lxml - The Python XML Toolkit September 2007

lxml@python.org

20 participants
33 discussions

[lxml-dev] Reparenting a node
by Lawrence Oluyede 30 Jan '23

30 Jan '23

I have a doc A and a doc B, I'd like to put a node extracted from A in the document B but I always get a ValueError: ValueError: Element is not a child of this node. I didn't find any "setparent" in the API. How can I do this? -- Lawrence, oluyede.org - neropercaso.it "It is difficult to get a man to understand something when his salary depends on not understanding it" - Upton Sinclair

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[lxml-dev] lxml has its page on launchpad
by Stefan Behnel 21 Sep '22

21 Sep '22

Hi all, I added the lxml project to launchpad, the Ubuntu Bug-Tracker. It also has a FAQ engine and a couple of other goodies. https://launchpad.net/lxml It's easy to sign up for launchpad, BTW, no 90%-footnotes-contract. Have fun, Stefan

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[lxml-dev] Building LXML Trunk
by Sidnei da Silva 31 Aug '22

31 Aug '22

Hi, I've tried to build lxml from trunk today, on Win32. Got the following error: src\lxml\etree.c(880) : error C2059: syntax error : ')' src\lxml\etree.c(881) : error C2059: syntax error : ')' src\lxml\etree.c(882) : error C2059: syntax error : ')' src\lxml\etree.c(883) : error C2059: syntax error : ')' Any clue? Smells like a Pyrex issue? -- Sidnei da Silva Enfold Systems http://enfoldsystems.com Fax +1 832 201 8856 Office +1 713 942 2377 Ext 214

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[lxml-dev] Pickling objectified trees
by Christian Zagrodnick 09 Jun '08

09 Jun '08

Hi, the other day I had to pickle objectified trees. I just thought to share my findings. Pickling is about serialization. IMHO the natural serialization of an objectified tree is its XML representation. So the following basically does that: -------------------------- import copy_reg import lxml.etree import lxml.objectify def treeFactory(state): """Un-Pickle factory.""" return lxml.objectify.fromstring(state) copy_reg.constructor(treeFactory) def reduceObjectifiedElement(object): """Reduce function for lxml.objectify trees. See http://docs.python.org/lib/pickle-protocol.html for details. """ return (treeFactory, (lxml.etree.tostring(object), )) copy_reg.pickle(lxml.objectify.ObjectifiedElement, reduceObjectifiedElement, treeFactory) ----------------------------------------- You might consider just registering the reduce function in lxml itself. Shouldn't hurt, should it. -- Christian Zagrodnick gocept gmbh & co. kg · forsterstrasse 29 · 06112 halle/saale www.gocept.com · fon. +49 345 12298894 · fax. +49 345 12298891

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[lxml-dev] lxml namespaces
by Maxim Sloyko 20 Feb '08

20 Feb '08

Hi All! I have a little problem with XML namespaces. In my application I have two XML processors, that process the same document, one after the other. The first one looks for nodes in 'ns1' namespace, and substitutes them, according to some algorithm. After this processor is finished, it is guaranteed that there are no more 'ns1' nodes left in the tree. 'ns1' namespace dclaration is still there, in the root node (well, I put it there manually). Now, when this namespace is no longer needed, I want to get rid of it, because it confuses some other processors (namely, my browser) So, the question is, how do I do that? del tree.getroot().nsmap['ns1'] does not seem to do the trick :( Thanks in advance and Happy Holidays! -- Maxim Sloyko

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[lxml-dev] prefix mappings
by FnH 06 Oct '07

06 Oct '07

Hi, I would like to generate the following serialization: <a xmls="foo"> <b xmls="bar"/> </a> Currently, the closest I can come is: <a xmls="foo" xmlns:x="bar"> <x:b/> </a> using the following code: a = Element("{foo}a", nsmap={None:"foo", "x":"bar"}) a.append(Element("{bar}b")) Note that even though these serializations are equivalent, sometimes remapping namespaces is neccessary to work around faulty implementations in other products. The feed validator for example warns against using namespace prefixes on elements for good reason. If you don't, many readers aren't able to parse your feed (http://www.intertwingly.net/wiki/pie/XmlNamespaceConformanceTests). If you're using xhtml as content this means remapping the default namespace. In order to solve this I think it would be a good idea to allow (or take into account) prefix mappings on non root nodes as well. The output I'd like could then be achieved by the following code snippet: a = Element("{foo}a", nsmap={None:"foo"}) a.append(Element("{bar}b", nsmap={None:"bar"})) What do you think? Regards, Nick

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[lxml-dev] Tag name validation and HTML
by James Graham 06 Oct '07

06 Oct '07

The development branch of lxml 2 appears to restrict the characters that may appear in a tag name. Whilst this may be appropriate for XML, it does not match the behavior of all common HTML UAs and, as such, does not match the current draft of the HTML 5 spec [1]. This is an issue for html5lib [2] as we are keen to keep support for building lxml trees from HTML input, something which is currently possible with lxml 1.3. In an only tangentially related question, is there a recommended way of creating a custom tag type, preferably using the same code for ElementTree and lxml.etree? In particular html5lib needs to create a notional document root element whilst parsing. So far, we have been using an ordinary Element with a .tag that cannot be produced by parsing any input e.g. root.tag="<DOCUMENT_ROOT>" but this doesn't feel very elegant. [1] http://www.whatwg.org/specs/web-apps/current-work/#tag-name0 [2] http://code.google.com/p/html5lib/ -- "Eternity's a terrible thought. I mean, where's it all going to end?" -- Tom Stoppard, Rosencrantz and Guildenstern are Dead

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[lxml-dev] lxml 2.0alpha1 released
by Stefan Behnel 06 Oct '07

06 Oct '07

Hi all, I'm proudly announcing the first alpha release of lxml 2.0. It features a major cleanup both behind the scenes and at the surface, that improves the XML tool integration and makes the API clearer and more consistent in many places. The major new addition, however, is the lxml.html package, a new toolkit for HTML handling. The web site for the pre-2.0 series is online at http://codespeak.net/lxml/dev/ The "what's new" page has a description of the major changes: http://codespeak.net/lxml/dev/lxml2.html and the ChangeLog has a more detailed list, see below. This being an alpha release means that not everything is stable, both in terms of crashes and the API. There will be a small number of alpha releases to make the advancements publicly available, before the beta releases focus on improving the stability. I warmly invite everyone to contribute to the final release by discussing the API changes and the new features on the mailing list. There is always space for improvements! There is currently a known problem with Microsoft's compilers, so Windows builds may not become available for 2.0alpha1. The next alpha will hopefully come with prebuilt binaries for that platform. Building with the more standards compliant MinGW compilers should work. Note that working on the code now requires Cython (version 0.9.6.5), an enhanced fork of Pyrex. lxml therefore no longer ships with a copy of Pyrex or Cython, but as usual, building from the distribution sources does not require Cython. It can be installed with "easy_install Cython" or from here: http://www.cython.org/ I hope that lxml 2.0 will become a straight continuation of the success story that lxml 1.x was already. Have fun, Stefan 2.0alpha1 (2007-09-02) Features added * Reimplemented objectify.E for better performance and improved integration with objectify. Provides extended type support based on registered PyTypes. * XSLT objects now support deep copying * New makeSubElement() C-API function that allows creating a new subelement straight with text, tail and attributes. * XPath extension functions can now access the current context node (context.context_node) and use a context dictionary (context.eval_context) from the context provided in their first parameter * HTML tag soup parser based on BeautifulSoup in lxml.html.ElementSoup * New module lxml.doctestcompare by Ian Bicking for writing simplified doctests based on XML/HTML output. Use by importing lxml.usedoctest or lxml.html.usedoctest from within a doctest. * New module lxml.cssselect by Ian Bicking for selecting Elements with CSS selectors. * New package lxml.html written by Ian Bicking for advanced HTML treatment. * Namespace class setup is now local to the ElementNamespaceClassLookup instance and no longer global. * Schematron validation (incomplete in libxml2) * Additional stringify argument to objectify.PyType() takes a conversion function to strings to support setting text values from arbitrary types. * Entity support through an Entity factory and element classes. XML parsers now have a resolve_entities keyword argument that can be set to False to keep entities in the document. * column field on error log entries to accompany the line field * Error specific messages in XPath parsing and evaluation NOTE: for evaluation errors, you will now get an XPathEvalError instead of an XPathSyntaxError. To catch both, you can except on XPathError. * The regular expression functions in XPath now support passing a node-set instead of a string * Extended type annotation in objectify: new xsiannotate() function * EXSLT RegExp support in standard XPath (not only XSLT) Bugs fixed * lxml.etree did not check tag/attribute names * The XML parser did not report undefined entities as error * The text in exceptions raised by XML parsers, validators and XPath evaluators now reports the first error that occurred instead of the last * Passing '' as XPath namespace prefix did not raise an error * Thread safety in XPath evaluators Other changes * objectify.PyType for None is now called "NoneType" * el.getiterator() renamed to el.iter(), following ElementTree 1.3 - original name is still available as alias * In the public C-API, findOrBuildNodeNs() was replaced by the more generic findOrBuildNodeNsPrefix * Major refactoring in XPath/XSLT extension function code * Network access in parsers disabled by default

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[lxml-dev] ElementSoup doesn't work as in doc/elementsoup.txt
by js 28 Sep '07

28 Sep '07

Hello. I'm learning ElementSoup, but it doesn't work the way it's supposed to be. I tried sample code in doc/elementsoup.txt but failed with error. --------------------------------------------------------------------------------------------------------------------- >>> tag_soup = '<meta><head><title>Hello</head<body onload=crash()>Hi all<p>' >>> from lxml.html.ElementSoup import parse >>> from StringIO import StringIO >>> root = parse(StringIO(tag_soup)) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/opt/local/lib/python2.5/site-packages/lxml-2.0alpha3-py2.5-macosx-10.3-i386.egg/lxml/html/ElementSoup.py", line 19, in parse root = _convert_tree(tree, makeelement) File "/opt/local/lib/python2.5/site-packages/lxml-2.0alpha3-py2.5-macosx-10.3-i386.egg/lxml/html/ElementSoup.py", line 40, in _convert_tree attrib=dict(beautiful_soup_tree.attrs)) File "parser.pxi", line 702, in etree._BaseParser.makeelement File "apihelpers.pxi", line 102, in etree._makeElement File "apihelpers.pxi", line 798, in etree._tagValidOrRaise ValueError: Invalid tag name u'[document]' --------------------------------------------------------------------------------------------------------------------- I'm using Python2.5 lxml-2.0alpha3 BeautifulSoup 3.0.4 Any clues?

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[lxml-dev] Any way to pass encoding to html.html_parser?
by js 27 Sep '07

27 Sep '07

Hello. A simple question about lxml2.0alpha3's new feature. > * Parsers accept an 'encoding' keyword argument that overrides the > encoding of the parsed documents. How can I pass encoding argument to the parser when using html.parse instead of etree.parse?

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lxml - The Python XML Toolkit September 2007