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">path</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="keyword-only-separator o"><abbr title="Keyword-only parameters separator (PEP 3102)"><span class="pre">*</span></abbr></span></em>, <em class="sig-param"><span class="n"><span class="pre">limit</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ssl</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">sock</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">server_hostname</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ssl_handshake_timeout</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ssl_shutdown_timeout</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.open_unix_connection" title="Link to this definition">¶</a></dt> | |
| <dd><p>Establish a Unix socket connection and return a pair of | |
| <code class="docutils literal notranslate"><span class="pre">(reader,</span> <span class="pre">writer)</span></code>.</p> | |
| <p>Similar to <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> but operates on Unix sockets.</p> | |
| <p>See also the documentation of <a class="reference internal" href="asyncio-eventloop.html#asyncio.loop.create_unix_connection" title="asyncio.loop.create_unix_connection"><code class="xref py py-meth docutils literal notranslate"><span class="pre">loop.create_unix_connection()</span></code></a>.</p> | |
| <div class="admonition note"> | |
| <p class="admonition-title">Note</p> | |
| <p>The <em>sock</em> argument transfers ownership of the socket to the | |
| <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> created. To close the socket, call its | |
| <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> method.</p> | |
| </div> | |
| <div class="availability docutils container"> | |
| <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Unix.</p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.7: </span>Added the <em>ssl_handshake_timeout</em> parameter. | |
| The <em>path</em> parameter can now be a <a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like object</span></a></p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.10: </span>Removed the <em>loop</em> parameter.</p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.11: </span>Added the <em>ssl_shutdown_timeout</em> parameter.</p> | |
| </div> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="asyncio.start_unix_server"> | |
| <em class="property"><span class="k"><span class="pre">async</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">asyncio.</span></span><span class="sig-name descname"><span class="pre">start_unix_server</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">client_connected_cb</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">path</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="keyword-only-separator o"><abbr title="Keyword-only parameters separator (PEP 3102)"><span class="pre">*</span></abbr></span></em>, <em class="sig-param"><span class="n"><span class="pre">limit</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">sock</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">backlog</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">100</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ssl</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ssl_handshake_timeout</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ssl_shutdown_timeout</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">start_serving</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">True</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">cleanup_socket</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">True</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.start_unix_server" title="Link to this definition">¶</a></dt> | |
| <dd><p>Start a Unix socket server.</p> | |
| <p>Similar to <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> but works with Unix sockets.</p> | |
| <p>If <em>cleanup_socket</em> is true then the Unix socket will automatically | |
| be removed from the filesystem when the server is closed, unless the | |
| socket has been replaced after the server has been created.</p> | |
| <p>See also the documentation of <a class="reference internal" href="asyncio-eventloop.html#asyncio.loop.create_unix_server" title="asyncio.loop.create_unix_server"><code class="xref py py-meth docutils literal notranslate"><span class="pre">loop.create_unix_server()</span></code></a>.</p> | |
| <div class="admonition note"> | |
| <p class="admonition-title">Note</p> | |
| <p>The <em>sock</em> argument transfers ownership of the socket to the | |
| server created. To close the socket, call the server’s | |
| <a class="reference internal" href="asyncio-eventloop.html#asyncio.Server.close" title="asyncio.Server.close"><code class="xref py py-meth docutils literal notranslate"><span class="pre">close()</span></code></a> method.</p> | |
| </div> | |
| <div class="availability docutils container"> | |
| <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Unix.</p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.7: </span>Added the <em>ssl_handshake_timeout</em> and <em>start_serving</em> parameters. | |
| The <em>path</em> parameter can now be a <a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like object</span></a>.</p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.10: </span>Removed the <em>loop</em> parameter.</p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.11: </span>Added the <em>ssl_shutdown_timeout</em> parameter.</p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.13: </span>Added the <em>cleanup_socket</em> parameter.</p> | |
| </div> | |
| </dd></dl> | |
| <section id="streamreader"> | |
| <h2>StreamReader<a class="headerlink" href="#streamreader" title="Link to this heading">¶</a></h2> | |
| <dl class="py class"> | |
| <dt class="sig sig-object py" id="asyncio.StreamReader"> | |
| <em class="property"><span class="k"><span class="pre">class</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">asyncio.</span></span><span class="sig-name descname"><span class="pre">StreamReader</span></span><a class="headerlink" href="#asyncio.StreamReader" title="Link to this definition">¶</a></dt> | |
| <dd><p>Represents a reader object that provides APIs to read data | |
| from the IO stream. As an <a class="reference internal" href="../glossary.html#term-asynchronous-iterable"><span class="xref std std-term">asynchronous iterable</span></a>, the | |
| object supports the <a class="reference internal" href="../reference/compound_stmts.html#async-for"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">async</span> <span class="pre">for</span></code></a> statement.</p> | |
| <p>It is not recommended to instantiate <em>StreamReader</em> objects | |
| directly; use <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> and <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> | |
| instead.</p> | |
| <dl class="py method"> | |
| <dt class="sig sig-object py" id="asyncio.StreamReader.feed_eof"> | |
| <span class="sig-name descname"><span class="pre">feed_eof</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader.feed_eof" title="Link to this definition">¶</a></dt> | |
| <dd><p>Acknowledge the EOF.</p> | |
| </dd></dl> | |
| <dl class="py method"> | |
| <dt class="sig sig-object py" id="asyncio.StreamReader.read"> | |
| <em class="property"><span class="k"><span class="pre">async</span></span><span class="w"> </span></em><span class="sig-name descname"><span class="pre">read</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">n</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">-1</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader.read" title="Link to this definition">¶</a></dt> | |
| <dd><p>Read up to <em>n</em> bytes from the stream.</p> | |
| <p>If <em>n</em> is not provided or set to <code class="docutils literal notranslate"><span class="pre">-1</span></code>, | |
| read until EOF, then return all read <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>. | |
| If 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>If <em>n</em> is <code class="docutils literal notranslate"><span class="pre">0</span></code>, return an empty <code class="docutils literal notranslate"><span class="pre">bytes</span></code> object immediately.</p> | |
| <p>If <em>n</em> is positive, return at most <em>n</em> available <code class="docutils literal notranslate"><span class="pre">bytes</span></code> | |
| as soon as at least 1 byte is available in the internal buffer. | |
| If EOF is received before any byte is read, return an empty | |
| <code class="docutils literal notranslate"><span class="pre">bytes</span></code> object.</p> | |
| </dd></dl> | |
| <dl class="py method"> | |
| <dt class="sig sig-object py" id="asyncio.StreamReader.readline"> | |
| <em class="property"><span class="k"><span class="pre">async</span></span><span class="w"> </span></em><span class="sig-name descname"><span class="pre">readline</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader.readline" title="Link 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 | |
| returns partially read data.</p> | |
| <p>If EOF is received and the internal buffer is empty, | |
| return an empty <code class="docutils literal notranslate"><span class="pre">bytes</span></code> object.</p> | |
| </dd></dl> | |
| <dl class="py method"> | |
| <dt class="sig sig-object py" id="asyncio.StreamReader.readexactly"> | |
| <em class="property"><span class="k"><span class="pre">async</span></span><span class="w"> </span></em><span class="sig-name descname"><span class="pre">readexactly</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">n</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader.readexactly" title="Link to this definition">¶</a></dt> | |
| <dd><p>Read exactly <em>n</em> bytes.</p> | |
| <p>Raise an <a class="reference internal" href="asyncio-exceptions.html#asyncio.IncompleteReadError" title="asyncio.IncompleteReadError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">IncompleteReadError</span></code></a> if EOF is reached before <em>n</em> | |
| can be read. Use the <a class="reference internal" href="asyncio-exceptions.html#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 to get the partially read data.</p> | |
| </dd></dl> | |
| <dl class="py method"> | |
| <dt class="sig sig-object py" id="asyncio.StreamReader.readuntil"> | |
| <em class="property"><span class="k"><span class="pre">async</span></span><span class="w"> </span></em><span class="sig-name descname"><span class="pre">readuntil</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">separator</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">b'\n'</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader.readuntil" title="Link to this definition">¶</a></dt> | |
| <dd><p>Read data from the stream until <em>separator</em> 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>If the amount of data read exceeds the configured stream limit, a | |
| <a class="reference internal" href="asyncio-exceptions.html#asyncio.LimitOverrunError" title="asyncio.LimitOverrunError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">LimitOverrunError</span></code></a> exception is raised, and the data | |
| is left in the internal buffer and can be read again.</p> | |
| <p>If EOF is reached before the complete separator is found, | |
| an <a class="reference internal" href="asyncio-exceptions.html#asyncio.IncompleteReadError" title="asyncio.IncompleteReadError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">IncompleteReadError</span></code></a> exception is raised, and the internal | |
| buffer is reset. The <a class="reference internal" href="asyncio-exceptions.html#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 a portion of the separator.</p> | |
| <p>The <em>separator</em> may also be a tuple of separators. In this | |
| case the return value will be the shortest possible that has any | |
| separator as the suffix. For the purposes of <a class="reference internal" href="asyncio-exceptions.html#asyncio.LimitOverrunError" title="asyncio.LimitOverrunError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">LimitOverrunError</span></code></a>, | |
| the shortest possible separator is considered to be the one that | |
| matched.</p> | |
| <div class="versionadded"> | |
| <p><span class="versionmodified added">Added in version 3.5.2.</span></p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.13: </span>The <em>separator</em> parameter may now be a <a class="reference internal" href="stdtypes.html#tuple" title="tuple"><code class="xref py py-class docutils literal notranslate"><span class="pre">tuple</span></code></a> of | |
| separators.</p> | |
| </div> | |
| </dd></dl> | |
| <dl class="py method"> | |
| <dt class="sig sig-object py" id="asyncio.StreamReader.at_eof"> | |
| <span class="sig-name descname"><span class="pre">at_eof</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamReader.at_eof" title="Link 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> | |
| </section> | |
| <section id="streamwriter"> | |
| <h2>StreamWriter<a class="headerlink" href="#streamwriter" title="Link to this heading">¶</a></h2> | |
| <dl class="py class"> | |
| <dt class="sig sig-object py" id="asyncio.StreamWriter"> | |
| <em class="property"><span class="k"><span class="pre">class</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">asyncio.</span></span><span class="sig-name descname"><span class="pre">StreamWriter</span></span><a class="headerlink" href="#asyncio.StreamWriter" title="Link to this definition">¶</a></dt> | |
| <dd><p>Represents a writer object that provides APIs to write data | |
| to the IO stream.</p> | |
| <p>It is not recommended to instantiate <em>StreamWriter</em> objects | |
| directly; use <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> and <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> | |
| instead.</p> | |
| <dl class="py method"> | |
| <dt class="sig sig-object py" id="asyncio.StreamWriter.write"> | |
| <span class="sig-name descname"><span class="pre">write</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">data</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.write" title="Link to this definition">¶</a></dt> | |
| <dd><p>The method attempts to write the <em>data</em> to the underlying socket immediately. | |
| If that fails, the data is queued in an internal write buffer until it can be | |
| sent.</p> | |
| <p>The <em>data</em> buffer should be a bytes, bytearray, or C-contiguous one-dimensional | |
| memoryview object.</p> | |
| <p>The method should be used along with the <code class="docutils literal notranslate"><span class="pre">drain()</span></code> method:</p> | |
| <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">stream</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">await</span> <span class="n">stream</span><span class="o">.</span><span class="n">drain</span><span class="p">()</span> | |
| </pre></div> | |
| </div> | |
| </dd></dl> | |
| <dl class="py method"> | |
| <dt class="sig sig-object py" id="asyncio.StreamWriter.writelines"> | |
| <span class="sig-name descname"><span class="pre">writelines</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">data</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.writelines" title="Link to this definition">¶</a></dt> | |
| <dd><p>The method writes a list (or any iterable) of bytes to the underlying socket | |
| immediately. | |
| If that fails, the data is queued in an internal write buffer until it can be | |
| sent.</p> | |
| <p>The method should be used along with the <code class="docutils literal notranslate"><span class="pre">drain()</span></code> method:</p> | |
| <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">stream</span><span class="o">.</span><span class="n">writelines</span><span class="p">(</span><span class="n">lines</span><span class="p">)</span> | |
| <span class="k">await</span> <span class="n">stream</span><span class="o">.</span><span class="n">drain</span><span class="p">()</span> | |
| </pre></div> | |
| </div> | |
| </dd></dl> | |
| <dl class="py method"> | |
| <dt class="sig sig-object py" id="asyncio.StreamWriter.close"> | |
| <span class="sig-name descname"><span class="pre">close</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.close" title="Link to this definition">¶</a></dt> | |
| <dd><p>The method closes the stream and the underlying socket.</p> | |
| <p>The method should be used, though not mandatory, | |
| along with the <code class="docutils literal notranslate"><span class="pre">wait_closed()</span></code> method:</p> | |
| <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">stream</span><span class="o">.</span><span class="n">close</span><span class="p">()</span> | |
| <span class="k">await</span> <span class="n">stream</span><span class="o">.</span><span class="n">wait_closed</span><span class="p">()</span> | |
| </pre></div> | |
| </div> | |
| </dd></dl> | |
| <dl class="py method"> | |
| <dt class="sig sig-object py" id="asyncio.StreamWriter.can_write_eof"> | |
| <span class="sig-name descname"><span class="pre">can_write_eof</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.can_write_eof" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return <code class="docutils literal notranslate"><span class="pre">True</span></code> if the underlying transport supports | |
| the <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> method, <code class="docutils literal notranslate"><span class="pre">False</span></code> otherwise.</p> | |
| </dd></dl> | |
| <dl class="py method"> | |
| <dt class="sig sig-object py" id="asyncio.StreamWriter.write_eof"> | |
| <span class="sig-name descname"><span class="pre">write_eof</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.write_eof" title="Link to this definition">¶</a></dt> | |
| <dd><p>Close the write end of the stream after the buffered write | |
| data is flushed.</p> | |
| </dd></dl> | |
| <dl class="py attribute"> | |
| <dt class="sig sig-object py" id="asyncio.StreamWriter.transport"> | |
| <span class="sig-name descname"><span class="pre">transport</span></span><a class="headerlink" href="#asyncio.StreamWriter.transport" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the underlying asyncio transport.</p> | |
| </dd></dl> | |
| <dl class="py method"> | |
| <dt class="sig sig-object py" id="asyncio.StreamWriter.get_extra_info"> | |
| <span class="sig-name descname"><span class="pre">get_extra_info</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">name</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">default</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.get_extra_info" title="Link to this definition">¶</a></dt> | |
| <dd><p>Access 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> for details.</p> | |
| </dd></dl> | |
| <dl class="py method"> | |
| <dt class="sig sig-object py" id="asyncio.StreamWriter.drain"> | |
| <em class="property"><span class="k"><span class="pre">async</span></span><span class="w"> </span></em><span class="sig-name descname"><span class="pre">drain</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.drain" title="Link to this definition">¶</a></dt> | |
| <dd><p>Wait until it is appropriate to resume writing to the stream. | |
| Example:</p> | |
| <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></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">await</span> <span class="n">writer</span><span class="o">.</span><span class="n">drain</span><span class="p">()</span> | |
| </pre></div> | |
| </div> | |
| <p>This is a flow control method that interacts with the underlying | |
| IO write buffer. When the size of the buffer reaches | |
| the high watermark, <em>drain()</em> blocks until the size of the | |
| buffer is drained down to the low watermark and writing can | |
| be resumed. When there is nothing to wait for, the <code class="xref py py-meth docutils literal notranslate"><span class="pre">drain()</span></code> | |
| returns immediately.</p> | |
| </dd></dl> | |
| <dl class="py method"> | |
| <dt class="sig sig-object py" id="asyncio.StreamWriter.start_tls"> | |
| <em class="property"><span class="k"><span class="pre">async</span></span><span class="w"> </span></em><span class="sig-name descname"><span class="pre">start_tls</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">sslcontext</span></span></em>, <em class="sig-param"><span class="keyword-only-separator o"><abbr title="Keyword-only parameters separator (PEP 3102)"><span class="pre">*</span></abbr></span></em>, <em class="sig-param"><span class="n"><span class="pre">server_hostname</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ssl_handshake_timeout</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ssl_shutdown_timeout</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.start_tls" title="Link to this definition">¶</a></dt> | |
| <dd><p>Upgrade an existing stream-based connection to TLS.</p> | |
| <p>Parameters:</p> | |
| <ul class="simple"> | |
| <li><p><em>sslcontext</em>: a configured instance of <a class="reference internal" href="ssl.html#ssl.SSLContext" title="ssl.SSLContext"><code class="xref py py-class docutils literal notranslate"><span class="pre">SSLContext</span></code></a>.</p></li> | |
| <li><p><em>server_hostname</em>: sets or overrides the host name that the target | |
| server’s certificate will be matched against.</p></li> | |
| <li><p><em>ssl_handshake_timeout</em> is the time in seconds to wait for the TLS | |
| handshake to complete before aborting the connection. <code class="docutils literal notranslate"><span class="pre">60.0</span></code> seconds | |
| if <code class="docutils literal notranslate"><span class="pre">None</span></code> (default).</p></li> | |
| <li><p><em>ssl_shutdown_timeout</em> is the time in seconds to wait for the SSL shutdown | |
| to complete before aborting the connection. <code class="docutils literal notranslate"><span class="pre">30.0</span></code> seconds if <code class="docutils literal notranslate"><span class="pre">None</span></code> | |
| (default).</p></li> | |
| </ul> | |
| <div class="versionadded"> | |
| <p><span class="versionmodified added">Added in version 3.11.</span></p> | |
| </div> | |
| <div class="versionchanged"> | |
| <p><span class="versionmodified changed">Changed in version 3.12: </span>Added the <em>ssl_shutdown_timeout</em> parameter.</p> | |
| </div> | |
| </dd></dl> | |
| <dl class="py method"> | |
| <dt class="sig sig-object py" id="asyncio.StreamWriter.is_closing"> | |
| <span class="sig-name descname"><span class="pre">is_closing</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.is_closing" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return <code class="docutils literal notranslate"><span class="pre">True</span></code> if the stream is closed or in the process of | |
| being closed.</p> | |
| <div class="versionadded"> | |
| <p><span class="versionmodified added">Added in version 3.7.</span></p> | |
| </div> | |
| </dd></dl> | |
| <dl class="py method"> | |
| <dt class="sig sig-object py" id="asyncio.StreamWriter.wait_closed"> | |
| <em class="property"><span class="k"><span class="pre">async</span></span><span class="w"> </span></em><span class="sig-name descname"><span class="pre">wait_closed</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.StreamWriter.wait_closed" title="Link to this definition">¶</a></dt> | |
| <dd><p>Wait until the stream is closed.</p> | |
| <p>Should be called after <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> to wait until the underlying | |
| connection is closed, ensuring that all data has been flushed | |
| before e.g. exiting the program.</p> | |
| <div class="versionadded"> | |
| <p><span class="versionmodified added">Added in version 3.7.</span></p> | |
| </div> | |
| </dd></dl> | |
| </dd></dl> | |
| </section> | |
| <section id="examples"> | |
| <h2>Examples<a class="headerlink" href="#examples" title="Link to this heading">¶</a></h2> | |
| <section id="tcp-echo-client-using-streams"> | |
| <span id="asyncio-tcp-echo-client-streams"></span><h3>TCP echo client using streams<a class="headerlink" href="#tcp-echo-client-using-streams" title="Link to this heading">¶</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="w"> </span><span class="nn">asyncio</span> | |
| <span class="k">async</span> <span class="k">def</span><span class="w"> </span><span class="nf">tcp_echo_client</span><span class="p">(</span><span class="n">message</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">await</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="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s1">'Send: </span><span class="si">{</span><span class="n">message</span><span class="si">!r}</span><span class="s1">'</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="k">await</span> <span class="n">writer</span><span class="o">.</span><span class="n">drain</span><span class="p">()</span> | |
| <span class="n">data</span> <span class="o">=</span> <span class="k">await</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="sa">f</span><span class="s1">'Received: </span><span class="si">{</span><span class="n">data</span><span class="o">.</span><span class="n">decode</span><span class="p">()</span><span class="si">!r}</span><span class="s1">'</span><span class="p">)</span> | |
| <span class="nb">print</span><span class="p">(</span><span class="s1">'Close the connection'</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="k">await</span> <span class="n">writer</span><span class="o">.</span><span class="n">wait_closed</span><span class="p">()</span> | |
| <span class="n">asyncio</span><span class="o">.</span><span class="n">run</span><span class="p">(</span><span class="n">tcp_echo_client</span><span class="p">(</span><span class="s1">'Hello World!'</span><span class="p">))</span> | |
| </pre></div> | |
| </div> | |
| <div class="admonition seealso"> | |
| <p class="admonition-title">See also</p> | |
| <p>The <a class="reference internal" href="asyncio-protocol.html#asyncio-example-tcp-echo-client-protocol"><span class="std std-ref">TCP echo client protocol</span></a> | |
| example uses the low-level <a class="reference internal" href="asyncio-eventloop.html#asyncio.loop.create_connection" title="asyncio.loop.create_connection"><code class="xref py py-meth docutils literal notranslate"><span class="pre">loop.create_connection()</span></code></a> method.</p> | |
| </div> | |
| </section> | |
| <section id="tcp-echo-server-using-streams"> | |
| <span id="asyncio-tcp-echo-server-streams"></span><h3>TCP echo server using streams<a class="headerlink" href="#tcp-echo-server-using-streams" title="Link to this heading">¶</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="w"> </span><span class="nn">asyncio</span> | |
| <span class="k">async</span> <span class="k">def</span><span class="w"> </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">await</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="sa">f</span><span class="s2">"Received </span><span class="si">{</span><span class="n">message</span><span class="si">!r}</span><span class="s2"> from </span><span class="si">{</span><span class="n">addr</span><span class="si">!r}</span><span class="s2">"</span><span class="p">)</span> | |
| <span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s2">"Send: </span><span class="si">{</span><span class="n">message</span><span class="si">!r}</span><span class="s2">"</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">await</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 connection"</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="k">await</span> <span class="n">writer</span><span class="o">.</span><span class="n">wait_closed</span><span class="p">()</span> | |
| <span class="k">async</span> <span class="k">def</span><span class="w"> </span><span class="nf">main</span><span class="p">():</span> | |
| <span class="n">server</span> <span class="o">=</span> <span class="k">await</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">addrs</span> <span class="o">=</span> <span class="s1">', '</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="nb">str</span><span class="p">(</span><span class="n">sock</span><span class="o">.</span><span class="n">getsockname</span><span class="p">())</span> <span class="k">for</span> <span class="n">sock</span> <span class="ow">in</span> <span class="n">server</span><span class="o">.</span><span class="n">sockets</span><span class="p">)</span> | |
| <span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s1">'Serving on </span><span class="si">{</span><span class="n">addrs</span><span class="si">}</span><span class="s1">'</span><span class="p">)</span> | |
| <span class="k">async</span> <span class="k">with</span> <span class="n">server</span><span class="p">:</span> | |
| <span class="k">await</span> <span class="n">server</span><span class="o">.</span><span class="n">serve_forever</span><span class="p">()</span> | |
| <span class="n">asyncio</span><span class="o">.</span><span class="n">run</span><span class="p">(</span><span class="n">main</span><span class="p">())</span> | |
| </pre></div> | |
| </div> | |
| <div class="admonition seealso"> | |
| <p class="admonition-title">See also</p> | |
| <p>The <a class="reference internal" href="asyncio-protocol.html#asyncio-example-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.loop.create_server" title="asyncio.loop.create_server"><code class="xref py py-meth docutils literal notranslate"><span class="pre">loop.create_server()</span></code></a> method.</p> | |
| </div> | |
| </section> | |
| <section id="get-http-headers"> | |
| <h3>Get HTTP headers<a class="headerlink" href="#get-http-headers" title="Link to this heading">¶</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="w"> </span><span class="nn">asyncio</span> | |
| <span class="kn">import</span><span class="w"> </span><span class="nn">urllib.parse</span> | |
| <span class="kn">import</span><span class="w"> </span><span class="nn">sys</span> | |
| <span class="k">async</span> <span class="k">def</span><span class="w"> </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">reader</span><span class="p">,</span> <span class="n">writer</span> <span class="o">=</span> <span class="k">await</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">reader</span><span class="p">,</span> <span class="n">writer</span> <span class="o">=</span> <span class="k">await</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">query</span> <span class="o">=</span> <span class="p">(</span> | |
| <span class="sa">f</span><span class="s2">"HEAD </span><span class="si">{</span><span class="n">url</span><span class="o">.</span><span class="n">path</span><span class="w"> </span><span class="ow">or</span><span class="w"> </span><span class="s1">'/'</span><span class="si">}</span><span class="s2"> HTTP/1.0</span><span class="se">\r\n</span><span class="s2">"</span> | |
| <span class="sa">f</span><span class="s2">"Host: </span><span class="si">{</span><span class="n">url</span><span class="o">.</span><span class="n">hostname</span><span class="si">}</span><span class="se">\r\n</span><span class="s2">"</span> | |
| <span class="sa">f</span><span class="s2">"</span><span class="se">\r\n</span><span class="s2">"</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">await</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="sa">f</span><span class="s1">'HTTP header> </span><span class="si">{</span><span class="n">line</span><span class="si">}</span><span class="s1">'</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="k">await</span> <span class="n">writer</span><span class="o">.</span><span class="n">wait_closed</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">asyncio</span><span class="o">.</span><span class="n">run</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> | |
| </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> | |
| </section> | |
| <section id="register-an-open-socket-to-wait-for-data-using-streams"> | |
| <span id="asyncio-example-create-connection-streams"></span><h3>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="Link to this heading">¶</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="w"> </span><span class="nn">asyncio</span> | |
| <span class="kn">import</span><span class="w"> </span><span class="nn">socket</span> | |
| <span class="k">async</span> <span class="k">def</span><span class="w"> </span><span class="nf">wait_for_data</span><span class="p">():</span> | |
| <span class="c1"># Get a reference to the current event loop because</span> | |
| <span class="c1"># we want to access low-level APIs.</span> | |
| <span class="n">loop</span> <span class="o">=</span> <span class="n">asyncio</span><span class="o">.</span><span class="n">get_running_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">socket</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">await</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="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">await</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="k">await</span> <span class="n">writer</span><span class="o">.</span><span class="n">wait_closed</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">asyncio</span><span class="o">.</span><span class="n">run</span><span class="p">(</span><span class="n">wait_for_data</span><span class="p">())</span> | |
| </pre></div> | |
| </div> | |
| <div class="admonition seealso"> | |
| <p class="admonition-title">See also</p> | |
| <p>The <a class="reference internal" href="asyncio-protocol.html#asyncio-example-create-connection"><span class="std std-ref">register an open socket to wait for data using a protocol</span></a> example uses a low-level protocol and | |
| the <a class="reference internal" href="asyncio-eventloop.html#asyncio.loop.create_connection" title="asyncio.loop.create_connection"><code class="xref py py-meth docutils literal notranslate"><span class="pre">loop.create_connection()</span></code></a> method.</p> | |
| <p>The <a class="reference internal" href="asyncio-eventloop.html#asyncio-example-watch-fd"><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.loop.add_reader" title="asyncio.loop.add_reader"><code class="xref py py-meth docutils literal notranslate"><span class="pre">loop.add_reader()</span></code></a> method to watch a file descriptor.</p> | |
| </div> | |
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| <ul> | |
| <li><a class="reference internal" href="#">Streams</a><ul> | |
| <li><a class="reference internal" href="#streamreader">StreamReader</a></li> | |
| <li><a class="reference internal" href="#streamwriter">StreamWriter</a></li> | |
| <li><a class="reference internal" href="#examples">Examples</a><ul> | |
| <li><a class="reference internal" href="#tcp-echo-client-using-streams">TCP echo client using streams</a></li> | |
| <li><a class="reference internal" href="#tcp-echo-server-using-streams">TCP echo server using streams</a></li> | |
| <li><a class="reference internal" href="#get-http-headers">Get HTTP headers</a></li> | |
| <li><a class="reference internal" href="#register-an-open-socket-to-wait-for-data-using-streams">Register an open socket to wait for data using streams</a></li> | |
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