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From "Dan Yamins" <dyam...@gmail.com>
Subject Re: [users@httpd] Premature end of script headers
Date Tue, 18 Nov 2008 16:12:13 GMT
> > ...
> > [Tue Nov 18 18:23:28 2008] [error] [client a.b.c.d] Premature end of
> > script headers: our_application.exe
> > ...
>
>
> ScriptLog might show you that your app is emitting an error message
> instead of e.g. Content-Type header.
>
> --
>

Actually, I've _also_  just started to have an intermittent and seemingly
obscure and very frustrating "premature end of script headers" problem.

I'm running a python script using CGI on a local apache-served virtual host.
(It' just an internal development project.)   The project involves layout of
some large graph network structures, which are then viewed via a web-based
graph-vieweing tool.  The script uses the "Pygraphviz" module (
http://networkx.lanl.gov/pygraphviz/)  to generate .svg files with layouts
of the graph and the "zgrviewer" applet to view the graphs.    During the
script, I first construct the graph.  After using the pygraphviz module to
do the layout of the graph as a data structure in memory, I invoke the
pygraphviz method "draw", which saves the graph to an .svg on disk.  Then I
issue the HTML code invoking the zgrviewer applet, which uses the saved .svg
file.

Sometimes -- only _sometimes_ -- when the script invokes the "draw" method,
I get a "premature end of script headers" problem, with error code 500.
Because the .draw method is outputing a file to disk, it seems like it might
be a permissions-related problem. But I can't figure out what t is easily,
becuase the problem only happens occasionally.  Moreover, when it happens,
if I just hit "refresh" on the browser to run the script again, then it
usually runs fine.    I haven't been able to figure out more than this.

Any suggestions greatly appreciated!
Thanks,
Dan

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