import httplib
from cStringIO import StringIO
from email.mime.multipart import MIMEMultipart
from email.mime.application import MIMEApplication
from email.generator import Generator
from email.encoders import encode_noop


class FormData(MIMEMultipart):
    '''A simple RFC2388 multipart/form-data implementation.

    Snippet from http://bugs.python.org/issue3244

    '''

    def __init__(self, boundary=None, _subparts=None, **kwargs):
        MIMEMultipart.__init__(self, _subtype='form-data',
                boundary=boundary, _subparts=_subparts, **kwargs)

    def attach(self, subpart):
        if 'MIME-Version' in subpart:
            if subpart['MIME-Version'] != self['MIME-Version']:
                raise ValueError('subpart has incompatible MIME-Version')
            # Note: This isn't strictly necessary, but there is no point in
            # including a MIME-Version header in each subpart.
            del subpart['MIME-Version']
        MIMEMultipart.attach(self, subpart)

    def attach_file(self, subpart, name, filename):
        '''
        Attach a subpart, setting it's Content-Disposition header to "file".
        '''
        name = name.replace('"', '\\"')
        filename = filename.replace('"', '\\"')
        subpart['Content-Disposition'] = \
                'form-data; name="%s"; filename="%s"' % (name, filename)
        self.attach(subpart)

    def get_request_data(self, trailing_newline=True):
        '''Return the encoded message body.'''
        f = StringIO()
        generator = Generator(f, mangle_from_=False)
        generator._dispatch(self)
        # HTTP needs a trailing newline.  Since our return value is likely to
        # be passed directly to an HTTP connection, we might as well add it
        # here.
        if trailing_newline:
            f.write('\n')
        body = f.getvalue()
        headers = dict(self)
        return body, headers

host = 'localhost'
port = 8080
data = 'raw\0data'

message = FormData()
attachment = MIMEApplication(data, _encoder=encode_noop)
message.attach_file(attachment, name='report', filename='bar.bin')
body, headers = message.get_request_data()

conn = httplib.HTTPConnection(host, port)
conn.request('POST', '/', body, headers)
response = conn.getresponse()
assert response.status == 200