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Forked from alee/views.py
Last active June 15, 2020 16:59
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Django Rest Framework SSO endpoint for Discourse forum
"""Single Sign On view for Discourse forum
The view returns the required payload and signature for discourse.
These payloads have to be urlencoded by the client and passed as
query parameter to the discourse sso login url.
Signature validation depends on settings.SECRET_KEY.
Add this as the secret key in discourse sso settings.
References:
- https://meta.discourse.org/t/sso-example-for-django/14258
- https://gist.github.com/alee/3c6161809ef78966454e434a8ed350d1
"""
import base64
import hashlib
import hmac
from urllib import parse
from django.conf import settings
from rest_framework.exceptions import ParseError
from rest_framework.permissions import IsAuthenticated
from rest_framework.response import Response
from rest_framework.views import APIView
class SSOView(APIView):
permission_classes = [IsAuthenticated]
def get(self, request):
"""Query params:
- sso: Single Sign On payload
- sig: Signature
"""
payload = request.query_params.get('sso')
signature = request.query_params.get('sig')
if None in [payload, signature]:
raise ParseError('No SSO payload or signature. Please contact support if this problem persists.')
# Validate the payload
payload = bytes(parse.unquote(payload), encoding='utf-8')
decoded = base64.decodebytes(payload).decode('utf-8')
if len(payload) == 0 or 'nonce' not in decoded:
raise ParseError('Invalid payload. Please contact support if this problem persists.')
key = bytes(settings.SECRET_KEY, encoding='utf-8') # must not be unicode
h = hmac.new(key, payload, digestmod=hashlib.sha256)
this_signature = h.hexdigest()
if not hmac.compare_digest(this_signature, signature):
raise ParseError('Invalid payload. Please contact support if this problem persists.')
# Build the return payload
qs = parse.parse_qs(decoded)
user = request.user
params = {
'nonce': qs['nonce'][0],
'email': user.email,
'external_id': user.id,
'username': user.username,
}
return_payload = base64.encodebytes(bytes(parse.urlencode(params), 'utf-8'))
h = hmac.new(key, return_payload, digestmod=hashlib.sha256)
return_sig = h.hexdigest()
# Redirect back to Discourse
# query_string = parse.urlencode({'sso': return_payload, 'sig': return_sig})
# discourse_sso_url = '{0}/session/sso_login?{1}'.format("", query_string)
return Response(
data={
'sso': return_payload,
'sig': return_sig
}
)
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