doc/core/howto/clients.html

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   3 <title>Twisted Documentation: Writing Clients</title>
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   6
   7   <body bgcolor="white">
   8     <h1 class="title">Writing Clients</h1>
   9     <div class="toc"><ol><li><a href="#auto0">Overview</a></li><li><a href="#auto1">Protocol</a></li><li><a href="#auto2">Simple, single-use clients</a></li><li><a href="#auto3">ClientFactory</a></li><ul><li><a href="#auto4">Reconnection</a></li></ul><li><a href="#auto5">A Higher-Level Example: ircLogBot</a></li><ul><li><a href="#auto6">Overview of ircLogBot</a></li><li><a href="#auto7">Persistent Data in the Factory</a></li></ul><li><a href="#auto8">Further Reading</a></li></ol></div>
  10     <div class="content">
  11     <span/>
  12
  13     <h2>Overview<a name="auto0"/></h2>
  14
  15     <p>Twisted is a framework designed to be very flexible, and let you write
  16     powerful clients. The cost of this flexibility is a few layers in the way
  17     to writing your client. This document covers creating clients that can be
  18     used for TCP, SSL and Unix sockets. UDP is covered <a href="udp.html" shape="rect">in
  19     a different document</a>.</p>
  20
  21     <p>At the base, the place where you actually implement the protocol parsing
  22     and handling, is the <code>Protocol</code> class. This class will usually be
  23     descended
  24     from <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.protocol.Protocol.html" title="twisted.internet.protocol.Protocol">twisted.internet.protocol.Protocol</a></code>. Most
  25     protocol handlers inherit either from this class or from one of its
  26     convenience children. An instance of the protocol class will be instantiated
  27     when you connect to the server and will go away when the connection is
  28     finished.  This means that persistent configuration is not saved in the
  29     <code>Protocol</code>.</p>
  30
  31     <p>The persistent configuration is kept in a <code>Factory</code>
  32     class, which usually inherits from <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.protocol.Factory.html" title="twisted.internet.protocol.Factory">twisted.internet.protocol.Factory</a></code>
  33     (or <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.protocol.ClientFactory.html" title="twisted.internet.protocol.ClientFactory">twisted.internet.protocol.ClientFactory</a></code>: see
  34     below). The default factory class just instantiates the <code>Protocol</code>
  35     and then sets the protocol's <code>factory</code> attribute to point to
  36     itself (the factory). This lets the <code>Protocol</code> access, and
  37     possibly modify, the persistent configuration.</p>
  38
  39     <h2>Protocol<a name="auto1"/></h2>
  40
  41     <p>As mentioned above, this and auxiliary classes and functions are where
  42     most of the code is. A Twisted protocol handles data in an asynchronous
  43     manner. This means that the protocol never waits for an event, but rather
  44     responds to events as they arrive from the network.</p>
  45
  46     <p>Here is a simple example:</p>
  47
  48     <pre class="python"><p class="py-linenumber">1
  49 2
  50 3
  51 4
  52 5
  53 6
  54 </p><span class="py-src-keyword">from</span> <span class="py-src-variable">twisted</span>.<span class="py-src-variable">internet</span>.<span class="py-src-variable">protocol</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">Protocol</span>
  55 <span class="py-src-keyword">from</span> <span class="py-src-variable">sys</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">stdout</span>
  56
  57 <span class="py-src-keyword">class</span> <span class="py-src-identifier">Echo</span>(<span class="py-src-parameter">Protocol</span>):
  58     <span class="py-src-keyword">def</span> <span class="py-src-identifier">dataReceived</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">data</span>):
  59         <span class="py-src-variable">stdout</span>.<span class="py-src-variable">write</span>(<span class="py-src-variable">data</span>)
  60 </pre>
  61
  62     <p>This is one of the simplest protocols.  It just writes whatever it reads
  63     from the connection to standard output. There are many events it does not
  64     respond to. Here is an example of a <code>Protocol</code> responding to
  65     another event:</p>
  66
  67     <pre class="python"><p class="py-linenumber">1
  68 2
  69 3
  70 4
  71 5
  72 6
  73 </p><span class="py-src-keyword">from</span> <span class="py-src-variable">twisted</span>.<span class="py-src-variable">internet</span>.<span class="py-src-variable">protocol</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">Protocol</span>
  74
  75 <span class="py-src-keyword">class</span> <span class="py-src-identifier">WelcomeMessage</span>(<span class="py-src-parameter">Protocol</span>):
  76     <span class="py-src-keyword">def</span> <span class="py-src-identifier">connectionMade</span>(<span class="py-src-parameter">self</span>):
  77         <span class="py-src-variable">self</span>.<span class="py-src-variable">transport</span>.<span class="py-src-variable">write</span>(<span class="py-src-string">&quot;Hello server, I am the client!\r\n&quot;</span>)
  78         <span class="py-src-variable">self</span>.<span class="py-src-variable">transport</span>.<span class="py-src-variable">loseConnection</span>()
  79 </pre>
  80
  81     <p>This protocol connects to the server, sends it a welcome message, and
  82     then terminates the connection.</p>
  83
  84     <p>The <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.protocol.BaseProtocol.connectionMade.html" title="twisted.internet.protocol.BaseProtocol.connectionMade">connectionMade</a></code> event is
  85     usually where set up of the <code>Protocol</code> object happens, as well as
  86     any initial greetings (as in the
  87     <code>WelcomeMessage</code> protocol above). Any tearing down of
  88     <code>Protocol</code>-specific objects is done in <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.protocol.Protocol.connectionLost.html" title="twisted.internet.protocol.Protocol.connectionLost">connectionLost</a></code>.</p>
  89
  90     <h2>Simple, single-use clients<a name="auto2"/></h2>
  91
  92     <p>In many cases, the protocol only needs to connect to the server once, and
  93     the code just wants to get a connected instance of the protocol. In those
  94     cases <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.endpoints.html" title="twisted.internet.endpoints">twisted.internet.endpoints</a></code> provides the
  95     appropriate API.</p>
  96
  97     <pre class="python"><p class="py-linenumber"> 1
  98  2
  99  3
 100  4
 101  5
 102  6
 103  7
 104  8
 105  9
 106 10
 107 11
 108 12
 109 13
 110 14
 111 15
 112 16
 113 17
 114 18
 115 19
 116 20
 117 21
 118 </p><span class="py-src-keyword">from</span> <span class="py-src-variable">twisted</span>.<span class="py-src-variable">internet</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">reactor</span>
 119 <span class="py-src-keyword">from</span> <span class="py-src-variable">twisted</span>.<span class="py-src-variable">internet</span>.<span class="py-src-variable">protocol</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">Factory</span>, <span class="py-src-variable">Protocol</span>
 120 <span class="py-src-keyword">from</span> <span class="py-src-variable">twisted</span>.<span class="py-src-variable">internet</span>.<span class="py-src-variable">endpoints</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">TCP4ClientEndpoint</span>
 121
 122 <span class="py-src-keyword">class</span> <span class="py-src-identifier">Greeter</span>(<span class="py-src-parameter">Protocol</span>):
 123     <span class="py-src-keyword">def</span> <span class="py-src-identifier">sendMessage</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">msg</span>):
 124         <span class="py-src-variable">self</span>.<span class="py-src-variable">transport</span>.<span class="py-src-variable">write</span>(<span class="py-src-string">&quot;MESSAGE %s\n&quot;</span> % <span class="py-src-variable">msg</span>)
 125
 126 <span class="py-src-keyword">class</span> <span class="py-src-identifier">GreeterFactory</span>(<span class="py-src-parameter">Factory</span>):
 127     <span class="py-src-keyword">def</span> <span class="py-src-identifier">buildProtocol</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">addr</span>):
 128         <span class="py-src-keyword">return</span> <span class="py-src-variable">Greeter</span>()
 129
 130 <span class="py-src-keyword">def</span> <span class="py-src-identifier">gotProtocol</span>(<span class="py-src-parameter">p</span>):
 131     <span class="py-src-variable">p</span>.<span class="py-src-variable">sendMessage</span>(<span class="py-src-string">&quot;Hello&quot;</span>)
 132     <span class="py-src-variable">reactor</span>.<span class="py-src-variable">callLater</span>(<span class="py-src-number">1</span>, <span class="py-src-variable">p</span>.<span class="py-src-variable">sendMessage</span>, <span class="py-src-string">&quot;This is sent in a second&quot;</span>)
 133     <span class="py-src-variable">reactor</span>.<span class="py-src-variable">callLater</span>(<span class="py-src-number">2</span>, <span class="py-src-variable">p</span>.<span class="py-src-variable">transport</span>.<span class="py-src-variable">loseConnection</span>)
 134
 135 <span class="py-src-variable">point</span> = <span class="py-src-variable">TCP4ClientEndpoint</span>(<span class="py-src-variable">reactor</span>, <span class="py-src-string">&quot;localhost&quot;</span>, <span class="py-src-number">1234</span>)
 136 <span class="py-src-variable">d</span> = <span class="py-src-variable">point</span>.<span class="py-src-variable">connect</span>(<span class="py-src-variable">GreeterFactory</span>())
 137 <span class="py-src-variable">d</span>.<span class="py-src-variable">addCallback</span>(<span class="py-src-variable">gotProtocol</span>)
 138 <span class="py-src-variable">reactor</span>.<span class="py-src-variable">run</span>()
 139 </pre>
 140
 141     <p>Regardless of the type of client endpoint, the way to set up a new
 142     connection is simply to call the <code>connect</code> method on it and pass
 143     in a factory.  This means it's easy to change the mechanism you're using to
 144     connect, without changing the rest of your program.  For example, to run
 145     the greeter example over SSL, the only change required is to instantiate an
 146     <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.endpoints.SSL4ClientEndpoint.html" title="twisted.internet.endpoints.SSL4ClientEndpoint">SSL4ClientEndpoint</a></code> instead of a
 147     <code>TCP4ClientEndpoint</code>.  To take advantage of this, functions and
 148     methods which initiates a new connection should generally accept an
 149     endpoint as an argument and let the caller construct it, rather than taking
 150     arguments like 'host' and 'port' and constructing its own before calling
 151     <code>connect</code>.</p>
 152
 153     <p>For more information on different ways you can make outgoing connections
 154     to different types of endpoints, as well as parsing strings into endpoints,
 155     see <a href="endpoints.html" shape="rect">the documentation for the endpoints
 156     API</a>.</p>
 157
 158     <div class="note"><strong>Note: </strong>If you've used <code>ClientFactory</code> before,
 159     make sure you remember that the <code>connect</code> method takes a
 160     <code>Factory</code>, not a <code>ClientFactory</code>.  Even if you pass a
 161     <code>ClientFactory</code> to <code>endpoint.connect</code>, its
 162     <code>clientConnectionFailed</code> and <code>clientConnectionLost</code>
 163     methods will not be called.</div>
 164
 165     <p>You may come across code using <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.protocol.ClientCreator.html" title="twisted.internet.protocol.ClientCreator">ClientCreator</a></code>, an older API which is not as flexible as
 166     the endpoint API.  Rather than calling <code>connect</code> on an endpoint,
 167     such code will look like this:</p>
 168
 169     <pre class="python"><p class="py-linenumber">1
 170 2
 171 3
 172 4
 173 5
 174 6
 175 7
 176 8
 177 </p><span class="py-src-keyword">from</span> <span class="py-src-variable">twisted</span>.<span class="py-src-variable">internet</span>.<span class="py-src-variable">protocol</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">ClientCreator</span>
 178
 179 ...
 180
 181 <span class="py-src-variable">creator</span> = <span class="py-src-variable">ClientCreator</span>(<span class="py-src-variable">reactor</span>, <span class="py-src-variable">Greeter</span>)
 182 <span class="py-src-variable">d</span> = <span class="py-src-variable">creator</span>.<span class="py-src-variable">connectTCP</span>(<span class="py-src-string">&quot;localhost&quot;</span>, <span class="py-src-number">1234</span>)
 183 <span class="py-src-variable">d</span>.<span class="py-src-variable">addCallback</span>(<span class="py-src-variable">gotProtocol</span>)
 184 <span class="py-src-variable">reactor</span>.<span class="py-src-variable">run</span>()
 185 </pre>
 186
 187     <p>In general, the endpoint API should be preferred in new code, as it lets
 188     the caller select the method of connecting.</p>
 189
 190     <h2>ClientFactory<a name="auto3"/></h2>
 191
 192     <p>Still, there's plenty of code out there that uses lower-level APIs, and
 193     a few features (such as automatic reconnection) have not been
 194     re-implemented with endpoints yet, so in some cases they may be more
 195     convenient to use.</p>
 196
 197     <p>To use the lower-level connection APIs, you will need to call one of the
 198     <em>reactor.connect*</em> methods directly.  For these cases, you need a
 199     <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.protocol.ClientFactory.html" title="twisted.internet.protocol.ClientFactory">ClientFactory</a></code>.
 200     The <code>ClientFactory</code> is in charge of creating the
 201     <code>Protocol</code> and also receives events relating to the connection
 202     state. This allows it to do things like reconnect in the event of a
 203     connection error. Here is an example of a simple <code>ClientFactory</code>
 204     that uses the <code>Echo</code> protocol (above) and also prints what state
 205     the connection is in.</p>
 206
 207     <pre class="python"><p class="py-linenumber"> 1
 208  2
 209  3
 210  4
 211  5
 212  6
 213  7
 214  8
 215  9
 216 10
 217 11
 218 12
 219 13
 220 14
 221 15
 222 16
 223 17
 224 18
 225 19
 226 20
 227 </p><span class="py-src-keyword">from</span> <span class="py-src-variable">twisted</span>.<span class="py-src-variable">internet</span>.<span class="py-src-variable">protocol</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">Protocol</span>, <span class="py-src-variable">ClientFactory</span>
 228 <span class="py-src-keyword">from</span> <span class="py-src-variable">sys</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">stdout</span>
 229
 230 <span class="py-src-keyword">class</span> <span class="py-src-identifier">Echo</span>(<span class="py-src-parameter">Protocol</span>):
 231     <span class="py-src-keyword">def</span> <span class="py-src-identifier">dataReceived</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">data</span>):
 232         <span class="py-src-variable">stdout</span>.<span class="py-src-variable">write</span>(<span class="py-src-variable">data</span>)
 233
 234 <span class="py-src-keyword">class</span> <span class="py-src-identifier">EchoClientFactory</span>(<span class="py-src-parameter">ClientFactory</span>):
 235     <span class="py-src-keyword">def</span> <span class="py-src-identifier">startedConnecting</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">connector</span>):
 236         <span class="py-src-keyword">print</span> <span class="py-src-string">'Started to connect.'</span>
 237
 238     <span class="py-src-keyword">def</span> <span class="py-src-identifier">buildProtocol</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">addr</span>):
 239         <span class="py-src-keyword">print</span> <span class="py-src-string">'Connected.'</span>
 240         <span class="py-src-keyword">return</span> <span class="py-src-variable">Echo</span>()
 241
 242     <span class="py-src-keyword">def</span> <span class="py-src-identifier">clientConnectionLost</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">connector</span>, <span class="py-src-parameter">reason</span>):
 243         <span class="py-src-keyword">print</span> <span class="py-src-string">'Lost connection.  Reason:'</span>, <span class="py-src-variable">reason</span>
 244
 245     <span class="py-src-keyword">def</span> <span class="py-src-identifier">clientConnectionFailed</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">connector</span>, <span class="py-src-parameter">reason</span>):
 246         <span class="py-src-keyword">print</span> <span class="py-src-string">'Connection failed. Reason:'</span>, <span class="py-src-variable">reason</span>
 247 </pre>
 248
 249     <p>To connect this <code>EchoClientFactory</code> to a server, you could use
 250     this code:</p>
 251
 252     <pre class="python"><p class="py-linenumber">1
 253 2
 254 3
 255 </p><span class="py-src-keyword">from</span> <span class="py-src-variable">twisted</span>.<span class="py-src-variable">internet</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">reactor</span>
 256 <span class="py-src-variable">reactor</span>.<span class="py-src-variable">connectTCP</span>(<span class="py-src-variable">host</span>, <span class="py-src-variable">port</span>, <span class="py-src-variable">EchoClientFactory</span>())
 257 <span class="py-src-variable">reactor</span>.<span class="py-src-variable">run</span>()
 258 </pre>
 259
 260     <p>Note that <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.protocol.ClientFactory.clientConnectionFailed.html" title="twisted.internet.protocol.ClientFactory.clientConnectionFailed">clientConnectionFailed</a></code>
 261     is called when a connection could not be established, and that <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.protocol.ClientFactory.clientConnectionLost.html" title="twisted.internet.protocol.ClientFactory.clientConnectionLost">clientConnectionLost</a></code>
 262     is called when a connection was made and then disconnected.</p>
 263
 264     <h3>Reconnection<a name="auto4"/></h3>
 265
 266     <p>Often, the connection of a client will be lost unintentionally due to
 267     network problems. One way to reconnect after a disconnection would be to
 268     call <code>connector.connect()</code> when the connection is lost:</p>
 269
 270     <pre class="python"><p class="py-linenumber">1
 271 2
 272 3
 273 4
 274 5
 275 </p><span class="py-src-keyword">from</span> <span class="py-src-variable">twisted</span>.<span class="py-src-variable">internet</span>.<span class="py-src-variable">protocol</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">ClientFactory</span>
 276
 277 <span class="py-src-keyword">class</span> <span class="py-src-identifier">EchoClientFactory</span>(<span class="py-src-parameter">ClientFactory</span>):
 278     <span class="py-src-keyword">def</span> <span class="py-src-identifier">clientConnectionLost</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">connector</span>, <span class="py-src-parameter">reason</span>):
 279         <span class="py-src-variable">connector</span>.<span class="py-src-variable">connect</span>()
 280 </pre>
 281
 282     <p>The connector passed as the first argument is the interface between a
 283     connection and a protocol. When the connection fails and the factory
 284     receives the <code>clientConnectionLost</code> event, the factory can
 285     call <code>connector.connect()</code> to start the connection over again
 286     from scratch.</p>
 287
 288     <p>
 289     However, most programs that want this functionality should
 290     implement <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.protocol.ReconnectingClientFactory.html" title="twisted.internet.protocol.ReconnectingClientFactory">ReconnectingClientFactory</a></code> instead,
 291     which tries to reconnect if a connection is lost or fails and which
 292     exponentially delays repeated reconnect attempts.
 293     </p>
 294
 295     <p>
 296     Here is the <code>Echo</code> protocol implemented with
 297     a <code>ReconnectingClientFactory</code>:
 298     </p>
 299
 300     <pre class="python"><p class="py-linenumber"> 1
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 325 </p><span class="py-src-keyword">from</span> <span class="py-src-variable">twisted</span>.<span class="py-src-variable">internet</span>.<span class="py-src-variable">protocol</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">Protocol</span>, <span class="py-src-variable">ReconnectingClientFactory</span>
 326 <span class="py-src-keyword">from</span> <span class="py-src-variable">sys</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">stdout</span>
 327
 328 <span class="py-src-keyword">class</span> <span class="py-src-identifier">Echo</span>(<span class="py-src-parameter">Protocol</span>):
 329     <span class="py-src-keyword">def</span> <span class="py-src-identifier">dataReceived</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">data</span>):
 330         <span class="py-src-variable">stdout</span>.<span class="py-src-variable">write</span>(<span class="py-src-variable">data</span>)
 331
 332 <span class="py-src-keyword">class</span> <span class="py-src-identifier">EchoClientFactory</span>(<span class="py-src-parameter">ReconnectingClientFactory</span>):
 333     <span class="py-src-keyword">def</span> <span class="py-src-identifier">startedConnecting</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">connector</span>):
 334         <span class="py-src-keyword">print</span> <span class="py-src-string">'Started to connect.'</span>
 335
 336     <span class="py-src-keyword">def</span> <span class="py-src-identifier">buildProtocol</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">addr</span>):
 337         <span class="py-src-keyword">print</span> <span class="py-src-string">'Connected.'</span>
 338         <span class="py-src-keyword">print</span> <span class="py-src-string">'Resetting reconnection delay'</span>
 339         <span class="py-src-variable">self</span>.<span class="py-src-variable">resetDelay</span>()
 340         <span class="py-src-keyword">return</span> <span class="py-src-variable">Echo</span>()
 341
 342     <span class="py-src-keyword">def</span> <span class="py-src-identifier">clientConnectionLost</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">connector</span>, <span class="py-src-parameter">reason</span>):
 343         <span class="py-src-keyword">print</span> <span class="py-src-string">'Lost connection.  Reason:'</span>, <span class="py-src-variable">reason</span>
 344         <span class="py-src-variable">ReconnectingClientFactory</span>.<span class="py-src-variable">clientConnectionLost</span>(<span class="py-src-variable">self</span>, <span class="py-src-variable">connector</span>, <span class="py-src-variable">reason</span>)
 345
 346     <span class="py-src-keyword">def</span> <span class="py-src-identifier">clientConnectionFailed</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">connector</span>, <span class="py-src-parameter">reason</span>):
 347         <span class="py-src-keyword">print</span> <span class="py-src-string">'Connection failed. Reason:'</span>, <span class="py-src-variable">reason</span>
 348         <span class="py-src-variable">ReconnectingClientFactory</span>.<span class="py-src-variable">clientConnectionFailed</span>(<span class="py-src-variable">self</span>, <span class="py-src-variable">connector</span>,
 349                                                          <span class="py-src-variable">reason</span>)
 350 </pre>
 351
 352     <h2>A Higher-Level Example: ircLogBot<a name="auto5"/></h2>
 353
 354     <h3>Overview of ircLogBot<a name="auto6"/></h3>
 355
 356     <p>The clients so far have been fairly simple.  A more complicated example
 357     comes with Twisted Words in the <code>doc/words/examples</code>
 358     directory.</p>
 359
 360     <div class="py-listing"><pre><p class="py-linenumber">  1
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 493 134
 494 </p><span class="py-src-comment"># twisted imports</span>
 495 <span class="py-src-keyword">from</span> <span class="py-src-variable">twisted</span>.<span class="py-src-variable">words</span>.<span class="py-src-variable">protocols</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">irc</span>
 496 <span class="py-src-keyword">from</span> <span class="py-src-variable">twisted</span>.<span class="py-src-variable">internet</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">reactor</span>, <span class="py-src-variable">protocol</span>
 497 <span class="py-src-keyword">from</span> <span class="py-src-variable">twisted</span>.<span class="py-src-variable">python</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">log</span>
 498
 499 <span class="py-src-comment"># system imports</span>
 500 <span class="py-src-keyword">import</span> <span class="py-src-variable">time</span>, <span class="py-src-variable">sys</span>
 501
 502
 503 <span class="py-src-keyword">class</span> <span class="py-src-identifier">MessageLogger</span>:
 504     <span class="py-src-string">&quot;&quot;&quot;
 505     An independent logger class (because separation of application
 506     and protocol logic is a good thing).
 507     &quot;&quot;&quot;</span>
 508     <span class="py-src-keyword">def</span> <span class="py-src-identifier">__init__</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">file</span>):
 509         <span class="py-src-variable">self</span>.<span class="py-src-variable">file</span> = <span class="py-src-variable">file</span>
 510
 511     <span class="py-src-keyword">def</span> <span class="py-src-identifier">log</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">message</span>):
 512         <span class="py-src-string">&quot;&quot;&quot;Write a message to the file.&quot;&quot;&quot;</span>
 513         <span class="py-src-variable">timestamp</span> = <span class="py-src-variable">time</span>.<span class="py-src-variable">strftime</span>(<span class="py-src-string">&quot;[%H:%M:%S]&quot;</span>, <span class="py-src-variable">time</span>.<span class="py-src-variable">localtime</span>(<span class="py-src-variable">time</span>.<span class="py-src-variable">time</span>()))
 514         <span class="py-src-variable">self</span>.<span class="py-src-variable">file</span>.<span class="py-src-variable">write</span>(<span class="py-src-string">'%s %s\n'</span> % (<span class="py-src-variable">timestamp</span>, <span class="py-src-variable">message</span>))
 515         <span class="py-src-variable">self</span>.<span class="py-src-variable">file</span>.<span class="py-src-variable">flush</span>()
 516
 517     <span class="py-src-keyword">def</span> <span class="py-src-identifier">close</span>(<span class="py-src-parameter">self</span>):
 518         <span class="py-src-variable">self</span>.<span class="py-src-variable">file</span>.<span class="py-src-variable">close</span>()
 519
 520
 521 <span class="py-src-keyword">class</span> <span class="py-src-identifier">LogBot</span>(<span class="py-src-parameter">irc</span>.<span class="py-src-parameter">IRCClient</span>):
 522     <span class="py-src-string">&quot;&quot;&quot;A logging IRC bot.&quot;&quot;&quot;</span>
 523
 524     <span class="py-src-variable">nickname</span> = <span class="py-src-string">&quot;twistedbot&quot;</span>
 525
 526     <span class="py-src-keyword">def</span> <span class="py-src-identifier">connectionMade</span>(<span class="py-src-parameter">self</span>):
 527         <span class="py-src-variable">irc</span>.<span class="py-src-variable">IRCClient</span>.<span class="py-src-variable">connectionMade</span>(<span class="py-src-variable">self</span>)
 528         <span class="py-src-variable">self</span>.<span class="py-src-variable">logger</span> = <span class="py-src-variable">MessageLogger</span>(<span class="py-src-variable">open</span>(<span class="py-src-variable">self</span>.<span class="py-src-variable">factory</span>.<span class="py-src-variable">filename</span>, <span class="py-src-string">&quot;a&quot;</span>))
 529         <span class="py-src-variable">self</span>.<span class="py-src-variable">logger</span>.<span class="py-src-variable">log</span>(<span class="py-src-string">&quot;[connected at %s]&quot;</span> %
 530                         <span class="py-src-variable">time</span>.<span class="py-src-variable">asctime</span>(<span class="py-src-variable">time</span>.<span class="py-src-variable">localtime</span>(<span class="py-src-variable">time</span>.<span class="py-src-variable">time</span>())))
 531
 532     <span class="py-src-keyword">def</span> <span class="py-src-identifier">connectionLost</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">reason</span>):
 533         <span class="py-src-variable">irc</span>.<span class="py-src-variable">IRCClient</span>.<span class="py-src-variable">connectionLost</span>(<span class="py-src-variable">self</span>, <span class="py-src-variable">reason</span>)
 534         <span class="py-src-variable">self</span>.<span class="py-src-variable">logger</span>.<span class="py-src-variable">log</span>(<span class="py-src-string">&quot;[disconnected at %s]&quot;</span> %
 535                         <span class="py-src-variable">time</span>.<span class="py-src-variable">asctime</span>(<span class="py-src-variable">time</span>.<span class="py-src-variable">localtime</span>(<span class="py-src-variable">time</span>.<span class="py-src-variable">time</span>())))
 536         <span class="py-src-variable">self</span>.<span class="py-src-variable">logger</span>.<span class="py-src-variable">close</span>()
 537
 538
 539     <span class="py-src-comment"># callbacks for events</span>
 540
 541     <span class="py-src-keyword">def</span> <span class="py-src-identifier">signedOn</span>(<span class="py-src-parameter">self</span>):
 542         <span class="py-src-string">&quot;&quot;&quot;Called when bot has succesfully signed on to server.&quot;&quot;&quot;</span>
 543         <span class="py-src-variable">self</span>.<span class="py-src-variable">join</span>(<span class="py-src-variable">self</span>.<span class="py-src-variable">factory</span>.<span class="py-src-variable">channel</span>)
 544
 545     <span class="py-src-keyword">def</span> <span class="py-src-identifier">joined</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">channel</span>):
 546         <span class="py-src-string">&quot;&quot;&quot;This will get called when the bot joins the channel.&quot;&quot;&quot;</span>
 547         <span class="py-src-variable">self</span>.<span class="py-src-variable">logger</span>.<span class="py-src-variable">log</span>(<span class="py-src-string">&quot;[I have joined %s]&quot;</span> % <span class="py-src-variable">channel</span>)
 548
 549     <span class="py-src-keyword">def</span> <span class="py-src-identifier">privmsg</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">user</span>, <span class="py-src-parameter">channel</span>, <span class="py-src-parameter">msg</span>):
 550         <span class="py-src-string">&quot;&quot;&quot;This will get called when the bot receives a message.&quot;&quot;&quot;</span>
 551         <span class="py-src-variable">user</span> = <span class="py-src-variable">user</span>.<span class="py-src-variable">split</span>(<span class="py-src-string">'!'</span>, <span class="py-src-number">1</span>)[<span class="py-src-number">0</span>]
 552         <span class="py-src-variable">self</span>.<span class="py-src-variable">logger</span>.<span class="py-src-variable">log</span>(<span class="py-src-string">&quot;&lt;%s&gt; %s&quot;</span> % (<span class="py-src-variable">user</span>, <span class="py-src-variable">msg</span>))
 553
 554         <span class="py-src-comment"># Check to see if they're sending me a private message</span>
 555         <span class="py-src-keyword">if</span> <span class="py-src-variable">channel</span> == <span class="py-src-variable">self</span>.<span class="py-src-variable">nickname</span>:
 556             <span class="py-src-variable">msg</span> = <span class="py-src-string">&quot;It isn't nice to whisper!  Play nice with the group.&quot;</span>
 557             <span class="py-src-variable">self</span>.<span class="py-src-variable">msg</span>(<span class="py-src-variable">user</span>, <span class="py-src-variable">msg</span>)
 558             <span class="py-src-keyword">return</span>
 559
 560         <span class="py-src-comment"># Otherwise check to see if it is a message directed at me</span>
 561         <span class="py-src-keyword">if</span> <span class="py-src-variable">msg</span>.<span class="py-src-variable">startswith</span>(<span class="py-src-variable">self</span>.<span class="py-src-variable">nickname</span> + <span class="py-src-string">&quot;:&quot;</span>):
 562             <span class="py-src-variable">msg</span> = <span class="py-src-string">&quot;%s: I am a log bot&quot;</span> % <span class="py-src-variable">user</span>
 563             <span class="py-src-variable">self</span>.<span class="py-src-variable">msg</span>(<span class="py-src-variable">channel</span>, <span class="py-src-variable">msg</span>)
 564             <span class="py-src-variable">self</span>.<span class="py-src-variable">logger</span>.<span class="py-src-variable">log</span>(<span class="py-src-string">&quot;&lt;%s&gt; %s&quot;</span> % (<span class="py-src-variable">self</span>.<span class="py-src-variable">nickname</span>, <span class="py-src-variable">msg</span>))
 565
 566     <span class="py-src-keyword">def</span> <span class="py-src-identifier">action</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">user</span>, <span class="py-src-parameter">channel</span>, <span class="py-src-parameter">msg</span>):
 567         <span class="py-src-string">&quot;&quot;&quot;This will get called when the bot sees someone do an action.&quot;&quot;&quot;</span>
 568         <span class="py-src-variable">user</span> = <span class="py-src-variable">user</span>.<span class="py-src-variable">split</span>(<span class="py-src-string">'!'</span>, <span class="py-src-number">1</span>)[<span class="py-src-number">0</span>]
 569         <span class="py-src-variable">self</span>.<span class="py-src-variable">logger</span>.<span class="py-src-variable">log</span>(<span class="py-src-string">&quot;* %s %s&quot;</span> % (<span class="py-src-variable">user</span>, <span class="py-src-variable">msg</span>))
 570
 571     <span class="py-src-comment"># irc callbacks</span>
 572
 573     <span class="py-src-keyword">def</span> <span class="py-src-identifier">irc_NICK</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">prefix</span>, <span class="py-src-parameter">params</span>):
 574         <span class="py-src-string">&quot;&quot;&quot;Called when an IRC user changes their nickname.&quot;&quot;&quot;</span>
 575         <span class="py-src-variable">old_nick</span> = <span class="py-src-variable">prefix</span>.<span class="py-src-variable">split</span>(<span class="py-src-string">'!'</span>)[<span class="py-src-number">0</span>]
 576         <span class="py-src-variable">new_nick</span> = <span class="py-src-variable">params</span>[<span class="py-src-number">0</span>]
 577         <span class="py-src-variable">self</span>.<span class="py-src-variable">logger</span>.<span class="py-src-variable">log</span>(<span class="py-src-string">&quot;%s is now known as %s&quot;</span> % (<span class="py-src-variable">old_nick</span>, <span class="py-src-variable">new_nick</span>))
 578
 579
 580     <span class="py-src-comment"># For fun, override the method that determines how a nickname is changed on</span>
 581     <span class="py-src-comment"># collisions. The default method appends an underscore.</span>
 582     <span class="py-src-keyword">def</span> <span class="py-src-identifier">alterCollidedNick</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">nickname</span>):
 583         <span class="py-src-string">&quot;&quot;&quot;
 584         Generate an altered version of a nickname that caused a collision in an
 585         effort to create an unused related name for subsequent registration.
 586         &quot;&quot;&quot;</span>
 587         <span class="py-src-keyword">return</span> <span class="py-src-variable">nickname</span> + <span class="py-src-string">'^'</span>
 588
 589
 590
 591 <span class="py-src-keyword">class</span> <span class="py-src-identifier">LogBotFactory</span>(<span class="py-src-parameter">protocol</span>.<span class="py-src-parameter">ClientFactory</span>):
 592     <span class="py-src-string">&quot;&quot;&quot;A factory for LogBots.
 593
 594     A new protocol instance will be created each time we connect to the server.
 595     &quot;&quot;&quot;</span>
 596
 597     <span class="py-src-keyword">def</span> <span class="py-src-identifier">__init__</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">channel</span>, <span class="py-src-parameter">filename</span>):
 598         <span class="py-src-variable">self</span>.<span class="py-src-variable">channel</span> = <span class="py-src-variable">channel</span>
 599         <span class="py-src-variable">self</span>.<span class="py-src-variable">filename</span> = <span class="py-src-variable">filename</span>
 600
 601     <span class="py-src-keyword">def</span> <span class="py-src-identifier">buildProtocol</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">addr</span>):
 602         <span class="py-src-variable">p</span> = <span class="py-src-variable">LogBot</span>()
 603         <span class="py-src-variable">p</span>.<span class="py-src-variable">factory</span> = <span class="py-src-variable">self</span>
 604         <span class="py-src-keyword">return</span> <span class="py-src-variable">p</span>
 605
 606     <span class="py-src-keyword">def</span> <span class="py-src-identifier">clientConnectionLost</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">connector</span>, <span class="py-src-parameter">reason</span>):
 607         <span class="py-src-string">&quot;&quot;&quot;If we get disconnected, reconnect to server.&quot;&quot;&quot;</span>
 608         <span class="py-src-variable">connector</span>.<span class="py-src-variable">connect</span>()
 609
 610     <span class="py-src-keyword">def</span> <span class="py-src-identifier">clientConnectionFailed</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">connector</span>, <span class="py-src-parameter">reason</span>):
 611         <span class="py-src-keyword">print</span> <span class="py-src-string">&quot;connection failed:&quot;</span>, <span class="py-src-variable">reason</span>
 612         <span class="py-src-variable">reactor</span>.<span class="py-src-variable">stop</span>()
 613
 614
 615 <span class="py-src-keyword">if</span> <span class="py-src-variable">__name__</span> == <span class="py-src-string">'__main__'</span>:
 616     <span class="py-src-comment"># initialize logging</span>
 617     <span class="py-src-variable">log</span>.<span class="py-src-variable">startLogging</span>(<span class="py-src-variable">sys</span>.<span class="py-src-variable">stdout</span>)
 618
 619     <span class="py-src-comment"># create factory protocol and application</span>
 620     <span class="py-src-variable">f</span> = <span class="py-src-variable">LogBotFactory</span>(<span class="py-src-variable">sys</span>.<span class="py-src-variable">argv</span>[<span class="py-src-number">1</span>], <span class="py-src-variable">sys</span>.<span class="py-src-variable">argv</span>[<span class="py-src-number">2</span>])
 621
 622     <span class="py-src-comment"># connect factory to this host and port</span>
 623     <span class="py-src-variable">reactor</span>.<span class="py-src-variable">connectTCP</span>(<span class="py-src-string">&quot;irc.freenode.net&quot;</span>, <span class="py-src-number">6667</span>, <span class="py-src-variable">f</span>)
 624
 625     <span class="py-src-comment"># run bot</span>
 626     <span class="py-src-variable">reactor</span>.<span class="py-src-variable">run</span>()
 627 </pre><div class="caption">Source listing - <a href="../../words/examples/ircLogBot.py"><span class="filename">../../words/examples/ircLogBot.py</span></a></div></div>
 628
 629     <p><code>ircLogBot.py</code> connects to an IRC server, joins a channel, and
 630     logs all traffic on it to a file. It demonstrates some of the
 631     connection-level logic of reconnecting on a lost connection, as well as
 632     storing persistent data in the <code>Factory</code>.</p>
 633
 634     <h3>Persistent Data in the Factory<a name="auto7"/></h3>
 635
 636     <p>Since the <code>Protocol</code> instance is recreated each time the
 637     connection is made, the client needs some way to keep track of data that
 638     should be persisted. In the case of the logging bot, it needs to know which
 639     channel it is logging, and where to log it.</p>
 640
 641     <pre class="python"><p class="py-linenumber"> 1
 642  2
 643  3
 644  4
 645  5
 646  6
 647  7
 648  8
 649  9
 650 10
 651 11
 652 12
 653 13
 654 14
 655 15
 656 16
 657 17
 658 18
 659 19
 660 20
 661 21
 662 22
 663 23
 664 24
 665 25
 666 </p><span class="py-src-keyword">from</span> <span class="py-src-variable">twisted</span>.<span class="py-src-variable">words</span>.<span class="py-src-variable">protocols</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">irc</span>
 667 <span class="py-src-keyword">from</span> <span class="py-src-variable">twisted</span>.<span class="py-src-variable">internet</span> <span class="py-src-keyword">import</span> <span class="py-src-variable">protocol</span>
 668
 669 <span class="py-src-keyword">class</span> <span class="py-src-identifier">LogBot</span>(<span class="py-src-parameter">irc</span>.<span class="py-src-parameter">IRCClient</span>):
 670
 671     <span class="py-src-keyword">def</span> <span class="py-src-identifier">connectionMade</span>(<span class="py-src-parameter">self</span>):
 672         <span class="py-src-variable">irc</span>.<span class="py-src-variable">IRCClient</span>.<span class="py-src-variable">connectionMade</span>(<span class="py-src-variable">self</span>)
 673         <span class="py-src-variable">self</span>.<span class="py-src-variable">logger</span> = <span class="py-src-variable">MessageLogger</span>(<span class="py-src-variable">open</span>(<span class="py-src-variable">self</span>.<span class="py-src-variable">factory</span>.<span class="py-src-variable">filename</span>, <span class="py-src-string">&quot;a&quot;</span>))
 674         <span class="py-src-variable">self</span>.<span class="py-src-variable">logger</span>.<span class="py-src-variable">log</span>(<span class="py-src-string">&quot;[connected at %s]&quot;</span> %
 675                         <span class="py-src-variable">time</span>.<span class="py-src-variable">asctime</span>(<span class="py-src-variable">time</span>.<span class="py-src-variable">localtime</span>(<span class="py-src-variable">time</span>.<span class="py-src-variable">time</span>())))
 676
 677     <span class="py-src-keyword">def</span> <span class="py-src-identifier">signedOn</span>(<span class="py-src-parameter">self</span>):
 678         <span class="py-src-variable">self</span>.<span class="py-src-variable">join</span>(<span class="py-src-variable">self</span>.<span class="py-src-variable">factory</span>.<span class="py-src-variable">channel</span>)
 679
 680
 681 <span class="py-src-keyword">class</span> <span class="py-src-identifier">LogBotFactory</span>(<span class="py-src-parameter">protocol</span>.<span class="py-src-parameter">ClientFactory</span>):
 682
 683     <span class="py-src-keyword">def</span> <span class="py-src-identifier">__init__</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">channel</span>, <span class="py-src-parameter">filename</span>):
 684         <span class="py-src-variable">self</span>.<span class="py-src-variable">channel</span> = <span class="py-src-variable">channel</span>
 685         <span class="py-src-variable">self</span>.<span class="py-src-variable">filename</span> = <span class="py-src-variable">filename</span>
 686
 687     <span class="py-src-keyword">def</span> <span class="py-src-identifier">buildProtocol</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">addr</span>):
 688         <span class="py-src-variable">p</span> = <span class="py-src-variable">LogBot</span>()
 689         <span class="py-src-variable">p</span>.<span class="py-src-variable">factory</span> = <span class="py-src-variable">self</span>
 690         <span class="py-src-keyword">return</span> <span class="py-src-variable">p</span>
 691 </pre>
 692
 693     <p>When the protocol is created, it gets a reference to the factory as
 694     <code>self.factory</code>. It can then access attributes of the factory in
 695     its logic. In the case of <code>LogBot</code>, it opens the file and
 696     connects to the channel stored in the factory.</p>
 697
 698     <p>Factories have a default implementation of <code>buildProtocol</code>
 699     that does the same thing the example above does, using
 700     the <code>protocol</code> attribute of the factory to create the protocol
 701     instance. In the example above, the factory could be rewritten to look
 702     like this:</p>
 703
 704     <pre class="python"><p class="py-linenumber">1
 705 2
 706 3
 707 4
 708 5
 709 6
 710 </p><span class="py-src-keyword">class</span> <span class="py-src-identifier">LogBotFactory</span>(<span class="py-src-parameter">protocol</span>.<span class="py-src-parameter">ClientFactory</span>):
 711     <span class="py-src-variable">protocol</span> = <span class="py-src-variable">LogBot</span>
 712
 713     <span class="py-src-keyword">def</span> <span class="py-src-identifier">__init__</span>(<span class="py-src-parameter">self</span>, <span class="py-src-parameter">channel</span>, <span class="py-src-parameter">filename</span>):
 714         <span class="py-src-variable">self</span>.<span class="py-src-variable">channel</span> = <span class="py-src-variable">channel</span>
 715         <span class="py-src-variable">self</span>.<span class="py-src-variable">filename</span> = <span class="py-src-variable">filename</span>
 716 </pre>
 717
 718     <h2>Further Reading<a name="auto8"/></h2>
 719
 720     <p>The <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.protocol.Protocol.html" title="twisted.internet.protocol.Protocol">Protocol</a></code>
 721     class used throughout this document is a base implementation
 722     of <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.interfaces.IProtocol.html" title="twisted.internet.interfaces.IProtocol">IProtocol</a></code>
 723     used in most Twisted applications for convenience. To learn about the
 724     complete <code>IProtocol</code> interface, see the API documentation for
 725     <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.interfaces.IProtocol.html" title="twisted.internet.interfaces.IProtocol">IProtocol</a></code>.</p>
 726
 727     <p>The <code>transport</code> attribute used in some examples in this
 728     document provides the <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.interfaces.ITCPTransport.html" title="twisted.internet.interfaces.ITCPTransport">ITCPTransport</a></code> interface. To learn
 729     about the complete interface, see the API documentation
 730     for <code class="API"><a href="http://twistedmatrix.com/documents/12.1.0/api/twisted.internet.interfaces.ITCPTransport.html" title="twisted.internet.interfaces.ITCPTransport">ITCPTransport</a></code>.</p>
 731
 732     <p>Interface classes are a way of specifying what methods and attributes an
 733     object has and how they behave. See the <a href="components.html" shape="rect">
 734     Components: Interfaces and Adapters</a> document for more information on
 735     using interfaces in Twisted.</p>
 736   </div>
 737
 738     <p><a href="index.html">Index</a></p>
 739     <span class="version">Version: 12.1.0</span>
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