lxml - The Python XML Toolkit July 2008

lxml@python.org

32 participants
43 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] Checking whether a node is a comment/element
by Geoffrey Sneddon 11 Jan '23

11 Jan '23

Hi, What's the best way to check whether a given node is a comment or an element? For the former, I'm currently using isinstance(node, etree._Comment), which is rather obviously sub-optimal. -- Geoffrey Sneddon <http://gsnedders.com/>

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[lxml-dev] lxml 2.0.5 released
by Stefan Behnel 11 Jan '23

11 Jan '23

Hi all, lxml 2.0.5 is on PyPI. This is a bug-fix-only release of the stable 2.0 series. Have fun, Stefan 2.0.5 (2008-05-01) Bugs fixed * Resolving to a filename in custom resolvers didn't work. * lxml did not honour libxslt's second error state "STOPPED", which let some XSLT errors pass silently. * Memory leak in Schematron with libxml2 >= 2.6.31.

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[lxml-dev] lxml has its page on launchpad
by Stefan Behnel 20 Sep '22

20 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 30 Aug '22

30 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] lxml 2.0 beta1 released
by Stefan Behnel 22 Dec '08

22 Dec '08

Hi all, I finally managed to push lxml 2.0beta1 over to PyPI. This release marks the end of the four month alpha cycle of lxml 2.0. The last stable release series, lxml 1.3, saw the light of day more than six months ago. http://codespeak.net/lxml/dev/ http://pypi.python.org/pypi/lxml/2.0beta1 The complete changelog for beta1 and the 2.0 alpha series follows below. Apart from a number of important fixes and enhancements, this beta release also finalises the major API changes that make the difference between 1.x and 2.x. Incompatible changes after this release will require a very good motivation. As usual, compatible enhancements will always be embraced - as will be updates, clarifications and fixes for the documentation! Asking back helps. I expect beta1 to also be the last beta release before lxml 2.0 final (hopefully not in the sense that alpha4/5/6 were), so please test as much as you can to spot any remaining bugs and problems. Note that this release depends on a bug fix in Cython that will hopefully be released as Cython 0.9.6.11 in a couple of days. I attached the necessary patch for those who want work on the sources. Another thing: there was a security advisory on the libxml2 mailing list. To prevent DoS attacks, systems that parse XML from untrusted sources should be updated to libxml2 2.6.31 (or should apply the patch that is referenced in Daniel's post below). http://mail.gnome.org/archives/xml/2008-January/msg00036.html Sidnei, when you build the Windows binaries, could you please wait for libxml2 2.6.31 to become available as binaries as well? Hopefully, that won't take too long... Have fun, Stefan 2.0beta1 (2008-01-11) ===================== Features added -------------- * Parse-time XML schema validation (``schema`` parser keyword). * XPath string results of the ``text()`` function and attribute selection make their Element container accessible through a ``getparent()`` method. As a side-effect, they are now always unicode objects (even ASCII strings). * ``XSLT`` objects are usable in any thread - at the cost of a deep copy if they were not created in that thread. * Invalid entity names and character references will be rejected by the ``Entity()`` factory. * ``entity.text`` returns the textual representation of the entity, e.g. ``&``. Bugs fixed ---------- * XPath on ElementTrees could crash when selecting the virtual root node of the ElementTree. * Compilation ``--without-threading`` was buggy in alpha5/6. Other changes ------------- * Minor performance tweaks for Element instantiation and subelement creation 2.0alpha6 (2007-12-19) ====================== Features added -------------- * New properties ``position`` and ``code`` on ParseError exception (as in ET 1.3) Bugs fixed ---------- * Memory leak in the ``parse()`` function. * Minor bugs in XSLT error message formatting. * Result document memory leak in target parser. Other changes ------------- * Various places in the XPath, XSLT and iteration APIs now require keyword-only arguments. * The argument order in ``element.itersiblings()`` was changed to match the order used in all other iteration methods. The second argument ('preceding') is now a keyword-only argument. * The ``getiterator()`` method on Elements and ElementTrees was reverted to return an iterator as it did in lxml 1.x. The ET API specification allows it to return either a sequence or an iterator, and it traditionally returned a sequence in ET and an iterator in lxml. However, it is now deprecated in favour of the ``iter()`` method, which should be used in new code wherever possible. * The 'pretty printed' serialisation of ElementTree objects now inserts newlines at the root level between processing instructions, comments and the root tag. * A 'pretty printed' serialisation is now terminated with a newline. * Second argument to ``lxml.etree.Extension()`` helper is no longer required, third argument is now a keyword-only argument ``ns``. * ``lxml.html.tostring`` takes an ``encoding`` argument. 2.0alpha5 (2007-11-24) ====================== Features added -------------- * Rich comparison of ``element.attrib`` proxies. * ElementTree compatible TreeBuilder class. * Use default prefixes for some common XML namespaces. * ``lxml.html.clean.Cleaner`` now allows for a ``host_whitelist``, and two overridable methods: ``allow_embedded_url(el, url)`` and the more general ``allow_element(el)``. * Extended slicing of Elements as in ``element[1:-1:2]``, both in etree and in objectify * Resolvers can now provide a ``base_url`` keyword argument when resolving a document as string data. * When using ``lxml.doctestcompare`` you can give the doctest option ``NOPARSE_MARKUP`` (like ``# doctest: +NOPARSE_MARKUP``) to suppress the special checking for one test. Bugs fixed ---------- * Target parser failed to report comments. * In the ``lxml.html`` ``iter_links`` method, links in ``<object>`` tags weren't recognized. (Note: plugin-specific link parameters still aren't recognized.) Also, the ``<embed>`` tag, though not standard, is now included in ``lxml.html.defs.special_inline_tags``. * Using custom resolvers on XSLT stylesheets parsed from a string could request ill-formed URLs. * With ``lxml.doctestcompare`` if you do ``<tag xmlns="...">`` in your output, it will then be namespace-neutral (before the ellipsis was treated as a real namespace). Other changes ------------- * The module source files were renamed to "lxml.*.pyx", such as "lxml.etree.pyx". This was changed for consistency with the way Pyrex commonly handles package imports. The main effect is that classes now know about their fully qualified class name, including the package name of their module. * Keyword-only arguments in some API functions, especially in the parsers and serialisers. 2.0alpha4 (2007-10-07) ====================== Features added -------------- Bugs fixed ---------- * AttributeError in feed parser on parse errors Other changes ------------- * Tag name validation in lxml.etree (and lxml.html) now distinguishes between HTML tags and XML tags based on the parser that was used to parse or create them. HTML tags no longer reject any non-ASCII characters in tag names but only spaces and the special characters ``<>&/"'``. 2.0alpha3 (2007-09-26) ====================== Features added -------------- * Separate ``feed_error_log`` property for the feed parser interface. The normal parser interface and ``iterparse`` continue to use ``error_log``. * The normal parsers and the feed parser interface are now separated and can be used concurrently on the same parser instance. * ``fromstringlist()`` and ``tostringlist()`` functions as in ElementTree 1.3 * ``iterparse()`` accepts an ``html`` boolean keyword argument for parsing with the HTML parser (note that this interface may be subject to change) * Parsers accept an ``encoding`` keyword argument that overrides the encoding of the parsed documents. * New C-API function ``hasChild()`` to test for children * ``annotate()`` function in objectify can annotate with Python types and XSI types in one step. Accompanied by ``xsiannotate()`` and ``pyannotate()``. Bugs fixed ---------- * XML feed parser setup problem * Type annotation for unicode strings in ``DataElement()`` Other changes ------------- * lxml.etree now emits a warning if you use XPath with libxml2 2.6.27 (which can crash on certain XPath errors) * Type annotation in objectify now preserves the already annotated type by default to prevent loosing type information that is already there. 2.0alpha2 (2007-09-15) ====================== Features added -------------- * ``ET.write()``, ``tostring()`` and ``tounicode()`` now accept a keyword argument ``method`` that can be one of 'xml' (or None), 'html' or 'text' to serialise as XML, HTML or plain text content. * ``iterfind()`` method on Elements returns an iterator equivalent to ``findall()`` * ``itertext()`` method on Elements * Setting a QName object as value of the .text property or as an attribute will resolve its prefix in the respective context * ElementTree-like parser target interface as described in http://effbot.org/elementtree/elementtree-xmlparser.htm * ElementTree-like feed parser interface on XMLParser and HTMLParser (``feed()`` and ``close()`` methods) Bugs fixed ---------- * lxml failed to serialise namespace declarations of elements other than the root node of a tree * Race condition in XSLT where the resolver context leaked between concurrent XSLT calls Other changes ------------- * ``element.getiterator()`` returns a list, use ``element.iter()`` to retrieve an iterator (ElementTree 1.3 compatible behaviour) 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] namespace strangeness in lxml 1.1
by Eric Jahn 23 Aug '08

23 Aug '08

Using python-lxml 1.1.1-1 which comes with Debian Etch, I am noticing some odd behavior in how lxml handles attribute namespaces, and namespaces in general. In the following code, all actual namespace urls should be mapped to namespaces in the resulting output, and they are, except if an attribute is involved: type="{http://domain2.info}someattribute Is this an lxml/libxml2 bug? The second odd behavior is that, for subelements, all the namespace declarations are automatically redeclared in the subelement tag, which is redundant. Does anyone know how to get around these problems? from lxml import etree NS1_NAMESPACE = "http://domain1.info" NS2_NAMESPACE = "http://domain2.info" NS1 = "{%s}" % NS1_NAMESPACE NS2 = "{%s}" % NS2_NAMESPACE NSMAP = {"NS1" : NS1_NAMESPACE , "NS2" : NS2_NAMESPACE} root = etree.Element(NS1 + "firstelement", nsmap=NSMAP) element = etree.Element(NS2 + "secondelement", nsmap=NSMAP, type = NS2 + "someattribute") root.append(element) print etree.tostring(root,pretty_print=True) Which results in the following output: <NS1:firstelement xmlns:NS1="http://domain1.info" xmlns:NS2="http://domain2.info"> <NS2:secondelement xmlns:NS1="http://domain1.info" xmlns:NS2="http://domain2.info" type="{http://domain2.info}someattribute"/> </NS1:firstelement>

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Re: [lxml-dev] Segfault on XSLT/XPath undefined variable error.
by Stefan Behnel 11 Aug '08

11 Aug '08

Hi, John Krukoff wrote: > First, uninstalled cython and upgraded to 2.1.1, just to make sure this > wasn't already fixed, since there were notes in the changelog about XSLT > logging. With the same method, I can still get the same crash: > > xmlXPathCompiledEval: evaluation failed > Segmentation fault (core dumped) > > With symbols, the backtrace has a bit more information: but still no line numbers ... Could you compile with "-O -ggdb"? > #0 0xb76fb740 in __pyx_f_4lxml_5etree__forwardError () > from /usr/lib/python2.5/site-packages/lxml-2.1.1-py2.5-linux-i686.egg/lxml/etree.so > #1 0xb76fbb12 in __pyx_f_4lxml_5etree__receiveXSLTError () > from /usr/lib/python2.5/site-packages/lxml-2.1.1-py2.5-linux-i686.egg/lxml/etree.so > #2 0xb766aef9 in xsltPrintErrorContext () from /usr/lib/libxslt.so.1 > #3 0xb766b091 in xsltTransformError () from /usr/lib/libxslt.so.1 > #4 0xb768d434 in xsltValueOf () from /usr/lib/libxslt.so.1 > #5 0xb768a5ba in ?? () from /usr/lib/libxslt.so.1 > #6 0x0828d230 in ?? () > #7 0x082bb618 in ?? () > #8 0x0828d578 in ?? () > #9 0x085db390 in ?? () > #10 0x00000000 in ?? () Hmmm, I have no idea where in the (pretty short) _forwardError() function it could crash, especially after having run correctly before. Also, I'm wondering why the later stack frames do not show up. Are you sure libxslt is actually called from lxml.etree here? Given your valgrind log, you seem to be using other XML libraries as well. Does any of them use libxslt independently? > I've attached the valgrind log, hopefully it's not too large for the > mailing list. It was. :) I won't forward it, since it's not really helpful to other readers. > Do you want the valgrind core file too? It's 150MB. I'm > trying to narrow down what I need to do first to get it to crash, I'll > let you know if I come up with a simple test case as a result. Please check any other libraries for libxslt usage first. The error log setup of lxml.etree is global for each thread, that might already be the problem here. If it is, it *might* be possible to remove the global setup at least for libxslt, but I will have to look into that. To figure out which library interferes here, you can install the debug packages for each library you use in the setup, until you get a complete stack trace above. Stefan

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Re: [lxml-dev] Transform parameter variables
by Stefan Behnel 05 Aug '08

05 Aug '08

Hi, it's good practice to a) reply to the list, b) avoid top-posting and c) read what people post. Niels Bjerre wrote: > Thank You for your response > > But I have problem with the_dict: > These 2 statements don't give the same result. > > 1. newdoc = transform(places.myplaces, area="'3751'") > 2. newdoc = transform(places.myplaces, {'area':'\"\'3751\'\"'}) > > 1. is passed to xslt: <xsl:param name="area" select="'ost'"/> > 2. is ignored > > I have tried with > {'area':'\'3751\''} and others The last line will work, but as I wrote before: > 2008/7/28 Stefan Behnel <stefan_ml(a)behnel.de> >> You can pass more than one kayword parameter, as everywhere in Python. >> If you want to pass them from a dictionary, do the usual >> >> result = transform(xml_tree, **the_dict) >> >> trick. Note the two stars before "the_dict". This is standard Python syntax for expanding a mapping into keyword arguments. Stefan

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[lxml-dev] XMLSchema validate and entities
by Eric Garin 31 Jul '08

31 Jul '08

Hello At first, congratulations, I'm using lxml for more that one year and enjoy the huge progress (and work) you have done. I'm using lxml to validate XML documents instances with etree.XMLSchema(schema_doc).validate(xml_doc). I've used to work with DTD's where it's possible to include standard sets of HTML entities declarations like for example for (  é etc ...). Now, working with XML schemas, sometimes I have some of those common HTML entities that appears (from an editor like FCK) in the content. And at the validation time, of course, I have an error like this : File "lxml.etree.pyx", line 2520, in lxml.etree.parse File "parser.pxi", line 1309, in lxml.etree._parseDocument File "parser.pxi", line 1338, in lxml.etree._parseDocumentFromURL File "parser.pxi", line 1248, in lxml.etree._parseDocFromFile File "parser.pxi", line 828, in lxml.etree._BaseParser._parseDocFromFile File "parser.pxi", line 452, in lxml.etree._ParserContext._handleParseResultDoc File "parser.pxi", line 536, in lxml.etree._handleParseResult File "parser.pxi", line 478, in lxml.etree._raiseParseError lxml.etree.XMLSyntaxError: Entity 'nbsp' not defined, line 21, column 16 1. Is there a way to escape those entities at validation time ? 2. Or Do I need to declare entities in the schema (I understand that this question is not in the lxml topic, but I didn't find a way to do that) Thank you. Eric ----------------------------------- * Eric Garin - eric(a)detede.com * * Entity XML Editorial * * www.detede.com * -----------------------------------

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lxml - The Python XML Toolkit July 2008