/usr/share/doc/python-eventlet-doc/html/examples.html is in python-eventlet-doc 0.19.0-6.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Examples — Eventlet 0.19.0 documentation</title>
<link rel="stylesheet" href="_static/classic.css" type="text/css" />
<link rel="stylesheet" href="_static/pygments.css" type="text/css" />
<script type="text/javascript">
var DOCUMENTATION_OPTIONS = {
URL_ROOT: './',
VERSION: '0.19.0',
COLLAPSE_INDEX: false,
FILE_SUFFIX: '.html',
HAS_SOURCE: true
};
</script>
<script type="text/javascript" src="_static/jquery.js"></script>
<script type="text/javascript" src="_static/underscore.js"></script>
<script type="text/javascript" src="_static/doctools.js"></script>
<link rel="index" title="Index" href="genindex.html" />
<link rel="search" title="Search" href="search.html" />
<link rel="top" title="Eventlet 0.19.0 documentation" href="index.html" />
<link rel="next" title="Using SSL With Eventlet" href="ssl.html" />
<link rel="prev" title="Greening The World" href="patching.html" />
</head>
<body role="document">
<div class="related" role="navigation" aria-label="related navigation">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="genindex.html" title="General Index"
accesskey="I">index</a></li>
<li class="right" >
<a href="py-modindex.html" title="Python Module Index"
>modules</a> |</li>
<li class="right" >
<a href="ssl.html" title="Using SSL With Eventlet"
accesskey="N">next</a> |</li>
<li class="right" >
<a href="patching.html" title="Greening The World"
accesskey="P">previous</a> |</li>
<li class="nav-item nav-item-0"><a href="index.html">Eventlet 0.19.0 documentation</a> »</li>
</ul>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body" role="main">
<div class="section" id="examples">
<h1>Examples<a class="headerlink" href="#examples" title="Permalink to this headline">¶</a></h1>
<p>Here are a bunch of small example programs that use Eventlet. All of these examples can be found in the <code class="docutils literal"><span class="pre">examples</span></code> directory of a source copy of Eventlet.</p>
<div class="section" id="web-crawler">
<span id="web-crawler-example"></span><h2>Web Crawler<a class="headerlink" href="#web-crawler" title="Permalink to this headline">¶</a></h2>
<p><code class="docutils literal"><span class="pre">examples/webcrawler.py</span></code></p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="ch">#!/usr/bin/env python</span>
<span class="sd">"""</span>
<span class="sd">This is a simple web "crawler" that fetches a bunch of urls using a pool to</span>
<span class="sd">control the number of outbound connections. It has as many simultaneously open</span>
<span class="sd">connections as coroutines in the pool.</span>
<span class="sd">The prints in the body of the fetch function are there to demonstrate that the</span>
<span class="sd">requests are truly made in parallel.</span>
<span class="sd">"""</span>
<span class="kn">import</span> <span class="nn">eventlet</span>
<span class="kn">from</span> <span class="nn">eventlet.green</span> <span class="k">import</span> <span class="n">urllib2</span>
<span class="n">urls</span> <span class="o">=</span> <span class="p">[</span>
<span class="s2">"https://www.google.com/intl/en_ALL/images/logo.gif"</span><span class="p">,</span>
<span class="s2">"http://python.org/images/python-logo.gif"</span><span class="p">,</span>
<span class="s2">"http://us.i1.yimg.com/us.yimg.com/i/ww/beta/y3.gif"</span><span class="p">,</span>
<span class="p">]</span>
<span class="k">def</span> <span class="nf">fetch</span><span class="p">(</span><span class="n">url</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"opening"</span><span class="p">,</span> <span class="n">url</span><span class="p">)</span>
<span class="n">body</span> <span class="o">=</span> <span class="n">urllib2</span><span class="o">.</span><span class="n">urlopen</span><span class="p">(</span><span class="n">url</span><span class="p">)</span><span class="o">.</span><span class="n">read</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"done with"</span><span class="p">,</span> <span class="n">url</span><span class="p">)</span>
<span class="k">return</span> <span class="n">url</span><span class="p">,</span> <span class="n">body</span>
<span class="n">pool</span> <span class="o">=</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">GreenPool</span><span class="p">(</span><span class="mi">200</span><span class="p">)</span>
<span class="k">for</span> <span class="n">url</span><span class="p">,</span> <span class="n">body</span> <span class="ow">in</span> <span class="n">pool</span><span class="o">.</span><span class="n">imap</span><span class="p">(</span><span class="n">fetch</span><span class="p">,</span> <span class="n">urls</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"got body from"</span><span class="p">,</span> <span class="n">url</span><span class="p">,</span> <span class="s2">"of length"</span><span class="p">,</span> <span class="nb">len</span><span class="p">(</span><span class="n">body</span><span class="p">))</span>
</pre></div>
</div>
</div>
<div class="section" id="wsgi-server">
<span id="wsgi-server-example"></span><h2>WSGI Server<a class="headerlink" href="#wsgi-server" title="Permalink to this headline">¶</a></h2>
<p><code class="docutils literal"><span class="pre">examples/wsgi.py</span></code></p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="sd">"""This is a simple example of running a wsgi application with eventlet.</span>
<span class="sd">For a more fully-featured server which supports multiple processes,</span>
<span class="sd">multiple threads, and graceful code reloading, see:</span>
<span class="sd">http://pypi.python.org/pypi/Spawning/</span>
<span class="sd">"""</span>
<span class="kn">import</span> <span class="nn">eventlet</span>
<span class="kn">from</span> <span class="nn">eventlet</span> <span class="k">import</span> <span class="n">wsgi</span>
<span class="k">def</span> <span class="nf">hello_world</span><span class="p">(</span><span class="n">env</span><span class="p">,</span> <span class="n">start_response</span><span class="p">):</span>
<span class="k">if</span> <span class="n">env</span><span class="p">[</span><span class="s1">'PATH_INFO'</span><span class="p">]</span> <span class="o">!=</span> <span class="s1">'/'</span><span class="p">:</span>
<span class="n">start_response</span><span class="p">(</span><span class="s1">'404 Not Found'</span><span class="p">,</span> <span class="p">[(</span><span class="s1">'Content-Type'</span><span class="p">,</span> <span class="s1">'text/plain'</span><span class="p">)])</span>
<span class="k">return</span> <span class="p">[</span><span class="s1">'Not Found</span><span class="se">\r\n</span><span class="s1">'</span><span class="p">]</span>
<span class="n">start_response</span><span class="p">(</span><span class="s1">'200 OK'</span><span class="p">,</span> <span class="p">[(</span><span class="s1">'Content-Type'</span><span class="p">,</span> <span class="s1">'text/plain'</span><span class="p">)])</span>
<span class="k">return</span> <span class="p">[</span><span class="s1">'Hello, World!</span><span class="se">\r\n</span><span class="s1">'</span><span class="p">]</span>
<span class="n">wsgi</span><span class="o">.</span><span class="n">server</span><span class="p">(</span><span class="n">eventlet</span><span class="o">.</span><span class="n">listen</span><span class="p">((</span><span class="s1">''</span><span class="p">,</span> <span class="mi">8090</span><span class="p">)),</span> <span class="n">hello_world</span><span class="p">)</span>
</pre></div>
</div>
</div>
<div class="section" id="echo-server">
<span id="echo-server-example"></span><h2>Echo Server<a class="headerlink" href="#echo-server" title="Permalink to this headline">¶</a></h2>
<p><code class="docutils literal"><span class="pre">examples/echoserver.py</span></code></p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="ch">#! /usr/bin/env python</span>
<span class="sd">"""\</span>
<span class="sd">Simple server that listens on port 6000 and echos back every input to</span>
<span class="sd">the client. To try out the server, start it up by running this file.</span>
<span class="sd">Connect to it with:</span>
<span class="sd"> telnet localhost 6000</span>
<span class="sd">You terminate your connection by terminating telnet (typically Ctrl-]</span>
<span class="sd">and then 'quit')</span>
<span class="sd">"""</span>
<span class="kn">from</span> <span class="nn">__future__</span> <span class="k">import</span> <span class="n">print_function</span>
<span class="kn">import</span> <span class="nn">eventlet</span>
<span class="k">def</span> <span class="nf">handle</span><span class="p">(</span><span class="n">fd</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"client connected"</span><span class="p">)</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="c1"># pass through every non-eof line</span>
<span class="n">x</span> <span class="o">=</span> <span class="n">fd</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">x</span><span class="p">:</span>
<span class="k">break</span>
<span class="n">fd</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="n">x</span><span class="p">)</span>
<span class="n">fd</span><span class="o">.</span><span class="n">flush</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"echoed"</span><span class="p">,</span> <span class="n">x</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="s1">' '</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"client disconnected"</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"server socket listening on port 6000"</span><span class="p">)</span>
<span class="n">server</span> <span class="o">=</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">listen</span><span class="p">((</span><span class="s1">'0.0.0.0'</span><span class="p">,</span> <span class="mi">6000</span><span class="p">))</span>
<span class="n">pool</span> <span class="o">=</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">GreenPool</span><span class="p">()</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">new_sock</span><span class="p">,</span> <span class="n">address</span> <span class="o">=</span> <span class="n">server</span><span class="o">.</span><span class="n">accept</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"accepted"</span><span class="p">,</span> <span class="n">address</span><span class="p">)</span>
<span class="n">pool</span><span class="o">.</span><span class="n">spawn_n</span><span class="p">(</span><span class="n">handle</span><span class="p">,</span> <span class="n">new_sock</span><span class="o">.</span><span class="n">makefile</span><span class="p">(</span><span class="s1">'rw'</span><span class="p">))</span>
<span class="k">except</span> <span class="p">(</span><span class="ne">SystemExit</span><span class="p">,</span> <span class="ne">KeyboardInterrupt</span><span class="p">):</span>
<span class="k">break</span>
</pre></div>
</div>
</div>
<div class="section" id="socket-connect">
<span id="socket-connect-example"></span><h2>Socket Connect<a class="headerlink" href="#socket-connect" title="Permalink to this headline">¶</a></h2>
<p><code class="docutils literal"><span class="pre">examples/connect.py</span></code></p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="sd">"""Spawn multiple workers and collect their results.</span>
<span class="sd">Demonstrates how to use the eventlet.green.socket module.</span>
<span class="sd">"""</span>
<span class="kn">from</span> <span class="nn">__future__</span> <span class="k">import</span> <span class="n">print_function</span>
<span class="kn">import</span> <span class="nn">eventlet</span>
<span class="kn">from</span> <span class="nn">eventlet.green</span> <span class="k">import</span> <span class="n">socket</span>
<span class="k">def</span> <span class="nf">geturl</span><span class="p">(</span><span class="n">url</span><span class="p">):</span>
<span class="n">c</span> <span class="o">=</span> <span class="n">socket</span><span class="o">.</span><span class="n">socket</span><span class="p">()</span>
<span class="n">ip</span> <span class="o">=</span> <span class="n">socket</span><span class="o">.</span><span class="n">gethostbyname</span><span class="p">(</span><span class="n">url</span><span class="p">)</span>
<span class="n">c</span><span class="o">.</span><span class="n">connect</span><span class="p">((</span><span class="n">ip</span><span class="p">,</span> <span class="mi">80</span><span class="p">))</span>
<span class="nb">print</span><span class="p">(</span><span class="s1">'</span><span class="si">%s</span><span class="s1"> connected'</span> <span class="o">%</span> <span class="n">url</span><span class="p">)</span>
<span class="n">c</span><span class="o">.</span><span class="n">sendall</span><span class="p">(</span><span class="s1">'GET /</span><span class="se">\r\n\r\n</span><span class="s1">'</span><span class="p">)</span>
<span class="k">return</span> <span class="n">c</span><span class="o">.</span><span class="n">recv</span><span class="p">(</span><span class="mi">1024</span><span class="p">)</span>
<span class="n">urls</span> <span class="o">=</span> <span class="p">[</span><span class="s1">'www.google.com'</span><span class="p">,</span> <span class="s1">'www.yandex.ru'</span><span class="p">,</span> <span class="s1">'www.python.org'</span><span class="p">]</span>
<span class="n">pile</span> <span class="o">=</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">GreenPile</span><span class="p">()</span>
<span class="k">for</span> <span class="n">x</span> <span class="ow">in</span> <span class="n">urls</span><span class="p">:</span>
<span class="n">pile</span><span class="o">.</span><span class="n">spawn</span><span class="p">(</span><span class="n">geturl</span><span class="p">,</span> <span class="n">x</span><span class="p">)</span>
<span class="c1"># note that the pile acts as a collection of return values from the functions</span>
<span class="c1"># if any exceptions are raised by the function they'll get raised here</span>
<span class="k">for</span> <span class="n">url</span><span class="p">,</span> <span class="n">result</span> <span class="ow">in</span> <span class="nb">zip</span><span class="p">(</span><span class="n">urls</span><span class="p">,</span> <span class="n">pile</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="s1">'</span><span class="si">%s</span><span class="s1">: </span><span class="si">%s</span><span class="s1">'</span> <span class="o">%</span> <span class="p">(</span><span class="n">url</span><span class="p">,</span> <span class="nb">repr</span><span class="p">(</span><span class="n">result</span><span class="p">)[:</span><span class="mi">50</span><span class="p">]))</span>
</pre></div>
</div>
</div>
<div class="section" id="multi-user-chat-server">
<span id="chat-server-example"></span><h2>Multi-User Chat Server<a class="headerlink" href="#multi-user-chat-server" title="Permalink to this headline">¶</a></h2>
<p><code class="docutils literal"><span class="pre">examples/chat_server.py</span></code></p>
<p>This is a little different from the echo server, in that it broadcasts the
messages to all participants, not just the sender.</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">eventlet</span>
<span class="kn">from</span> <span class="nn">eventlet.green</span> <span class="k">import</span> <span class="n">socket</span>
<span class="n">PORT</span> <span class="o">=</span> <span class="mi">3001</span>
<span class="n">participants</span> <span class="o">=</span> <span class="nb">set</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">read_chat_forever</span><span class="p">(</span><span class="n">writer</span><span class="p">,</span> <span class="n">reader</span><span class="p">):</span>
<span class="n">line</span> <span class="o">=</span> <span class="n">reader</span><span class="o">.</span><span class="n">readline</span><span class="p">()</span>
<span class="k">while</span> <span class="n">line</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"Chat:"</span><span class="p">,</span> <span class="n">line</span><span class="o">.</span><span class="n">strip</span><span class="p">())</span>
<span class="k">for</span> <span class="n">p</span> <span class="ow">in</span> <span class="n">participants</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="k">if</span> <span class="n">p</span> <span class="ow">is</span> <span class="ow">not</span> <span class="n">writer</span><span class="p">:</span> <span class="c1"># Don't echo</span>
<span class="n">p</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="n">line</span><span class="p">)</span>
<span class="n">p</span><span class="o">.</span><span class="n">flush</span><span class="p">()</span>
<span class="k">except</span> <span class="n">socket</span><span class="o">.</span><span class="n">error</span> <span class="k">as</span> <span class="n">e</span><span class="p">:</span>
<span class="c1"># ignore broken pipes, they just mean the participant</span>
<span class="c1"># closed its connection already</span>
<span class="k">if</span> <span class="n">e</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">!=</span> <span class="mi">32</span><span class="p">:</span>
<span class="k">raise</span>
<span class="n">line</span> <span class="o">=</span> <span class="n">reader</span><span class="o">.</span><span class="n">readline</span><span class="p">()</span>
<span class="n">participants</span><span class="o">.</span><span class="n">remove</span><span class="p">(</span><span class="n">writer</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"Participant left chat."</span><span class="p">)</span>
<span class="k">try</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"ChatServer starting up on port </span><span class="si">%s</span><span class="s2">"</span> <span class="o">%</span> <span class="n">PORT</span><span class="p">)</span>
<span class="n">server</span> <span class="o">=</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">listen</span><span class="p">((</span><span class="s1">'0.0.0.0'</span><span class="p">,</span> <span class="n">PORT</span><span class="p">))</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="n">new_connection</span><span class="p">,</span> <span class="n">address</span> <span class="o">=</span> <span class="n">server</span><span class="o">.</span><span class="n">accept</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"Participant joined chat."</span><span class="p">)</span>
<span class="n">new_writer</span> <span class="o">=</span> <span class="n">new_connection</span><span class="o">.</span><span class="n">makefile</span><span class="p">(</span><span class="s1">'w'</span><span class="p">)</span>
<span class="n">participants</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">new_writer</span><span class="p">)</span>
<span class="n">eventlet</span><span class="o">.</span><span class="n">spawn_n</span><span class="p">(</span><span class="n">read_chat_forever</span><span class="p">,</span>
<span class="n">new_writer</span><span class="p">,</span>
<span class="n">new_connection</span><span class="o">.</span><span class="n">makefile</span><span class="p">(</span><span class="s1">'r'</span><span class="p">))</span>
<span class="k">except</span> <span class="p">(</span><span class="ne">KeyboardInterrupt</span><span class="p">,</span> <span class="ne">SystemExit</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"ChatServer exiting."</span><span class="p">)</span>
</pre></div>
</div>
</div>
<div class="section" id="feed-scraper">
<span id="feed-scraper-example"></span><h2>Feed Scraper<a class="headerlink" href="#feed-scraper" title="Permalink to this headline">¶</a></h2>
<p><code class="docutils literal"><span class="pre">examples/feedscraper.py</span></code></p>
<p>This example requires <a class="reference external" href="http://www.feedparser.org/">Feedparser</a> to be installed or on the PYTHONPATH.</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="sd">"""A simple web server that accepts POSTS containing a list of feed urls,</span>
<span class="sd">and returns the titles of those feeds.</span>
<span class="sd">"""</span>
<span class="kn">import</span> <span class="nn">eventlet</span>
<span class="n">feedparser</span> <span class="o">=</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">import_patched</span><span class="p">(</span><span class="s1">'feedparser'</span><span class="p">)</span>
<span class="c1"># the pool provides a safety limit on our concurrency</span>
<span class="n">pool</span> <span class="o">=</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">GreenPool</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">fetch_title</span><span class="p">(</span><span class="n">url</span><span class="p">):</span>
<span class="n">d</span> <span class="o">=</span> <span class="n">feedparser</span><span class="o">.</span><span class="n">parse</span><span class="p">(</span><span class="n">url</span><span class="p">)</span>
<span class="k">return</span> <span class="n">d</span><span class="o">.</span><span class="n">feed</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">'title'</span><span class="p">,</span> <span class="s1">''</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">app</span><span class="p">(</span><span class="n">environ</span><span class="p">,</span> <span class="n">start_response</span><span class="p">):</span>
<span class="k">if</span> <span class="n">environ</span><span class="p">[</span><span class="s1">'REQUEST_METHOD'</span><span class="p">]</span> <span class="o">!=</span> <span class="s1">'POST'</span><span class="p">:</span>
<span class="n">start_response</span><span class="p">(</span><span class="s1">'403 Forbidden'</span><span class="p">,</span> <span class="p">[])</span>
<span class="k">return</span> <span class="p">[]</span>
<span class="c1"># the pile collects the result of a concurrent operation -- in this case,</span>
<span class="c1"># the collection of feed titles</span>
<span class="n">pile</span> <span class="o">=</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">GreenPile</span><span class="p">(</span><span class="n">pool</span><span class="p">)</span>
<span class="k">for</span> <span class="n">line</span> <span class="ow">in</span> <span class="n">environ</span><span class="p">[</span><span class="s1">'wsgi.input'</span><span class="p">]</span><span class="o">.</span><span class="n">readlines</span><span class="p">():</span>
<span class="n">url</span> <span class="o">=</span> <span class="n">line</span><span class="o">.</span><span class="n">strip</span><span class="p">()</span>
<span class="k">if</span> <span class="n">url</span><span class="p">:</span>
<span class="n">pile</span><span class="o">.</span><span class="n">spawn</span><span class="p">(</span><span class="n">fetch_title</span><span class="p">,</span> <span class="n">url</span><span class="p">)</span>
<span class="c1"># since the pile is an iterator over the results,</span>
<span class="c1"># you can use it in all sorts of great Pythonic ways</span>
<span class="n">titles</span> <span class="o">=</span> <span class="s1">'</span><span class="se">\n</span><span class="s1">'</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">pile</span><span class="p">)</span>
<span class="n">start_response</span><span class="p">(</span><span class="s1">'200 OK'</span><span class="p">,</span> <span class="p">[(</span><span class="s1">'Content-type'</span><span class="p">,</span> <span class="s1">'text/plain'</span><span class="p">)])</span>
<span class="k">return</span> <span class="p">[</span><span class="n">titles</span><span class="p">]</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s1">'__main__'</span><span class="p">:</span>
<span class="kn">from</span> <span class="nn">eventlet</span> <span class="k">import</span> <span class="n">wsgi</span>
<span class="n">wsgi</span><span class="o">.</span><span class="n">server</span><span class="p">(</span><span class="n">eventlet</span><span class="o">.</span><span class="n">listen</span><span class="p">((</span><span class="s1">'localhost'</span><span class="p">,</span> <span class="mi">9010</span><span class="p">)),</span> <span class="n">app</span><span class="p">)</span>
</pre></div>
</div>
</div>
<div class="section" id="port-forwarder">
<span id="forwarder-example"></span><h2>Port Forwarder<a class="headerlink" href="#port-forwarder" title="Permalink to this headline">¶</a></h2>
<p><code class="docutils literal"><span class="pre">examples/forwarder.py</span></code></p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="sd">""" This is an incredibly simple port forwarder from port 7000 to 22 on</span>
<span class="sd">localhost. It calls a callback function when the socket is closed, to</span>
<span class="sd">demonstrate one way that you could start to do interesting things by</span>
<span class="sd">starting from a simple framework like this.</span>
<span class="sd">"""</span>
<span class="kn">import</span> <span class="nn">eventlet</span>
<span class="k">def</span> <span class="nf">closed_callback</span><span class="p">():</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"called back"</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">forward</span><span class="p">(</span><span class="n">source</span><span class="p">,</span> <span class="n">dest</span><span class="p">,</span> <span class="n">cb</span><span class="o">=</span><span class="k">lambda</span><span class="p">:</span> <span class="kc">None</span><span class="p">):</span>
<span class="sd">"""Forwards bytes unidirectionally from source to dest"""</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="n">d</span> <span class="o">=</span> <span class="n">source</span><span class="o">.</span><span class="n">recv</span><span class="p">(</span><span class="mi">32384</span><span class="p">)</span>
<span class="k">if</span> <span class="n">d</span> <span class="o">==</span> <span class="s1">''</span><span class="p">:</span>
<span class="n">cb</span><span class="p">()</span>
<span class="k">break</span>
<span class="n">dest</span><span class="o">.</span><span class="n">sendall</span><span class="p">(</span><span class="n">d</span><span class="p">)</span>
<span class="n">listener</span> <span class="o">=</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">listen</span><span class="p">((</span><span class="s1">'localhost'</span><span class="p">,</span> <span class="mi">7000</span><span class="p">))</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="n">client</span><span class="p">,</span> <span class="n">addr</span> <span class="o">=</span> <span class="n">listener</span><span class="o">.</span><span class="n">accept</span><span class="p">()</span>
<span class="n">server</span> <span class="o">=</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">connect</span><span class="p">((</span><span class="s1">'localhost'</span><span class="p">,</span> <span class="mi">22</span><span class="p">))</span>
<span class="c1"># two unidirectional forwarders make a bidirectional one</span>
<span class="n">eventlet</span><span class="o">.</span><span class="n">spawn_n</span><span class="p">(</span><span class="n">forward</span><span class="p">,</span> <span class="n">client</span><span class="p">,</span> <span class="n">server</span><span class="p">,</span> <span class="n">closed_callback</span><span class="p">)</span>
<span class="n">eventlet</span><span class="o">.</span><span class="n">spawn_n</span><span class="p">(</span><span class="n">forward</span><span class="p">,</span> <span class="n">server</span><span class="p">,</span> <span class="n">client</span><span class="p">)</span>
</pre></div>
</div>
</div>
<div class="section" id="recursive-web-crawler">
<span id="recursive-crawler-example"></span><h2>Recursive Web Crawler<a class="headerlink" href="#recursive-web-crawler" title="Permalink to this headline">¶</a></h2>
<p><code class="docutils literal"><span class="pre">examples/recursive_crawler.py</span></code></p>
<p>This is an example recursive web crawler that fetches linked pages from a seed url.</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="sd">"""This is a recursive web crawler. Don't go pointing this at random sites;</span>
<span class="sd">it doesn't respect robots.txt and it is pretty brutal about how quickly it</span>
<span class="sd">fetches pages.</span>
<span class="sd">The code for this is very short; this is perhaps a good indication</span>
<span class="sd">that this is making the most effective use of the primitves at hand.</span>
<span class="sd">The fetch function does all the work of making http requests,</span>
<span class="sd">searching for new urls, and dispatching new fetches. The GreenPool</span>
<span class="sd">acts as sort of a job coordinator (and concurrency controller of</span>
<span class="sd">course).</span>
<span class="sd">"""</span>
<span class="kn">from</span> <span class="nn">__future__</span> <span class="k">import</span> <span class="n">with_statement</span>
<span class="kn">from</span> <span class="nn">eventlet.green</span> <span class="k">import</span> <span class="n">urllib2</span>
<span class="kn">import</span> <span class="nn">eventlet</span>
<span class="kn">import</span> <span class="nn">re</span>
<span class="c1"># http://daringfireball.net/2009/11/liberal_regex_for_matching_urls</span>
<span class="n">url_regex</span> <span class="o">=</span> <span class="n">re</span><span class="o">.</span><span class="n">compile</span><span class="p">(</span><span class="sa">r</span><span class="s1">'\b(([\w-]+://?|www[.])[^\s()<>]+(?:\([\w\d]+\)|([^[:punct:]\s]|/)))'</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">fetch</span><span class="p">(</span><span class="n">url</span><span class="p">,</span> <span class="n">seen</span><span class="p">,</span> <span class="n">pool</span><span class="p">):</span>
<span class="sd">"""Fetch a url, stick any found urls into the seen set, and</span>
<span class="sd"> dispatch any new ones to the pool."""</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"fetching"</span><span class="p">,</span> <span class="n">url</span><span class="p">)</span>
<span class="n">data</span> <span class="o">=</span> <span class="s1">''</span>
<span class="k">with</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">Timeout</span><span class="p">(</span><span class="mi">5</span><span class="p">,</span> <span class="kc">False</span><span class="p">):</span>
<span class="n">data</span> <span class="o">=</span> <span class="n">urllib2</span><span class="o">.</span><span class="n">urlopen</span><span class="p">(</span><span class="n">url</span><span class="p">)</span><span class="o">.</span><span class="n">read</span><span class="p">()</span>
<span class="k">for</span> <span class="n">url_match</span> <span class="ow">in</span> <span class="n">url_regex</span><span class="o">.</span><span class="n">finditer</span><span class="p">(</span><span class="n">data</span><span class="p">):</span>
<span class="n">new_url</span> <span class="o">=</span> <span class="n">url_match</span><span class="o">.</span><span class="n">group</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span>
<span class="c1"># only send requests to eventlet.net so as not to destroy the internet</span>
<span class="k">if</span> <span class="n">new_url</span> <span class="ow">not</span> <span class="ow">in</span> <span class="n">seen</span> <span class="ow">and</span> <span class="s1">'eventlet.net'</span> <span class="ow">in</span> <span class="n">new_url</span><span class="p">:</span>
<span class="n">seen</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">new_url</span><span class="p">)</span>
<span class="c1"># while this seems stack-recursive, it's actually not:</span>
<span class="c1"># spawned greenthreads start their own stacks</span>
<span class="n">pool</span><span class="o">.</span><span class="n">spawn_n</span><span class="p">(</span><span class="n">fetch</span><span class="p">,</span> <span class="n">new_url</span><span class="p">,</span> <span class="n">seen</span><span class="p">,</span> <span class="n">pool</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">crawl</span><span class="p">(</span><span class="n">start_url</span><span class="p">):</span>
<span class="sd">"""Recursively crawl starting from *start_url*. Returns a set of</span>
<span class="sd"> urls that were found."""</span>
<span class="n">pool</span> <span class="o">=</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">GreenPool</span><span class="p">()</span>
<span class="n">seen</span> <span class="o">=</span> <span class="nb">set</span><span class="p">()</span>
<span class="n">fetch</span><span class="p">(</span><span class="n">start_url</span><span class="p">,</span> <span class="n">seen</span><span class="p">,</span> <span class="n">pool</span><span class="p">)</span>
<span class="n">pool</span><span class="o">.</span><span class="n">waitall</span><span class="p">()</span>
<span class="k">return</span> <span class="n">seen</span>
<span class="n">seen</span> <span class="o">=</span> <span class="n">crawl</span><span class="p">(</span><span class="s2">"http://eventlet.net"</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"I saw these urls:"</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"</span><span class="se">\n</span><span class="s2">"</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">seen</span><span class="p">))</span>
</pre></div>
</div>
</div>
<div class="section" id="producer-consumer-web-crawler">
<span id="producer-consumer-example"></span><h2>Producer Consumer Web Crawler<a class="headerlink" href="#producer-consumer-web-crawler" title="Permalink to this headline">¶</a></h2>
<p><code class="docutils literal"><span class="pre">examples/producer_consumer.py</span></code></p>
<p>This is an example implementation of the producer/consumer pattern as well as being identical in functionality to the recursive web crawler.</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="sd">"""This is a recursive web crawler. Don't go pointing this at random sites;</span>
<span class="sd">it doesn't respect robots.txt and it is pretty brutal about how quickly it</span>
<span class="sd">fetches pages.</span>
<span class="sd">This is a kind of "producer/consumer" example; the fetch function produces</span>
<span class="sd">jobs, and the GreenPool itself is the consumer, farming out work concurrently.</span>
<span class="sd">It's easier to write it this way rather than writing a standard consumer loop;</span>
<span class="sd">GreenPool handles any exceptions raised and arranges so that there's a set</span>
<span class="sd">number of "workers", so you don't have to write that tedious management code</span>
<span class="sd">yourself.</span>
<span class="sd">"""</span>
<span class="kn">from</span> <span class="nn">__future__</span> <span class="k">import</span> <span class="n">with_statement</span>
<span class="kn">from</span> <span class="nn">eventlet.green</span> <span class="k">import</span> <span class="n">urllib2</span>
<span class="kn">import</span> <span class="nn">eventlet</span>
<span class="kn">import</span> <span class="nn">re</span>
<span class="c1"># http://daringfireball.net/2009/11/liberal_regex_for_matching_urls</span>
<span class="n">url_regex</span> <span class="o">=</span> <span class="n">re</span><span class="o">.</span><span class="n">compile</span><span class="p">(</span><span class="sa">r</span><span class="s1">'\b(([\w-]+://?|www[.])[^\s()<>]+(?:\([\w\d]+\)|([^[:punct:]\s]|/)))'</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">fetch</span><span class="p">(</span><span class="n">url</span><span class="p">,</span> <span class="n">outq</span><span class="p">):</span>
<span class="sd">"""Fetch a url and push any urls found into a queue."""</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"fetching"</span><span class="p">,</span> <span class="n">url</span><span class="p">)</span>
<span class="n">data</span> <span class="o">=</span> <span class="s1">''</span>
<span class="k">with</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">Timeout</span><span class="p">(</span><span class="mi">5</span><span class="p">,</span> <span class="kc">False</span><span class="p">):</span>
<span class="n">data</span> <span class="o">=</span> <span class="n">urllib2</span><span class="o">.</span><span class="n">urlopen</span><span class="p">(</span><span class="n">url</span><span class="p">)</span><span class="o">.</span><span class="n">read</span><span class="p">()</span>
<span class="k">for</span> <span class="n">url_match</span> <span class="ow">in</span> <span class="n">url_regex</span><span class="o">.</span><span class="n">finditer</span><span class="p">(</span><span class="n">data</span><span class="p">):</span>
<span class="n">new_url</span> <span class="o">=</span> <span class="n">url_match</span><span class="o">.</span><span class="n">group</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span>
<span class="n">outq</span><span class="o">.</span><span class="n">put</span><span class="p">(</span><span class="n">new_url</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">producer</span><span class="p">(</span><span class="n">start_url</span><span class="p">):</span>
<span class="sd">"""Recursively crawl starting from *start_url*. Returns a set of</span>
<span class="sd"> urls that were found."""</span>
<span class="n">pool</span> <span class="o">=</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">GreenPool</span><span class="p">()</span>
<span class="n">seen</span> <span class="o">=</span> <span class="nb">set</span><span class="p">()</span>
<span class="n">q</span> <span class="o">=</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">Queue</span><span class="p">()</span>
<span class="n">q</span><span class="o">.</span><span class="n">put</span><span class="p">(</span><span class="n">start_url</span><span class="p">)</span>
<span class="c1"># keep looping if there are new urls, or workers that may produce more urls</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="k">while</span> <span class="ow">not</span> <span class="n">q</span><span class="o">.</span><span class="n">empty</span><span class="p">():</span>
<span class="n">url</span> <span class="o">=</span> <span class="n">q</span><span class="o">.</span><span class="n">get</span><span class="p">()</span>
<span class="c1"># limit requests to eventlet.net so we don't crash all over the internet</span>
<span class="k">if</span> <span class="n">url</span> <span class="ow">not</span> <span class="ow">in</span> <span class="n">seen</span> <span class="ow">and</span> <span class="s1">'eventlet.net'</span> <span class="ow">in</span> <span class="n">url</span><span class="p">:</span>
<span class="n">seen</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">url</span><span class="p">)</span>
<span class="n">pool</span><span class="o">.</span><span class="n">spawn_n</span><span class="p">(</span><span class="n">fetch</span><span class="p">,</span> <span class="n">url</span><span class="p">,</span> <span class="n">q</span><span class="p">)</span>
<span class="n">pool</span><span class="o">.</span><span class="n">waitall</span><span class="p">()</span>
<span class="k">if</span> <span class="n">q</span><span class="o">.</span><span class="n">empty</span><span class="p">():</span>
<span class="k">break</span>
<span class="k">return</span> <span class="n">seen</span>
<span class="n">seen</span> <span class="o">=</span> <span class="n">producer</span><span class="p">(</span><span class="s2">"http://eventlet.net"</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"I saw these urls:"</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"</span><span class="se">\n</span><span class="s2">"</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">seen</span><span class="p">))</span>
</pre></div>
</div>
</div>
<div class="section" id="websocket-server-example">
<span id="websocket-example"></span><h2>Websocket Server Example<a class="headerlink" href="#websocket-server-example" title="Permalink to this headline">¶</a></h2>
<p><code class="docutils literal"><span class="pre">examples/websocket.py</span></code></p>
<p>This exercises some of the features of the websocket server
implementation.</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">eventlet</span>
<span class="kn">from</span> <span class="nn">eventlet</span> <span class="k">import</span> <span class="n">wsgi</span>
<span class="kn">from</span> <span class="nn">eventlet</span> <span class="k">import</span> <span class="n">websocket</span>
<span class="kn">from</span> <span class="nn">eventlet.support</span> <span class="k">import</span> <span class="n">six</span>
<span class="c1"># demo app</span>
<span class="kn">import</span> <span class="nn">os</span>
<span class="kn">import</span> <span class="nn">random</span>
<span class="nd">@websocket</span><span class="o">.</span><span class="n">WebSocketWSGI</span>
<span class="k">def</span> <span class="nf">handle</span><span class="p">(</span><span class="n">ws</span><span class="p">):</span>
<span class="sd">""" This is the websocket handler function. Note that we</span>
<span class="sd"> can dispatch based on path in here, too."""</span>
<span class="k">if</span> <span class="n">ws</span><span class="o">.</span><span class="n">path</span> <span class="o">==</span> <span class="s1">'/echo'</span><span class="p">:</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="n">m</span> <span class="o">=</span> <span class="n">ws</span><span class="o">.</span><span class="n">wait</span><span class="p">()</span>
<span class="k">if</span> <span class="n">m</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>
<span class="k">break</span>
<span class="n">ws</span><span class="o">.</span><span class="n">send</span><span class="p">(</span><span class="n">m</span><span class="p">)</span>
<span class="k">elif</span> <span class="n">ws</span><span class="o">.</span><span class="n">path</span> <span class="o">==</span> <span class="s1">'/data'</span><span class="p">:</span>
<span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="n">six</span><span class="o">.</span><span class="n">moves</span><span class="o">.</span><span class="n">range</span><span class="p">(</span><span class="mi">10000</span><span class="p">):</span>
<span class="n">ws</span><span class="o">.</span><span class="n">send</span><span class="p">(</span><span class="s2">"0 </span><span class="si">%s</span><span class="s2"> </span><span class="si">%s</span><span class="se">\n</span><span class="s2">"</span> <span class="o">%</span> <span class="p">(</span><span class="n">i</span><span class="p">,</span> <span class="n">random</span><span class="o">.</span><span class="n">random</span><span class="p">()))</span>
<span class="n">eventlet</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">0.1</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">dispatch</span><span class="p">(</span><span class="n">environ</span><span class="p">,</span> <span class="n">start_response</span><span class="p">):</span>
<span class="sd">""" This resolves to the web page or the websocket depending on</span>
<span class="sd"> the path."""</span>
<span class="k">if</span> <span class="n">environ</span><span class="p">[</span><span class="s1">'PATH_INFO'</span><span class="p">]</span> <span class="o">==</span> <span class="s1">'/data'</span><span class="p">:</span>
<span class="k">return</span> <span class="n">handle</span><span class="p">(</span><span class="n">environ</span><span class="p">,</span> <span class="n">start_response</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">start_response</span><span class="p">(</span><span class="s1">'200 OK'</span><span class="p">,</span> <span class="p">[(</span><span class="s1">'content-type'</span><span class="p">,</span> <span class="s1">'text/html'</span><span class="p">)])</span>
<span class="k">return</span> <span class="p">[</span><span class="nb">open</span><span class="p">(</span><span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">join</span><span class="p">(</span>
<span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">dirname</span><span class="p">(</span><span class="vm">__file__</span><span class="p">),</span>
<span class="s1">'websocket.html'</span><span class="p">))</span><span class="o">.</span><span class="n">read</span><span class="p">()]</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s2">"__main__"</span><span class="p">:</span>
<span class="c1"># run an example app from the command line</span>
<span class="n">listener</span> <span class="o">=</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">listen</span><span class="p">((</span><span class="s1">'127.0.0.1'</span><span class="p">,</span> <span class="mi">7000</span><span class="p">))</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"</span><span class="se">\n</span><span class="s2">Visit http://localhost:7000/ in your websocket-capable browser.</span><span class="se">\n</span><span class="s2">"</span><span class="p">)</span>
<span class="n">wsgi</span><span class="o">.</span><span class="n">server</span><span class="p">(</span><span class="n">listener</span><span class="p">,</span> <span class="n">dispatch</span><span class="p">)</span>
</pre></div>
</div>
</div>
<div class="section" id="websocket-multi-user-chat-example">
<span id="websocket-chat-example"></span><h2>Websocket Multi-User Chat Example<a class="headerlink" href="#websocket-multi-user-chat-example" title="Permalink to this headline">¶</a></h2>
<p><code class="docutils literal"><span class="pre">examples/websocket_chat.py</span></code></p>
<p>This is a mashup of the websocket example and the multi-user chat example, showing how you can do the same sorts of things with websockets that you can do with regular sockets.</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">os</span>
<span class="kn">import</span> <span class="nn">eventlet</span>
<span class="kn">from</span> <span class="nn">eventlet</span> <span class="k">import</span> <span class="n">wsgi</span>
<span class="kn">from</span> <span class="nn">eventlet</span> <span class="k">import</span> <span class="n">websocket</span>
<span class="n">PORT</span> <span class="o">=</span> <span class="mi">7000</span>
<span class="n">participants</span> <span class="o">=</span> <span class="nb">set</span><span class="p">()</span>
<span class="nd">@websocket</span><span class="o">.</span><span class="n">WebSocketWSGI</span>
<span class="k">def</span> <span class="nf">handle</span><span class="p">(</span><span class="n">ws</span><span class="p">):</span>
<span class="n">participants</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">ws</span><span class="p">)</span>
<span class="k">try</span><span class="p">:</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="n">m</span> <span class="o">=</span> <span class="n">ws</span><span class="o">.</span><span class="n">wait</span><span class="p">()</span>
<span class="k">if</span> <span class="n">m</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>
<span class="k">break</span>
<span class="k">for</span> <span class="n">p</span> <span class="ow">in</span> <span class="n">participants</span><span class="p">:</span>
<span class="n">p</span><span class="o">.</span><span class="n">send</span><span class="p">(</span><span class="n">m</span><span class="p">)</span>
<span class="k">finally</span><span class="p">:</span>
<span class="n">participants</span><span class="o">.</span><span class="n">remove</span><span class="p">(</span><span class="n">ws</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">dispatch</span><span class="p">(</span><span class="n">environ</span><span class="p">,</span> <span class="n">start_response</span><span class="p">):</span>
<span class="sd">"""Resolves to the web page or the websocket depending on the path."""</span>
<span class="k">if</span> <span class="n">environ</span><span class="p">[</span><span class="s1">'PATH_INFO'</span><span class="p">]</span> <span class="o">==</span> <span class="s1">'/chat'</span><span class="p">:</span>
<span class="k">return</span> <span class="n">handle</span><span class="p">(</span><span class="n">environ</span><span class="p">,</span> <span class="n">start_response</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">start_response</span><span class="p">(</span><span class="s1">'200 OK'</span><span class="p">,</span> <span class="p">[(</span><span class="s1">'content-type'</span><span class="p">,</span> <span class="s1">'text/html'</span><span class="p">)])</span>
<span class="n">html_path</span> <span class="o">=</span> <span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">dirname</span><span class="p">(</span><span class="vm">__file__</span><span class="p">),</span> <span class="s1">'websocket_chat.html'</span><span class="p">)</span>
<span class="k">return</span> <span class="p">[</span><span class="nb">open</span><span class="p">(</span><span class="n">html_path</span><span class="p">)</span><span class="o">.</span><span class="n">read</span><span class="p">()</span> <span class="o">%</span> <span class="p">{</span><span class="s1">'port'</span><span class="p">:</span> <span class="n">PORT</span><span class="p">}]</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s2">"__main__"</span><span class="p">:</span>
<span class="c1"># run an example app from the command line</span>
<span class="n">listener</span> <span class="o">=</span> <span class="n">eventlet</span><span class="o">.</span><span class="n">listen</span><span class="p">((</span><span class="s1">'127.0.0.1'</span><span class="p">,</span> <span class="n">PORT</span><span class="p">))</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"</span><span class="se">\n</span><span class="s2">Visit http://localhost:7000/ in your websocket-capable browser.</span><span class="se">\n</span><span class="s2">"</span><span class="p">)</span>
<span class="n">wsgi</span><span class="o">.</span><span class="n">server</span><span class="p">(</span><span class="n">listener</span><span class="p">,</span> <span class="n">dispatch</span><span class="p">)</span>
</pre></div>
</div>
</div>
</div>
</div>
</div>
</div>
<div class="sphinxsidebar" role="navigation" aria-label="main navigation">
<div class="sphinxsidebarwrapper">
<h3><a href="index.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Examples</a><ul>
<li><a class="reference internal" href="#web-crawler">Web Crawler</a></li>
<li><a class="reference internal" href="#wsgi-server">WSGI Server</a></li>
<li><a class="reference internal" href="#echo-server">Echo Server</a></li>
<li><a class="reference internal" href="#socket-connect">Socket Connect</a></li>
<li><a class="reference internal" href="#multi-user-chat-server">Multi-User Chat Server</a></li>
<li><a class="reference internal" href="#feed-scraper">Feed Scraper</a></li>
<li><a class="reference internal" href="#port-forwarder">Port Forwarder</a></li>
<li><a class="reference internal" href="#recursive-web-crawler">Recursive Web Crawler</a></li>
<li><a class="reference internal" href="#producer-consumer-web-crawler">Producer Consumer Web Crawler</a></li>
<li><a class="reference internal" href="#websocket-server-example">Websocket Server Example</a></li>
<li><a class="reference internal" href="#websocket-multi-user-chat-example">Websocket Multi-User Chat Example</a></li>
</ul>
</li>
</ul>
<h4>Previous topic</h4>
<p class="topless"><a href="patching.html"
title="previous chapter">Greening The World</a></p>
<h4>Next topic</h4>
<p class="topless"><a href="ssl.html"
title="next chapter">Using SSL With Eventlet</a></p>
<div role="note" aria-label="source link">
<h3>This Page</h3>
<ul class="this-page-menu">
<li><a href="_sources/examples.txt"
rel="nofollow">Show Source</a></li>
</ul>
</div>
<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>
<div class="clearer"></div>
</div>
<div class="related" role="navigation" aria-label="related navigation">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="genindex.html" title="General Index"
>index</a></li>
<li class="right" >
<a href="py-modindex.html" title="Python Module Index"
>modules</a> |</li>
<li class="right" >
<a href="ssl.html" title="Using SSL With Eventlet"
>next</a> |</li>
<li class="right" >
<a href="patching.html" title="Greening The World"
>previous</a> |</li>
<li class="nav-item nav-item-0"><a href="index.html">Eventlet 0.19.0 documentation</a> »</li>
</ul>
</div>
<div class="footer" role="contentinfo">
© Copyright 2005-2017, Eventlet Contributors.
Created using <a href="http://sphinx-doc.org/">Sphinx</a> 1.4.9.
</div>
<script>
(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','//www.google-analytics.com/analytics.js','ga');
ga('create', 'UA-42952223-1', 'eventlet.net');
ga('send', 'pageview');
</script>
</body>
</html>
|