disqus_tag.py

#python3 example

import base64
import hashlib
import hmac
import simplejson
import time

from django import template
from django.conf import settings

register = template.Library()


@register.simple_tag(takes_context=True)
def disqus_sso(context, callback_func="null"):
    """
    Return the HTML/js code to enable DISQUS SSO - so logged in users on
    your site can be logged in to disqus seemlessly.
    """
    DISQUS_SECRET_KEY = getattr(settings, 'DISQUS_SECRET_KEY', None)
    if DISQUS_SECRET_KEY is None:
        return "<p>You need to set DISQUS_SECRET_KEY before you can use SSO</p>"
    DISQUS_PUBLIC_KEY = getattr(settings, 'DISQUS_PUBLIC_KEY', None)
    if DISQUS_PUBLIC_KEY is None:
        return "<p>You need to set DISQUS_PUBLIC_KEY before you can use SSO</p>"

    # we have to make it bytes rather than string(unicode) or the HMAC blows up
    DISQUS_SECRET_KEY = bytes(DISQUS_SECRET_KEY, 'ascii')
    DISQUS_PUBLIC_KEY = bytes(DISQUS_PUBLIC_KEY, 'ascii')
    user = context['user']
    if user.is_anonymous():
        return ""
    # create a JSON packet of our data attributes
    data = simplejson.dumps({
        'id': user.id,
        'username': user.username,
        'email': user.email,
    })
    # encode the data to base64
    message = base64.b64encode(bytes(data, 'ascii'))
    # generate a timestamp for signing the message
    timestamp = int(time.time())
    input_data = bytes('%s %s' % (message.decode(), timestamp), 'ascii')
    # generate our hmac signature
    sig = hmac.HMAC(DISQUS_SECRET_KEY, input_data, hashlib.sha1).hexdigest()

    # return a script tag to insert the sso message
    return """function disqus_config() {
this.page.remote_auth_s3 = "%(message)s %(sig)s %(timestamp)s";
this.page.api_key = "%(pub_key)s";
this.callbacks.onNewComment = [%(callback_func)s];
}""" % dict(
        message=message.decode(),
        timestamp=timestamp,
        sig=sig,
        pub_key=DISQUS_PUBLIC_KEY.decode(),
        callback_func=callback_func,
    )