[IronPython] End of the World? No just end of the line.

M. David Peterson xmlhacker at gmail.com
Mon Mar 5 20:29:36 CET 2007

I would just like to take a time out to congratulate Sylvain on coming up
with a subject line that brings tears of joy to a phreak-geek like me who
takes pride in coming up with cheezy one-liners such as that so eloquently
displayed in the subject of the original post.

Thanks for the laugh/smile, Sylvain! :D

On 3/3/07, Sylvain Hellegouarch <sh at defuze.org> wrote:
> Hi folks,
> Working with M. David Peterson trying to run the CherryPy HTTP server on
> IP under Windows we ran into a fairly subtle bug that was actually not
> so subtle at all.
> When the server accepts a connection it maps the socket into a file
> object so that it can read and write with a nice API.
> When using IPCE socket module this achieves the same by doing this:
> def makefile(self, mode='r', bufsize=-1):
>     stream = NetworkStream(self.socket)
>     return file(stream, mode)
> This works great when you don't care about the way the end of the lines
> is defined but if you do be ready for some hair-tearing hours.
> Indeed with IronPython running on Windows with the .NET framework the
> end of the line is defined as <LF> whereas for instance on Linux with
> Mono it's <CR><LF>.
> If I'm not mistaken CPython always ensures the end of line is <CR><LF>
> so that people don't have to worry about the underlying OS behavior.
> The problem I faced is that HTTP marks the end of the header lists via a
> <CR><LF> but because CherryPy reads the socket as a file it only gets a
> <LF> with IP under Windows and therefore fails miserably. I've added a
> test for a single <LF> in my copy of CherryPy and it fixed the problem.
> But this is a bit of a hassle.
> I don't think there is a bug of any of the part here. However I believe
> there should be either a very clear warning that this difference will
> always exists and Python developer will have to check for that case, or
> maybe IP should find a way to ensure that <CR><LF> is always returned
> even under Windows (which I doubt is an easy thing to do).
> In any case if your code depends on the line ending be aware of that
> difference as you could end up swearing too loud for your own good.
> - Sylvain
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M. David Peterson
http://mdavid.name | http://www.oreillynet.com/pub/au/2354 |
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