[XML-SIG] PyXML, 4suite, libxml2... what should I choose?

Frans Englich frans.englich at telia.com
Fri Dec 10 20:40:03 CET 2004

On Sunday 05 December 2004 22:13, Uche Ogbuji wrote:
> On Mon, 2004-11-29 at 19:34 +0000, Frans Englich wrote:
> > I need some guidance for the various XML implementations.

Hello Uche, 

Here's a late reply. I settled for libxml2 because it provides all 
functionality(I can unfortunately not switch to RNG), and I will have to live 
with its quirky API. Your reply was very informative, great to have some 
insight in this spurr of implementations.



> Well, at the minimum you'll get argument :-)
> > In my project I use the Python DOM classes for instantiations of my XML
> > data, and I need XPath functionality,
> 4Suite has an XPath implementation that is very easy to use and makes
> extending XPath with functions implemented in Python very simple.
> http://uche.ogbuji.net/tech/akara/nodes/2003-01-01/basic-xpath
> > WXS validation,
> 4Suite does not support WXS.  Advantage libxml2 here.  Then again, if
> you have a choice in the matter you really should consider using RELAX
> NG instead, which is superior to WXS and is supported by 4Suite.
> > and XSLT processing.
> 4Suite's XSLT processor is also easy to use and extend.
> http://uche.ogbuji.net/tech/akara/nodes/2003-01-01/basic-xslt
> > Currently, I pipe out my structures to libxml2/libxslt's xmllint/xsltproc
> > for doing validation, and XSLT processing. libxml2 is capable, but the
> > solution is ugly, and slow(de-serialization/serialization). In addition,
> > I lack XPath functionality. I have no intentions to skip Python's XML
> > structures, and use for example libxml2's.
> Out of curiousity, by "Python's XML structures" do you mean minidom?  If
> so, what motivates this reservation?  I should add the disclaimer that
> 4Suitee's XPath and XSLT features require Domlette rather than minidom.
> Domlette is very similar to minidom (much more so than libxml2's DOM-
> like structures).  Domlette is also IMO as pythonic as you can get and
> still be DOM-like (more Pythonic and you're into the territory of
> ElementTree and data bindings such as Anobind, GenerateDS and Gnosis
> Objectify).
> > So, my plan is to get XPath somewhere, and perhaps be able to substitute
> > libxml2 for something more Pythonic while I'm at it.
> You should at least give 4Suite a try if this is your bottom line.
> > From what I can tell, there is three major packages to keep an eye on: 1)
> > standard Python; 2) PyXML; 3) 4suite. Let me see if I got this straight:
> >
> > * Python have _no_ XPath implementation (right?)
> Right.
> > * PyXML install an XPath implementation(written by fourthought) into
> > Python's package xml(xml.xpath). Is it version 1.0? Is it robust and
> > stable?
> It's pretty robust and stable.  It is based on very old code from
> 4Suite's XPath and the latter has been optimized a great deal and has
> added a lot of useful features.
> > * PyXML has xml.xslt; not an option since it's not stable/production
> > quality, according to the docs -- or what is its status? How much
> > "experimental" is it?
> Basing XSLT on plain DOM is a bit tricky, which is why in 4Suite we've
> settled on Domlette-only.  It will take a lot of work to get Python's
> xml.xslt compliant and efficient while still using plain old minidom.
> Again, it's based on old code from 4Suite which has been much optimized
> and otherwise improved since then.
> > * 4suite has XPath(another implementation written by fourthought..?) and
> > robust xslt.
> It's a much newer version of the XSLT in PyXML.
> > * Neither PyXML nor 4suite has a W3C XML Schema stack, so I'll have to
> > look elsewhere; one alternative is XSV but it brings in addition a
> > dependency on PyLTXML. Looks like continuing to pipe to libxml2's
> > xmllint(or link) is still the best alternative.
> I suppose another option is to use Trang to convert WXS to RELAX NG and
> then use XVIF or 4Suite.
> > What is the best option(s) for me? With my interest of keeping the
> > dependencies down, should I go for PyXML-XPath + PyXML-XSLT _if_ it's
> > good enough or libxslt + libxml2-WXS? I could use 4suite's XSLT, but
> > since I nevertheless will have a dependency on libxml2/libxslt for WXS I
> > can use that(and eat the speed penalty).
> > Important is it has a future(maintained..) and is stable/trustable.
> >
> > What should I go for, and what have I missed?
> >
> > BTW, is there any plans to merge any XSLT/XPath stack into vanilla
> > Python? (when?) It's functionality often needed, AFAICT.
> XPath is a little language, and XSLT a not-so-little one, so I'd expect
> they're too much to stuff into core Pylib, even with the "batteries
> included" philosophy.  Add to that the fact that something a bit richer
> than minidom would be needed for the data model (if the implementation
> is to be at all efficient) and I'd say it's a stretch.
> > Yes, I'm new on the Python & XML front..
> Welcome.

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