Gdata allows you to authenticate using user info, ex. username/password... here is a code snipet from the gdata python api /gdata-2.0.18/samples/docs/docs_example.py file that comes with the api
class DocsSample(object):
"""A DocsSample object demonstrates the Document List feed."""
def init(self, email, password):
"""Constructor for the DocsSample object.
Takes an email and password corresponding to a gmail account to
demonstrate the functionality of the Document List feed.
Args:
email: [string] The e-mail address of the account to use for the sample.
password: [string] The password corresponding to the account specified by
the email parameter.
Returns:
A DocsSample object used to run the sample demonstrating the
functionality of the Document List feed.
"""
source = 'Document List Python Sample'
self.gd_client = gdata.docs.service.DocsService()
self.gd_client.ClientLogin(email, password, source=source)
# Setup a spreadsheets service for downloading spreadsheets
self.gs_client = gdata.spreadsheet.service.SpreadsheetsService()
self.gs_client.ClientLogin(email, password, source=source)
if you invoke this as {python ./docs_example.py --user username --pw password} it will skip asking you for it, but it will ask you for it if you don't. However this is being depreciated but still works in most situations outside networks that directly work with Google as this often times will now require oauth2. This being said, it does have security drawbacks, specifically scope, and poor password protection, which is why it is being deprecated...but that should answer your question a little better...