[XML-SIG] 4Suite now works with mod_python just fine

Uche Ogbuji uche.ogbuji at fourthought.com
Sat Oct 9 21:52:21 CEST 2004

On Wed, 2004-09-22 at 19:26, Thomas Henry Sutton wrote:
> \Finally: we are using libxml2 and libxslt because we had to abandon  
> 4Suite due to instability. Are there known problems with using 4Suite  
> with ModPython and Apache 2? We had a range of problems (complaining  
> about the expat version 'til we recompiled Apache, Apache SEGFAULTing  
> when trying to do XSLT processing, etc) which suggest to me at least  
> that there are some problems with the way 4Suite does things.

No.  Actually the bugs turned out to be in *Python*.  There has been a
long history of problems running 4Suite under mod_python, and they
baffled everyone until recently.  As one of the main people working with
the problem, Robert Sanderson says:

"[T]he reason that mod_python wouldn't work before (Python 2.2) was that
the python interpreter used a busted method to determine if it was in
restricted mode or not and it would think that mod_python was restricted
when it wasn't, so the unicode codecs couldn't be loaded
[This problem] was fixed in 2.3, thankfully, as it was a showstopper."

You also mentioned segfaults.  Almost all XML parsing segfaults reported
under 4Suite and pyexpat have been traced to recent, broken expat builds
(fixed late last year).  Making sure you have the latest code across the
board is *highly* advisable.  I'd be *very* surprised if you get seg
faults outside such circumstances, as the 4Suite core libs (as opposedf
to the server platform) have proven rock solid stable for years now.

There is one residual problem in that Apache seems to confuse the
dynamic loader to load the wrong version of expat (i.e. not the version
4Suite builds in).  He did get us to work around that problem by
upgrading 4Suite's built-in expat to 1.95.8, which I did yesterday. 
Now, using the latest 4Suite, we have 2 success reports with mod_python,
in situations that used not to work.

So if libxslt is working for you, it's all good, but if you do want to
use 4Suite, as long as you grab the latest code base, all should be
well.  Let us know if not.

Uche Ogbuji                                    Fourthought, Inc.
http://uche.ogbuji.net    http://4Suite.org    http://fourthought.com
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