Mailman 3 November 2007 - lxml - The Python XML Toolkit

[lxml-dev] iterparse() reimplementation cancelled
by Stefan Behnel 24 Nov '07

24 Nov '07

Hi all, just a quick note regarding the planned iterparse() reimplementation. I did not include it in 2.0 alpha5, as my attempts have shown that passing a custom parser at the API level would imply too many semantic quirks, especially since iterparse() can't support every option that the normal parsers can. Also, parsing against a TreeBuilder (as ET does) would kill a lot of features such as HTML tag soup fixing, DTD validation and default attributes. So I now think that it's better to keep the current implementation based on the normal parser, even if it is not completely safe to use with all working ET code (as mentioned in the compatibility docs). Any comments or objections to this decision? Stefan

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[lxml-dev] TreeBuilder implementation in lxml.etree
by Stefan Behnel 23 Nov '07

23 Nov '07

Hi all, lxml.etree now has an ET compatible TreeBuilder class that is integrated into the parser framework, i.e. you can create a parser with "target=TreeBuilder()" and have it build a tree for you just the way ET does. Or, you can create a TreeBuilder instance and call the event methods yourself to get the same effect without parsing. There is one little difference to ET: the start() method has the following signature: def start(self, tag, attrs, nsmap=None): whereas in ET it's def start(self, tag, attrs): so lxml.etree accepts an additional "nsmap" argument here. This is required as lxml's parser would otherwise loose the namespace prefix mappings, so the generated trees would declare namespaces wherever a tag uses them first in the hierarchy and not where they were originally declared in the parsed document (which usually means the root element). Also, this supports prefixed text values that refer to declared namespaces (see for example the QName class). If you want to write code that subclasses the TreeBuilder and that should still work with both ET and lxml.etree, you should use the above signature. There is a bit of code that tries to figure out if the method can be called with three arguments, but I'm not sure it works in all cases. It's essentially this: import inspect arguments = inspect.getargspec(target.start) if len(arguments[0]) > 3: # self + 3 arguments takes_nsmap = True elif arguments[1] is not None: # '*args' parameter takes_nsmap = True else: takes_nsmap = False Hope this is useful, Stefan

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[lxml-dev] Pb with namespaces on attributs
by Alain Poirier 14 Nov '07

14 Nov '07

An attribut of a node, inserted then removed from a tree, can lose its namespace : >>> from lxml import etree as ET >>> parent = ET.Element('parent') >>> parent.set('{http://foo/bar}x', 'a') >>> child = ET.SubElement(parent, 'child') >>> child.set('{http://foo/bar}x', 'b') >>> print ET.tostring(child), child.nsmap <child xmlns:ns0="http://foo/bar" ns0:x="b"/> {'ns0': 'http://foo/bar'} >>> child = parent[0] >>> parent.clear() >>> print ET.tostring(child), child.nsmap <child x="b"/> {} It happends when the tree already knows the namespace used. A bug in lxml or in libxml2 (tested with lxml-2.0alpha4 and libxml2 2.6.28 / 2.6.30) ?

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[lxml-dev] 2.0 release plan, any news?
by jholg＠gmx.de 14 Nov '07

14 Nov '07

Hi, any plans on releasing another 2.0 alpha-cycle, or even going into Beta phase? Just asking, as I'm about to package an lxml-based app by the end of week. I've no real issues with using an alpha-snapshot as this runs smoothly, but of course would still prefer to ship an official release. Cheers, Holger -- GMX FreeMail: 1 GB Postfach, 5 E-Mail-Adressen, 10 Free SMS. Alle Infos und kostenlose Anmeldung: http://www.gmx.net/de/go/freemail

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[lxml-dev] XSD Validation: No matching global declaration.
by John Lovell 08 Nov '07

08 Nov '07

Hi All: I don't know if my schema is invalid or if this represents a bug in lxml or libxml2. Here is the situation... I have a XML Schema that looks like this: <schema xmlns="http://www.w3.org/2001/XMLSchema" xmlns:sif="http://www.sifinfo.org/infrastructure/1.x" targetNamespace="http://www.sifinfo.org/infrastructure/1.x"> <import namespace="http://www.w3.org/XML/1998/namespace" schemaLocation="http://www.w3.org/2001/xml.xsd"/> ... <element name="Authentication"> <complexType> <sequence> <element ref="sif:AuthenticationInfo" minOccurs="0" maxOccurs="unbounded"/> <element ref="sif:SIF_ExtendedElements" minOccurs="0" maxOccurs="1"/> </sequence> <attribute name="RefId" type="sif:RefIdType" use="required"/> <attribute name="SifRefId" type="sif:RefIdType" use="required"/> <attribute name="SifRefIdType" use="required"> <simpleType> <restriction base="string"> <enumeration value="StudentPersonal"/> <enumeration value="StaffPersonal"/> <enumeration value="StudentContact"/> <enumeration value="EmployeePersonal"/> </restriction> </simpleType> </attribute> </complexType> </element> ... </schema> I am trying to validate this data: <?xml version="1.0"?> <Authentication xmlns:ns3="http://www.w3.org/2001/XMLSchema" ns3:RefId="27D1CAEA85C2BAA647A01B551D21E1EB" ns3:SifRefId="211242238C60A55E25B2B86BB337C244" ns3:SifRefIdType="EmployeePersonal"> <AuthenticationInfo> <System xmlns:ns0="http://www.w3.org/2001/XMLSchema" ns0:Type="Application">&amp;1&lt;tNk44}F2</System> <Username>;pl}ee&apos;-</Username> <DistinguishedName>mlZm@JD</DistinguishedName> <Password xmlns:ns1="http://www.w3.org/2001/XMLSchema" ns1:Algorithm="MD5" ns1:KeyName="(v4kSY.">l1uqg!</Password> </AuthenticationInfo> <SIF_ExtendedElements> <SIF_ExtendedElement xmlns:ns2="http://www.w3.org/2001/XMLSchema" ns2:Name="%~T=">ZE72n/l</SIF_ExtendedElement> </SIF_ExtendedElements> </Authentication> The error log shows the following error: ../1.5r1/XSD/Infrastructure/Authentication__Authentication.xml:2:ERROR:S CHEMASV:SCHEMAV_CVC_ELT_1: Element 'Authentication': No matching global declaration available for the validation root. The same code given diffrent files works fine. Does anyone have any ideas why I am getting this message? Required version information: lxml.etree: (1, 3, 4, 0) libxml used: (2, 6, 30) libxml compiled: (2, 6, 30) libxslt used: (1, 1, 21) libxslt compiled: (1, 1, 22) Thanks, John W. Lovell Web Applications Engineer Northwest Educational Service District 1601 R Avenue Anacortes, WA 98221 <mailto:jlovell@esd189.org> www.esd189.org <http://www.esd189.org/> Together We Can ...

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Re: [lxml-dev] Failing lxml.html tests
by Ian Bicking 05 Nov '07

05 Nov '07

(I had sent this to Stefan, but maybe someone on the list will recognize something about what's going on here) Stefan Behnel wrote: > Ian Bicking wrote: >> When I run the tests just get a lot of these: >> >> >> ====================================================================== >> ERROR: test_write_method_text >> (lxml.tests.test_elementtree.ElementTreeTestCase) >> ---------------------------------------------------------------------- >> Traceback (most recent call last): >> File "unittest.py", line 260, in run >> testMethod() >> File "/home/ianb/src/lxml/src/lxml/tests/test_elementtree.py", line >> 777, in test_write_method_text >> tree.write(f, method="text") >> TypeError: write() got an unexpected keyword argument 'method' >> >> ---------------------------------------------------------------------- >> >> >> I've deleted all the .c files and rebuilt, and I'm still getting these >> exceptions. Do you know what that is from? > > Hmm, maybe you have easy_installed an older version of lxml? Setuptools plug > eggs into the system before the PYTHONPATH, so test.py may not be able to > import the correct version. The version output should tell you, though... There were some other lxml eggs on the path, but I think the trunk was above them since I'd just run "python setup.py develop". I tried python setup.py install, just in case there was something weird about develop, but same thing (either way it seems to be running out of the checkout, so presumably test.py is fixing up the path somehow). Here's the version information test.py gave: webdev$ python test.py TESTED VERSION: 2.0.alpha4-47900 Python: (2, 4, 4, 'candidate', 1) lxml.etree: (2, 0, -196, 47900) libxml used: (2, 6, 26) libxml compiled: (2, 6, 26) libxslt used: (1, 1, 17) libxslt compiled: (1, 1, 17) -- Ian Bicking : ianb(a)colorstudy.com : http://blog.ianbicking.org

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[lxml-dev] lxml trunk now requires Cython 0.9.6.8
by Stefan Behnel 04 Nov '07

04 Nov '07

Hi all, the current trunk now requires Cython 0.9.6.8 to build, as will 2.0alpha5. Many of the changes that lxml required in Pyrex (and that Cython provided) have now gone back into the mainstream distribution - but different. It was decided that Cython would follow these incompatible language changes, which now required some minor changes in lxml. This also means that external modules that use the C-API of lxml will need a little adaption as the name of the public import function has changed from "import_etree" to "import_lxml__etree". Everything else should work just as before. Note that lxml 1.3 will not be adapted. Future versions will continue to ship with a patched Pyrex and will not build with Cython or future Pyrex versions. Stefan

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lxml - The Python XML Toolkit November 2007