multipart.py

# Derived from http://code.activestate.com/recipes/146306/
import httplib
import mimetypes


def post_multipart(host, selector='/', fields={}, files={}):
    """
    Post fields and files to an http host as multipart/form-data.
    fields is a dict mapping keys to input values for regular form fields.
    files is a dict of {name: (filename, value)} data to be uploaded as files.
    Returns the server's response text.
    """
    content_type, body = encode_multipart_formdata(fields, files)
    h = httplib.HTTP(host)
    h.putrequest('POST', selector)
    h.putheader('content-type', content_type)
    h.putheader('content-length', str(len(body)))
    h.endheaders()
    h.send(body)
    errcode, errmsg, headers = h.getreply()
    return h.file.read()


def encode_multipart_formdata(fields, files):
    """
    fields is a dict mapping keys to input values for regular form fields.
    files is a dict of {name: (filename, value)} data to be uploaded as files.
    Return (content_type, body) ready for httplib.HTTP instance
    """
    BOUNDARY = '----------ThIs_Is_tHe_bouNdaRY_$'
    CRLF = '\r\n'
    L = []
    for key, value in fields.items():
        L.append('--' + BOUNDARY)
        L.append('Content-Disposition: form-data; name="%s"' % key)
        L.append('')
        L.append(value)
    for key, (filename, value) in files.items():
        L.append('--' + BOUNDARY)
        L.append('Content-Disposition: form-data; name="%s"; filename="%s"'
                 % (key, filename))
        L.append('Content-Type: %s' % get_content_type(filename))
        L.append('')
        L.append(value)
    L.append('--' + BOUNDARY + '--')
    L.append('')
    body = CRLF.join(L)
    content_type = 'multipart/form-data; boundary=%s' % BOUNDARY
    return content_type, body


def get_content_type(filename):
    return mimetypes.guess_type(filename)[0] or 'application/octet-stream'