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<h1>Source code for django.dispatch.dispatcher</h1><div class="highlight"><pre> <span></span><span class="kn">import</span> <span class="nn">sys</span> <span class="kn">import</span> <span class="nn">threading</span> <span class="kn">import</span> <span class="nn">weakref</span> <span class="kn">from</span> <span class="nn">django.utils.inspect</span> <span class="k">import</span> <span class="n">func_accepts_kwargs</span> <span class="kn">from</span> <span class="nn">django.utils.six.moves</span> <span class="k">import</span> <span class="nb">range</span> <span class="k">if</span> <span class="n">sys</span><span class="o">.</span><span class="n">version_info</span> <span class="o"><</span> <span class="p">(</span><span class="mi">3</span><span class="p">,</span> <span class="mi">4</span><span class="p">):</span> <span class="kn">from</span> <span class="nn">.weakref_backports</span> <span class="k">import</span> <span class="n">WeakMethod</span> <span class="k">else</span><span class="p">:</span> <span class="kn">from</span> <span class="nn">weakref</span> <span class="k">import</span> <span class="n">WeakMethod</span> <span class="k">def</span> <span class="nf">_make_id</span><span class="p">(</span><span class="n">target</span><span class="p">):</span> <span class="k">if</span> <span class="nb">hasattr</span><span class="p">(</span><span class="n">target</span><span class="p">,</span> <span class="s1">'__func__'</span><span class="p">):</span> <span class="k">return</span> <span class="p">(</span><span class="nb">id</span><span class="p">(</span><span class="n">target</span><span class="o">.</span><span class="n">__self__</span><span class="p">),</span> <span class="nb">id</span><span class="p">(</span><span class="n">target</span><span class="o">.</span><span class="n">__func__</span><span class="p">))</span> <span class="k">return</span> <span class="nb">id</span><span class="p">(</span><span class="n">target</span><span class="p">)</span> <span class="n">NONE_ID</span> <span class="o">=</span> <span class="n">_make_id</span><span class="p">(</span><span class="kc">None</span><span class="p">)</span> <span class="c1"># A marker for caching</span> <span class="n">NO_RECEIVERS</span> <span class="o">=</span> <span class="nb">object</span><span class="p">()</span> <div class="viewcode-block" id="Signal"><a class="viewcode-back" href="../../../topics/signals.html#django.dispatch.Signal">[docs]</a><span class="k">class</span> <span class="nc">Signal</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span> <span class="sd">"""</span> <span class="sd"> Base class for all signals</span> <span class="sd"> Internal attributes:</span> <span class="sd"> receivers</span> <span class="sd"> { receiverkey (id) : weakref(receiver) }</span> <span class="sd"> """</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">providing_args</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="n">use_caching</span><span class="o">=</span><span class="kc">False</span><span class="p">):</span> <span class="sd">"""</span> <span class="sd"> Create a new signal.</span> <span class="sd"> providing_args</span> <span class="sd"> A list of the arguments this signal can pass along in a send() call.</span> <span class="sd"> """</span> <span class="bp">self</span><span class="o">.</span><span class="n">receivers</span> <span class="o">=</span> <span class="p">[]</span> <span class="k">if</span> <span class="n">providing_args</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span> <span class="n">providing_args</span> <span class="o">=</span> <span class="p">[]</span> <span class="bp">self</span><span class="o">.</span><span class="n">providing_args</span> <span class="o">=</span> <span class="nb">set</span><span class="p">(</span><span class="n">providing_args</span><span class="p">)</span> <span class="bp">self</span><span class="o">.</span><span class="n">lock</span> <span class="o">=</span> <span class="n">threading</span><span class="o">.</span><span class="n">Lock</span><span class="p">()</span> <span class="bp">self</span><span class="o">.</span><span class="n">use_caching</span> <span class="o">=</span> <span class="n">use_caching</span> <span class="c1"># For convenience we create empty caches even if they are not used.</span> <span class="c1"># A note about caching: if use_caching is defined, then for each</span> <span class="c1"># distinct sender we cache the receivers that sender has in</span> <span class="c1"># 'sender_receivers_cache'. The cache is cleaned when .connect() or</span> <span class="c1"># .disconnect() is called and populated on send().</span> <span class="bp">self</span><span class="o">.</span><span class="n">sender_receivers_cache</span> <span class="o">=</span> <span class="n">weakref</span><span class="o">.</span><span class="n">WeakKeyDictionary</span><span class="p">()</span> <span class="k">if</span> <span class="n">use_caching</span> <span class="k">else</span> <span class="p">{}</span> <span class="bp">self</span><span class="o">.</span><span class="n">_dead_receivers</span> <span class="o">=</span> <span class="kc">False</span> <div class="viewcode-block" id="Signal.connect"><a class="viewcode-back" href="../../../topics/signals.html#django.dispatch.Signal.connect">[docs]</a> <span class="k">def</span> <span class="nf">connect</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">receiver</span><span class="p">,</span> <span class="n">sender</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="n">weak</span><span class="o">=</span><span class="kc">True</span><span class="p">,</span> <span class="n">dispatch_uid</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span> <span class="sd">"""</span> <span class="sd"> Connect receiver to sender for signal.</span> <span class="sd"> Arguments:</span> <span class="sd"> receiver</span> <span class="sd"> A function or an instance method which is to receive signals.</span> <span class="sd"> Receivers must be hashable objects.</span> <span class="sd"> If weak is True, then receiver must be weak referenceable.</span> <span class="sd"> Receivers must be able to accept keyword arguments.</span> <span class="sd"> If a receiver is connected with a dispatch_uid argument, it</span> <span class="sd"> will not be added if another receiver was already connected</span> <span class="sd"> with that dispatch_uid.</span> <span class="sd"> sender</span> <span class="sd"> The sender to which the receiver should respond. Must either be</span> <span class="sd"> of type Signal, or None to receive events from any sender.</span> <span class="sd"> weak</span> <span class="sd"> Whether to use weak references to the receiver. By default, the</span> <span class="sd"> module will attempt to use weak references to the receiver</span> <span class="sd"> objects. If this parameter is false, then strong references will</span> <span class="sd"> be used.</span> <span class="sd"> dispatch_uid</span> <span class="sd"> An identifier used to uniquely identify a particular instance of</span> <span class="sd"> a receiver. This will usually be a string, though it may be</span> <span class="sd"> anything hashable.</span> <span class="sd"> """</span> <span class="kn">from</span> <span class="nn">django.conf</span> <span class="k">import</span> <span class="n">settings</span> <span class="c1"># If DEBUG is on, check that we got a good receiver</span> <span class="k">if</span> <span class="n">settings</span><span class="o">.</span><span class="n">configured</span> <span class="ow">and</span> <span class="n">settings</span><span class="o">.</span><span class="n">DEBUG</span><span class="p">:</span> <span class="k">assert</span> <span class="n">callable</span><span class="p">(</span><span class="n">receiver</span><span class="p">),</span> <span class="s2">"Signal receivers must be callable."</span> <span class="c1"># Check for **kwargs</span> <span class="k">if</span> <span class="ow">not</span> <span class="n">func_accepts_kwargs</span><span class="p">(</span><span class="n">receiver</span><span class="p">):</span> <span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s2">"Signal receivers must accept keyword arguments (**kwargs)."</span><span class="p">)</span> <span class="k">if</span> <span class="n">dispatch_uid</span><span class="p">:</span> <span class="n">lookup_key</span> <span class="o">=</span> <span class="p">(</span><span class="n">dispatch_uid</span><span class="p">,</span> <span class="n">_make_id</span><span class="p">(</span><span class="n">sender</span><span class="p">))</span> <span class="k">else</span><span class="p">:</span> <span class="n">lookup_key</span> <span class="o">=</span> <span class="p">(</span><span class="n">_make_id</span><span class="p">(</span><span class="n">receiver</span><span class="p">),</span> <span class="n">_make_id</span><span class="p">(</span><span class="n">sender</span><span class="p">))</span> <span class="k">if</span> <span class="n">weak</span><span class="p">:</span> <span class="n">ref</span> <span class="o">=</span> <span class="n">weakref</span><span class="o">.</span><span class="n">ref</span> <span class="n">receiver_object</span> <span class="o">=</span> <span class="n">receiver</span> <span class="c1"># Check for bound methods</span> <span class="k">if</span> <span class="nb">hasattr</span><span class="p">(</span><span class="n">receiver</span><span class="p">,</span> <span class="s1">'__self__'</span><span class="p">)</span> <span class="ow">and</span> <span class="nb">hasattr</span><span class="p">(</span><span class="n">receiver</span><span class="p">,</span> <span class="s1">'__func__'</span><span class="p">):</span> <span class="n">ref</span> <span class="o">=</span> <span class="n">WeakMethod</span> <span class="n">receiver_object</span> <span class="o">=</span> <span class="n">receiver</span><span class="o">.</span><span class="n">__self__</span> <span class="k">if</span> <span class="n">sys</span><span class="o">.</span><span class="n">version_info</span> <span class="o">>=</span> <span class="p">(</span><span class="mi">3</span><span class="p">,</span> <span class="mi">4</span><span class="p">):</span> <span class="n">receiver</span> <span class="o">=</span> <span class="n">ref</span><span class="p">(</span><span class="n">receiver</span><span class="p">)</span> <span class="n">weakref</span><span class="o">.</span><span class="n">finalize</span><span class="p">(</span><span class="n">receiver_object</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">_remove_receiver</span><span class="p">)</span> <span class="k">else</span><span class="p">:</span> <span class="n">receiver</span> <span class="o">=</span> <span class="n">ref</span><span class="p">(</span><span class="n">receiver</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">_remove_receiver</span><span class="p">)</span> <span class="k">with</span> <span class="bp">self</span><span class="o">.</span><span class="n">lock</span><span class="p">:</span> <span class="bp">self</span><span class="o">.</span><span class="n">_clear_dead_receivers</span><span class="p">()</span> <span class="k">for</span> <span class="n">r_key</span><span class="p">,</span> <span class="n">_</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">receivers</span><span class="p">:</span> <span class="k">if</span> <span class="n">r_key</span> <span class="o">==</span> <span class="n">lookup_key</span><span class="p">:</span> <span class="k">break</span> <span class="k">else</span><span class="p">:</span> <span class="bp">self</span><span class="o">.</span><span class="n">receivers</span><span class="o">.</span><span class="n">append</span><span class="p">((</span><span class="n">lookup_key</span><span class="p">,</span> <span class="n">receiver</span><span class="p">))</span> <span class="bp">self</span><span class="o">.</span><span class="n">sender_receivers_cache</span><span class="o">.</span><span class="n">clear</span><span class="p">()</span></div> <div class="viewcode-block" id="Signal.disconnect"><a class="viewcode-back" href="../../../topics/signals.html#django.dispatch.Signal.disconnect">[docs]</a> <span class="k">def</span> <span class="nf">disconnect</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">receiver</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="n">sender</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="n">weak</span><span class="o">=</span><span class="kc">True</span><span class="p">,</span> <span class="n">dispatch_uid</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span> <span class="sd">"""</span> <span class="sd"> Disconnect receiver from sender for signal.</span> <span class="sd"> If weak references are used, disconnect need not be called. The receiver</span> <span class="sd"> will be remove from dispatch automatically.</span> <span class="sd"> Arguments:</span> <span class="sd"> receiver</span> <span class="sd"> The registered receiver to disconnect. May be none if</span> <span class="sd"> dispatch_uid is specified.</span> <span class="sd"> sender</span> <span class="sd"> The registered sender to disconnect</span> <span class="sd"> weak</span> <span class="sd"> The weakref state to disconnect</span> <span class="sd"> dispatch_uid</span> <span class="sd"> the unique identifier of the receiver to disconnect</span> <span class="sd"> """</span> <span class="k">if</span> <span class="n">dispatch_uid</span><span class="p">:</span> <span class="n">lookup_key</span> <span class="o">=</span> <span class="p">(</span><span class="n">dispatch_uid</span><span class="p">,</span> <span class="n">_make_id</span><span class="p">(</span><span class="n">sender</span><span class="p">))</span> <span class="k">else</span><span class="p">:</span> <span class="n">lookup_key</span> <span class="o">=</span> <span class="p">(</span><span class="n">_make_id</span><span class="p">(</span><span class="n">receiver</span><span class="p">),</span> <span class="n">_make_id</span><span class="p">(</span><span class="n">sender</span><span class="p">))</span> <span class="n">disconnected</span> <span class="o">=</span> <span class="kc">False</span> <span class="k">with</span> <span class="bp">self</span><span class="o">.</span><span class="n">lock</span><span class="p">:</span> <span class="bp">self</span><span class="o">.</span><span class="n">_clear_dead_receivers</span><span class="p">()</span> <span class="k">for</span> <span class="n">index</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">receivers</span><span class="p">)):</span> <span class="p">(</span><span class="n">r_key</span><span class="p">,</span> <span class="n">_</span><span class="p">)</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">receivers</span><span class="p">[</span><span class="n">index</span><span class="p">]</span> <span class="k">if</span> <span class="n">r_key</span> <span class="o">==</span> <span class="n">lookup_key</span><span class="p">:</span> <span class="n">disconnected</span> <span class="o">=</span> <span class="kc">True</span> <span class="k">del</span> <span class="bp">self</span><span class="o">.</span><span class="n">receivers</span><span class="p">[</span><span class="n">index</span><span class="p">]</span> <span class="k">break</span> <span class="bp">self</span><span class="o">.</span><span class="n">sender_receivers_cache</span><span class="o">.</span><span class="n">clear</span><span class="p">()</span> <span class="k">return</span> <span class="n">disconnected</span></div> <span class="k">def</span> <span class="nf">has_listeners</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">sender</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span> <span class="k">return</span> <span class="nb">bool</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_live_receivers</span><span class="p">(</span><span class="n">sender</span><span class="p">))</span> <div class="viewcode-block" id="Signal.send"><a class="viewcode-back" href="../../../topics/signals.html#django.dispatch.Signal.send">[docs]</a> <span class="k">def</span> <span class="nf">send</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">sender</span><span class="p">,</span> <span class="o">**</span><span class="n">named</span><span class="p">):</span> <span class="sd">"""</span> <span class="sd"> Send signal from sender to all connected receivers.</span> <span class="sd"> If any receiver raises an error, the error propagates back through send,</span> <span class="sd"> terminating the dispatch loop. So it's possible that all receivers</span> <span class="sd"> won't be called if an error is raised.</span> <span class="sd"> Arguments:</span> <span class="sd"> sender</span> <span class="sd"> The sender of the signal. Either a specific object or None.</span> <span class="sd"> named</span> <span class="sd"> Named arguments which will be passed to receivers.</span> <span class="sd"> Returns a list of tuple pairs [(receiver, response), ... ].</span> <span class="sd"> """</span> <span class="n">responses</span> <span class="o">=</span> <span class="p">[]</span> <span class="k">if</span> <span class="ow">not</span> <span class="bp">self</span><span class="o">.</span><span class="n">receivers</span> <span class="ow">or</span> <span class="bp">self</span><span class="o">.</span><span class="n">sender_receivers_cache</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">sender</span><span class="p">)</span> <span class="ow">is</span> <span class="n">NO_RECEIVERS</span><span class="p">:</span> <span class="k">return</span> <span class="n">responses</span> <span class="k">for</span> <span class="n">receiver</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_live_receivers</span><span class="p">(</span><span class="n">sender</span><span class="p">):</span> <span class="n">response</span> <span class="o">=</span> <span class="n">receiver</span><span class="p">(</span><span class="n">signal</span><span class="o">=</span><span class="bp">self</span><span class="p">,</span> <span class="n">sender</span><span class="o">=</span><span class="n">sender</span><span class="p">,</span> <span class="o">**</span><span class="n">named</span><span class="p">)</span> <span class="n">responses</span><span class="o">.</span><span class="n">append</span><span class="p">((</span><span class="n">receiver</span><span class="p">,</span> <span class="n">response</span><span class="p">))</span> <span class="k">return</span> <span class="n">responses</span></div> <div class="viewcode-block" id="Signal.send_robust"><a class="viewcode-back" href="../../../topics/signals.html#django.dispatch.Signal.send_robust">[docs]</a> <span class="k">def</span> <span class="nf">send_robust</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">sender</span><span class="p">,</span> <span class="o">**</span><span class="n">named</span><span class="p">):</span> <span class="sd">"""</span> <span class="sd"> Send signal from sender to all connected receivers catching errors.</span> <span class="sd"> Arguments:</span> <span class="sd"> sender</span> <span class="sd"> The sender of the signal. Can be any python object (normally one</span> <span class="sd"> registered with a connect if you actually want something to</span> <span class="sd"> occur).</span> <span class="sd"> named</span> <span class="sd"> Named arguments which will be passed to receivers. These</span> <span class="sd"> arguments must be a subset of the argument names defined in</span> <span class="sd"> providing_args.</span> <span class="sd"> Return a list of tuple pairs [(receiver, response), ... ]. May raise</span> <span class="sd"> DispatcherKeyError.</span> <span class="sd"> If any receiver raises an error (specifically any subclass of</span> <span class="sd"> Exception), the error instance is returned as the result for that</span> <span class="sd"> receiver. The traceback is always attached to the error at</span> <span class="sd"> ``__traceback__``.</span> <span class="sd"> """</span> <span class="n">responses</span> <span class="o">=</span> <span class="p">[]</span> <span class="k">if</span> <span class="ow">not</span> <span class="bp">self</span><span class="o">.</span><span class="n">receivers</span> <span class="ow">or</span> <span class="bp">self</span><span class="o">.</span><span class="n">sender_receivers_cache</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">sender</span><span class="p">)</span> <span class="ow">is</span> <span class="n">NO_RECEIVERS</span><span class="p">:</span> <span class="k">return</span> <span class="n">responses</span> <span class="c1"># Call each receiver with whatever arguments it can accept.</span> <span class="c1"># Return a list of tuple pairs [(receiver, response), ... ].</span> <span class="k">for</span> <span class="n">receiver</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_live_receivers</span><span class="p">(</span><span class="n">sender</span><span class="p">):</span> <span class="k">try</span><span class="p">:</span> <span class="n">response</span> <span class="o">=</span> <span class="n">receiver</span><span class="p">(</span><span class="n">signal</span><span class="o">=</span><span class="bp">self</span><span class="p">,</span> <span class="n">sender</span><span class="o">=</span><span class="n">sender</span><span class="p">,</span> <span class="o">**</span><span class="n">named</span><span class="p">)</span> <span class="k">except</span> <span class="ne">Exception</span> <span class="k">as</span> <span class="n">err</span><span class="p">:</span> <span class="k">if</span> <span class="ow">not</span> <span class="nb">hasattr</span><span class="p">(</span><span class="n">err</span><span class="p">,</span> <span class="s1">'__traceback__'</span><span class="p">):</span> <span class="n">err</span><span class="o">.</span><span class="n">__traceback__</span> <span class="o">=</span> <span class="n">sys</span><span class="o">.</span><span class="n">exc_info</span><span class="p">()[</span><span class="mi">2</span><span class="p">]</span> <span class="n">responses</span><span class="o">.</span><span class="n">append</span><span class="p">((</span><span class="n">receiver</span><span class="p">,</span> <span class="n">err</span><span class="p">))</span> <span class="k">else</span><span class="p">:</span> <span class="n">responses</span><span class="o">.</span><span class="n">append</span><span class="p">((</span><span class="n">receiver</span><span class="p">,</span> <span class="n">response</span><span class="p">))</span> <span class="k">return</span> <span class="n">responses</span></div> <span class="k">def</span> <span class="nf">_clear_dead_receivers</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="c1"># Note: caller is assumed to hold self.lock.</span> <span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">_dead_receivers</span><span class="p">:</span> <span class="bp">self</span><span class="o">.</span><span class="n">_dead_receivers</span> <span class="o">=</span> <span class="kc">False</span> <span class="n">new_receivers</span> <span class="o">=</span> <span class="p">[]</span> <span class="k">for</span> <span class="n">r</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">receivers</span><span class="p">:</span> <span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">r</span><span class="p">[</span><span class="mi">1</span><span class="p">],</span> <span class="n">weakref</span><span class="o">.</span><span class="n">ReferenceType</span><span class="p">)</span> <span class="ow">and</span> <span class="n">r</span><span class="p">[</span><span class="mi">1</span><span class="p">]()</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span> <span class="k">continue</span> <span class="n">new_receivers</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">r</span><span class="p">)</span> <span class="bp">self</span><span class="o">.</span><span class="n">receivers</span> <span class="o">=</span> <span class="n">new_receivers</span> <span class="k">def</span> <span class="nf">_live_receivers</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">sender</span><span class="p">):</span> <span class="sd">"""</span> <span class="sd"> Filter sequence of receivers to get resolved, live receivers.</span> <span class="sd"> This checks for weak references and resolves them, then returning only</span> <span class="sd"> live receivers.</span> <span class="sd"> """</span> <span class="n">receivers</span> <span class="o">=</span> <span class="kc">None</span> <span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">use_caching</span> <span class="ow">and</span> <span class="ow">not</span> <span class="bp">self</span><span class="o">.</span><span class="n">_dead_receivers</span><span class="p">:</span> <span class="n">receivers</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">sender_receivers_cache</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">sender</span><span class="p">)</span> <span class="c1"># We could end up here with NO_RECEIVERS even if we do check this case in</span> <span class="c1"># .send() prior to calling _live_receivers() due to concurrent .send() call.</span> <span class="k">if</span> <span class="n">receivers</span> <span class="ow">is</span> <span class="n">NO_RECEIVERS</span><span class="p">:</span> <span class="k">return</span> <span class="p">[]</span> <span class="k">if</span> <span class="n">receivers</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span> <span class="k">with</span> <span class="bp">self</span><span class="o">.</span><span class="n">lock</span><span class="p">:</span> <span class="bp">self</span><span class="o">.</span><span class="n">_clear_dead_receivers</span><span class="p">()</span> <span class="n">senderkey</span> <span class="o">=</span> <span class="n">_make_id</span><span class="p">(</span><span class="n">sender</span><span class="p">)</span> <span class="n">receivers</span> <span class="o">=</span> <span class="p">[]</span> <span class="k">for</span> <span class="p">(</span><span class="n">receiverkey</span><span class="p">,</span> <span class="n">r_senderkey</span><span class="p">),</span> <span class="n">receiver</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">receivers</span><span class="p">:</span> <span class="k">if</span> <span class="n">r_senderkey</span> <span class="o">==</span> <span class="n">NONE_ID</span> <span class="ow">or</span> <span class="n">r_senderkey</span> <span class="o">==</span> <span class="n">senderkey</span><span class="p">:</span> <span class="n">receivers</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">receiver</span><span class="p">)</span> <span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">use_caching</span><span class="p">:</span> <span class="k">if</span> <span class="ow">not</span> <span class="n">receivers</span><span class="p">:</span> <span class="bp">self</span><span class="o">.</span><span class="n">sender_receivers_cache</span><span class="p">[</span><span class="n">sender</span><span class="p">]</span> <span class="o">=</span> <span class="n">NO_RECEIVERS</span> <span class="k">else</span><span class="p">:</span> <span class="c1"># Note, we must cache the weakref versions.</span> <span class="bp">self</span><span class="o">.</span><span class="n">sender_receivers_cache</span><span class="p">[</span><span class="n">sender</span><span class="p">]</span> <span class="o">=</span> <span class="n">receivers</span> <span class="n">non_weak_receivers</span> <span class="o">=</span> <span class="p">[]</span> <span class="k">for</span> <span class="n">receiver</span> <span class="ow">in</span> <span class="n">receivers</span><span class="p">:</span> <span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">receiver</span><span class="p">,</span> <span class="n">weakref</span><span class="o">.</span><span class="n">ReferenceType</span><span class="p">):</span> <span class="c1"># Dereference the weak reference.</span> <span class="n">receiver</span> <span class="o">=</span> <span class="n">receiver</span><span class="p">()</span> <span class="k">if</span> <span class="n">receiver</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span> <span class="n">non_weak_receivers</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">receiver</span><span class="p">)</span> <span class="k">else</span><span class="p">:</span> <span class="n">non_weak_receivers</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">receiver</span><span class="p">)</span> <span class="k">return</span> <span class="n">non_weak_receivers</span> <span class="k">def</span> <span class="nf">_remove_receiver</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">receiver</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span> <span class="c1"># Mark that the self.receivers list has dead weakrefs. If so, we will</span> <span class="c1"># clean those up in connect, disconnect and _live_receivers while</span> <span class="c1"># holding self.lock. Note that doing the cleanup here isn't a good</span> <span class="c1"># idea, _remove_receiver() will be called as side effect of garbage</span> <span class="c1"># collection, and so the call can happen while we are already holding</span> <span class="c1"># self.lock.</span> <span class="bp">self</span><span class="o">.</span><span class="n">_dead_receivers</span> <span class="o">=</span> <span class="kc">True</span></div> <div class="viewcode-block" id="receiver"><a class="viewcode-back" href="../../../topics/signals.html#django.dispatch.receiver">[docs]</a><span class="k">def</span> <span class="nf">receiver</span><span class="p">(</span><span class="n">signal</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span> <span class="sd">"""</span> <span class="sd"> A decorator for connecting receivers to signals. Used by passing in the</span> <span class="sd"> signal (or list of signals) and keyword arguments to connect::</span> <span class="sd"> @receiver(post_save, sender=MyModel)</span> <span class="sd"> def signal_receiver(sender, **kwargs):</span> <span class="sd"> ...</span> <span class="sd"> @receiver([post_save, post_delete], sender=MyModel)</span> <span class="sd"> def signals_receiver(sender, **kwargs):</span> <span class="sd"> ...</span> <span class="sd"> """</span> <span class="k">def</span> <span class="nf">_decorator</span><span class="p">(</span><span class="n">func</span><span class="p">):</span> <span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">signal</span><span class="p">,</span> <span class="p">(</span><span class="nb">list</span><span class="p">,</span> <span class="nb">tuple</span><span class="p">)):</span> <span class="k">for</span> <span class="n">s</span> <span class="ow">in</span> <span class="n">signal</span><span class="p">:</span> <span class="n">s</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="n">func</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">)</span> <span class="k">else</span><span class="p">:</span> <span class="n">signal</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="n">func</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">)</span> <span class="k">return</span> <span class="n">func</span> <span class="k">return</span> <span class="n">_decorator</span></div> </pre></div> </div> </div> </div> <div class="yui-b" id="sidebar"> <div class="sphinxsidebar" role="navigation" aria-label="main navigation"> <div class="sphinxsidebarwrapper"> <h3>Browse</h3> <ul> </ul> <h3>You are here:</h3> <ul> <li> <a href="../../../index.html">Django 1.8.19 documentation</a> <ul><li><a href="../../index.html">Module code</a> <ul><li><a href="../../django.html">django</a> <ul><li>django.dispatch.dispatcher</li></ul> </li></ul></li></ul> </li> </ul> <div id="searchbox" style="display: none" role="search"> <h3>Quick search</h3> <form class="search" action="../../../search.html" method="get"> <div><input type="text" name="q" /></div> <div><input type="submit" value="Go" /></div> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> </div> <script type="text/javascript">$('#searchbox').show(0);</script> </div> </div> <h3>Last update:</h3> <p class="topless">Jan 06, 2019</p> </div> </div> <div id="ft"> <div class="nav"> <a href="../../index.html" title="Module code" accesskey="U">up</a></div> </div> </div> <div class="clearer"></div> </div> </body> </html>