Mailman 3 April 2019 - lxml - The Python XML Toolkit

[lxml-dev] lxml has its page on launchpad
by Stefan Behnel 11 Apr '23

11 Apr '23

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] Checking whether a node is a comment/element
by Geoffrey Sneddon 10 Apr '23

10 Apr '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] 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] 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] 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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Accessing variables from within an XSL file
by Adrian Bool 05 Apr '21

05 Apr '21

Hi, I'm trying to extract from data from XSL files on an IBM DataPower system. I can't change the XSLT files - and therefore need to work around their current structure to get the info I need. I'm doing this from within Python 3.7 using etree.__version__ 4.3.3. Here are my imports, a dummy XML object and a cutdown version of the XSL file from the IBM system: from lxml import etree from textwrap import dedent xml = etree.XML("""<root></root>""") xsl = etree.XML(dedent( """<?xml version="1.0"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:dp="http://www.datapower.com/extensions" extension-element-prefixes="dp"> <xsl:template match="node()|@*"> <xsl:copy> <xsl:apply-templates select="node()|@*"/> </xsl:copy> <xsl:variable name="destination_url"> <xsl:value-of select="'https://my.domain.example.com/'" /> </xsl:variable>  <dp:set-variable name="'var://context/mpgw/Destination'" value="$destination_url" /> </xsl:template> </xsl:stylesheet> """)) My goal is to use lxml to process this file and extract the contents of the DataPower variable 'var://context/mpgw/Destination' - i.e. the contents of the xsl:variable $destination_url - in the above case ' https://my.domain.example.com/'. I've created an XSLT extension for the "dp:set-variable" element to try to capture this information: class MyExtElement(etree.XSLTExtension): def execute(self, context, self_node, input_node, output_parent): if self_node.tag == '{ http://www.datapower.com/extensions}set-variable': print(f"Setting variable of name {self_node.get('name')} to value {self_node.get('value')}") extensions = { ('http://www.datapower.com/extensions', 'set-variable') : MyExtElement() } result = etree.XSLT(xsl, extensions=extensions)(xml) print(f"Result: {result}") When this is being called; instead of the value of destination_url I'm getting the static "$destination_url" string instead - with the output of the above script being: Setting variable of name 'var://context/mpgw/Destination' to value $destination_url Result: <?xml version="1.0"?> <root/> I am rather suprised that the $destination_url xsl:variable was not being evaluated - does anyone know why this is the case? Given the above, I've been trying to find a way to access the $destination_url xsl:variable from within my XSLTExtension - but unfortunately with no luck. Some things I've tried: * Calling self.process_children(context) within the extension - this just results in an empty list. * I've used dir() to look through the context, self_node and input_node args to try to find somewhere the variables may be accessible but with no luck. * I've used deepcopy to clone self_node to get an xpath function on this argument and made some attempts at using xpath to access the xsl variable - all unsuccessful: node = deepcopy(self_node) node.xpath("""<xsl:value-of select="$destination_url">""") *** lxml.etree.XPathEvalError: Invalid expression node.xpath("""$destination_url""") *** lxml.etree.XPathEvalError: Undefined variable node.xpath("""xsl:$destination_url""") *** lxml.etree.XPathEvalError: Invalid expression node.xpath("""xsl:$destination_url""", namespaces={'xsl':'http://www.w3.org/1999/XSL/Transform'}) *** lxml.etree.XPathEvalError: Invalid expressio node.xpath("""$destination_url""", namespaces={'xsl':'http://www.w3.org/1999/XSL/Transform'}) *** lxml.etree.XPathEvalError: Undefined variable node.xpath("""/xsl:$destination_url""", namespaces={'xsl':'http://www.w3.org/1999/XSL/Transform'}) *** lxml.etree.XPathEvalError: Invalid expression node.xpath("""<xsl:value-of select="$destination_url">""", namespaces={'xsl':'http://www.w3.org/1999/XSL/Transform'}) *** lxml.etree.XPathEvalError: Invalid expression I'm lost now! Any suggestions greatly appreciated! Cheers, aid

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Install steps question
by Elin Klaseen 29 Apr '19

29 Apr '19

Hello New to lxml. Not a sophisticated user. On an openSUSE (tumbleweed). Python (2.7.10) site packages are on a shared mount (say under /XXXX). Have done: # STATICBUILD=true pip install --target=/XXXX/opt/python/lib/python2.7/site-packages lxml Collecting lxml Using cached https://files.pythonhosted.org/packages/35/8a/5e066949f2b40caac32c7b2a77da6… Installing collected packages: lxml Successfully installed lxml-4.3.3 The python path finds the lxml package, but not the etree module. > python Python 2.7.10 (default, Jul 31 2015, 15:45:52) [GCC 4.1.2 20061115 (prerelease) (SUSE Linux)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> from lxml import etree Traceback (most recent call last): File "<stdin>", line 1, in <module> ImportError: cannot import name etree >>> import lxml >>> Here is what is in the (above pip-installed) site-packages. # ls -lrt total 11056 -rw-r--r-- 1 root root 9406 Apr 29 12:15 sax.py -rw-r--r-- 1 root root 10189 Apr 29 12:15 _elementpath.py -rwxr-xr-x 1 root root 250837 Apr 29 12:15 sax.cpython-36m-x86_64-linux-gnu.so -rwxr-xr-x 1 root root 306132 Apr 29 12:15 _elementpath.cpython-36m-x86_64-linux-gnu.so -rwxr-xr-x 1 root root 6687968 Apr 29 12:15 etree.cpython-36m-x86_64-linux-gnu.so -rw-r--r-- 1 root root 230 Apr 29 12:15 usedoctest.py -rw-r--r-- 1 root root 551 Apr 29 12:15 __init__.py -rw-r--r-- 1 root root 17466 Apr 29 12:15 etree_api.h -rw-r--r-- 1 root root 7668 Apr 29 12:15 ElementInclude.py -rw-r--r-- 1 root root 7975 Apr 29 12:15 builder.py -rwxr-xr-x 1 root root 3766994 Apr 29 12:15 objectify.cpython-36m-x86_64-linux-gnu.so -rw-r--r-- 1 root root 17471 Apr 29 12:15 lxml.etree_api.h -rw-r--r-- 1 root root 3366 Apr 29 12:15 cssselect.py -rw-r--r-- 1 root root 92 Apr 29 12:15 pyclasslookup.py -rw-r--r-- 1 root root 8554 Apr 29 12:15 lxml.etree.h -rw-r--r-- 1 root root 8554 Apr 29 12:15 etree.h -rw-r--r-- 1 root root 18339 Apr 29 12:15 doctestcompare.py -rwxr-xr-x 1 root root 144548 Apr 29 12:15 builder.cpython-36m-x86_64-linux-gnu.so drwxr-xr-x 3 root root 4096 Apr 29 12:15 html drwxr-xr-x 4 root root 58 Apr 29 12:15 isoschematron drwxr-xr-x 2 root root 4096 Apr 29 12:15 __pycache__ drwxr-xr-x 6 root root 4096 Apr 29 12:15 includes What am I missing/misdoing in this install process? Thanks in advance, Elin.

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AttributeError: 'str' object has no attribute 'copy' from lxml.etree._XSLTResultTree.write_output
by Jan Pazdziora 18 Apr '19

18 Apr '19

When OSError happens during lxml.etree._XSLTResultTree.write_output, exception AttributeError: 'str' object has no attribute 'copy' is raised, instead of some error indicating the real cause of the problem. Consider the following poor man's test to attempt to write to a file in subdirectory which does not exist. diff --git a/src/lxml/tests/test_xslt.py b/src/lxml/tests/test_xslt.py index f6b48fb9..6fd5dada 100644 --- a/src/lxml/tests/test_xslt.py +++ b/src/lxml/tests/test_xslt.py @@ -223,6 +223,20 @@ class ETreeXSLTTestCase(HelperTestCase): finally: os.unlink(f.name) + def test_xslt_write_output_file_oserror(self): + with self._xslt_setup() as res: + f = NamedTemporaryFile(suffix='.xml.gz', delete=False) + name_in_subdir = f.name.replace('.xml.gz', '/a.xml.gz') + try: + try: + res[0].write_output(name_in_subdir, compression=1) + finally: + f.close() + with gzip.GzipFile(f.name) as f: + res[0] = f.read().decode("UTF-16") + finally: + os.unlink(f.name) + def test_xslt_unicode(self): expected = ''' <?xml version="1.0"?> When running this test, I get ====================================================================== ERROR: test_xslt_write_output_file_oserror (src.lxml.tests.test_xslt.ETreeXSLTTestCase) ---------------------------------------------------------------------- Traceback (most recent call last): File "/home/adelton/project/lxml/src/lxml/tests/test_xslt.py", line 232, in test_xslt_write_output_file_oserror res[0].write_output(name_in_subdir, compression=1) File "src/lxml/xslt.pxi", line 753, in lxml.etree._XSLTResultTree.write_output if self._context_node is not None: File "src/lxml/etree.pyx", line 207, in lxml.etree.LxmlError.__init__ else: AttributeError: 'str' object has no attribute 'copy' It seems like the handling within lxml.etree.LxmlError fails, making it hard to catch the real error in the code which uses lxml. -- Jan Pazdziora Senior Principal Software Engineer, Security Engineering, Red Hat

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Extending PyErrorLog and level_map
by Majewski, Steven Dennis (sdm7g) 18 Apr '19

18 Apr '19

I’m trying to extend PyErrorLog, and since I’m using XMLParser( recover=True ), I’m trying to change all of the reported Levels to WARNING and log XML Syntax errors via etree.use_global_python_log(XMLErrorLog(logger=logging.getLogger(__name__).getChild('XMLParser'))) When I try to add level_map as an instance variable in my classes __init__() method, I get an error message saying that it’s not a writable attribute. When I add a level_map as a class variable, it doesn’t complain, but it doesn’t appear to use it in the mapping. With this mapping, everything is still tagged as CRITICAL or ERROR. class XMLErrorLog(etree.PyErrorLog): level_map = { etree.ErrorLevels.WARNING : logging.WARNING, etree.ErrorLevels.ERROR : logging.WARNING, etree.ErrorLevels.FATAL : logging.WARNING } I have then tried to modify level of the _LogEntry passed to receive before calling log method, but that also does not appear to be possible. I’ve finally managed to get something to work by using: class LogEntry(object): level = 1 And in my XMLErrorLog class: def receive(self, log_entry ): logrepr = "[ %s:%d:%d:%s:%s:%s: %s ]" % ( '', log_entry.line, log_entry.column, "Warning", log_entry.domain_name, log_entry.type_name, log_entry.message) self.log( LogEntry(), logrepr ) But it seemed from the documentation that providing the level_map in my class should have been enough. Am I missing something, or is the documentation incorrect ? — Steve Majewski

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lxml.de web site
by Thomas Burg 05 Apr '19

05 Apr '19

Hello At my end I observe that https://lxml.de automatically redirect to https://www.fridaysforfuture.org/ Is this the normal behavior ? Thx Thomas

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