http://chriskief.com/2012/12/30/django-register-with-oauth-yahoo/

yahoo.py

import urllib2
import urlparse
import time
import oauth2 as oauth
from django.conf import settings
from django.core.urlresolvers import reverse
from django.core.context_processors import csrf


def get_authorization_url(request):

        # URL to where we will redirect to
        redirect_url = settings.SITE_URL + reverse('register_yahoo')

        # set the api URL
        url = 'https://api.login.yahoo.com/oauth/v2/get_request_token'

        # required params for yahoo
        params = {
            'oauth_callback': redirect_url,
            'oauth_timestamp': str(int(time.time())),
            'oauth_nonce': unicode(csrf(request)['csrf_token']),
            'oauth_version': '1.0',
            'xoauth_lang_pref': 'en-us'
        }

        # create the consumer
        consumer = oauth.Consumer(key=settings.YAHOO_CONSUMER_KEY, secret=settings.YAHOO_CONSUMER_SECRET)

        # create the request
        req = oauth.Request(method='GET', url=url, parameters=params)

        # sign the request
        signature_method = oauth.SignatureMethod_PLAINTEXT()
        req.sign_request(signature_method, consumer, None)

        # get the request token from yahoo
        response = urllib2.urlopen(req.to_url()).read()

        # parse the response
        params = urlparse.parse_qs(response)

        # store the returned values
        request.session['yahoo_oauth_token'] = params['oauth_token'][0]
        request.session['yahoo_oauth_token_secret'] = params['oauth_token_secret'][0]

        # get the authorization URL
        url = 'https://api.login.yahoo.com/oauth/v2/request_auth?oauth_token=' + params['oauth_token'][0]

        return url