Switch from database-persisted auth codes to stateless JSON Web Tokens :)

Pipfile

@@ -38,6 +38,7 @@ django-shorturls = "*"
 accept-types = "*"
 django-analytical = "*"
 django-model-utils = "*"
+pyjwt = "*"
 
 
 [dev-packages]

Pipfile.lock

@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "0c229a0ec55a08b58868faee7ce35a6adc3621d8e8619a67ec8939afcccc7dfe"
+            "sha256": "2afb7a864b8a0b60e8c0935dab11b91989cb33749272f4a5271dde8b53cafa43"
         },
         "host-environment-markers": {
             "implementation_name": "cpython",
@@ -66,10 +66,10 @@
         },
         "django": {
             "hashes": [
-                "sha256:7ab6a9c798a5f9f359ee6da3677211f883fb02ef32cebe9b29751eb7a871febf",
-                "sha256:c3b42ca1efa1c0a129a9e863134cc3fe705c651dea3a04a7998019e522af0c60"
+                "sha256:75ce405d60f092f6adf904058d023eeea0e6d380f8d9c36134bac73da736023d",
+                "sha256:8918e392530d8fc6965a56af6504229e7924c27265893f3949aa0529cd1d4b99"
             ],
-            "version": "==1.11.6"
+            "version": "==1.11.7"
         },
         "django-activeurl": {
             "hashes": [
@@ -193,10 +193,10 @@
         },
         "html5lib": {
             "hashes": [
-                "sha256:08a3efc117a4fc8c82c3c6d10d6f58ae266428d57ed50258a1466d2cd88de745",
-                "sha256:0d5fd54d5b2b79b876007a70c033a4023577768d18022c15681c00561432a0f9"
+                "sha256:b8934484cf22f1db684c0fae27569a0db404d0208d20163fbf51cc537245d008",
+                "sha256:ee747c0ffd3028d2722061936b5c65ee4fe13c8e4613519b4447123fc4546298"
             ],
-            "version": "==1.0b10"
+            "version": "==0.999999999"
         },
         "idna": {
             "hashes": [
@@ -351,6 +351,13 @@
             ],
             "version": "==2.7.3.2"
         },
+        "pyjwt": {
+            "hashes": [
+                "sha256:a4e5f1441e3ca7b382fd0c0b416777ced1f97c64ef0c33bfa39daf38505cfd2f",
+                "sha256:500be75b17a63f70072416843dc80c8821109030be824f4d14758f114978bae7"
+            ],
+            "version": "==1.5.3"
+        },
         "python-memcached": {
             "hashes": [
                 "sha256:2775829cb54b9e4c5b3bbd8028680f0c0ab695db154b9c46f0f074ff97540eb6"

lemonauth/migrations/0002_delete_indieauthcode.py

@@ -0,0 +1,18 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.7 on 2017-11-02 05:35
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('lemonauth', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.DeleteModel(
+            name='IndieAuthCode',
+        ),
+    ]

lemonauth/models.py

@@ -1,29 +0,0 @@
-from django.db import models
-from secrets import token_hex
-
-
-class IndieAuthCodeManager(models.Manager):
-    def create_from_qdict(self, d):
-        code = self.create(
-            me=d['me'],
-            client_id=d['client_id'],
-            redirect_uri=d['redirect_uri'],
-            response_type=d.get('response_type', 'id'),
-            scope=" ".join(d.getlist('scope')),
-        )
-        code.code = token_hex(32)
-        return code
-
-
-class IndieAuthCode(models.Model):
-    objects = IndieAuthCodeManager()
-    code = models.CharField(max_length=64, unique=True)
-    me = models.CharField(max_length=255)
-    client_id = models.CharField(max_length=255)
-    redirect_uri = models.CharField(max_length=255)
-    response_type = models.CharField(
-        max_length=4,
-        choices=(('id', 'id'), ('code', 'code')),
-        default='id',
-    )
-    scope = models.CharField(max_length=200, blank=True)

lemonauth/tokens.py

@@ -0,0 +1,27 @@
+import jwt
+
+from datetime import datetime, timedelta
+from django.conf import settings
+
+
+def gen_auth_code(post):
+    params = {'me': post['me']}
+    if 'state' in post:
+        params['state'] = post['state']
+
+    code = {
+        'me': post['me'],
+        'client_id': post['client_id'],
+        'redirect_uri': post['redirect_uri'],
+        'response_type': post.get('response_type', 'id'),
+        'exp': datetime.utcnow() + timedelta(minutes=10),
+    }
+    if 'scope' in post:
+        code['scope'] = ' '.join(post.getlist('scope'))
+
+    params['code'] = jwt.encode(code, settings.SECRET_KEY)
+    return params
+
+
+def verify_auth_code(c):
+    return jwt.decode(c, settings.SECRET_KEY)

lemonauth/views/indie.py

@@ -11,7 +11,7 @@ from django.views.decorators.http import require_POST
 from lemoncurry import breadcrumbs, utils
 from urllib.parse import urlencode, urljoin, urlunparse, urlparse
 
-from ..models import IndieAuthCode
+from .. import tokens
 
 breadcrumbs.add('lemonauth:indie', label='indieauth', parent='home:index')
 
@@ -88,28 +88,23 @@ class IndieView(TemplateView):
     def post(self, request):
         post = request.POST.dict()
         try:
-            code = IndieAuthCode.objects.get(code=post.get('code'))
-        except IndieAuthCode.DoesNotExist:
+            code = tokens.verify_auth_code(post.get('code'))
+        except Exception:
+            # if anything at all goes wrong when decoding the auth code, bail
+            # out immediately.
             return utils.forbid('invalid auth code')
 
-        # We always delete the code immediately to ensure it's only single-use.
-        # If you pass the right code but the wrong other info, bad luck, you
-        # need a new code.
-        code.delete()
-
-        # After deleting the code from the DB, we verify the other parameters
-        # of the request.
-        if code.response_type != 'id':
+        if code['response_type'] != 'id':
             return utils.bad_req(
                 'this endpoint only supports response_type=id'
             )
-        if post.get('client_id') != code.client_id:
+        if post.get('client_id') != code['client_id']:
             return utils.forbid('client id did not match')
-        if post.get('redirect_uri') != code.redirect_uri:
+        if post.get('redirect_uri') != code['redirect_uri']:
             return utils.forbid('redirect uri did not match')
 
         # If we got here, it's valid! Yay!
-        return utils.choose_type(request, {'me': code.me}, {
+        return utils.choose_type(request, {'me': code['me']}, {
             'application/json': JsonResponse,
             'application/x-www-form-urlencoded': utils.form_encoded_response,
         })
@@ -118,9 +113,6 @@ class IndieView(TemplateView):
 @login_required
 @require_POST
 def approve(request):
-    code = IndieAuthCode.objects.create_from_qdict(request.POST)
-    code.save()
-    params = {'code': code.code, 'me': code.me}
-    if 'state' in request.POST:
-        params['state'] = request.POST['state']
-    return redirect(code.redirect_uri + '?' + urlencode(params))
+    post = request.POST
+    params = tokens.gen_auth_code(post)
+    return redirect(post['redirect_uri'] + '?' + urlencode(params))