lxml - The Python XML Toolkit May 2011

lxml@python.org

14 participants
15 discussions

[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 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] confusing xpath performance characteristics
by jholg＠gmx.de 24 Aug '12

24 Aug '12

Hi, I ran into some performance characteristics of lxml/libxml2 xpath that I find rather confusing: I try to find the @type attribute of a certain element in an XML Schema (which contains lots of complexType definitions with lots of elements in them; unfortunately I can't post the schema): >>> timeit.Timer(stmt="""xpath(schema)""", setup="""from lxml import etree, objectify; schema=etree.parse('NDM.xsd').getroot(); xpath = etree.XPath('//xs:element[@name="equity"]/@type', namespaces={'xs': 'http://www.w3.org/2001/XMLSchema'})""").repeat(number=10) [0.095885038375854492, 0.096823930740356445, 0.096174955368041992] So I think I'm being smart and give a little more path information - reckoning that this should *improve* performance: >>> timeit.Timer(stmt="""xpath(schema)""", setup="""from lxml import etree, objectify; schema=etree.parse('NDM.xsd').getroot(); xpath = etree.XPath('/xs:schema//xs:element[@name="equity"]/@type', namespaces={'xs': 'http://www.w3.org/2001/XMLSchema'})""").repeat(number=10) [0.1770780086517334, 0.1775970458984375, 0.17748594284057617] Hm. Performance degrades slightly. I'm adding even more of the path to where my desired elements live in the schema: >>> timeit.Timer(stmt="""xpath(schema)""", setup="""from lxml import etree, objectify; schema=etree.parse('xsd/NDM.xsd').getroot(); xpath = etree.XPath('/xs:schema/xs:complexType//xs:element[@name="equity"]/@type', namespaces={'xs': 'http://www.w3.org/2001/XMLSchema'})""").repeat(number=10) [103.79744100570679, 103.83671712875366, 103.61817717552185] What??? >>> timeit.Timer(stmt="""xpath(schema)""", setup="""from lxml import etree, objectify; schema=etree.parse('/ae/data/pydev/hjoukl/NDM/SVN_CO/TRUNK/ndm/reference/xsd/NDM.xsd').getroot(); xpath = etree.XPath('/xs:schema/xs:complexType/*/xs:element[@name="equity"]/@type', namespaces={'xs': 'http://www.w3.org/2001/XMLSchema'})""").repeat(number=10) [0.044407129287719727, 0.044126987457275391, 0.044229030609130859] >>> Ok, this version's better than my naive approach, which seems logical to me. But why would '/xs:schema/xs:complexType//xs:element[@name="equity"]/@type' perform drastically slower than '/xs:schema/xs:complexType//xs:element[@name="equity"]/@type' ? libxml2 problem? Running the same xpaths in Oxygen I don't notice performance differences (can't profile this). Holger -- GRATIS für alle GMX-Mitglieder: Die maxdome Movie-FLAT! Jetzt freischalten unter http://portal.gmx.net/de/go/maxdome01

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[lxml-dev] Codespeak shutting down: migration plans?
by Luciano Ramalho 23 Jul '11

23 Jul '11

Dear colleagues, As a long-time user of lxml I was shocked to read a message today from Holger Krekel about the end of Codespeak (see full text at the end of this). First we need to thank Holger for all these years of free service. Then we need to quickly plan and execute a migration to some other repository. I am willing to help, but I am no core developer of lxml, and in fact this is my first message ever to this mailing list, so I think we need someone better known to this community to lead the migration effort. lxml as a key piece of the Python ecosystem and for the benefit of its present and future users and the wider Python community we need to make sure it continues to be available, and to make sure as many references (pypi!) as possible point to the new canonical repository. Finally, a big thank you to Martijn, Philikon, Stefan and all the others who have built this great piece of software. Cheers, -- Luciano Ramalho programador repentista || stand-up programmer Twitter: @luciano ######################################### hi codespeak.net users, (sorry if you get mail twice, i wanted to make sure ...) after 8 years of operation codespeak.net services are bound to terminate, starting END OF FEBRUARY 2011 Background: one of the original codespeak purposes was to offer subversion (then in version 0.17) for the PyPy and other projects but today this is not too interesting given the pletora of VCS hosting solutions. Also, there aren't too many admins besides me, the hosting is costing money, PyPy's repository has moved to Bitbucket and i am re-shuffling my priorities preparing for my soon to emerge father-hood. After February 2011 i probably won't be able to help much with any transition issues or questions. The host will keep on running for a while but i give no guaruantees. Some remarks regarding termination wrt to the FEB 2011 deadline: * the subversion repo will turn read-only (and will eventually be switched off). * Shell accounts will be restricted to those people who need it *and* mail me about it. Some time later they will be gone as well. * Mailing lists will be terminated as well unless i get a mail asking me to postpone termination for a specific time. You can go to your respective mailman admin page and extract a list of members. If you mail me i can also provide a list of members. * Any remaining web docs/pages will probably continue to exist for a while but i also prefer them to be moved away by end Feb 2011. Note that the codespeak svn repository contains a lot of projects. For migration you have two options: do a flat import just of your project checkout directory into a new version system. This is super-simple, obviously. If you want to preserve history for your project please mail me and i either provide you a full dump or a filtered dump only containing your project. So long and I hope you all had a good time and enjoyed the services and also have a good transition now. see you in other places, holger krekel _______________________________________________ codespeak-ann(a)codespeak.net http://codespeak.net/mailman/listinfo/codespeak-ann

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etree.XSLT logging exception
by David Chandek-Stark 27 May '11

27 May '11

Using lxml 2.2.8 on Python 2.4, I am wresting with a problem that I have never seen before: Exception Type: TypeError Exception Value: Cannot convert lxml.etree._RotatingErrorLog to lxml.etree._BaseErrorLog This happens when calling etree.XSLT(xsltdoc). I may be able to provide more details if it's helpful, but really I guess I'd just like to disable lxml's logging altogether, if that's possible -- at least to eliminate that as the real source of the problem. The error *sounds* like it's trying to rotate a log and can't do it, maybe due to an IOError (permissions or something). I have no idea where it's trying to write this log. As I said, I've been using lxml for a long time and never experienced this error before. I'd appreciate any clues to this mystery. Thanks, David -- David Chandek-Stark dchandekstark(a)gmail.com

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etree.parse close open file object
by bertrand neron 24 May '11

24 May '11

Hello Since the version 2.3 of lxml, I have a problem with parse function of etree. When I a provide an open file object to the etree.parse function, the file object is automatically closed by parse. Is there a way to keep the file open? Thanks for help. Best regards, Bertrand Néron

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Forcing XHTML serialization
by Laurence Rowe 18 May '11

18 May '11

Hi Stephen, I'm trying to work out how to enable the HTML compatible XHTML serialization that is triggered by an XHTML 1.0 doctype without specifying that doctype - I want to use the HTML5 "<!DOCTYPE html>" instead. I see that in version 2.7.2 libxml2 added an XML_SAVE_XHTML flag to force the HTML compatible XHTML serialization behaviour. That flag has since been added to lxml's tree.pxd, but I'm unable to find an example that uses it. Is it possible to enable the flag somehow with lxml? Also, in http://mail.gnome.org/archives/xml/2008-September/msg00029.html there is mention of an option to disable the automatic meta content-type tag generation. Do you know if anything came of it? Many thanks, Laurence

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Unable to generate JavaScript using XSLT
by Martin Aspeli 16 May '11

16 May '11

Hi, I have an XML file format and an XSLT format to turn it into a JavaScript file (see below). This works on the command line: ==== $ xsltproc corejet-to-jit.xsl catalogue.xml // corejet-output.js, generated from Corejet Requirements Catalogue var custom_color_for = function(num_passing, num_pending, total) { var weighted = ( num_passing + (0.3 * num_pending) ) / total; var red = (255 * weighted) / 100; var green = (255*(100-weighted)) / 100; if (total==0) { red = 0; green = 0; } return 'rgb('+red+','+green+',0)'; } var metadata = { 'project': 'Test project', 'testTime': '2011-01-02T12:05:00' } var json = { 'id': 'root', 'name': 'Test project', 'data': {}, 'children': [ { 'id': 'epic-E1', 'name': 'First epic', 'data': { '$area': 6 * 10, '$color': custom_color_for(1, 0, 2) }, 'children': [ { 'id': 'story-S1', 'name': 'S1', 'data': { 'title': 'First story', '$area': 3 * 10, '$color': custom_color_for(1, 0, 2) }, 'children': [ { 'id': 'scenario-First scenario', 'name': '', 'data': { 'title': 'First scenario', '$color': '#0a0' , '$area': (3 / 2) * 10, }, 'children': [], }, { 'id': 'scenario-Second scenario', 'name': '', 'data': { 'title': 'Second scenario', '$color': '#a00' , '$area': (3 / 2) * 10, }, 'children': [], }, ] }, { 'id': 'story-S2', 'name': 'S2', 'data': { 'title': 'Second story', '$area': 3 * 10, '$color': custom_color_for(0, 0, 0) }, 'children': [ ] }, ] }, { 'id': 'epic-E2', 'name': 'Second epic', 'data': { '$area': 0 * 10, '$color': custom_color_for(0, 0, 0) }, 'children': [ ] }, ] }; ==== However, I can't apply the transform (or at least read the results) using lxml: >>> from lxml import etree >>> input = etree.parse(open('catalogue.xml')) >>> xslt = etree.parse(open('corejet-to-jit.xsl')) >>> output = input.xslt(xslt) >>> etree.tostring(output, pretty_print=True) is None True >>> output.getroot() is None True Why is this? Does it have to do with the slightly unorthodox XSL? Martin catalogue.xml: <requirementscatalogue project="Test project" extractTime="2011-01-02T12:01:00" testTime="2011-01-02T12:05:00"> <epic id="E1" title="First epic"> <story id="S1" title="First story" points="3" requirementStatus="open" priority="high"> <scenario name="First scenario" testStatus="pass"> <given>something</given> <when>something happens</when> <then>do something</then> <then>and something else</then> </scenario> <scenario name="Second scenario" testStatus="mismatch"> <given>something</given> <when>something happens</when> <then>do something</then> <then>and something else</then> </scenario> </story> <story id="S2" title="Second story" points="3" requirementStatus="closed" requirementResolution="fixed" priority="high"/> </epic> <epic id="E2" title="Second epic"/> </requirementscatalogue> corejet-to-jit.xsl: <?xml version="1.0" encoding="UTF-8"?> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:output omit-xml-declaration="yes"/> <xsl:template match="//requirementscatalogue"> // corejet-output.js, generated from Corejet Requirements Catalogue var custom_color_for = function(num_passing, num_pending, total) { var weighted = ( num_passing + (0.3 * num_pending) ) / total; var red = (255 * weighted) / 100; var green = (255*(100-weighted)) / 100; if (total==0) { red = 0; green = 0; } return 'rgb('+red+','+green+',0)'; } var metadata = { 'project': '<xsl:value-of select="@project"/>', 'testTime': '<xsl:value-of select="@testTime"/>' } var json = { 'id': 'root', 'name': '<xsl:value-of select="@project"/>', 'data': {}, 'children': [ <xsl:apply-templates select="epic"/> ] }; </xsl:template> <xsl:template match="epic"> { 'id': 'epic-<xsl:value-of select="@id"/>', 'name': '<xsl:value-of select="@title"/>', 'data': { '$area': <xsl:value-of select="sum(child::story/@points)"/> * 10, <xsl:variable name="num_passing"><xsl:value-of select="count(story/scenario[@testStatus='pass'])"/></xsl:variable> <xsl:variable name="num_pending"><xsl:value-of select="count(story/scenario[@testStatus='pending'])"/></xsl:variable> <xsl:variable name="total_scenarios"><xsl:value-of select="count(story/scenario)"/></xsl:variable> '$color': custom_color_for(<xsl:number value="$num_passing"/>, <xsl:number value="$num_pending"/>, <xsl:number value="$total_scenarios"/>) }, 'children': [ <xsl:apply-templates select="story"/> ] }, </xsl:template> <xsl:template match="story"> { 'id': 'story-<xsl:value-of select="@id"/>', 'name': '<xsl:value-of select="@id"/>', 'data': { 'title': '<xsl:value-of select="@title"/>', '$area': <xsl:value-of select="@points"/> * 10, <xsl:variable name="num_passing"><xsl:value-of select="count(scenario[@testStatus='pass'])"/></xsl:variable> <xsl:variable name="num_pending"><xsl:value-of select="count(scenario[@testStatus='pending'])"/></xsl:variable> <xsl:variable name="total_scenarios"><xsl:value-of select="count(scenario)"/></xsl:variable> '$color': custom_color_for(<xsl:number value="$num_passing"/>, <xsl:number value="$num_pending"/>, <xsl:number value="$total_scenarios"/>) }, 'children': [ <xsl:apply-templates select="scenario"/> ] }, </xsl:template> <xsl:template match="scenario"> { 'id': 'scenario-<xsl:value-of select="@name"/>', 'name': '', 'data': { 'title': '<xsl:value-of select="@name"/>', '$color': <xsl:choose> <xsl:when test="@testStatus='pass'"> '#0a0' </xsl:when> <xsl:when test="@testStatus='pending'"> '#aa0' </xsl:when> <xsl:otherwise> '#a00' </xsl:otherwise> </xsl:choose>, '$area': (<xsl:value-of select="../@points"/> / <xsl:value-of select="count(../scenario)"/>) * 10, }, 'children': [], }, </xsl:template> </xsl:stylesheet>

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lxml - The Python XML Toolkit May 2011