/usr/share/doc/python-lxml/html/lxmlhtml.html is in python-lxml-doc 4.2.1-1.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 | <!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" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="generator" content="Docutils 0.12: http://docutils.sourceforge.net/" />
<title>lxml.html</title>
<meta name="author" content="Ian Bicking" />
<link rel="stylesheet" href="style.css" type="text/css" />
<script type="text/javascript">
function trigger_menu(event) {
var sidemenu = document.getElementById("sidemenu");
var classes = sidemenu.getAttribute("class");
classes = (classes.indexOf(" visible") === -1) ? classes + " visible" : classes.replace(" visible", "");
sidemenu.setAttribute("class", classes);
event.preventDefault();
event.stopPropagation();
}
function hide_menu() {
var sidemenu = document.getElementById("sidemenu");
var classes = sidemenu.getAttribute("class");
if (classes.indexOf(" visible") !== -1) {
sidemenu.setAttribute("class", classes.replace(" visible", ""));
}
}
</script><meta content="width=device-width, initial-scale=1" name="viewport" /></head>
<body onclick="hide_menu()">
<div class="document" id="lxml-html">
<div class="sidemenu" id="sidemenu"><div class="menutrigger" onclick="trigger_menu(event)">Menu</div><div class="menu"><ul id="lxml-section"><li><span class="section title">lxml</span><ul class="menu foreign" id="index-menu"><li class="menu title"><a href="index.html">lxml</a><ul class="submenu"><li class="menu item"><a href="index.html#introduction">Introduction</a></li><li class="menu item"><a href="index.html#support-the-project">Support the project</a></li><li class="menu item"><a href="index.html#documentation">Documentation</a></li><li class="menu item"><a href="index.html#download">Download</a></li><li class="menu item"><a href="index.html#mailing-list">Mailing list</a></li><li class="menu item"><a href="index.html#bug-tracker">Bug tracker</a></li><li class="menu item"><a href="index.html#license">License</a></li><li class="menu item"><a href="index.html#old-versions">Old Versions</a></li><li class="menu item"><a href="index.html#legal-notice-for-donations">Legal Notice for Donations</a></li></ul></li></ul><ul class="menu foreign" id="intro-menu"><li class="menu title"><a href="intro.html">Why lxml?</a><ul class="submenu"><li class="menu item"><a href="intro.html#motto">Motto</a></li><li class="menu item"><a href="intro.html#aims">Aims</a></li></ul></li></ul><ul class="menu foreign" id="installation-menu"><li class="menu title"><a href="installation.html">Installing lxml</a><ul class="submenu"><li class="menu item"><a href="installation.html#where-to-get-it">Where to get it</a></li><li class="menu item"><a href="installation.html#requirements">Requirements</a></li><li class="menu item"><a href="installation.html#installation">Installation</a></li><li class="menu item"><a href="installation.html#building-lxml-from-dev-sources">Building lxml from dev sources</a></li><li class="menu item"><a href="installation.html#using-lxml-with-python-libxml2">Using lxml with python-libxml2</a></li><li class="menu item"><a href="installation.html#source-builds-on-ms-windows">Source builds on MS Windows</a></li><li class="menu item"><a href="installation.html#source-builds-on-macos-x">Source builds on MacOS-X</a></li></ul></li></ul><ul class="menu foreign" id="performance-menu"><li class="menu title"><a href="performance.html">Benchmarks and Speed</a><ul class="submenu"><li class="menu item"><a href="performance.html#general-notes">General notes</a></li><li class="menu item"><a href="performance.html#how-to-read-the-timings">How to read the timings</a></li><li class="menu item"><a href="performance.html#parsing-and-serialising">Parsing and Serialising</a></li><li class="menu item"><a href="performance.html#the-elementtree-api">The ElementTree API</a></li><li class="menu item"><a href="performance.html#xpath">XPath</a></li><li class="menu item"><a href="performance.html#a-longer-example">A longer example</a></li><li class="menu item"><a href="performance.html#lxml-objectify">lxml.objectify</a></li></ul></li></ul><ul class="menu foreign" id="compatibility-menu"><li class="menu title"><a href="compatibility.html">ElementTree compatibility of lxml.etree</a></li></ul><ul class="menu foreign" id="FAQ-menu"><li class="menu title"><a href="FAQ.html">lxml FAQ - Frequently Asked Questions</a><ul class="submenu"><li class="menu item"><a href="FAQ.html#general-questions">General Questions</a></li><li class="menu item"><a href="FAQ.html#installation">Installation</a></li><li class="menu item"><a href="FAQ.html#contributing">Contributing</a></li><li class="menu item"><a href="FAQ.html#bugs">Bugs</a></li><li class="menu item"><a href="FAQ.html#id1">Threading</a></li><li class="menu item"><a href="FAQ.html#parsing-and-serialisation">Parsing and Serialisation</a></li><li class="menu item"><a href="FAQ.html#xpath-and-document-traversal">XPath and Document Traversal</a></li></ul></li></ul></li></ul><ul id="Developing with lxml-section"><li><span class="section title">Developing with lxml</span><ul class="menu foreign" id="tutorial-menu"><li class="menu title"><a href="tutorial.html">The lxml.etree Tutorial</a><ul class="submenu"><li class="menu item"><a href="tutorial.html#the-element-class">The Element class</a></li><li class="menu item"><a href="tutorial.html#the-elementtree-class">The ElementTree class</a></li><li class="menu item"><a href="tutorial.html#parsing-from-strings-and-files">Parsing from strings and files</a></li><li class="menu item"><a href="tutorial.html#namespaces">Namespaces</a></li><li class="menu item"><a href="tutorial.html#the-e-factory">The E-factory</a></li><li class="menu item"><a href="tutorial.html#elementpath">ElementPath</a></li></ul></li></ul><ul class="menu foreign" id="api index-menu"><li class="menu title"><a href="api/index.html">API reference</a></li></ul><ul class="menu foreign" id="api-menu"><li class="menu title"><a href="api.html">APIs specific to lxml.etree</a><ul class="submenu"><li class="menu item"><a href="api.html#lxml-etree">lxml.etree</a></li><li class="menu item"><a href="api.html#other-element-apis">Other Element APIs</a></li><li class="menu item"><a href="api.html#trees-and-documents">Trees and Documents</a></li><li class="menu item"><a href="api.html#iteration">Iteration</a></li><li class="menu item"><a href="api.html#error-handling-on-exceptions">Error handling on exceptions</a></li><li class="menu item"><a href="api.html#error-logging">Error logging</a></li><li class="menu item"><a href="api.html#serialisation">Serialisation</a></li><li class="menu item"><a href="api.html#incremental-xml-generation">Incremental XML generation</a></li><li class="menu item"><a href="api.html#cdata">CDATA</a></li><li class="menu item"><a href="api.html#xinclude-and-elementinclude">XInclude and ElementInclude</a></li><li class="menu item"><a href="api.html#write-c14n-on-elementtree">write_c14n on ElementTree</a></li></ul></li></ul><ul class="menu foreign" id="parsing-menu"><li class="menu title"><a href="parsing.html">Parsing XML and HTML with lxml</a><ul class="submenu"><li class="menu item"><a href="parsing.html#parsers">Parsers</a></li><li class="menu item"><a href="parsing.html#the-target-parser-interface">The target parser interface</a></li><li class="menu item"><a href="parsing.html#the-feed-parser-interface">The feed parser interface</a></li><li class="menu item"><a href="parsing.html#incremental-event-parsing">Incremental event parsing</a></li><li class="menu item"><a href="parsing.html#iterparse-and-iterwalk">iterparse and iterwalk</a></li><li class="menu item"><a href="parsing.html#python-unicode-strings">Python unicode strings</a></li></ul></li></ul><ul class="menu foreign" id="validation-menu"><li class="menu title"><a href="validation.html">Validation with lxml</a><ul class="submenu"><li class="menu item"><a href="validation.html#validation-at-parse-time">Validation at parse time</a></li><li class="menu item"><a href="validation.html#id1">DTD</a></li><li class="menu item"><a href="validation.html#relaxng">RelaxNG</a></li><li class="menu item"><a href="validation.html#xmlschema">XMLSchema</a></li><li class="menu item"><a href="validation.html#id2">Schematron</a></li><li class="menu item"><a href="validation.html#id3">(Pre-ISO-Schematron)</a></li></ul></li></ul><ul class="menu foreign" id="xpathxslt-menu"><li class="menu title"><a href="xpathxslt.html">XPath and XSLT with lxml</a><ul class="submenu"><li class="menu item"><a href="xpathxslt.html#xpath">XPath</a></li><li class="menu item"><a href="xpathxslt.html#xslt">XSLT</a></li></ul></li></ul><ul class="menu foreign" id="objectify-menu"><li class="menu title"><a href="objectify.html">lxml.objectify</a><ul class="submenu"><li class="menu item"><a href="objectify.html#the-lxml-objectify-api">The lxml.objectify API</a></li><li class="menu item"><a href="objectify.html#asserting-a-schema">Asserting a Schema</a></li><li class="menu item"><a href="objectify.html#objectpath">ObjectPath</a></li><li class="menu item"><a href="objectify.html#python-data-types">Python data types</a></li><li class="menu item"><a href="objectify.html#how-data-types-are-matched">How data types are matched</a></li><li class="menu item"><a href="objectify.html#what-is-different-from-lxml-etree">What is different from lxml.etree?</a></li></ul></li></ul><ul class="menu current" id="lxmlhtml-menu"><li class="menu title"><a href="lxmlhtml.html">lxml.html</a><ul class="submenu"><li class="menu item"><a href="lxmlhtml.html#parsing-html">Parsing HTML</a></li><li class="menu item"><a href="lxmlhtml.html#html-element-methods">HTML Element Methods</a></li><li class="menu item"><a href="lxmlhtml.html#running-html-doctests">Running HTML doctests</a></li><li class="menu item"><a href="lxmlhtml.html#creating-html-with-the-e-factory">Creating HTML with the E-factory</a></li><li class="menu item"><a href="lxmlhtml.html#working-with-links">Working with links</a></li><li class="menu item"><a href="lxmlhtml.html#forms">Forms</a></li><li class="menu item"><a href="lxmlhtml.html#cleaning-up-html">Cleaning up HTML</a></li><li class="menu item"><a href="lxmlhtml.html#html-diff">HTML Diff</a></li><li class="menu item"><a href="lxmlhtml.html#examples">Examples</a></li></ul></li></ul><ul class="menu foreign" id="cssselect-menu"><li class="menu title"><a href="cssselect.html">lxml.cssselect</a><ul class="submenu"><li class="menu item"><a href="cssselect.html#the-cssselector-class">The CSSSelector class</a></li><li class="menu item"><a href="cssselect.html#the-cssselect-method">The cssselect method</a></li><li class="menu item"><a href="cssselect.html#supported-selectors">Supported Selectors</a></li><li class="menu item"><a href="cssselect.html#namespaces">Namespaces</a></li></ul></li></ul><ul class="menu foreign" id="elementsoup-menu"><li class="menu title"><a href="elementsoup.html">BeautifulSoup Parser</a><ul class="submenu"><li class="menu item"><a href="elementsoup.html#parsing-with-the-soupparser">Parsing with the soupparser</a></li><li class="menu item"><a href="elementsoup.html#entity-handling">Entity handling</a></li><li class="menu item"><a href="elementsoup.html#using-soupparser-as-a-fallback">Using soupparser as a fallback</a></li><li class="menu item"><a href="elementsoup.html#using-only-the-encoding-detection">Using only the encoding detection</a></li></ul></li></ul><ul class="menu foreign" id="html5parser-menu"><li class="menu title"><a href="html5parser.html">html5lib Parser</a><ul class="submenu"><li class="menu item"><a href="html5parser.html#differences-to-regular-html-parsing">Differences to regular HTML parsing</a></li><li class="menu item"><a href="html5parser.html#function-reference">Function Reference</a></li></ul></li></ul></li></ul><ul id="Extending lxml-section"><li><span class="section title">Extending lxml</span><ul class="menu foreign" id="resolvers-menu"><li class="menu title"><a href="resolvers.html">Document loading and URL resolving</a><ul class="submenu"><li class="menu item"><a href="resolvers.html#xml-catalogs">XML Catalogs</a></li><li class="menu item"><a href="resolvers.html#uri-resolvers">URI Resolvers</a></li><li class="menu item"><a href="resolvers.html#document-loading-in-context">Document loading in context</a></li><li class="menu item"><a href="resolvers.html#i-o-access-control-in-xslt">I/O access control in XSLT</a></li></ul></li></ul><ul class="menu foreign" id="extensions-menu"><li class="menu title"><a href="extensions.html">Python extensions for XPath and XSLT</a><ul class="submenu"><li class="menu item"><a href="extensions.html#xpath-extension-functions">XPath Extension functions</a></li><li class="menu item"><a href="extensions.html#xslt-extension-elements">XSLT extension elements</a></li></ul></li></ul><ul class="menu foreign" id="element classes-menu"><li class="menu title"><a href="element_classes.html">Using custom Element classes in lxml</a><ul class="submenu"><li class="menu item"><a href="element_classes.html#background-on-element-proxies">Background on Element proxies</a></li><li class="menu item"><a href="element_classes.html#element-initialization">Element initialization</a></li><li class="menu item"><a href="element_classes.html#setting-up-a-class-lookup-scheme">Setting up a class lookup scheme</a></li><li class="menu item"><a href="element_classes.html#generating-xml-with-custom-classes">Generating XML with custom classes</a></li><li class="menu item"><a href="element_classes.html#id1">Implementing namespaces</a></li></ul></li></ul><ul class="menu foreign" id="sax-menu"><li class="menu title"><a href="sax.html">Sax support</a><ul class="submenu"><li class="menu item"><a href="sax.html#building-a-tree-from-sax-events">Building a tree from SAX events</a></li><li class="menu item"><a href="sax.html#producing-sax-events-from-an-elementtree-or-element">Producing SAX events from an ElementTree or Element</a></li><li class="menu item"><a href="sax.html#interfacing-with-pulldom-minidom">Interfacing with pulldom/minidom</a></li></ul></li></ul><ul class="menu foreign" id="capi-menu"><li class="menu title"><a href="capi.html">The public C-API of lxml.etree</a><ul class="submenu"><li class="menu item"><a href="capi.html#passing-generated-trees-through-python">Passing generated trees through Python</a></li><li class="menu item"><a href="capi.html#writing-external-modules-in-cython">Writing external modules in Cython</a></li><li class="menu item"><a href="capi.html#writing-external-modules-in-c">Writing external modules in C</a></li></ul></li></ul></li></ul><ul id="Developing lxml-section"><li><span class="section title">Developing lxml</span><ul class="menu foreign" id="build-menu"><li class="menu title"><a href="build.html">How to build lxml from source</a><ul class="submenu"><li class="menu item"><a href="build.html#cython">Cython</a></li><li class="menu item"><a href="build.html#github-git-and-hg">Github, git and hg</a></li><li class="menu item"><a href="build.html#building-the-sources">Building the sources</a></li><li class="menu item"><a href="build.html#running-the-tests-and-reporting-errors">Running the tests and reporting errors</a></li><li class="menu item"><a href="build.html#building-an-egg-or-wheel">Building an egg or wheel</a></li><li class="menu item"><a href="build.html#building-lxml-on-macos-x">Building lxml on MacOS-X</a></li><li class="menu item"><a href="build.html#static-linking-on-windows">Static linking on Windows</a></li><li class="menu item"><a href="build.html#building-debian-packages-from-svn-sources">Building Debian packages from SVN sources</a></li></ul></li></ul><ul class="menu foreign" id="lxml source howto-menu"><li class="menu title"><a href="lxml-source-howto.html">How to read the source of lxml</a><ul class="submenu"><li class="menu item"><a href="lxml-source-howto.html#what-is-cython">What is Cython?</a></li><li class="menu item"><a href="lxml-source-howto.html#where-to-start">Where to start?</a></li><li class="menu item"><a href="lxml-source-howto.html#lxml-etree">lxml.etree</a></li><li class="menu item"><a href="lxml-source-howto.html#python-modules">Python modules</a></li><li class="menu item"><a href="lxml-source-howto.html#lxml-objectify">lxml.objectify</a></li><li class="menu item"><a href="lxml-source-howto.html#lxml-html">lxml.html</a></li></ul></li></ul><ul class="menu foreign" id="changes 4 2 1-menu"><li class="menu title"><a href="changes-4.2.1.html">Release Changelog</a></li></ul><ul class="menu foreign" id="credits-menu"><li class="menu title"><a href="credits.html">Credits</a><ul class="submenu"><li class="menu item"><a href="credits.html#main-contributors">Main contributors</a></li><li class="menu item"><a href="credits.html#special-thanks-goes-to">Special thanks goes to:</a></li></ul></li></ul></li><li><a href="http://lxml.de/sitemap.html">Sitemap</a></li></ul></div></div><h1 class="title">lxml.html</h1>
<table class="docinfo" frame="void" rules="none">
<col class="docinfo-name" />
<col class="docinfo-content" />
<tbody valign="top">
<tr><th class="docinfo-name">Author:</th>
<td>Ian Bicking</td></tr>
</tbody>
</table>
<p>Since version 2.0, lxml comes with a dedicated Python package for
dealing with HTML: <tt class="docutils literal">lxml.html</tt>. It is based on lxml's HTML parser,
but provides a special Element API for HTML elements, as well as a
number of utilities for common HTML processing tasks.</p>
<div class="contents topic" id="contents">
<p class="topic-title first">Contents</p>
<ul class="simple">
<li><a class="reference internal" href="#parsing-html" id="id1">Parsing HTML</a><ul>
<li><a class="reference internal" href="#parsing-html-fragments" id="id2">Parsing HTML fragments</a></li>
<li><a class="reference internal" href="#really-broken-pages" id="id3">Really broken pages</a></li>
</ul>
</li>
<li><a class="reference internal" href="#html-element-methods" id="id4">HTML Element Methods</a></li>
<li><a class="reference internal" href="#running-html-doctests" id="id5">Running HTML doctests</a></li>
<li><a class="reference internal" href="#creating-html-with-the-e-factory" id="id6">Creating HTML with the E-factory</a><ul>
<li><a class="reference internal" href="#viewing-your-html" id="id7">Viewing your HTML</a></li>
</ul>
</li>
<li><a class="reference internal" href="#working-with-links" id="id8">Working with links</a><ul>
<li><a class="reference internal" href="#functions" id="id9">Functions</a></li>
</ul>
</li>
<li><a class="reference internal" href="#forms" id="id10">Forms</a><ul>
<li><a class="reference internal" href="#form-filling-example" id="id11">Form Filling Example</a></li>
<li><a class="reference internal" href="#form-submission" id="id12">Form Submission</a></li>
</ul>
</li>
<li><a class="reference internal" href="#cleaning-up-html" id="id13">Cleaning up HTML</a><ul>
<li><a class="reference internal" href="#autolink" id="id14">autolink</a></li>
<li><a class="reference internal" href="#wordwrap" id="id15">wordwrap</a></li>
</ul>
</li>
<li><a class="reference internal" href="#html-diff" id="id16">HTML Diff</a></li>
<li><a class="reference internal" href="#examples" id="id17">Examples</a><ul>
<li><a class="reference internal" href="#microformat-example" id="id18">Microformat Example</a></li>
</ul>
</li>
</ul>
</div>
<p>The main API is based on the <a class="reference external" href="tutorial.html">lxml.etree</a> API, and thus, on the <a class="reference external" href="http://effbot.org/zone/element-index.htm">ElementTree</a>
API.</p>
<div class="section" id="parsing-html">
<h1>Parsing HTML</h1>
<div class="section" id="parsing-html-fragments">
<h2>Parsing HTML fragments</h2>
<p>There are several functions available to parse HTML:</p>
<dl class="docutils">
<dt><tt class="docutils literal">parse(filename_url_or_file)</tt>:</dt>
<dd><p class="first">Parses the named file or url, or if the object has a <tt class="docutils literal">.read()</tt>
method, parses from that.</p>
<p class="last">If you give a URL, or if the object has a <tt class="docutils literal">.geturl()</tt> method (as
file-like objects from <tt class="docutils literal">urllib.urlopen()</tt> have), then that URL
is used as the base URL. You can also provide an explicit
<tt class="docutils literal">base_url</tt> keyword argument.</p>
</dd>
<dt><tt class="docutils literal">document_fromstring(string)</tt>:</dt>
<dd>Parses a document from the given string. This always creates a
correct HTML document, which means the parent node is <tt class="docutils literal"><html></tt>,
and there is a body and possibly a head.</dd>
<dt><tt class="docutils literal">fragment_fromstring(string, create_parent=False)</tt>:</dt>
<dd>Returns an HTML fragment from a string. The fragment must contain
just a single element, unless <tt class="docutils literal">create_parent</tt> is given;
e.g., <tt class="docutils literal">fragment_fromstring(string, <span class="pre">create_parent='div')</span></tt> will
wrap the element in a <tt class="docutils literal"><div></tt>.</dd>
<dt><tt class="docutils literal">fragments_fromstring(string)</tt>:</dt>
<dd>Returns a list of the elements found in the fragment.</dd>
<dt><tt class="docutils literal">fromstring(string)</tt>:</dt>
<dd>Returns <tt class="docutils literal">document_fromstring</tt> or <tt class="docutils literal">fragment_fromstring</tt>, based
on whether the string looks like a full document, or just a
fragment.</dd>
</dl>
</div>
<div class="section" id="really-broken-pages">
<h2>Really broken pages</h2>
<p>The normal HTML parser is capable of handling broken HTML, but for
pages that are far enough from HTML to call them 'tag soup', it may
still fail to parse the page in a useful way. A way to deal with this
is <a class="reference external" href="elementsoup.html">ElementSoup</a>, which deploys the well-known <a class="reference external" href="http://www.crummy.com/software/BeautifulSoup/">BeautifulSoup</a> parser to
build an lxml HTML tree.</p>
<p>However, note that the most common problem with web pages is the lack
of (or the existence of incorrect) encoding declarations. It is
therefore often sufficient to only use the encoding detection of
BeautifulSoup, called UnicodeDammit, and to leave the rest to lxml's
own HTML parser, which is several times faster.</p>
</div>
</div>
<div class="section" id="html-element-methods">
<h1>HTML Element Methods</h1>
<p>HTML elements have all the methods that come with ElementTree, but
also include some extra methods:</p>
<dl class="docutils">
<dt><tt class="docutils literal">.drop_tree()</tt>:</dt>
<dd>Drops the element and all its children. Unlike
<tt class="docutils literal"><span class="pre">el.getparent().remove(el)</span></tt> this does <em>not</em> remove the tail
text; with <tt class="docutils literal">drop_tree</tt> the tail text is merged with the previous
element.</dd>
<dt><tt class="docutils literal">.drop_tag()</tt>:</dt>
<dd>Drops the tag, but keeps its children and text.</dd>
<dt><tt class="docutils literal">.find_class(class_name)</tt>:</dt>
<dd>Returns a list of all the elements with the given CSS class name.
Note that class names are space separated in HTML, so
<tt class="docutils literal"><span class="pre">doc.find_class_name('highlight')</span></tt> will find an element like
<tt class="docutils literal"><div <span class="pre">class="sidebar</span> highlight"></tt>. Class names <em>are</em> case
sensitive.</dd>
<dt><tt class="docutils literal">.find_rel_links(rel)</tt>:</dt>
<dd>Returns a list of all the <tt class="docutils literal"><a <span class="pre">rel="{rel}"></span></tt> elements. E.g.,
<tt class="docutils literal"><span class="pre">doc.find_rel_links('tag')</span></tt> returns all the links <a class="reference external" href="http://microformats.org/wiki/rel-tag">marked as
tags</a>.</dd>
<dt><tt class="docutils literal">.get_element_by_id(id, default=None)</tt>:</dt>
<dd>Return the element with the given <tt class="docutils literal">id</tt>, or the <tt class="docutils literal">default</tt> if
none is found. If there are multiple elements with the same id
(which there shouldn't be, but there often is), this returns only
the first.</dd>
<dt><tt class="docutils literal">.text_content()</tt>:</dt>
<dd>Returns the text content of the element, including the text
content of its children, with no markup.</dd>
<dt><tt class="docutils literal">.cssselect(expr)</tt>:</dt>
<dd>Select elements from this element and its children, using a CSS
selector expression. (Note that <tt class="docutils literal">.xpath(expr)</tt> is also
available as on all lxml elements.)</dd>
<dt><tt class="docutils literal">.label</tt>:</dt>
<dd>Returns the corresponding <tt class="docutils literal"><label></tt> element for this element, if
any exists (None if there is none). Label elements have a
<tt class="docutils literal">label.for_element</tt> attribute that points back to the element.</dd>
<dt><tt class="docutils literal">.base_url</tt>:</dt>
<dd>The base URL for this element, if one was saved from the parsing.
This attribute is not settable. Is None when no base URL was
saved.</dd>
<dt><tt class="docutils literal">.classes</tt>:</dt>
<dd>Returns a set-like object that allows accessing and modifying the
names in the 'class' attribute of the element. (New in lxml 3.5).</dd>
<dt><tt class="docutils literal">.set(key, value=None)</tt>:</dt>
<dd>Sets an HTML attribute. If no value is given, or if the value is
<tt class="docutils literal">None</tt>, it creates a boolean attribute like <tt class="docutils literal"><form <span class="pre">novalidate></form></span></tt>
or <tt class="docutils literal"><div <span class="pre">custom-attribute></div></span></tt>. In XML, attributes must
have at least the empty string as their value like <tt class="docutils literal"><form
<span class="pre">novalidate=""></form></span></tt>, but HTML boolean attributes can also be
just present or absent from an element without having a value.</dd>
</dl>
</div>
<div class="section" id="running-html-doctests">
<h1>Running HTML doctests</h1>
<p>One of the interesting modules in the <tt class="docutils literal">lxml.html</tt> package deals with
doctests. It can be hard to compare two HTML pages for equality, as
whitespace differences aren't meaningful and the structural formatting
can differ. This is even more a problem in doctests, where output is
tested for equality and small differences in whitespace or the order
of attributes can let a test fail. And given the verbosity of
tag-based languages, it may take more than a quick look to find the
actual differences in the doctest output.</p>
<p>Luckily, lxml provides the <tt class="docutils literal">lxml.doctestcompare</tt> module that
supports relaxed comparison of XML and HTML pages and provides a
readable diff in the output when a test fails. The HTML comparison is
most easily used by importing the <tt class="docutils literal">usedoctest</tt> module in a doctest:</p>
<div class="syntax"><pre><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">lxml.html.usedoctest</span>
</pre></div>
<p>Now, if you have an HTML document and want to compare it to an expected result
document in a doctest, you can do the following:</p>
<div class="syntax"><pre><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">lxml.html</span>
<span class="gp">>>> </span><span class="n">html</span> <span class="o">=</span> <span class="n">lxml</span><span class="o">.</span><span class="n">html</span><span class="o">.</span><span class="n">fromstring</span><span class="p">(</span><span class="s1">'''</span><span class="se">\</span>
<span class="gp">... </span><span class="s1"> <html><body onload="" color="white"></span>
<span class="gp">... </span><span class="s1"> <p>Hi !</p></span>
<span class="gp">... </span><span class="s1"> </body></html></span>
<span class="gp">... </span><span class="s1">'''</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">lxml</span><span class="o">.</span><span class="n">html</span><span class="o">.</span><span class="n">tostring</span><span class="p">(</span><span class="n">html</span><span class="p">)</span>
<span class="go"><html><body onload="" color="white"><p>Hi !</p></body></html></span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">lxml</span><span class="o">.</span><span class="n">html</span><span class="o">.</span><span class="n">tostring</span><span class="p">(</span><span class="n">html</span><span class="p">)</span>
<span class="go"><html> <body color="white" onload=""> <p>Hi !</p> </body> </html></span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">lxml</span><span class="o">.</span><span class="n">html</span><span class="o">.</span><span class="n">tostring</span><span class="p">(</span><span class="n">html</span><span class="p">)</span>
<span class="go"><html></span>
<span class="go"> <body color="white" onload=""></span>
<span class="go"> <p>Hi !</p></span>
<span class="go"> </body></span>
<span class="go"></html></span>
</pre></div>
<p>In documentation, you would likely prefer the pretty printed HTML output, as
it is the most readable. However, the three documents are equivalent from the
point of view of an HTML tool, so the doctest will silently accept any of the
above. This allows you to concentrate on readability in your doctests, even
if the real output is a straight ugly HTML one-liner.</p>
<p>Note that there is also an <tt class="docutils literal">lxml.usedoctest</tt> module which you can
import for XML comparisons. The HTML parser notably ignores
namespaces and some other XMLisms.</p>
</div>
<div class="section" id="creating-html-with-the-e-factory">
<h1>Creating HTML with the E-factory</h1>
<p>lxml.html comes with a predefined HTML vocabulary for the <a class="reference external" href="http://online.effbot.org/2006_11_01_archive.htm#et-builder">E-factory</a>,
originally written by Fredrik Lundh. This allows you to quickly generate HTML
pages and fragments:</p>
<div class="syntax"><pre><span class="gp">>>> </span><span class="kn">from</span> <span class="nn">lxml.html</span> <span class="kn">import</span> <span class="n">builder</span> <span class="k">as</span> <span class="n">E</span>
<span class="gp">>>> </span><span class="kn">from</span> <span class="nn">lxml.html</span> <span class="kn">import</span> <span class="n">usedoctest</span>
<span class="gp">>>> </span><span class="n">html</span> <span class="o">=</span> <span class="n">E</span><span class="o">.</span><span class="n">HTML</span><span class="p">(</span>
<span class="gp">... </span> <span class="n">E</span><span class="o">.</span><span class="n">HEAD</span><span class="p">(</span>
<span class="gp">... </span> <span class="n">E</span><span class="o">.</span><span class="n">LINK</span><span class="p">(</span><span class="n">rel</span><span class="o">=</span><span class="s2">"stylesheet"</span><span class="p">,</span> <span class="n">href</span><span class="o">=</span><span class="s2">"great.css"</span><span class="p">,</span> <span class="nb">type</span><span class="o">=</span><span class="s2">"text/css"</span><span class="p">),</span>
<span class="gp">... </span> <span class="n">E</span><span class="o">.</span><span class="n">TITLE</span><span class="p">(</span><span class="s2">"Best Page Ever"</span><span class="p">)</span>
<span class="gp">... </span> <span class="p">),</span>
<span class="gp">... </span> <span class="n">E</span><span class="o">.</span><span class="n">BODY</span><span class="p">(</span>
<span class="gp">... </span> <span class="n">E</span><span class="o">.</span><span class="n">H1</span><span class="p">(</span><span class="n">E</span><span class="o">.</span><span class="n">CLASS</span><span class="p">(</span><span class="s2">"heading"</span><span class="p">),</span> <span class="s2">"Top News"</span><span class="p">),</span>
<span class="gp">... </span> <span class="n">E</span><span class="o">.</span><span class="n">P</span><span class="p">(</span><span class="s2">"World News only on this page"</span><span class="p">,</span> <span class="n">style</span><span class="o">=</span><span class="s2">"font-size: 200%"</span><span class="p">),</span>
<span class="gp">... </span> <span class="s2">"Ah, and here's some more text, by the way."</span><span class="p">,</span>
<span class="gp">... </span> <span class="n">lxml</span><span class="o">.</span><span class="n">html</span><span class="o">.</span><span class="n">fromstring</span><span class="p">(</span><span class="s2">"<p>... and this is a parsed fragment ...</p>"</span><span class="p">)</span>
<span class="gp">... </span> <span class="p">)</span>
<span class="gp">... </span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">lxml</span><span class="o">.</span><span class="n">html</span><span class="o">.</span><span class="n">tostring</span><span class="p">(</span><span class="n">html</span><span class="p">)</span>
<span class="go"><html></span>
<span class="go"> <head></span>
<span class="go"> <link href="great.css" rel="stylesheet" type="text/css"></span>
<span class="go"> <title>Best Page Ever</title></span>
<span class="go"> </head></span>
<span class="go"> <body></span>
<span class="go"> <h1 class="heading">Top News</h1></span>
<span class="go"> <p style="font-size: 200%">World News only on this page</p></span>
<span class="go"> Ah, and here's some more text, by the way.</span>
<span class="go"> <p>... and this is a parsed fragment ...</p></span>
<span class="go"> </body></span>
<span class="go"></html></span>
</pre></div>
<p>Note that you should use <tt class="docutils literal">lxml.html.tostring</tt> and <strong>not</strong>
<tt class="docutils literal">lxml.tostring</tt>. <tt class="docutils literal">lxml.tostring(doc)</tt> will return the XML
representation of the document, which is not valid HTML. In
particular, things like <tt class="docutils literal"><script <span class="pre">src="..."></script></span></tt> will be
serialized as <tt class="docutils literal"><script <span class="pre">src="..."</span> /></tt>, which completely confuses
browsers.</p>
<div class="section" id="viewing-your-html">
<h2>Viewing your HTML</h2>
<p>A handy method for viewing your HTML:
<tt class="docutils literal">lxml.html.open_in_browser(lxml_doc)</tt> will write the document to
disk and open it in a browser (with the <a class="reference external" href="http://python.org/doc/current/lib/module-webbrowser.html">webbrowser module</a>).</p>
</div>
</div>
<div class="section" id="working-with-links">
<h1>Working with links</h1>
<p>There are several methods on elements that allow you to see and modify
the links in a document.</p>
<dl class="docutils">
<dt><tt class="docutils literal">.iterlinks()</tt>:</dt>
<dd><p class="first">This yields <tt class="docutils literal">(element, attribute, link, pos)</tt> for every link in
the document. <tt class="docutils literal">attribute</tt> may be None if the link is in the
text (as will be the case with a <tt class="docutils literal"><style></tt> tag with
<tt class="docutils literal">@import</tt>).</p>
<p>This finds any link in an <tt class="docutils literal">action</tt>, <tt class="docutils literal">archive</tt>, <tt class="docutils literal">background</tt>,
<tt class="docutils literal">cite</tt>, <tt class="docutils literal">classid</tt>, <tt class="docutils literal">codebase</tt>, <tt class="docutils literal">data</tt>, <tt class="docutils literal">href</tt>,
<tt class="docutils literal">longdesc</tt>, <tt class="docutils literal">profile</tt>, <tt class="docutils literal">src</tt>, <tt class="docutils literal">usemap</tt>, <tt class="docutils literal">dynsrc</tt>, or
<tt class="docutils literal">lowsrc</tt> attribute. It also searches <tt class="docutils literal">style</tt> attributes for
<tt class="docutils literal">url(link)</tt>, and <tt class="docutils literal"><style></tt> tags for <tt class="docutils literal">@import</tt> and <tt class="docutils literal">url()</tt>.</p>
<p class="last">This function does <em>not</em> pay attention to <tt class="docutils literal"><base href></tt>.</p>
</dd>
<dt><tt class="docutils literal">.resolve_base_href()</tt>:</dt>
<dd>This function will modify the document in-place to take account of
<tt class="docutils literal"><base href></tt> if the document contains that tag. In the process
it will also remove that tag from the document.</dd>
<dt><tt class="docutils literal">.make_links_absolute(base_href, resolve_base_href=True)</tt>:</dt>
<dd><p class="first">This makes all links in the document absolute, assuming that
<tt class="docutils literal">base_href</tt> is the URL of the document. So if you pass
<tt class="docutils literal"><span class="pre">base_href="http://localhost/foo/bar.html"</span></tt> and there is a link
to <tt class="docutils literal">baz.html</tt> that will be rewritten as
<tt class="docutils literal"><span class="pre">http://localhost/foo/baz.html</span></tt>.</p>
<p class="last">If <tt class="docutils literal">resolve_base_href</tt> is true, then any <tt class="docutils literal"><base href></tt> tag
will be taken into account (just calling
<tt class="docutils literal">self.resolve_base_href()</tt>).</p>
</dd>
<dt><tt class="docutils literal">.rewrite_links(link_repl_func, resolve_base_href=True, base_href=None)</tt>:</dt>
<dd><p class="first">This rewrites all the links in the document using your given link
replacement function. If you give a <tt class="docutils literal">base_href</tt> value, all
links will be passed in after they are joined with this URL.</p>
<p>For each link <tt class="docutils literal">link_repl_func(link)</tt> is called. That function
then returns the new link, or None to remove the attribute or tag
that contains the link. Note that all links will be passed in,
including links like <tt class="docutils literal">"#anchor"</tt> (which is purely internal), and
things like <tt class="docutils literal">"mailto:bob@example.com"</tt> (or <tt class="docutils literal"><span class="pre">javascript:...</span></tt>).</p>
<p class="last">If you want access to the context of the link, you should use
<tt class="docutils literal">.iterlinks()</tt> instead.</p>
</dd>
</dl>
<div class="section" id="functions">
<h2>Functions</h2>
<p>In addition to these methods, there are corresponding functions:</p>
<ul class="simple">
<li><tt class="docutils literal">iterlinks(html)</tt></li>
<li><tt class="docutils literal">make_links_absolute(html, base_href, <span class="pre">...)</span></tt></li>
<li><tt class="docutils literal">rewrite_links(html, link_repl_func, <span class="pre">...)</span></tt></li>
<li><tt class="docutils literal">resolve_base_href(html)</tt></li>
</ul>
<p>These functions will parse <tt class="docutils literal">html</tt> if it is a string, then return the new
HTML as a string. If you pass in a document, the document will be copied
(except for <tt class="docutils literal">iterlinks()</tt>), the method performed, and the new document
returned.</p>
</div>
</div>
<div class="section" id="forms">
<h1>Forms</h1>
<p>Any <tt class="docutils literal"><form></tt> elements in a document are available through
the list <tt class="docutils literal">doc.forms</tt> (e.g., <tt class="docutils literal">doc.forms[0]</tt>). Form, input, select,
and textarea elements each have special methods.</p>
<p>Input elements (including <tt class="docutils literal"><select></tt> and <tt class="docutils literal"><textarea></tt>) have these
attributes:</p>
<dl class="docutils">
<dt><tt class="docutils literal">.name</tt>:</dt>
<dd>The name of the element.</dd>
<dt><tt class="docutils literal">.value</tt>:</dt>
<dd><p class="first">The value of an input, the content of a textarea, the selected
option(s) of a select. This attribute can be set.</p>
<p class="last">In the case of a select that takes multiple options (<tt class="docutils literal"><select
multiple></tt>) this will be a set of the selected options; you can
add or remove items to select and unselect the options.</p>
</dd>
</dl>
<p>Select attributes:</p>
<dl class="docutils">
<dt><tt class="docutils literal">.value_options</tt>:</dt>
<dd>For select elements, this is all the <em>possible</em> values (the values
of all the options).</dd>
<dt><tt class="docutils literal">.multiple</tt>:</dt>
<dd>For select elements, true if this is a <tt class="docutils literal"><select multiple></tt>
element.</dd>
</dl>
<p>Input attributes:</p>
<dl class="docutils">
<dt><tt class="docutils literal">.type</tt>:</dt>
<dd>The type attribute in <tt class="docutils literal"><input></tt> elements.</dd>
<dt><tt class="docutils literal">.checkable</tt>:</dt>
<dd>True if this can be checked (i.e., true for type=radio and
type=checkbox).</dd>
<dt><tt class="docutils literal">.checked</tt>:</dt>
<dd>If this element is checkable, the checked state. Raises
AttributeError on non-checkable inputs.</dd>
</dl>
<p>The form itself has these attributes:</p>
<dl class="docutils">
<dt><tt class="docutils literal">.inputs</tt>:</dt>
<dd>A dictionary-like object that can be used to access input elements
by name. When there are multiple input elements with the same
name, this returns list-like structures that can also be used to
access the options and their values as a group.</dd>
<dt><tt class="docutils literal">.fields</tt>:</dt>
<dd><p class="first">A dictionary-like object used to access <em>values</em> by their name.
<tt class="docutils literal">form.inputs</tt> returns elements, this only returns values.
Setting values in this dictionary will effect the form inputs.
Basically <tt class="docutils literal">form.fields[x]</tt> is equivalent to
<tt class="docutils literal"><span class="pre">form.inputs[x].value</span></tt> and <tt class="docutils literal">form.fields[x] = y</tt> is equivalent
to <tt class="docutils literal"><span class="pre">form.inputs[x].value</span> = y</tt>. (Note that sometimes
<tt class="docutils literal">form.inputs[x]</tt> returns a compound object, but these objects
also have <tt class="docutils literal">.value</tt> attributes.)</p>
<p class="last">If you set this attribute, it is equivalent to
<tt class="docutils literal"><span class="pre">form.fields.clear();</span> form.fields.update(new_value)</tt></p>
</dd>
<dt><tt class="docutils literal">.form_values()</tt>:</dt>
<dd>Returns a list of <tt class="docutils literal">[(name, value), <span class="pre">...]</span></tt>, suitable to be passed
to <tt class="docutils literal">urllib.urlencode()</tt> for form submission.</dd>
<dt><tt class="docutils literal">.action</tt>:</dt>
<dd>The <tt class="docutils literal">action</tt> attribute. This is resolved to an absolute URL if
possible.</dd>
<dt><tt class="docutils literal">.method</tt>:</dt>
<dd>The <tt class="docutils literal">method</tt> attribute, which defaults to <tt class="docutils literal">GET</tt>.</dd>
</dl>
<div class="section" id="form-filling-example">
<h2>Form Filling Example</h2>
<p>Note that you can change any of these attributes (values, method,
action, etc) and then serialize the form to see the updated values.
You can, for instance, do:</p>
<div class="syntax"><pre><span class="gp">>>> </span><span class="kn">from</span> <span class="nn">lxml.html</span> <span class="kn">import</span> <span class="n">fromstring</span><span class="p">,</span> <span class="n">tostring</span>
<span class="gp">>>> </span><span class="n">form_page</span> <span class="o">=</span> <span class="n">fromstring</span><span class="p">(</span><span class="s1">'''<html><body><form></span>
<span class="gp">... </span><span class="s1"> Your name: <input type="text" name="name"> <br></span>
<span class="gp">... </span><span class="s1"> Your phone: <input type="text" name="phone"> <br></span>
<span class="gp">... </span><span class="s1"> Your favorite pets: <br></span>
<span class="gp">... </span><span class="s1"> Dogs: <input type="checkbox" name="interest" value="dogs"> <br></span>
<span class="gp">... </span><span class="s1"> Cats: <input type="checkbox" name="interest" value="cats"> <br></span>
<span class="gp">... </span><span class="s1"> Llamas: <input type="checkbox" name="interest" value="llamas"> <br></span>
<span class="gp">... </span><span class="s1"> <input type="submit"></form></body></html>'''</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">form</span> <span class="o">=</span> <span class="n">form_page</span><span class="o">.</span><span class="n">forms</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span>
<span class="gp">>>> </span><span class="n">form</span><span class="o">.</span><span class="n">fields</span> <span class="o">=</span> <span class="nb">dict</span><span class="p">(</span>
<span class="gp">... </span> <span class="n">name</span><span class="o">=</span><span class="s1">'John Smith'</span><span class="p">,</span>
<span class="gp">... </span> <span class="n">phone</span><span class="o">=</span><span class="s1">'555-555-3949'</span><span class="p">,</span>
<span class="gp">... </span> <span class="n">interest</span><span class="o">=</span><span class="nb">set</span><span class="p">([</span><span class="s1">'cats'</span><span class="p">,</span> <span class="s1">'llamas'</span><span class="p">]))</span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">tostring</span><span class="p">(</span><span class="n">form</span><span class="p">)</span>
<span class="go"><html></span>
<span class="go"> <body></span>
<span class="go"> <form></span>
<span class="go"> Your name:</span>
<span class="go"> <input name="name" type="text" value="John Smith"></span>
<span class="go"> <br>Your phone:</span>
<span class="go"> <input name="phone" type="text" value="555-555-3949"></span>
<span class="go"> <br>Your favorite pets:</span>
<span class="go"> <br>Dogs:</span>
<span class="go"> <input name="interest" type="checkbox" value="dogs"></span>
<span class="go"> <br>Cats:</span>
<span class="go"> <input checked name="interest" type="checkbox" value="cats"></span>
<span class="go"> <br>Llamas:</span>
<span class="go"> <input checked name="interest" type="checkbox" value="llamas"></span>
<span class="go"> <br></span>
<span class="go"> <input type="submit"></span>
<span class="go"> </form></span>
<span class="go"> </body></span>
<span class="go"></html></span>
</pre></div>
</div>
<div class="section" id="form-submission">
<h2>Form Submission</h2>
<p>You can submit a form with <tt class="docutils literal">lxml.html.submit_form(form_element)</tt>.
This will return a file-like object (the result of
<tt class="docutils literal">urllib.urlopen()</tt>).</p>
<p>If you have extra input values you want to pass you can use the
keyword argument <tt class="docutils literal">extra_values</tt>, like <tt class="docutils literal"><span class="pre">extra_values={'submit':</span>
<span class="pre">'Yes!'}</span></tt>. This is the only way to get submit values into the form,
as there is no state of "submitted" for these elements.</p>
<p>You can pass in an alternate opener with the <tt class="docutils literal">open_http</tt> keyword
argument, which is a function with the signature <tt class="docutils literal">open_http(method,
url, values)</tt>.</p>
<p>Example:</p>
<div class="syntax"><pre><span class="gp">>>> </span><span class="kn">from</span> <span class="nn">lxml.html</span> <span class="kn">import</span> <span class="n">parse</span><span class="p">,</span> <span class="n">submit_form</span>
<span class="gp">>>> </span><span class="n">page</span> <span class="o">=</span> <span class="n">parse</span><span class="p">(</span><span class="s1">'http://tinyurl.com'</span><span class="p">)</span><span class="o">.</span><span class="n">getroot</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">page</span><span class="o">.</span><span class="n">forms</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span><span class="o">.</span><span class="n">fields</span><span class="p">[</span><span class="s1">'url'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'http://lxml.de/'</span>
<span class="gp">>>> </span><span class="n">result</span> <span class="o">=</span> <span class="n">parse</span><span class="p">(</span><span class="n">submit_form</span><span class="p">(</span><span class="n">page</span><span class="o">.</span><span class="n">forms</span><span class="p">[</span><span class="mi">0</span><span class="p">]))</span><span class="o">.</span><span class="n">getroot</span><span class="p">()</span>
<span class="gp">>>> </span><span class="p">[</span><span class="n">a</span><span class="o">.</span><span class="n">attrib</span><span class="p">[</span><span class="s1">'href'</span><span class="p">]</span> <span class="k">for</span> <span class="n">a</span> <span class="ow">in</span> <span class="n">result</span><span class="o">.</span><span class="n">xpath</span><span class="p">(</span><span class="s2">"//a[@target='_blank']"</span><span class="p">)]</span>
<span class="go">['http://tinyurl.com/2xae8s', 'http://preview.tinyurl.com/2xae8s']</span>
</pre></div>
</div>
</div>
<div class="section" id="cleaning-up-html">
<h1>Cleaning up HTML</h1>
<p>The module <tt class="docutils literal">lxml.html.clean</tt> provides a <tt class="docutils literal">Cleaner</tt> class for cleaning up
HTML pages. It supports removing embedded or script content, special tags,
CSS style annotations and much more.</p>
<p>Say, you have an evil web page from an untrusted source that contains lots of
content that upsets browsers and tries to run evil code on the client side:</p>
<div class="syntax"><pre><span class="gp">>>> </span><span class="n">html</span> <span class="o">=</span> <span class="s1">'''</span><span class="se">\</span>
<span class="gp">... </span><span class="s1"><html></span>
<span class="gp">... </span><span class="s1"> <head></span>
<span class="gp">... </span><span class="s1"> <script type="text/javascript" src="evil-site"></script></span>
<span class="gp">... </span><span class="s1"> <link rel="alternate" type="text/rss" src="evil-rss"></span>
<span class="gp">... </span><span class="s1"> <style></span>
<span class="gp">... </span><span class="s1"> body {background-image: url(javascript:do_evil)};</span>
<span class="gp">... </span><span class="s1"> div {color: expression(evil)};</span>
<span class="gp">... </span><span class="s1"> </style></span>
<span class="gp">... </span><span class="s1"> </head></span>
<span class="gp">... </span><span class="s1"> <body onload="evil_function()"></span>
<span class="gp">... </span><span class="s1"> <!-- I am interpreted for EVIL! --></span>
<span class="gp">... </span><span class="s1"> <a href="javascript:evil_function()">a link</a></span>
<span class="gp">... </span><span class="s1"> <a href="#" onclick="evil_function()">another link</a></span>
<span class="gp">... </span><span class="s1"> <p onclick="evil_function()">a paragraph</p></span>
<span class="gp">... </span><span class="s1"> <div style="display: none">secret EVIL!</div></span>
<span class="gp">... </span><span class="s1"> <object> of EVIL! </object></span>
<span class="gp">... </span><span class="s1"> <iframe src="evil-site"></iframe></span>
<span class="gp">... </span><span class="s1"> <form action="evil-site"></span>
<span class="gp">... </span><span class="s1"> Password: <input type="password" name="password"></span>
<span class="gp">... </span><span class="s1"> </form></span>
<span class="gp">... </span><span class="s1"> <blink>annoying EVIL!</blink></span>
<span class="gp">... </span><span class="s1"> <a href="evil-site">spam spam SPAM!</a></span>
<span class="gp">... </span><span class="s1"> <image src="evil!"></span>
<span class="gp">... </span><span class="s1"> </body></span>
<span class="gp">... </span><span class="s1"></html>'''</span>
</pre></div>
<p>To remove the all suspicious content from this unparsed document, use the
<tt class="docutils literal">clean_html</tt> function:</p>
<div class="syntax"><pre><span class="gp">>>> </span><span class="kn">from</span> <span class="nn">lxml.html.clean</span> <span class="kn">import</span> <span class="n">clean_html</span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">clean_html</span><span class="p">(</span><span class="n">html</span><span class="p">)</span>
<span class="go"><div><style>/* deleted */</style><body></span>
<span class="go"> <a href="">a link</a></span>
<span class="go"> <a href="#">another link</a></span>
<span class="go"> <p>a paragraph</p></span>
<span class="go"> <div>secret EVIL!</div></span>
<span class="go"> of EVIL!</span>
<span class="go"> Password:</span>
<span class="go"> annoying EVIL!<a href="evil-site">spam spam SPAM!</a></span>
<span class="go"> <img src="evil!"></body></div></span>
</pre></div>
<p>The <tt class="docutils literal">Cleaner</tt> class supports several keyword arguments to control exactly
which content is removed:</p>
<div class="syntax"><pre><span class="gp">>>> </span><span class="kn">from</span> <span class="nn">lxml.html.clean</span> <span class="kn">import</span> <span class="n">Cleaner</span>
<span class="gp">>>> </span><span class="n">cleaner</span> <span class="o">=</span> <span class="n">Cleaner</span><span class="p">(</span><span class="n">page_structure</span><span class="o">=</span><span class="bp">False</span><span class="p">,</span> <span class="n">links</span><span class="o">=</span><span class="bp">False</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">cleaner</span><span class="o">.</span><span class="n">clean_html</span><span class="p">(</span><span class="n">html</span><span class="p">)</span>
<span class="go"><html></span>
<span class="go"> <head></span>
<span class="go"> <link rel="alternate" src="evil-rss" type="text/rss"></span>
<span class="go"> <style>/* deleted */</style></span>
<span class="go"> </head></span>
<span class="go"> <body></span>
<span class="go"> <a href="">a link</a></span>
<span class="go"> <a href="#">another link</a></span>
<span class="go"> <p>a paragraph</p></span>
<span class="go"> <div>secret EVIL!</div></span>
<span class="go"> of EVIL!</span>
<span class="go"> Password:</span>
<span class="go"> annoying EVIL!</span>
<span class="go"> <a href="evil-site">spam spam SPAM!</a></span>
<span class="go"> <img src="evil!"></span>
<span class="go"> </body></span>
<span class="go"></html></span>
<span class="gp">>>> </span><span class="n">cleaner</span> <span class="o">=</span> <span class="n">Cleaner</span><span class="p">(</span><span class="n">style</span><span class="o">=</span><span class="bp">True</span><span class="p">,</span> <span class="n">links</span><span class="o">=</span><span class="bp">True</span><span class="p">,</span> <span class="n">add_nofollow</span><span class="o">=</span><span class="bp">True</span><span class="p">,</span>
<span class="gp">... </span> <span class="n">page_structure</span><span class="o">=</span><span class="bp">False</span><span class="p">,</span> <span class="n">safe_attrs_only</span><span class="o">=</span><span class="bp">False</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">cleaner</span><span class="o">.</span><span class="n">clean_html</span><span class="p">(</span><span class="n">html</span><span class="p">)</span>
<span class="go"><html></span>
<span class="go"> <head></span>
<span class="go"> </head></span>
<span class="go"> <body></span>
<span class="go"> <a href="">a link</a></span>
<span class="go"> <a href="#">another link</a></span>
<span class="go"> <p>a paragraph</p></span>
<span class="go"> <div>secret EVIL!</div></span>
<span class="go"> of EVIL!</span>
<span class="go"> Password:</span>
<span class="go"> annoying EVIL!</span>
<span class="go"> <a href="evil-site" rel="nofollow">spam spam SPAM!</a></span>
<span class="go"> <img src="evil!"></span>
<span class="go"> </body></span>
<span class="go"></html></span>
</pre></div>
<p>You can also whitelist some otherwise dangerous content with
<tt class="docutils literal"><span class="pre">Cleaner(host_whitelist=['www.youtube.com'])</span></tt>, which would allow
embedded media from YouTube, while still filtering out embedded media
from other sites.</p>
<p>See the docstring of <tt class="docutils literal">Cleaner</tt> for the details of what can be
cleaned.</p>
<div class="section" id="autolink">
<h2>autolink</h2>
<p>In addition to cleaning up malicious HTML, <tt class="docutils literal">lxml.html.clean</tt>
contains functions to do other things to your HTML. This includes
autolinking:</p>
<pre class="literal-block">
autolink(doc, ...)
autolink_html(html, ...)
</pre>
<p>This finds anything that looks like a link (e.g.,
<tt class="docutils literal"><span class="pre">http://example.com</span></tt>) in the <em>text</em> of an HTML document, and
turns it into an anchor. It avoids making bad links.</p>
<p>Links in the elements <tt class="docutils literal"><textarea></tt>, <tt class="docutils literal"><pre></tt>, <tt class="docutils literal"><code></tt>,
anything in the head of the document. You can pass in a list of
elements to avoid in <tt class="docutils literal"><span class="pre">avoid_elements=['textarea',</span> <span class="pre">...]</span></tt>.</p>
<p>Links to some hosts can be avoided. By default links to
<tt class="docutils literal">localhost*</tt>, <tt class="docutils literal">example.*</tt> and <tt class="docutils literal">127.0.0.1</tt> are not
autolinked. Pass in <tt class="docutils literal"><span class="pre">avoid_hosts=[list_of_regexes]</span></tt> to control
this.</p>
<p>Elements with the <tt class="docutils literal">nolink</tt> CSS class are not autolinked. Pass
in <tt class="docutils literal"><span class="pre">avoid_classes=['code',</span> <span class="pre">...]</span></tt> to control this.</p>
<p>The <tt class="docutils literal">autolink_html()</tt> version of the function parses the HTML
string first, and returns a string.</p>
</div>
<div class="section" id="wordwrap">
<h2>wordwrap</h2>
<p>You can also wrap long words in your html:</p>
<pre class="literal-block">
word_break(doc, max_width=40, ...)
word_break_html(html, ...)
</pre>
<p>This finds any long words in the text of the document and inserts
<tt class="docutils literal">&#8203;</tt> in the document (which is the Unicode zero-width space).</p>
<p>This avoids the elements <tt class="docutils literal"><pre></tt>, <tt class="docutils literal"><textarea></tt>, and <tt class="docutils literal"><code></tt>.
You can control this with <tt class="docutils literal"><span class="pre">avoid_elements=['textarea',</span> <span class="pre">...]</span></tt>.</p>
<p>It also avoids elements with the CSS class <tt class="docutils literal">nobreak</tt>. You can
control this with <tt class="docutils literal"><span class="pre">avoid_classes=['code',</span> <span class="pre">...]</span></tt>.</p>
<p>Lastly you can control the character that is inserted with
<tt class="docutils literal"><span class="pre">break_character=u'\u200b'</span></tt>. However, you cannot insert markup,
only text.</p>
<p><tt class="docutils literal">word_break_html(html)</tt> parses the HTML document and returns a
string.</p>
</div>
</div>
<div class="section" id="html-diff">
<h1>HTML Diff</h1>
<p>The module <tt class="docutils literal">lxml.html.diff</tt> offers some ways to visualize
differences in HTML documents. These differences are <em>content</em>
oriented. That is, changes in markup are largely ignored; only
changes in the content itself are highlighted.</p>
<p>There are two ways to view differences: <tt class="docutils literal">htmldiff</tt> and
<tt class="docutils literal">html_annotate</tt>. One shows differences with <tt class="docutils literal"><ins></tt> and
<tt class="docutils literal"><del></tt>, while the other annotates a set of changes similar to <tt class="docutils literal">svn
blame</tt>. Both these functions operate on text, and work best with
content fragments (only what goes in <tt class="docutils literal"><body></tt>), not complete
documents.</p>
<p>Example of <tt class="docutils literal">htmldiff</tt>:</p>
<div class="syntax"><pre><span class="gp">>>> </span><span class="kn">from</span> <span class="nn">lxml.html.diff</span> <span class="kn">import</span> <span class="n">htmldiff</span><span class="p">,</span> <span class="n">html_annotate</span>
<span class="gp">>>> </span><span class="n">doc1</span> <span class="o">=</span> <span class="s1">'''<p>Here is some text.</p>'''</span>
<span class="gp">>>> </span><span class="n">doc2</span> <span class="o">=</span> <span class="s1">'''<p>Here is <b>a lot</b> of <i>text</i>.</p>'''</span>
<span class="gp">>>> </span><span class="n">doc3</span> <span class="o">=</span> <span class="s1">'''<p>Here is <b>a little</b> <i>text</i>.</p>'''</span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">htmldiff</span><span class="p">(</span><span class="n">doc1</span><span class="p">,</span> <span class="n">doc2</span><span class="p">)</span>
<span class="go"><p>Here is <ins><b>a lot</b> of <i>text</i>.</ins> <del>some text.</del> </p></span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">html_annotate</span><span class="p">([(</span><span class="n">doc1</span><span class="p">,</span> <span class="s1">'author1'</span><span class="p">),</span> <span class="p">(</span><span class="n">doc2</span><span class="p">,</span> <span class="s1">'author2'</span><span class="p">),</span>
<span class="gp">... </span> <span class="p">(</span><span class="n">doc3</span><span class="p">,</span> <span class="s1">'author3'</span><span class="p">)])</span>
<span class="go"><p><span title="author1">Here is</span></span>
<span class="go"> <b><span title="author2">a</span></span>
<span class="go"> <span title="author3">little</span></b></span>
<span class="go"> <i><span title="author2">text</span></i></span>
<span class="go"> <span title="author2">.</span></p></span>
</pre></div>
<p>As you can see, it is imperfect as such things tend to be. On larger
tracts of text with larger edits it will generally do better.</p>
<p>The <tt class="docutils literal">html_annotate</tt> function can also take an optional second
argument, <tt class="docutils literal">markup</tt>. This is a function like <tt class="docutils literal">markup(text,
version)</tt> that returns the given text marked up with the given
version. The default version, the output of which you see in the
example, looks like:</p>
<div class="syntax"><pre><span class="k">def</span> <span class="nf">default_markup</span><span class="p">(</span><span class="n">text</span><span class="p">,</span> <span class="n">version</span><span class="p">):</span>
<span class="k">return</span> <span class="s1">'<span title="</span><span class="si">%s</span><span class="s1">"></span><span class="si">%s</span><span class="s1"></span>'</span> <span class="o">%</span> <span class="p">(</span>
<span class="n">cgi</span><span class="o">.</span><span class="n">escape</span><span class="p">(</span><span class="nb">unicode</span><span class="p">(</span><span class="n">version</span><span class="p">),</span> <span class="mi">1</span><span class="p">),</span> <span class="n">text</span><span class="p">)</span>
</pre></div>
</div>
<div class="section" id="examples">
<h1>Examples</h1>
<div class="section" id="microformat-example">
<h2>Microformat Example</h2>
<p>This example parses the <a class="reference external" href="http://microformats.org/wiki/hcard">hCard</a>
microformat.</p>
<p>First we get the page:</p>
<div class="syntax"><pre><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">urllib</span>
<span class="gp">>>> </span><span class="kn">from</span> <span class="nn">lxml.html</span> <span class="kn">import</span> <span class="n">fromstring</span>
<span class="gp">>>> </span><span class="n">url</span> <span class="o">=</span> <span class="s1">'http://microformats.org/'</span>
<span class="gp">>>> </span><span class="n">content</span> <span class="o">=</span> <span class="n">urllib</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="gp">>>> </span><span class="n">doc</span> <span class="o">=</span> <span class="n">fromstring</span><span class="p">(</span><span class="n">content</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">doc</span><span class="o">.</span><span class="n">make_links_absolute</span><span class="p">(</span><span class="n">url</span><span class="p">)</span>
</pre></div>
<p>Then we create some objects to put the information in:</p>
<div class="syntax"><pre><span class="gp">>>> </span><span class="k">class</span> <span class="nc">Card</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="gp">... </span> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="o">**</span><span class="n">kw</span><span class="p">):</span>
<span class="gp">... </span> <span class="k">for</span> <span class="n">name</span><span class="p">,</span> <span class="n">value</span> <span class="ow">in</span> <span class="n">kw</span><span class="p">:</span>
<span class="gp">... </span> <span class="nb">setattr</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">name</span><span class="p">,</span> <span class="n">value</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">class</span> <span class="nc">Phone</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="gp">... </span> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">phone</span><span class="p">,</span> <span class="n">types</span><span class="o">=</span><span class="p">()):</span>
<span class="gp">... </span> <span class="bp">self</span><span class="o">.</span><span class="n">phone</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">types</span> <span class="o">=</span> <span class="n">phone</span><span class="p">,</span> <span class="n">types</span>
</pre></div>
<p>And some generally handy functions for microformats:</p>
<div class="syntax"><pre><span class="gp">>>> </span><span class="k">def</span> <span class="nf">get_text</span><span class="p">(</span><span class="n">el</span><span class="p">,</span> <span class="n">class_name</span><span class="p">):</span>
<span class="gp">... </span> <span class="n">els</span> <span class="o">=</span> <span class="n">el</span><span class="o">.</span><span class="n">find_class</span><span class="p">(</span><span class="n">class_name</span><span class="p">)</span>
<span class="gp">... </span> <span class="k">if</span> <span class="n">els</span><span class="p">:</span>
<span class="gp">... </span> <span class="k">return</span> <span class="n">els</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span><span class="o">.</span><span class="n">text_content</span><span class="p">()</span>
<span class="gp">... </span> <span class="k">else</span><span class="p">:</span>
<span class="gp">... </span> <span class="k">return</span> <span class="s1">''</span>
<span class="gp">>>> </span><span class="k">def</span> <span class="nf">get_value</span><span class="p">(</span><span class="n">el</span><span class="p">):</span>
<span class="gp">... </span> <span class="k">return</span> <span class="n">get_text</span><span class="p">(</span><span class="n">el</span><span class="p">,</span> <span class="s1">'value'</span><span class="p">)</span> <span class="ow">or</span> <span class="n">el</span><span class="o">.</span><span class="n">text_content</span><span class="p">()</span>
<span class="gp">>>> </span><span class="k">def</span> <span class="nf">get_all_texts</span><span class="p">(</span><span class="n">el</span><span class="p">,</span> <span class="n">class_name</span><span class="p">):</span>
<span class="gp">... </span> <span class="k">return</span> <span class="p">[</span><span class="n">e</span><span class="o">.</span><span class="n">text_content</span><span class="p">()</span> <span class="k">for</span> <span class="n">e</span> <span class="ow">in</span> <span class="n">els</span><span class="o">.</span><span class="n">find_class</span><span class="p">(</span><span class="n">class_name</span><span class="p">)]</span>
<span class="gp">>>> </span><span class="k">def</span> <span class="nf">parse_addresses</span><span class="p">(</span><span class="n">el</span><span class="p">):</span>
<span class="gp">... </span> <span class="c1"># Ideally this would parse street, etc.</span>
<span class="gp">... </span> <span class="k">return</span> <span class="n">el</span><span class="o">.</span><span class="n">find_class</span><span class="p">(</span><span class="s1">'adr'</span><span class="p">)</span>
</pre></div>
<p>Then the parsing:</p>
<div class="syntax"><pre><span class="gp">>>> </span><span class="k">for</span> <span class="n">el</span> <span class="ow">in</span> <span class="n">doc</span><span class="o">.</span><span class="n">find_class</span><span class="p">(</span><span class="s1">'hcard'</span><span class="p">):</span>
<span class="gp">... </span> <span class="n">card</span> <span class="o">=</span> <span class="n">Card</span><span class="p">()</span>
<span class="gp">... </span> <span class="n">card</span><span class="o">.</span><span class="n">el</span> <span class="o">=</span> <span class="n">el</span>
<span class="gp">... </span> <span class="n">card</span><span class="o">.</span><span class="n">fn</span> <span class="o">=</span> <span class="n">get_text</span><span class="p">(</span><span class="n">el</span><span class="p">,</span> <span class="s1">'fn'</span><span class="p">)</span>
<span class="gp">... </span> <span class="n">card</span><span class="o">.</span><span class="n">tels</span> <span class="o">=</span> <span class="p">[]</span>
<span class="gp">... </span> <span class="k">for</span> <span class="n">tel_el</span> <span class="ow">in</span> <span class="n">card</span><span class="o">.</span><span class="n">find_class</span><span class="p">(</span><span class="s1">'tel'</span><span class="p">):</span>
<span class="gp">... </span> <span class="n">card</span><span class="o">.</span><span class="n">tels</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">Phone</span><span class="p">(</span><span class="n">get_value</span><span class="p">(</span><span class="n">tel_el</span><span class="p">),</span>
<span class="gp">... </span> <span class="n">get_all_texts</span><span class="p">(</span><span class="n">tel_el</span><span class="p">,</span> <span class="s1">'type'</span><span class="p">)))</span>
<span class="gp">... </span> <span class="n">card</span><span class="o">.</span><span class="n">addresses</span> <span class="o">=</span> <span class="n">parse_addresses</span><span class="p">(</span><span class="n">el</span><span class="p">)</span>
</pre></div>
</div>
</div>
</div>
<div class="footer">
<hr class="footer" />
Generated on: 2018-03-21.
</div>
</body>
</html>
|