lxml - The Python XML Toolkit November 2017

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9 participants
10 discussions

[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] Checking whether a node is a comment/element
by Geoffrey Sneddon 11 Jan '23

11 Jan '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] 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] lxml has its page on launchpad
by Stefan Behnel 20 Sep '22

20 Sep '22

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] Building LXML Trunk
by Sidnei da Silva 30 Aug '22

30 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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starting root.iter(*tags) midway through
by Chris Jerdonek 26 Nov '17

26 Nov '17

Hi, I have a seemingly simple lxml.etree use case, but the API doesn't seem to support it. Say I have an Element "root" at the root of a tree, and say I have an element "element" inside the tree. Is there an efficient way to get the element **after** "element" (in document order), and matching given tags? It would suffice to be able to specify the starting point for the iterator `root.iter(*tags)` -- in other words to start it midway through. Is there a way to do that that doesn't involve, say, first iterating through the first elements of `root.iter(*tags)`? Thanks, --Chris

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XML Schema validation
by Frank Millman 22 Nov '17

22 Nov '17

Hi all I seems that there are two ways of validating an xml document with XML Schema. 1. Create a XMLParser object and pass it an XMLSchema object as an argument. If you use this parser object with etree.parse() or etree.fromstring(), it validates the document against the schema while parsing. 2. Parse the document first, and then validate it using XMLSchema.validate() or XMLSchema.assertValid(). I have always used the first method – I was unaware of the second one. However, I have just found a particular error that is detected by the second method, but not by the first one. The error is the use of duplicate “id” attributes, if it is specified in the schema as being of type “xs:ID”. I have a document with duplicate ids. Validating with the first method passes. Validating the same document, with the same schema, using the second method, gives the following - lxml.etree.DocumentInvalid: Element '{http://www.omg.org/spec/BPMN/20100524/MODEL}dataOutput', attribute 'id': 'user_row_id' is not a valid value of the atomic type 'xs:ID'., line 38 Is this a bug? Should I always use the second method? I am using lxml version 4.1.1. Thanks Frank Millman P.S. This is a copy of a message I posted on 26/03/2017. I got no reply to that, so I thought I would try again. I was using version 3.6.4 then, but the behaviour is the same with 4.1.1.

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lxml xslt functions suppport
by P. Remek 15 Nov '17

15 Nov '17

Hello, are XSLT functions supported in lxml (I am now using 4.1 lxml)? For example I have: <xsl:function name="foo:prettyIndent"> <xsl:param name="s"/> <xsl:for-each select="1 to 4*($s - 2)"> </xsl:for-each> </xsl:function> And then use it in "select" statements in temaplates. When I use my function in the select statement, I get "XSLTParseError: Invalid expression" - so I suspect that this feature is not supported in lxml. Regards, remek

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insert() makes _ElementTree forget?
by Duthie, Roger J.A. 08 Nov '17

08 Nov '17

Dear LXML.de mailing list, This is my first post to the list. I have been using LXML for a few months now and have been learning the idiosyncrasies of the package over this time. I'm now at the point when I can question the behaviour of the package. Hopefully, someone can explain what is going on in my code and whether it is known and anticipated behaviour. The situation I'd like to present occurs when parsing an XSD, then modifying it and creating an XML Schema validator using LXML. It seems that if I parse an XSD - i.e. parse([...XSD...]) - with relative links - in an <xs:include> element, in this case - then create a validator from the resultant _ElementTree, all is well (cf., Example 1, below); however, if I modify the _ElementTree - by inserting an <xs:import> element, in this case - the validation creating fails (cf., Example 2). If the XSD is modified to have an absolute path specified in the <xs:include> element, the validation creation passes (cf., Example 3). So, I can get round the problem by making further modifications, but why should I have to? (In fact, I'm not sure that this modification would be so trivial in the general case.) Additionally, specifying a base_url at the parse() stage seems to have no effect. It seems like the _ElementTree object forgets it's origin when the tree is modified. Is this expected? I would like to be able to understand the processes LXML is undertaking. Perhaps there is another way to parse, which is better suited. I look forward to hearing sage words of wisdom. Thanks in advance, Roger -------------- Code examples: -------------- This example shows that the XSD is fine if a validator is simply created without modifying the _ElementTree: # Example 1 : this code is fine from lxml import etree # create initial xsd etree gco_etree = etree.parse('http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/…') # attempt to create a validator - THIS IS FINE! gco_val = etree.XMLSchema(gco_etree) This second one shows that my intended method fails, if I add in an additional _Element into the _ElementTree: # Example 2: this code will fail from lxml import etree # create initial xsd etree gco_etree = etree.parse('http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/…') # create the SDN extension import element xs_namespace = 'http://www.w3.org/2001/XMLSchema' xs_nsmap = {'xs':xs_namespace} import_tag = '{%s}import' % xs_namespace sdn_import_attrib = {'namespace':'http://www.seadatanet.org','schemaLocation':'http://schemas.seadatanet.org/Standards-Software/Metadata-formats/SDN2_CDI_…'} sdn_import_element = etree.Element(import_tag, attrib=sdn_import_attrib, nsmap=xs_nsmap) # inject the SDN import element into the ISO schema gco_etree.getroot().insert(0,sdn_import_element) # attempt to create a validator - THIS WILL FAIL gco_val = etree.XMLSchema(gco_etree) This third one shows that it is the fact that the include element has a relative link that causes the issue: # Example 3 : this code is also fine from lxml import etree # create initial xsd etree gco_etree = etree.parse('http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/…') # create the SDN extension import element xs_namespace = 'http://www.w3.org/2001/XMLSchema' xs_nsmap = {'xs':xs_namespace} import_tag = '{%s}import' % xs_namespace sdn_import_attrib = {'namespace':'http://www.seadatanet.org','schemaLocation':'http://schemas.seadatanet.org/Standards-Software/Metadata-formats/SDN2_CDI_…'} sdn_import_element = etree.Element(import_tag, attrib=sdn_import_attrib, nsmap=xs_nsmap) # remove the old include element bad_include = gco_etree.getroot().find('xs:include',namespaces=xs_nsmap)[0] gco_etree.getroot().remove(bad_include) #create absolute include element include_tag = '{%s}include' % xs_namespace gcoBasicTypes_include_attrib = {'schemaLocation':'http://www.isotc211.org/2005/gco/basicTypes.xsd'} gcoBasicTypes_include_element = etree.Element(include_tag, attrib=gcoBasicTypes_include_attrib, nsmap=xs_nsmap) # inject the new include gco_etree.getroot().insert(0,gcoBasicTypes_include_element) # inject the SDN import element into the ISO schema gco_etree.getroot().insert(0,sdn_import_element) # attempt to create a validator - THIS IS ALSO FINE gco_val = etree.XMLSchema(gco_etree) ----------- System Info ----------- Python : sys.version_info(major=3, minor=4, micro=5, releaselevel='final', serial=0) lxml.etree : (3, 8, 0, 0) libxml used : (2, 9, 3) libxml compiled : (2, 9, 3) libxslt used : (1, 1, 29) libxslt compiled : (1, 1, 29) ________________________________ This message (and any attachments) is for the recipient only. NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system. ________________________________

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Idea: add with_top=True param to lxml.html.tostring()
by martin＠bitdweller.com 06 Nov '17

06 Nov '17

Hey folks, to get the HTML within an element as a string (ie. innerHTML) you currently need to: ''.join([x.text, *[lxml.html.tostring(y,encoding='unicode') for y in x]]) I therefore think a with_top=True parameter should be added to lxml.html.tostring(). Best regards, Martin

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lxml - The Python XML Toolkit November 2017