Parsing MIME-encoded data in an HTTP request
in [Python]
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From: Ron Garret on 3 Jul 2008 16:59 I'm writing a little HTTP server and need to parse request content that is mime-encoded. All the MIME routines in the Python standard library seem to have been subsumed into the email package, which makes this operation a little awkward. It seems I have to do the following: 1. Extract the content-length header from the HTTP request and use that to read the payload. 2. Stick some artificial-looking headers onto the beginning of this payload to make it look like an email message (including the content-type and content-transfer-encoding headers) 3. Parse the resulting string into a email message That works, but it feels way too hackish for my tastes. Surely there must be a better/more standard way of doing this? Thanks, rg
From: s0suk3 on 3 Jul 2008 23:50 On Jul 3, 3:59 pm, Ron Garret <rNOSPA...(a)flownet.com> wrote: > I'm writing a little HTTP server and need to parse request content that > is mime-encoded. All the MIME routines in the Python standard library > seem to have been subsumed into the email package, which makes this > operation a little awkward. To deal with messages of that kind, I've seen modules such as 'rfc822', and 'mimetools' (which apparently builds itself from 'rfc822', so it might be more complete). There's also 'mimetypes', in case you need to deal with file extensions and their corresponding MIME media type. > It seems I have to do the following: > > 1. Extract the content-length header from the HTTP request and use that > to read the payload. > > 2. Stick some artificial-looking headers onto the beginning of this > payload to make it look like an email message (including the > content-type and content-transfer-encoding headers) > > 3. Parse the resulting string into a email message > Email? Why does an HTTP server need to build an email message? I remember doing things like that some time ago when building an HTTP server myself (http://code.google.com/p/sws-d/). Incidentally, I resisted the urge to use much of the Python's library facilities (most things are done manually; am I a knucklehead or what!? :). You might wanna take a look to get some ideas. Sebastian
From: Ron Garret on 4 Jul 2008 03:17 In article <4834df8f-2cf8-434c-8c95-ff53024766c8(a)p25g2000hsf.googlegroups.com>, s0suk3(a)gmail.com wrote: > On Jul 3, 3:59 pm, Ron Garret <rNOSPA...(a)flownet.com> wrote: > > I'm writing a little HTTP server and need to parse request content that > > is mime-encoded. All the MIME routines in the Python standard library > > seem to have been subsumed into the email package, which makes this > > operation a little awkward. > > To deal with messages of that kind, I've seen modules such as > 'rfc822', and 'mimetools' (which apparently builds itself from > 'rfc822', so it might be more complete). There's also 'mimetypes', in > case you need to deal with file extensions and their corresponding > MIME media type. From the mimetools docs: "Deprecated since release 2.3. The email package should be used in preference to the module. This module is present only to maintain backward compatibility." > > > It seems I have to do the following: > > > > 1. Extract the content-length header from the HTTP request and use that > > to read the payload. > > > > 2. Stick some artificial-looking headers onto the beginning of this > > payload to make it look like an email message (including the > > content-type and content-transfer-encoding headers) > > > > 3. Parse the resulting string into a email message > > > > Email? Why does an HTTP server need to build an email message? It shouldn't. That's my whole point. But see the docs excerpt above. > I remember doing things like that some time ago when building an HTTP > server myself (http://code.google.com/p/sws-d/). Incidentally, I > resisted the urge to use much of the Python's library facilities (most > things are done manually; am I a knucklehead or what!? :). You might > wanna take a look to get some ideas. I'd much prefer not to reinvent this particular wheel. rg
From: Michael Ströder on 4 Jul 2008 03:49 Ron Garret wrote: > I'm writing a little HTTP server and need to parse request content that > is mime-encoded. All the MIME routines in the Python standard library > seem to have been subsumed into the email package, which makes this > operation a little awkward. How about using cgi.parse_multipart()? Ciao, Michael.
From: Ron Garret on 4 Jul 2008 18:30
In article <3a11k5-al7.ln1(a)nb2.stroeder.com>, Michael Str�der <michael(a)stroeder.com> wrote: > Ron Garret wrote: > > I'm writing a little HTTP server and need to parse request content that > > is mime-encoded. All the MIME routines in the Python standard library > > seem to have been subsumed into the email package, which makes this > > operation a little awkward. > > How about using cgi.parse_multipart()? > > Ciao, Michael. Unfortunately cgi.parse_multipart doesn't handle nested multiparts, which the requests I'm getting have. You have to use a FieldStorage object to do that, and that only works if you're actually in a cgi environment, which I am not. The server responds to these requests directly. Anyway, thanks for the idea. rg |