Mailman 3 December 2009 - lxml - The Python XML Toolkit

Re: [lxml-dev] etree not printing pretty :(
by Stefan Behnel Dec. 29, 2009

Dec. 29, 2009

Martin Seiler, 19.11.2009 12:05: >>> I am rather new to python and lxml and I wonder about the output of my >>> tree. I add an Element, which contains some childs to a tree. When I >>> write the output everything is in pretty print, but the elements I >>> appended. They show up in one line. >> did you read this? >> >> http://codespeak.net/lxml/FAQ.html#why-doesn-t-the-pretty-print-option-refo… > > Yes, I did and applied before. If I print out the Element before > appending it, it works fine, just after appending it to an existing tree > it shows this behavior. libxml2 uses a heuristic to handle document-style content. When it finds tail text on an element, it switches to keeping text content intact within the respective subtree. That's likely the problem here. Setting the .tail property of each element to None should fix this, i.e. for el in root.iter(): el.tail = None > Also changing the call to: > >> et.ElementTree(element=eggs, parser=parser).write(xmlout, pretty_print=True) > > doesn't help? No. Setting a different parser here doesn't do anything (probably worth an exception...) Stefan

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[lxml-dev] embedding sub-elements in text attributes
by Richard Baron Penman Dec. 29, 2009

Dec. 29, 2009

Hello, I want to emphasize certain words in a HTML document, and my current solution is: tree = etree.fromstring(html) for e in tree.getiterator(): for attr in 'text', 'tail': words = getattr(e, attr) or '' for word in words.split(): if important(word): setattr(e, attr, getattr(e, attr).replace(word, '' + word + '')) The above examines the text of each element and emphasizes the important words it finds. However it does this by embedding HTML tags in the text attributes, which is escaped when rendering so that I need to counter with: html = etree.tostring(tree).replace('>', '>').replace('<', '<') This makes me uncomfortable so I want to do it properly. However to embed a new Element I would need to shift around the 'text' and 'tail' attributes so that the emphasized text appeared at the same position. And this would be really tricky when iterating as above. Any advice how to do this properly would be appreciated. I am sure there is something I have missed in the API! (Although ideally from the ElementTree API so that I could this use it when lxml is not available.) thanks, Richard

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[lxml-dev] XML Catalogs
by dsoulayrol＠free.fr Dec. 28, 2009

Dec. 28, 2009

Hello. I'd like to use catalogs to locate XSL stylesheets the way it is done in this document: http://www.sagehill.net/docbookxsl/WriteCatalog.html I'm not sure it is possible to do this with lxml, and how I could achieve this. The only information I found on using catalogs is the use of external_id etree.DTD: http://codespeak.net/lxml/validation.html Does anyone has the answer? -- David

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Re: [lxml-dev] Different node instance depending on method of access
by Stefan Behnel Dec. 25, 2009

Dec. 25, 2009

Hi, the mailing list would have been the place to ask this. Kevin D Smith, 25.12.2009 00:01: > I'm trying to use lxml to parse a document, apply CSS styles to the > nodes, then walk through the document to render it to another format. > The problem is that different ways of accessing the document return > different instances of the nodes. I really need to work on the same > instance no matter what way I access them. > > doc.find('body') returns <Element body at 101da2ef0> > > CSSSelector('body')(doc) returns <Element body at 101da2ef0> > > for action, elem in etree.iterwalk(doc, events=('start',)): > if elem.tag == 'body': return elem > > returns <Element body at 101da2b48> > > Using saxify(doc, handler) and processing styles in the event handlers > gives the following: > > CSSSelector('html, address, blockquote, body, dd, div, dl, dt, fieldset, > form, frame, frameset, h1, h2, h3, h4, h5, h6, noframes, ol, p, ul, > center, dir, hr, menu, pre')(self.doc) returns <Element body at > 101da2ce8> {u'display': 'block'} > > CSSSelector('body') returns <Element body at 101da2ae0> > > As you can see, within the context of the iterwalk and saxify, the node > instances aren't the same as returned by doc.find and CSSSelector > outside of iterwalk and saxify. It's not because you are using different ways to get to the element, it's because you are throwing away the reference in between. This might help: http://codespeak.net/lxml/element_classes.html#background-on-element-proxies > Is there a way to guarantee that all of > these methods will use the same nodes? You didn't write /why/ you consider this a requirement - it likely isn't one. But if you really need this, you can cache the element instances like this: cache = list(root_element.iter()) # do stuff with the elements in the tree del cache As long as you don't add elements to the tree, this will ensure that you always get the same instances back. If you add elements, just add them to the cache as well. Stefan

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[lxml-dev] Replacing node.text with a node structure
by Andreas Jung Dec. 22, 2009

Dec. 22, 2009

Hi there, I have an XML structure like this hello bar world <other> .... </other> and need it to transform to this hello <foo> bar </foo> world <other> .... </other> p_node.text == 'hello bar world' should be replaced with a text node + Element node + another text node. How can I do this using lxml? Andreas

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[lxml-dev] better schematron support
by jholg＠gmx.de Dec. 22, 2009

Dec. 22, 2009

Hi, schematron support in lxml is currently a second-class citizen due to libxml2 restrictions, see e.g. http://mail.gnome.org/archives/xml/2007-August/msg00016.html where Stefan commented on error reporting deficiencies or http://mail.gnome.org/archives/xml/2009-September/msg00022.html where Daniel of libxml2 fame comments on a feature request to support schematron embedded in XML Schema, basically stating that the implementation is incomplete. However, there is a pure-XSLT implementation of the now-ISO-standardized schematron by its inventor (and editor of the standard) Rick Jelliffe, the so-called skeleton implementation: http://www.schematron.com/ (Daniel also mentions this in his comment) Basically, the "skeleton" toolchain creates an xslt that is used for validation. Indeed, schematron itself is just a well-defined way of using xslt for validation, which I was looking into but really wasn't aware that schematron does this exactly. The "skeleton" implementation is available in both xslt 1 and 2 notions. The toolchain steps are (taken from www.schematron.com, modifications by me) 0) [Extract from XML Schema/RelaxNG schema)] 1) Process inclusions 2) Process abstract patterns 3) Compile the schema 4) Validate which translates to xsltproc XSD2Schtrn.xsl XMLSchema.xsd > theSchema.sch or xsltproc RNG2Schtrn.xsl RelaxNGSchema.rng > theSchema.sch xsltproc iso_dsdl_include.xsl theSchema.sch > theSchema1.sch xsltproc iso_abstract_expand.xsl theSchema1.sch > theSchema2.sch xsltproc iso_svrl_for_xsltn.xsl theSchema2.sch > theSchema.xsl xsltproc theSchema.xsl myDocument.xml > myResult.xml Enter libxslt aka lxml's xslt capabilities: It looks pretty easy to integrate this xslt-based toolchain into lxml, effectively enabling full ISO schematron support. I suggest complementing the current lxml schematron support using this approach: - add the necessary stylesheets (extraction and skeleton implementation) to the lxml codebase - add a convenient API to support xslt-based schematron validation to lxml that - hides toolchain steps, at least in default mode - fits in with the current validators' API - provides support for the parameters used for the separate toolchain steps And finally: Maybe somebody has already done this with lxml + schematron. Care to step forward? Any Comments? Holger -- Jetzt kostenlos herunterladen: Internet Explorer 8 und Mozilla Firefox 3.5 - sicherer, schneller und einfacher! http://portal.gmx.net/de/go/chbrowser

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[lxml-dev] Valadtion not correct.
by Johan Jordaan Dec. 18, 2009

Dec. 18, 2009

The below code validates two pieces of xml to the provided xsd. The first piece xml should be valid (I have independently verified this with another validatior). The second piece should be invalid;l which it is. Is this a bug in lxml or have i missed something? from lxml import etree from StringIO import StringIO f = StringIO(''' <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <xsd:complexType name="Fruit"> <xsd:attribute name="name" type="xsd:string"/> </xsd:complexType> <xsd:complexType name="FruitArray"> <xsd:sequence> <xsd:element name="fruit" minOccurs="0" maxOccurs="unbounded" type="Fruit"/> </xsd:sequence> </xsd:complexType> <xsd:element name="fruit_basket"> <xsd:complexType> <xsd:sequence> <xsd:element name="fruits" minOccurs="1" maxOccurs="1" type="FruitArray"/> <xsd:element name="favourite_fruit" minOccurs="1" maxOccurs="1"> <xsd:complexType> <xsd:attribute name="name" use="required"/> </xsd:complexType> </xsd:element> </xsd:sequence> </xsd:complexType> <xsd:key name="fruit_lookup"> <xsd:selector xpath="fruits/fruit"/> <xsd:field xpath="@name"/> </xsd:key> <xsd:keyref name="favourite_fruit_constraint" refer="fruit_lookup"> <xsd:selector xpath="favourite_fruit"/> <xsd:field xpath="@name"/> </xsd:keyref> </xsd:element> </xsd:schema> ''') xmlschema_doc = etree.parse(f) xmlschema = etree.XMLSchema(xmlschema_doc) valid = StringIO(''' <fruit_basket> <fruits> <fruit name="Apple"/> <fruit name="Peach"/> <fruit name="Bananna"/> </fruits> <favourite_fruit name="Apple"/> </fruit_basket> ''') doc = etree.parse(valid) print "Valid","Valid" if xmlschema.validate(doc) else "Invalid" invalid = StringIO(''' <fruit_basket> <fruits> <fruit name="Apple"/> <fruit name="Peach"/> <fruit name="Bananna"/> </fruits> <favourite_fruit name="xxx"/> </fruit_basket> ''') doc = etree.parse(invalid) print "Invalid","Valid" if xmlschema.validate(doc) else "Invalid"

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[lxml-dev] RelaxNG validation result depending of python version
by Nicolas Delaby Dec. 16, 2009

Dec. 16, 2009

Hi, I' have a issue with RelaxNG validation depending of version of python used. xmllint => No errors Python 2.6.4 => No Errors Python 2.4.6 => Errors as the version of libraries are the same, i don't know how to find the weakness in my python2.4 installation. Do you have any clue to help me understanding this issue ? Nicolas # xmllint --version xmllint: using libxml version 20706 For both python2.4 and python2.6 >>> etree.LXML_VERSION (2, 2, 4, 0) >>> etree.LIBXML_VERSION (2, 7, 6) >>> etree.LIBXML_COMPILED_VERSION (2, 7, 6) >>> etree.LIBXSLT_VERSION (1, 1, 20) >>> etree.LIBXSLT_COMPILED_VERSION (1, 1, 20) PS: I try to validate ODF content with oasis rng http://docs.oasis-open.org/office/v1.1/OS/OpenDocument-schema-v1.1.rng -- Nicolas Delaby Nexedi: Consulting and Development of Libre / Open Source Software http://www.nexedi.com/

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Re: [lxml-dev] Cant add a new elements
by Terry Brown Dec. 15, 2009

Dec. 15, 2009

On Tue, 15 Dec 2009 00:19:11 -0500 Ovnicraft <ovnicraft(a)gmail.com> wrote: > Hi folk, i am trying to add elements for my file[1], i wrote a dirty > script[2] for that, but when i print the root i see doesnt change. > I am forgeting something? I ran your code (Ubuntu 9.10, python 2.6, lxml 2.1.5) and it seemed to work: http://pastebin.com/m142da07e Only changes were that I commented out the pdb lines. Cheers -Terry > best regards, > > [1] http://pastebin.com/mfb48def > [2] http://pastebin.com/m7cae532e >

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[lxml-dev] Cant add a new elements
by Ovnicraft Dec. 15, 2009

Dec. 15, 2009

Hi folk, i am trying to add elements for my file[1], i wrote a dirty script[2] for that, but when i print the root i see doesnt change. I am forgeting something? best regards, [1] http://pastebin.com/mfb48def [2] http://pastebin.com/m7cae532e -- Cristian Salamea CEO GnuThink Software Labs Software Libre / Open Source (+593-8) 4-36-44-48

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