Body serialization for a sucessfull multipart/related upload to google drive

Multipart-related drive v2 api.py

import os
import tempfile
from fabric.api import task

def _serialize_body(fp, metadata, payload, boundary='boundary'):
    """
    serialize multi-part body
    """
    # Metadata
    fp.write('\r\n')
    fp.write('--%s\r\n' % boundary)
    fp.write('Content-Type: application/json; charset=UTF-8\r\n\r\n')
    fp.write('%s\r\n' % (json.dumps(metadata)))
    # file data
    fp.write('--%s\r\n' % boundary)
    fp.write('Content-Type: text/csv;\r\n\r\n')
    fp.write('%s\r\n' % (payload))
    fp.write('--%s--\r\n\r\n' % boundary)
    
  @task
def create_file_mp(input_path, parent_folder=None):
    """
    upload a csv or excel file to drive and convert it to spreadsheet format
    - by default it will have the persmission of parent folders
    """

    bits = input_path.split('/')
    if len(bits):
        filename = input_path.split('/')[-1]
    else:
        filename = input_path

    try:
        with open(input_path, 'rU') as f:
            print "Uploading %s ..." % (filename)
            payload = f.read()
    except IOError, e:
        print "could not open %s. Reason: %s" % (input_path, e)

    # Check if we have the required credentials
    check_credentials()

    # metadata
    metadata = {
        'title': filename,
    }

    # Find given folder defaulting the app_config DRIVE_BASE_FOLDER
    if parent_folder:
        parent_id = search_folder(parent_folder)
    else:
        parent_id = app_config.DRIVE_BASE_FOLDER

    if parent_id:
        metadata['parents'] = [{'id': parent_id}]

    # boundary
    b = 'driveboundary'
    with tempfile.NamedTemporaryFile() as fp:
        print fp.name
        _serialize_body(fp, metadata, payload, b)
        fp.seek(0)
        content_len = os.path.getsize(fp.name)
        # Prepare API request
        kwargs = {
            'credentials': get_credentials(),
            'url': UPLOAD_MULTIPART_URL_TEMPLATE,
            'method': 'POST',
            'headers': {
                'Content-Type': 'multipart/related; boundary=%s' % (b),
                'Content-Length': content_len},
            'body': fp.read()
        }
        print kwargs
        resp = app_config.authomatic.access(**kwargs)

    if resp.status == 200:
        spreadsheet_key = resp.data['id']
        spreadsheet_url = SPREADSHEET_VIEW_TEMPLATE % spreadsheet_key
        print 'New spreadsheet created successfully!'
        print 'View it at %s' % spreadsheet_url
        return True
    print resp.content
    print ('Error creating spreadsheet (status code %s) with message %s' %
           (resp.status, resp.reason))
    return False