Mailman 3 August 2012 - lxml - The Python XML Toolkit

[lxml-dev] lxml has its page on launchpad
by Stefan Behnel April 11, 2023

April 11, 2023

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 April 10, 2023

April 10, 2023

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 Jan. 30, 2023

Jan. 30, 2023

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 Jan. 11, 2023

Jan. 11, 2023

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 Aug. 31, 2022

Aug. 31, 2022

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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Memory leak when parsing XML files in sequence?
by Maarten van Gompel (proycon) May 3, 2013

May 3, 2013

Hi, I stumbled across what I think it a memory leak within the lxml module. I am parsing literally millions of mostly small XML files, in sequence. In the following, simplified, fashion: index = glob.glob('/path/to/dir/with/huge/number/of/xml/files/*xml') for f in index: d = lxml.etree.parse(f) The problem is that (almost) every iteration, memory usage is increased. But note that d gets overwritten everytime and the reference to the previous document should be lost (I don't reference it anywhere else). Even an explicit 'del d' and gc.collect() within the loop doesn't help to clear up the extra memory. I used objgraph to debug a bit and the Python reference counts remain unchanged as I would expect, leaving me to conclude that this is a memory leak problem in the lxml module. This becomes problematic quickly when dealing with millions of XML files. I attach a short log excerpt in which I extracted resident memory usage from ps after each iteration and measure the increase. Note that I only parse the documents, to be overwritten each time, I don't do anything else with them in this test case. Is this a known problem? Is there anything else I explicitly need to do to free the memory used? The problem does not reproduce if I reload the same document over and over again. Memory usage remains constant then. It only happens when new documents are loaded, and even then in some rare cases the problem dos not occur for some or several iterations, most notably at the start of the log. I also attach an example of an XML file. Python 2.7.2 (ubuntu 11.10, x86_64) lxml.etree : (2, 3, 0, 0) libxml used : (2, 7, 8) libxml compiled : (2, 7, 8) libxslt used : (1, 1, 26) libxslt compiled : (1, 1, 26) Regards, -- Maarten van Gompel (Proycon) E-mail: proycon(a)anaproy.nl Homepage: http://proycon.anaproy.nl Google+: https://plus.google.com/105334152965507305708 Facebook: http://facebook.com/proycon Twitter: http://twitter.com/proycon

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Apache2 crashes
by Brieuc SCHAFF Feb. 12, 2013

Feb. 12, 2013

Hi, We are using lxml in several of our applications with Python 2.6 and from time to time, the application stops responding after a segmentation fault error, and this kind of backtrace: *Jul 1 15:35:01 server4 httpd: *** glibc detected *** /usr/sbin/apache2: malloc(): smallbin double linked list corrupted: 0x00007f583a03f500 **** *Jul 1 15:35:01 server4 httpd: ======= Backtrace: =========* *Jul 1 15:35:01 server4 httpd: /lib/libc.so.6(+0x77806)[0x7f58376c2806]* *Jul 1 15:35:01 server4 httpd: /lib/libc.so.6(+0x7bb39)[0x7f58376c6b39]* *Jul 1 15:35:01 server4 httpd: /lib/libc.so.6(__libc_malloc+0x6e)[0x7f58376c77de]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libxml2.so.2(xmlInitParserCtxt+0x317)[0x7f58343f2887]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libxml2.so.2(xmlNewParserCtxt+0x2c)[0x7f58343f2acc]* *Jul 1 15:35:01 server4 httpd: /usr/lib/python2.6/dist-packages/lxml/etree.so(+0x54eda)[0x7f5818db6eda]* *Jul 1 15:35:01 server4 httpd: /usr/lib/python2.6/dist-packages/lxml/etree.so(+0xddcf3)[0x7f5818e3fcf3]* *Jul 1 15:35:01 server4 httpd: /usr/lib/python2.6/dist-packages/lxml/etree.so(+0xab5ee)[0x7f5818e0d5ee]* *Jul 1 15:35:01 server4 httpd: /usr/lib/python2.6/dist-packages/lxml/etree.so(+0xb7d8e)[0x7f5818e19d8e]* *Jul 1 15:35:01 server4 httpd: /usr/lib/python2.6/dist-packages/lxml/etree.so(+0xb827e)[0x7f5818e1a27e]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyEval_EvalFrameEx+0x51a0)[0x7f582face030]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyEval_EvalFrameEx+0x5a98)[0x7f582face928]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyEval_EvalCodeEx+0x920)[0x7f582facfd60]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libpython2.6.so.1.0(+0x7dd60)[0x7f582fa55d60]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyObject_Call+0x53)[0x7f582fa282e3]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyEval_EvalFrameEx+0x3adf)[0x7f582facc96f]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyEval_EvalCodeEx+0x920)[0x7f582facfd60]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libpython2.6.so.1.0(+0x7dd60)[0x7f582fa55d60]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyObject_Call+0x53)[0x7f582fa282e3]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libpython2.6.so.1.0(+0x61cef)[0x7f582fa39cef]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyObject_Call+0x53)[0x7f582fa282e3]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libpython2.6.so.1.0(+0xb66dc)[0x7f582fa8e6dc]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyObject_Call+0x53)[0x7f582fa282e3]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyEval_CallObjectWithKeywords+0x43)[0x7f582fac8193] * *Jul 1 15:35:01 server4 httpd: /usr/lib/apache2/modules/mod_wsgi.so(+0x12fdb)[0x7f582fe9bfdb]* *Jul 1 15:35:01 server4 httpd: /usr/lib/apache2/modules/mod_wsgi.so(+0x17eed)[0x7f582fea0eed]* *Jul 1 15:35:01 server4 httpd: /usr/lib/libapr-1.so.0(+0x29eb3)[0x7f5837c14eb3]* *Jul 1 15:35:01 server4 httpd: /lib/libpthread.so.0(+0x69ca)[0x7f58379d49ca]* *Jul 1 15:35:01 server4 httpd: /lib/libc.so.6(clone+0x6d)[0x7f5837731cdd]* ----------------- *Jul 11 10:44:48 server4 httpd: *** glibc detected *** /usr/sbin/apache2: munmap_chunk(): invalid pointer: 0x00007f3968b8cb68 **** *Jul 11 10:44:48 server4 httpd: ======= Backtrace: =========* *Jul 11 10:44:48 server4 httpd: /lib/libc.so.6(+0x77806)[0x7f39789dd806]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libxml2.so.2(xmlResetError+0x22)[0x7f39755038e2]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libxml2.so.2(__xmlRaiseError+0x237)[0x7f3975504e07]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libxml2.so.2(__xmlSimpleError+0x6b)[0x7f397550543b]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libxml2.so.2(xmlParserInputBufferGrow+0x16b)[0x7f397553271b]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libxml2.so.2(xmlParserInputGrow+0x4c)[0x7f397550739c]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libxml2.so.2(+0x3bd52)[0x7f397550bd52]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libxml2.so.2(xmlParseDocument+0x4b8)[0x7f39755204c8]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libxml2.so.2(+0x505c5)[0x7f39755205c5]* *Jul 11 10:44:48 server4 httpd: /usr/lib/python2.6/dist-packages/lxml/etree.so(+0x8fab0)[0x7f3958ad8ab0]* *Jul 11 10:44:48 server4 httpd: /usr/lib/python2.6/dist-packages/lxml/etree.so(+0x2daa0)[0x7f3958a76aa0]* *Jul 11 10:44:48 server4 httpd: /usr/lib/python2.6/dist-packages/lxml/etree.so(+0x2ddc9)[0x7f3958a76dc9]* *Jul 11 10:44:48 server4 httpd: /usr/lib/python2.6/dist-packages/lxml/etree.so(+0xc26f0)[0x7f3958b0b6f0]* *Jul 11 10:44:48 server4 httpd: /usr/lib/python2.6/dist-packages/lxml/etree.so(+0xc431e)[0x7f3958b0d31e]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyEval_EvalFrameEx+0x51a0)[0x7f397063b030]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyEval_EvalCodeEx+0x920)[0x7f397063cd60]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libpython2.6.so.1.0(+0x7dd60)[0x7f39705c2d60]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyObject_Call+0x53)[0x7f39705952e3]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyEval_EvalFrameEx+0x3adf)[0x7f397063996f]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyEval_EvalCodeEx+0x920)[0x7f397063cd60]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libpython2.6.so.1.0(+0x7dd60)[0x7f39705c2d60]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyObject_Call+0x53)[0x7f39705952e3]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libpython2.6.so.1.0(+0x61cef)[0x7f39705a6cef]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyObject_Call+0x53)[0x7f39705952e3]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libpython2.6.so.1.0(+0xb66dc)[0x7f39705fb6dc]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyObject_Call+0x53)[0x7f39705952e3]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libpython2.6.so.1.0(PyEval_CallObjectWithKeywords+0x43)[0x7f3970635193] * *Jul 11 10:44:48 server4 httpd: /usr/lib/apache2/modules/mod_wsgi.so(+0x12fdb)[0x7f3970a08fdb]* *Jul 11 10:44:48 server4 httpd: /usr/lib/apache2/modules/mod_wsgi.so(+0x17eed)[0x7f3970a0deed]* *Jul 11 10:44:48 server4 httpd: /usr/lib/libapr-1.so.0(+0x29eb3)[0x7f3978f2feb3]* *Jul 11 10:44:48 server4 httpd: /lib/libpthread.so.0(+0x69ca)[0x7f3978cef9ca]* *Jul 11 10:44:48 server4 httpd: /lib/libc.so.6(clone+0x6d)[0x7f3978a4ccdd]* Stopping apache and restarting it fix the issue, but we have no idea why this is happening. We use Unbuntu 10.10's package of lxml, which is version 2.2.4. *>>> print("%-20s: %s" % ('Python', sys.version_info))* *Python : (2, 6, 5, 'final', 0)* *>>> print("%-20s: %s" % ('lxml.etree', etree.LXML_VERSION))* *lxml.etree : (2, 2, 4, 0)* *>>> print("%-20s: %s" % ('libxml used', etree.LIBXML_VERSION))* *libxml used : (2, 7, 6)* *>>> print("%-20s: %s" % ('libxml compiled', etree.LIBXML_COMPILED_VERSION))* *libxml compiled : (2, 7, 6)* *>>> print("%-20s: %s" % ('libxslt used', etree.LIBXSLT_VERSION))* *libxslt used : (1, 1, 26)* *>>> print("%-20s: %s" % ('libxslt compiled', etree.LIBXSLT_COMPILED_VERSION))* *libxslt compiled : (1, 1, 26)* * * Do you have any idea of what could cause these issues ? I wonder if upgrading to a newer version of the library could change anything. Thanks in advance for any answer you could provide. Regards, B. _____________________ Brieuc SCHAFF +33609898260 _____________________

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Memory debugging
by Christian Heimes Sept. 19, 2012

Sept. 19, 2012

Hello, I'd like to suggest a trival feature for lxml. libxml2 and libxslt support extended memory debugging when both libraries are compiled with the the '--with-mem-debug' flag [1]. This is useful to debug how many memory is actually used by the XML and XSTL code. In order to show the amount of used memory and memory blocks, the two functions xmlMemBlocks() [2] and xmlMemUsed() [3] needs to be wrapped. Both functions are available in non-debug builds and return 0 in that case. It might be worth to wrap the other debug helpers like xmlMemDisplay(FILE *) [4], too. Regards, Christian Example patch: diff -ru lxml-2.3.4.orig/src/lxml/lxml.etree.pyx lxml-2.3.4/src/lxml/lxml.etree.pyx --- lxml-2.3.4.orig/src/lxml/lxml.etree.pyx 2012-03-26 12:28:58.000000000 +0200 +++ lxml-2.3.4/src/lxml/lxml.etree.pyx 2012-05-03 18:33:00.702130662 +0200 @@ -2956,6 +2956,11 @@ except _TargetParserResult, result_container: return result_container.result +def memoryUsed(): + return tree.xmlMemUsed() + +def memoryBlocks(): + return tree.xmlMemBlocks() ################################################################################ # Include submodules diff -ru lxml-2.3.4.orig/src/lxml/tree.pxd lxml-2.3.4/src/lxml/tree.pxd --- lxml-2.3.4.orig/src/lxml/tree.pxd 2011-09-25 18:58:05.000000000 +0200 +++ lxml-2.3.4/src/lxml/tree.pxd 2012-05-03 17:44:50.323798041 +0200 @@ -322,6 +322,7 @@ cdef extern from "libxml/xmlmemory.h": cdef void* xmlMalloc(size_t size) nogil cdef int xmlMemBlocks() nogil + cdef int xmlMemUsed() nogil cdef extern from "etree_defs.h": cdef bint _isElement(xmlNode* node) nogil [1] http://xmlsoft.org/html/libxml-xmlmemory.html#DEBUG_MEMORY [2] http://xmlsoft.org/html/libxml-xmlmemory.html#xmlMemBlocks [3] http://xmlsoft.org/html/libxml-xmlmemory.html#xmlMemUsed [4] http://xmlsoft.org/html/libxml-xmlmemory.html#xmlMemDisplay

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Building lxml with mac os x mountain lion fails.
by Mark Grandi Sept. 12, 2012

Sept. 12, 2012

Hello, I'm trying to build lxml on mac os x 10.8 and the build fails. I've also tried to change the compiler from gcc to clang, and it still fails. Output: http://paste.ubuntu.com/1172867/ (this is the output when CC=clang) any ideas? =/ ~mark

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lxml 3.0 alpha2 released
by Stefan Behnel Aug. 24, 2012

Aug. 24, 2012

Hi everyone, I'm proud to announce the second alpha release of lxml 3.0. This release features initial support for PyPy and a new tree API for DTDs (by Walter Dörwald), as well as some major cleanups in the code base. The lxml.cssselect package was moved into a separate PyPI project nicely extended and maintained by Simon Sapin. Originally, this release was targeted as lxml 2.4, but some major improvements as well as a couple of potentially incompatible changes make "3.0" appear more appropriate. This release is available from PyPI: http://pypi.python.org/pypi/lxml/3.0alpha2 The documentation is here: http://lxml.de/3.0/ Download: http://lxml.de/files/lxml-3.0alpha2.tgz Signature: http://lxml.de/files/lxml-3.0alpha2.tgz.asc GitHub: https://github.com/lxml/lxml/commit/ff1ba90049003f8badfb0a833125d09d8692af1d This release was built using Cython 0.17b3. If you are interested in commercial support or customisations for the lxml package, please contact me directly. Have fun, Stefan 3.0alpha2 (2012-08-23) ====================== Features added -------------- * The .iter() method of elements now accepts tag arguments like "{*}name" to search for elements with a given local name in any namespace. With this addition, all combinations of wildcards now work as expected: "{ns}name", "{}name", "{*}name", "{ns}*", "{}*" and "{*}*". Note that "name" is equivalent to "{}name", but "*" is "{*}*". The same change applies to the .getiterator(), .itersiblings(), .iterancestors(), .iterdescendants(), .iterchildren() and .itertext() methods, the strip_attributes(), strip_elements() and strip_tags() functions as well as the iterparse() function. * C14N allows specifying the inclusive prefixes to be promoted to top-level during exclusive serialisation. Bugs fixed ---------- * Passing long Unicode strings into the feed() parser interface failed to read the entire string. Other changes ------------- * The code was adapted to work with the upcoming libxml2 2.9.0 release. 3.0alpha1 (2012-07-31) ====================== Features added -------------- * Initial support for building in PyPy (through cpyext). * DTD objects gained an API that allows read access to their declarations. * xpathgrep.py gained support for parsing line-by-line (e.g. from grep output) and for surrounding the output with a new root tag. * E-factory in lxml.builder accepts subtypes of known data types (such as string subtypes) when building elements around them. * Tree iteration and iterparse() with a selective tag argument supports passing a set of tags. Tree nodes will be returned by the iterators if they match any of the tags. Bugs fixed ---------- * The .find*() methods in lxml.objectify no longer use XPath internally, which makes them faster in many cases (especially when short circuiting after a single or couple of elements) and fixes some behavioural differences compared to lxml.etree. Note that this means that they no longer support arbitrary XPath expressions but only the subset that the ElementPath language supports. The previous implementation was also redundant with the normal XPath support, which can be used as a replacement. * el.find('*') could accidentally return a comment or processing instruction that happened to be in the wrong spot. (Same for the other .find*() methods.) * The error logging is less intrusive and avoids a global setup where possible. * Fixed undefined names in html5lib parser. * xpathgrep.py did not work in Python 3. * Element.attrib.update() did not accept an attrib of another Element as parameter. * For subtypes of ElementBase that make the .text or .tail properties immutable (as in objectify, for example), inserting text when creating Elements through the E-Factory feature of the class constructor would fail with an exception, stating that the text cannot be modified. Other changes -------------- * The code base was overhauled to properly use 'const' where the API of libxml2 and libxslt requests it. This also has an impact on the public C-API of lxml itself, as defined in etreepublic.pxd, as well as the provided declarations in the lxml/includes/ directory. Code that uses these declarations may have to be adapted. On the plus side, this fixes several C compiler warnings, also for user code, thus making it easier to spot real problems again. * The functionality of "lxml.cssselect" was moved into a separate PyPI package called "cssselect". To continue using it, you must install that package separately. The "lxml.cssselect" module is still available and provides the same interface, provided the "cssselect" package can be imported at runtime. * Element attributes passed in as an attrib dict or as keyword arguments are now sorted by (namespaced) name before being created to make their order predictable for serialisation and iteration. Note that adding or deleting attributes afterwards does not take that order into account, i.e. setting a new attribute appends it after the existing ones. * Several classes that are for internal use only were removed from the lxml.etree module dict: _InputDocument, _ResolverRegistry, _ResolverContext, _BaseContext, _ExsltRegExp, _IterparseContext, _TempStore, _ExceptionContext, __ContentOnlyElement, _AttribIterator, _NamespaceRegistry, _ClassNamespaceRegistry, _FunctionNamespaceRegistry, _XPathFunctionNamespaceRegistry, _ParserDictionaryContext, _FileReaderContext, _ParserContext, _PythonSaxParserTarget, _TargetParserContext, _ReadOnlyProxy, _ReadOnlyPIProxy, _ReadOnlyEntityProxy, _ReadOnlyElementProxy, _OpaqueNodeWrapper, _OpaqueDocumentWrapper, _ModifyContentOnlyProxy, _ModifyContentOnlyPIProxy, _ModifyContentOnlyEntityProxy, _AppendOnlyElementProxy, _SaxParserContext, _FilelikeWriter, _ParserSchemaValidationContext, _XPathContext, _XSLTResolverContext, _XSLTContext, _XSLTQuotedStringParam * Several internal classes can no longer be inherited from: _InputDocument, _ResolverRegistry, _ExsltRegExp, _ElementUnicodeResult, _IterparseContext, _TempStore, _AttribIterator, _ClassNamespaceRegistry, _XPathFunctionNamespaceRegistry, _ParserDictionaryContext, _FileReaderContext, _PythonSaxParserTarget, _TargetParserContext, _ReadOnlyPIProxy, _ReadOnlyEntityProxy, _OpaqueDocumentWrapper, _ModifyContentOnlyPIProxy, _ModifyContentOnlyEntityProxy, _AppendOnlyElementProxy, _FilelikeWriter, _ParserSchemaValidationContext, _XPathContext, _XSLTResolverContext, _XSLTContext, _XSLTQuotedStringParam, _XSLTResultTree, _XSLTProcessingInstruction

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