Multiparts

#!/usr/bin/python

####
# 02/2006 Will Holcomb <[email protected]>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
"""
Usage:
  Enables the use of multipart/form-data for posting forms

Inspirations:
  Upload files in python:
    http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/146306
  urllib2_file:
    Fabien Seisen: <[email protected]>

Example:
  import MultipartPostHandler, urllib2, cookielib

  cookies = cookielib.CookieJar()
  opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cookies),
                                MultipartPostHandler.MultipartPostHandler)
  params = { "username" : "bob", "password" : "riviera",
             "file" : open("filename", "rb") }
  opener.open("http://wwww.bobsite.com/upload/", params)

Further Example:
  The main function of this file is a sample which downloads a page and
  then uploads it to the W3C validator.
"""

import urllib
import urllib2
import mimetools, mimetypes
import os, stat

class Callable:
    def __init__(self, anycallable):
        self.__call__ = anycallable

# Controls how sequences are uncoded. If true, elements may be given multiple values by
#  assigning a sequence.
doseq = 1

class MultipartPostHandler(urllib2.BaseHandler):
    handler_order = urllib2.HTTPHandler.handler_order - 10 # needs to run first

    def http_request(self, request):
        data = request.get_data()
        if data is not None and type(data) != str:
            v_files = []
            v_vars = []
            try:
                 for(key, value) in data.items():
                     if type(value) == file:
                         v_files.append((key, value))
                     else:
                         v_vars.append((key, value))
            except TypeError:
                systype, value, traceback = sys.exc_info()
                raise TypeError, "not a valid non-string sequence or mapping object", traceback

            if len(v_files) == 0:
                data = urllib.urlencode(v_vars, doseq)
            else:
                boundary, data = self.multipart_encode(v_vars, v_files)
                contenttype = 'multipart/form-data; boundary=%s' % boundary
                if(request.has_header('Content-Type')
                   and request.get_header('Content-Type').find('multipart/form-data') != 0):
                    print "Replacing %s with %s" % (request.get_header('content-type'), 'multipart/form-data')
                request.add_unredirected_header('Content-Type', contenttype)

            request.add_data(data)
        return request

    def multipart_encode(vars, files, boundary = None, buffer = None):
        if boundary is None:
            boundary = mimetools.choose_boundary()
        if buffer is None:
            buffer = ''
        for(key, value) in vars:
            buffer += '--%s\r\n' % boundary
            buffer += 'Content-Disposition: form-data; name="%s"' % key
            buffer += '\r\n\r\n' + value + '\r\n'
        for(key, fd) in files:
            file_size = os.fstat(fd.fileno())[stat.ST_SIZE]
            filename = fd.name.split('/')[-1]
            contenttype = mimetypes.guess_type(filename)[0] or 'application/octet-stream'
            buffer += '--%s\r\n' % boundary
            buffer += 'Content-Disposition: form-data; name="%s"; filename="%s"\r\n' % (key, filename)
            buffer += 'Content-Type: %s\r\n' % contenttype
            # buffer += 'Content-Length: %s\r\n' % file_size
            fd.seek(0)
            buffer += '\r\n' + fd.read() + '\r\n'
        buffer += '--%s--\r\n\r\n' % boundary
        return boundary, buffer
    multipart_encode = Callable(multipart_encode)

    https_request = http_request