Re: [xslt] Issues using parameters with namespaces
On Tue, Mar 1, 2022 at 3:37 AM Nick Wellnhofer wrote: > On 28/02/2022 22:07, George Joseph wrote: > > Actually "//*[name()='dm:device']" works as well so maybe that's what > I'll do. > > This seems like the best work-around. > Yeah makes sense. I'll need to do some performance testing regardless of which way I go since I'm parsing SIP messages in real time. > > Is there any reason why path parameters with namespaces haven't been > > supported? > > Would a pull request to add the namespaces > in xsltNewTransformContext be > > considered? > > How parameters are passed isn't covered by the standard, so it's up to the > implementation to come up with something. It seems natural to allow XPath > expressions, but it's not clear how to handle namespaces. Simply taking > the > namespace defitinions from the root element of the root stylesheet should > do > what most people expect, but it is somewhat fragile. > > True. > 1. Passing parameters from the command line > > Supporting namespaces in a clean way would probably require a separate > channel > to register namespaces just for parameter evaluation. Even Saxon doesn't > seem > to support custom namespaces in parameter expressions: > > "The static context for this XPath expression includes only the standard > namespaces conventionally bound to the prefixes xs, fn, xsi, and saxon." > [1] > > 2. Passing parameters using the API > > The most flexible approach is probably an API to set parameters directly, > similar to Saxon's XsltTransformer [2]. This would even allow to pass > nodes > from external documents as parameters. But if you want to combine that > with > XPath expressions, you'd have to evaluate them yourself. > > Nick > > Gotcha. Thanks for all your help Nick! > > [1] > https://www.saxonica.com/documentation11/index.html#!using-xsl/commandline > [2] > > https://www.saxonica.com/documentation11/index.html#!javadoc/net.sf.saxon.s9api/XsltTransformer@setParameter > ___ xslt mailing list, project page http://xmlsoft.org/XSLT/ xslt@gnome.org https://mail.gnome.org/mailman/listinfo/xslt
Re: [xslt] Issues using parameters with namespaces
On Mon, Feb 28, 2022 at 2:01 PM George Joseph wrote: > > > On Mon, Feb 28, 2022 at 1:04 PM Nick Wellnhofer > wrote: > >> On 28/02/2022 20:54, George Joseph via xslt wrote: >> > I think it works because xsltProcessUserParamInternal only sets >> > xpctxt->namespaces = NULL but it doesn't clear xpctxt->nsHash which is >> where >> > xmlXPathRegisterNs puts the namespaces to be registered. >> >> Right, the XPath engine uses both ->namespaces and ->nsHash. >> >> > Can you give me a hint? I've had absolutely no luck is trying to pass >> a path >> > as a string and getting it to result in something other than "The >> 'select' >> > expression >> > did not evaluate to a node set" even in an absurdly simple example. >> I'm passing >> > the path double quoted "'/dm:device'" and have tried various >> combinations of >> > "select=" and "with-param".Even Google is failing me so any help >> would be >> > appreciated. >> >> I meant that you should only use string or integer literals in parameter >> values and no other XPath expressions at all. This means to rework your >> stylesheets, of course. >> > > I think I'll stick with my solution to add the namespaces to the xpath > context. :) > Actually "//*[name()='dm:device']" works as well so maybe that's what I'll do. > Is there any reason why path parameters with namespaces haven't been > supported? > Would a pull request to add the namespaces in xsltNewTransformContext be > considered? > > > > >> >> Nick >> >> ___ xslt mailing list, project page http://xmlsoft.org/XSLT/ xslt@gnome.org https://mail.gnome.org/mailman/listinfo/xslt
Re: [xslt] Issues using parameters with namespaces
On Mon, Feb 28, 2022 at 1:04 PM Nick Wellnhofer wrote: > On 28/02/2022 20:54, George Joseph via xslt wrote: > > I think it works because xsltProcessUserParamInternal only sets > > xpctxt->namespaces = NULL but it doesn't clear xpctxt->nsHash which is > where > > xmlXPathRegisterNs puts the namespaces to be registered. > > Right, the XPath engine uses both ->namespaces and ->nsHash. > > > Can you give me a hint? I've had absolutely no luck is trying to pass > a path > > as a string and getting it to result in something other than "The > 'select' > > expression > > did not evaluate to a node set" even in an absurdly simple example. I'm > passing > > the path double quoted "'/dm:device'" and have tried various > combinations of > > "select=" and "with-param".Even Google is failing me so any help > would be > > appreciated. > > I meant that you should only use string or integer literals in parameter > values and no other XPath expressions at all. This means to rework your > stylesheets, of course. > I think I'll stick with my solution to add the namespaces to the xpath context. :) Is there any reason why path parameters with namespaces haven't been supported? Would a pull request to add the namespaces in xsltNewTransformContext be considered? > > Nick > > ___ xslt mailing list, project page http://xmlsoft.org/XSLT/ xslt@gnome.org https://mail.gnome.org/mailman/listinfo/xslt
Re: [xslt] Issues using parameters with namespaces
On Mon, Feb 28, 2022 at 11:42 AM Nick Wellnhofer wrote: > On 28/02/2022 18:50, George Joseph via xslt wrote: > > I've been having a heck of a time trying to pass a parameter > > to xsltApplyStylesheet > > that has namespaces in the xpath expression. > > This use case is simply not supported. > Okay. > > > Finally I did find a workaround by calling xsltNewTransformContext() > then > > iterating > > over the nsDefs in the stylesheet document and > calling xmlXPathRegisterNs on > > ctxt->xpathCtxt for each nsDef. > > I'm a bit puzzled that this worked at all. See the code here: > > > > https://gitlab.gnome.org/GNOME/libxslt/-/blob/master/libxslt/variables.c#L1581 I think it works because xsltProcessUserParamInternal only sets xpctxt->namespaces = NULL but it doesn't clear xpctxt->nsHash which is where xmlXPathRegisterNs puts the namespaces to be registered. > > > But the expression is compiled before resetting the namespaces, so I guess > that's why. > > > I would have thought this would have been done automatically though. > Did I > > miss something or is there a better way to do this? > > No, I'd recommend that you only use string and integer params. > Can you give me a hint? I've had absolutely no luck is trying to pass a path as a string and getting it to result in something other than "The 'select' expression did not evaluate to a node set" even in an absurdly simple example. I'm passing the path double quoted "'/dm:device'" and have tried various combinations of "select=" and "with-param".Even Google is failing me so any help would be appreciated. Thanks! > > Nick > ___ xslt mailing list, project page http://xmlsoft.org/XSLT/ xslt@gnome.org https://mail.gnome.org/mailman/listinfo/xslt
[xslt] Issues using parameters with namespaces
Greetings, I've been having a heck of a time trying to pass a parameter to xsltApplyStylesheet that has namespaces in the xpath expression. For example (abbreviated): stylesheet: xml: ... $ xsltproc --param path "//dm:device" pidf_lo.xslt pidf_lo_test.xml XPath error : Undefined namespace prefix runtime error Evaluating user parameter path failed if I hard code that select="//dm:device" it works fine. Finally I did find a workaround by calling xsltNewTransformContext() then iterating over the nsDefs in the stylesheet document and calling xmlXPathRegisterNs on ctxt->xpathCtxt for each nsDef. I would have thought this would have been done automatically though. Did I miss something or is there a better way to do this? Thanks! -- George Joseph Asterisk Software Developer Check us out at www.sangoma.com and www.asterisk.org [image: image.png] ___ xslt mailing list, project page http://xmlsoft.org/XSLT/ xslt@gnome.org https://mail.gnome.org/mailman/listinfo/xslt
