Python + OAuth

As part of a current project I had the misfortune of having to to deal with a bunch of OAuth authenticated web services using a command line script in Python. Usually this isn’t really a problem as most decent client libraries for services such as Twitter or Foursquare can handle the authentication requests themselves, usually wrapping their own internal OAuth implementation. However, when it comes to web services that don’t have existing python client libraries, you have to do the implementation yourself. Unfortunately support for OAuth in Python is a mess, so this is not the most pleasant of tasks, especially when most stackoverflow posts on the topic point to massively outdated and unmaintained Python libraries.

Fortunately after some digging around, I was able to find a nice, well maintained and fairly well documented solution: rauth, which is very clean and easy to use. As an example, I was trying to connect to the Fitbit API, and it really was as simple as following their example.

Firstly, we create an OAuth1Service:

import rauth
from _credentials import consumer_key, consumer_secret

base_url = "https://api.fitbit.com"
request_token_url = base_url + "/oauth/request_token"
access_token_url = base_url + "/oauth/access_token"
authorize_url = "http://www.fitbit.com/oauth/authorize"

fitbit = rauth.OAuth1Service(
 name="fitbit",
 consumer_key=consumer_key,
 consumer_secret=consumer_secret,
 request_token_url=request_token_url,
 access_token_url=access_token_url,
 authorize_url=authorize_url,
 base_url=base_url)

Then we get the temporary request token credentials:

request_token, request_token_secret = fitbit.get_request_token()

print " request_token = %s" % request_token
print " request_token_secret = %s" % request_token_secret
print

We then ask the user to authorise our application, and give us the PIN so we can prove to the service that they authorised us:

authorize_url = fitbit.get_authorize_url(request_token)

print "Go to the following page in your browser: " + authorize_url
print

accepted = 'n'
while accepted.lower() == 'n':
 accepted = raw_input('Have you authorized me? (y/n) ')
pin = raw_input('Enter PIN from browser ')

Finally, we can create an authenticated session and access user data from the service:

session = fitbit.get_auth_session(request_token,
 request_token_secret,
 method="POST",
 data={'oauth_verifier': pin})

print ""
print " access_token = %s" % session.access_token
print " access_token_secret = %s" % session.access_token_secret
print ""

url = base_url + "/1/" + "user/-/profile.json"

r = session.get(url, params={}, header_auth=True)
print r.json()

It really is that easy to perform a 3-legged OAuth authentication on the command line. If you’re only interested in data from 1 user, and you want to run the app multiple times, once you have the access token and secret, there’s nothing to stop you just storing those and re-creating your session each time without having to re-authenticate (assuming the service does not expire access tokens):

base_url = "https://api.fitbit.com/"
api_version = "1/"
token = (fitbit_oauth_token, fitbit_oauth_secret)
consumer = (fitbit_consumer_key, fitbit_consumer_secret)

session = rauth.OAuth1Session(consumer[0], consumer[1], token[0], token[1])
url = base_url + api_version + "user/-/profile.json"
r = session.get(url, params={}, header_auth=True)
print r.json()

So there we have it. Simple OAuth authentication on the command line, in Python. As always, the code is available on github if you’re interested.