Mailman 3 January 2012 - lxml - The Python XML Toolkit

Shorthand for etree.SubElement()
by Kerrick Staley Jan. 6, 2012

Jan. 6, 2012

Hello, Is it possible to write etree.SubElement(node, tagName) as node.someMethod(tagName) ? I have the code td = etree.SubElement(tBody, 'td') etree.SubElement(td, 'p').text = 'some text' and would like to replace it with tBody.someMethod('td').someMethod('p').text = 'some text' . Thanks, Kerrick

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Easy Install no longer working
by Ben Bouchard Jan. 4, 2012

Jan. 4, 2012

Hello, Just thought I'd give you a heads up that using easy_install for lxml appears to be broken following the update. It appears to resolve the package to .tgz (what the previous extension was), however the new one is clearly a tar.gz. This returns a 404, preventing the install from proceeding. Most references I found to the update appear to be correct on pypi, but I did notice that the link on the homepage under "Download" still uses the old extension. I might be hitting a bad cache somewhere, but just thought I'd let you guys know if not. -- Benjamin Bouchard Software Engineer MicroStrain Inc. 802.862.6629 www.microstrain.com Confidentiality Notice: This communication may contain information which is proprietary and/or confidential and is intended exclusively for the person(s) to whom it is addressed. If you are not an intended recipient, you may not forward, copy, use, save or rely on this communication, and any such action is prohibited and unauthorized. If you have received this communication in error, please reply to this communication notifying sender and permanently deleting all copies, including your reply. MicroStrain, Inc. 459 Hurricane Lane, Suite 102, Williston, VT 05495 USA.

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lxml 2.3.3 released
by Stefan Behnel Jan. 4, 2012

Jan. 4, 2012

Hi everyone, I'm happy to announce the release of lxml 2.3.3. This is a bug fix release of the stable 2.3 series. Above all, it fixes a crash bug in iterparse() for HTML parsing. http://lxml.de/ http://pypi.python.org/pypi/lxml/2.3.3/ This release was built using Cython 0.15.1. It is recommended (although not required) to use at least libxml2 2.7.8 with lxml, which fixes a number of important bugs compared to the previous 2.7.x releases. Note that this release does not support CPython 2.3, which has long terminated its extended security-fix-only maintenance period back in March 2008. CPython 2.4.x and 2.5.x, although equally out of maintenance by python.org, continue to be supported to accommodate for their long term maintenance in certain Linux/Unix server installations. Please consider supporting the project financially. See the project home page on this. Thank you! Have fun, Stefan 2.3.3 (2012-01-04) Features added * lxml.html.tostring() gained new serialisation options with_tail and doctype. Bugs fixed * Fixed a crash when using iterparse() for HTML parsing and requesting start events. * Fixed parsing of more selectors in cssselect. Whitespace before pseudo- elements and pseudo-classes is significant as it is a descendant combinator. "E :pseudo" should parse the same as "E *:pseudo", not "E:pseudo". Patch by Simon Sapin. * lxml.html.diff no longer raises an exception when hitting 'img' tags without 'src' attribute.

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lxml debug version
by Yaron Jan. 3, 2012

Jan. 3, 2012

Hello, I would appreciate if anyone can explain how to build lxml Windows DEBUG kit. If anyone has an already compiled debug version, that will be great. Many thanks in advance, Yaron

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Minimal example of lxml writing an XML file and then reading and validating it against an XSD
by Duane Kaufman Jan. 3, 2012

Jan. 3, 2012

Hi, My name is Duane Kaufman, and I am new to this list (please be gentle :) I am new to XML (not to Python), and I am wrestling with trying to get lxml to perform a task for me (I am on Windows XP, Python 2.7 lxml 2.3). I want to: 1) Use lxml to create an XML file 2) (Manually) create an XML Schema (XSD) file for the created XML file 3) Use lxml to read the XML file, validating it against the XSD file from 2) I have tried: MyXMLWriter.py: #------------------------- ScriptRootDir = r'H:\My Documents\Manufacturing\my_python\XML_Test\XMLSchema_test' def main(): global ScriptRootDir # Script to test the use of package lxml to pass XML messages containing data # This script will write out an XML file which will be a message with data from lxml import objectify from lxml import etree import os root = objectify.Element("root") root.StationName = objectify.DataElement("BaseDispensing", _xsi="string") root.MessageType = objectify.DataElement("BasePartUnloadedData", _xsi="string") objectify.deannotate(root, xsi=False) print(etree.tostring(root, pretty_print=True, xml_declaration=True)) et = etree.ElementTree(root) fp = open(os.path.join(ScriptRootDir, "Test.xml"), "w") et.write(fp, pretty_print=True, xml_declaration=True) fp.close() if __name__ == '__main__': main() #------------------------ Output from MyXMLWriter.py (Test.xml): #------------------------ <?xml version='1.0' encoding='ASCII'?> <root xmlns:py="http://codespeak.net/lxml/objectify/pytype":xsd="http://www.w3 .org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <StationName xsi:type="xsd:string">BaseDispensing</StationName> <MessageType xsi:type="xsd:string">BasePartUnloadedData</MessageType> </root> #----------------------- Test.xsd: #------------------ <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"> </xsd:schema> #------------------ MyXMLReader.py: #------------------ ScriptRootDir = r'H:\My Documents\Manufacturing\my_python\XML_Test\XMLSchema_test' XMLSchemaFilename = "Test2.xsd" def main(): global ScriptRootDir # Script to test the use of package lxml to pass XML messages containing data # This script will read in an XML file which will be a message with data # into a Python data structure from lxml import etree import os # read and parse XML Schema file xsd_doc = etree.parse(XMLSchemaFilename) xsd = etree.XMLSchema(xsd_doc) MessageObject = etree.parse(os.path.join(ScriptRootDir, "Test.xml")) xsd.validate(MessageObject) print xsd.error_log if __name__ == '__main__': main() #------------------------ When running MyXMLReader.py, I get the output: file:///H:/My%20Documents/Manufacturing/my_python/XML_Test/XMLSchema_tes t/Test.xml:1:0:ERROR:SCHEMASV:SCHEMAV_CVC_ELT_1: Element 'root': No matching global declaration available for the validation root. How do I get this to work from end-to-end? Thanks in advance, Duane

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Passing xpath results to ElementMaker
by Jeffrey Yasskin Jan. 3, 2012

Jan. 3, 2012

I'm writing an XML-transforming script with lxml, and I've run into two unexpected behaviors: First, ElementMaker doesn't accept the string results of xpath expressions: >>> elem = etree.parse(io.StringIO('<root><node>text</node></root>')) >>> E.b(elem.xpath('string(node)')) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/opt/local/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/lxml/builder.py", line 220, in __call__ raise TypeError("bad argument type: %r" % item) TypeError: bad argument type: 'text' >>> type(elem.xpath('string(node)')) <class 'lxml.etree._ElementUnicodeResult'> This happens because https://github.com/lxml/lxml/blob/master/src/lxml/builder.py#L215 looks up the exact type of the argument in a dict, rather than doing something that can respect _ElementUnicodeResult's inheritance from str. Is this the right behavior for some reason I haven't thought of, or is it just an oversight? The workaround is straightforward—just pass the xpath result through str()—but it seems more verbose than should be necessary. Second, ElementMaker doesn't accept lists at all: >>> etree.tostring(E.b(elem.xpath('node'))) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/opt/local/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/lxml/builder.py", line 220, in __call__ raise TypeError("bad argument type: %r" % item) TypeError: bad argument type: [<Element node at 0x106eb8d70>] Accepting lists would also be useful for building HTML documents as E.section("Header text", function_returning_element_sequence(), "Footer text"). The workarounds for this are straightforward too: >>> etree.tostring(E.b(elem.xpath('node')[0])) b'<b><node>text</node></b>' >>> etree.tostring(E.b(*elem.xpath('node'))) b'<b/>' ... oops. Looks like ElementMaker re-parents nodes passed to it rather than copying them when they already have a parent. That's a third surprise, although it makes sense if ElementMaker was only intended for building entirely new documents, rather than copying bits from existing documents. This is with python-3.2.2, lxml-2.3.0, and libxml-2.7.8, Are these worth filing bugs/feature requests about? Thanks, Jeffrey

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