generic support library for signed-token-based auth schemes
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tokenlib Prep version 0.3.1 Jan 8, 2014
.gitignore Support for Python3. Nov 26, 2012
LICENSE.txt Clarify licensing info Jul 24, 2013 Initial commit. Feb 22, 2012
README.rst Add to the README. Feb 22, 2012
tox.ini Support for Python3. Nov 26, 2012



This is generic support library for doing token-based authentication. You might use it to build a login system using bearer tokens, two-legged oauth, or MAC Access authentication.

Given a server-side master secret, you can serialize a dict of data into an opaque, unforgeable authentication token:

>>> token = tokenlib.make_token({"userid": 42}, secret="I_LIKE_UNICORNS")
>>> print token

Later, you can use the same secret to verify the token and extract the embedded data:

>>> data = tokenlib.parse_token(token, secret="I_LIKE_UNICORNS")
>>> print data
{u'userid': 42, u'expires': 1329875384.073159, u'salt': u'1c033f'}

Notice that the data includes an expiry time. If you try to parse an expired token, it will fail:

>>> # Use now=XXX to simulate a time in the future.
>>> tokenlib.parse_token(token, secret="I_LIKE_UNICORNS", now=9999999999)
Traceback (most recent call last):
ValueError: token has expired

Likewise, it will fail if the token was constructed with a non-matching secret key:

>>> tokenlib.parse_token(token, secret="I_HATE_UNICORNS")
Traceback (most recent call last):
ValueError: token has invalid signature

Each token also has an associated "token secret". This is a secret key that can be shared with the consumer of the token to enable authentication schemes such as MAC Access Authentication of Two-Legged OAuth:

>>> key = tokenlib.get_token_secret(token, secret="I_LIKE_UNICORNS")
>>> print key

For applications that are using the same settings over and over again, you will probably want to create a TokenManager object rather than using the module-level convenience functions:

>>> manager = tokenlib.TokenManager(secret="I_LIKE_UNICORNS")
>>> data = manager.parse_token(token)
>>> print data
{u'userid': 42, u'expires': 1329875384.073159, u'salt': u'1c033f'}

This will let you customize e.g. the token expiry timeout or hash module without repeating the settings in each call.