def parse_blob_info(file_storage):
"""Parse a BlobInfo record from file upload field_storage.
Args:
file_storage: werkzeug.FileStorage that represents uploaded blob.
Returns:
BlobInfo record as parsed from the field-storage instance.
None if there was no field_storage.
Raises:
BlobInfoParseError when provided field_storage does not contain enough
information to construct a BlobInfo object.
"""
if file_storage is None:
return None
field_name = file_storage.name
def get_value(dict, name):
value = dict.get(name, None)
if value is None:
raise blobstore.BlobInfoParseError('Field %s has no %s.' %
(field_name, name))
return value
filename = file_storage.filename
content_type, cdict = cgi.parse_header(
file_storage.headers['Content-Type'])
blob_key = blobstore.BlobKey(get_value(cdict, 'blob-key'))
upload_content = email.message_from_file(file_storage.stream)
content_type = get_value(upload_content, 'content-type')
size = get_value(upload_content, 'content-length')
creation_string = get_value(upload_content,
blobstore.UPLOAD_INFO_CREATION_HEADER)
try:
size = int(size)
except (TypeError, ValueError):
raise blobstore.BlobInfoParseError(
'%s is not a valid value for %s size.' % (size, field_name))
try:
creation = parse_creation(creation_string, field_name)
except CreationFormatError, e:
raise blobstore.BlobInfoParseError(
'Could not parse creation for %s: %s' % (field_name, str(e)))
def get_value(dict, name):
value = dict.get(name, None)
if value is None:
raise blobstore.BlobInfoParseError('Field %s has no %s.' %
(field_name, name))
return value