Add Discord authentication

Fixes #12

sidewinder/identity/admin.py

@@ -4,7 +4,7 @@
 from django.urls import path
 from solo.admin import SingletonModelAdmin
 
-from sidewinder.identity.models import User, RedditCredentials, RedditApplication
+from sidewinder.identity.models import User, RedditCredentials, DiscordCredentials, RedditApplication, DiscordApplication
 
 
 class IdentityUserChangeForm(UserChangeForm):
@@ -17,17 +17,20 @@ class UserAdmin(admin.ModelAdmin):
     form = IdentityUserChangeForm
     list_display = ('username', 'uid', 'pronouns',)
     list_filter = ('is_staff', 'is_active',)
-    readonly_fields = ('uid',)
+    readonly_fields = ('uid', 'discord_id',)
     change_password_form = AdminPasswordChangeForm
     change_user_password_template = None
 
     fieldsets = (
         ('User details', {
-            "fields": ('username', 'uid', 'password', 'date_joined',)
+            "fields": ('username', 'password', 'date_joined',)
         }),
         ('Profile', {
             "fields": ('email', 'pronouns',)
         }),
+        ('Connections', {
+            "fields": ('uid', 'discord_id',)
+        }),
         ('Permissions', {
             "fields": ('is_active', 'is_staff', 'is_superuser', 'groups', 'user_permissions',)
         }),
@@ -44,10 +47,10 @@ def lookup_allowed(self, lookup, value):
         # Don't allow lookups involving passwords.
         return not lookup.startswith('password') and super().lookup_allowed(lookup, value)
 
-@admin.register(RedditApplication)
-class RedditAppAdmin(SingletonModelAdmin):
+@admin.register(RedditApplication, DiscordApplication)
+class RedditDiscordAppAdmin(SingletonModelAdmin):
     list_display = ('name',)
 
-@admin.register(RedditCredentials)
-class RedditCredentialsAdmin(admin.ModelAdmin):
+@admin.register(RedditCredentials, DiscordCredentials)
+class CredentialsAdmin(admin.ModelAdmin):
     list_display = ('user', 'last_refresh',)

sidewinder/identity/migrations/0005_add_discord_authentication.py

@@ -0,0 +1,52 @@
+# Generated by Django 4.0.3 on 2023-04-22 22:02
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('identity', '0004_increase_client_id_secret_length'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='DiscordApplication',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=128)),
+                ('client_id', models.CharField(max_length=20)),
+                ('client_secret', models.CharField(max_length=32)),
+            ],
+            options={
+                'verbose_name': 'Discord Application',
+                'verbose_name_plural': 'Discord Applications',
+            },
+        ),
+        migrations.AddField(
+            model_name='user',
+            name='discord_id',
+            field=models.CharField(blank=True, verbose_name='Discord ID', max_length=20),
+        ),
+        migrations.AlterField(
+            model_name='redditcredentials',
+            name='user',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='reddit_tokens', to=settings.AUTH_USER_MODEL),
+        ),
+        migrations.CreateModel(
+            name='DiscordCredentials',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('access_token', models.CharField(max_length=200)),
+                ('refresh_token', models.CharField(max_length=200)),
+                ('last_refresh', models.DateTimeField()),
+                ('user', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='discord_tokens', to=settings.AUTH_USER_MODEL)),
+            ],
+            options={
+                'verbose_name': 'Discord Credentials',
+                'verbose_name_plural': 'Discord Credentials',
+            },
+        ),
+    ]

sidewinder/identity/models.py

@@ -31,6 +31,8 @@ class User(AbstractBaseUser, PermissionsMixin, UserMixin):
     email = models.EmailField(verbose_name='email address', blank=True)
     pronouns = models.CharField(max_length=300, default='unspecified')
 
+    discord_id = models.CharField(max_length=20, verbose_name="Discord ID", blank=True)
+
     USERNAME_FIELD = 'username'
     EMAIL_FIELD = 'email'
     REQUIRED_FIELDS = ['uid', 'email']
@@ -50,16 +52,40 @@ class Meta:
         verbose_name = 'Reddit Application'
         verbose_name_plural = 'Reddit Applications'
 
-class RedditCredentials(models.Model):
-    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='tokens')
+class DiscordApplication(SingletonModel):
+    name = models.CharField(max_length=128)
+
+    client_id = models.CharField(max_length=20)
+    client_secret = models.CharField(max_length=32)
+
+    class Meta:
+        verbose_name = 'Discord Application'
+        verbose_name_plural = 'Discord Applications'
 
+class Credentials(models.Model):
     access_token = models.CharField(max_length=200)
     refresh_token = models.CharField(max_length=200)
     last_refresh = models.DateTimeField()
 
+    class Meta:
+        abstract = True
+
+class RedditCredentials(Credentials):
+    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='reddit_tokens')
+
     def __str__(self):
         return f"{self.user.username} - Reddit"
 
     class Meta:
         verbose_name = 'Reddit Credentials'
         verbose_name_plural = 'Reddit Credentials'
+
+class DiscordCredentials(Credentials):
+    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='discord_tokens')
+
+    def __str__(self):
+        return f"{self.user.username} - Discord"
+
+    class Meta:
+        verbose_name = 'Discord Credentials'
+        verbose_name_plural = 'Discord Credentials'

sidewinder/identity/urls.py

@@ -6,5 +6,7 @@
     path('@me', views.get_current_user),
     path('@me/profile/', views.edit_profile),
     path('reddit/login/', views.reddit_login),
-    path('reddit/authorize/', views.authorize_callback),
+    path('discord/login/', views.discord_login),
+    path('reddit/authorize/', views.reddit_authorize_callback),
+    path('discord/authorize/', views.discord_authorize_callback),
 ]

sidewinder/identity/views.py

@@ -1,3 +1,5 @@
+import requests
+
 from django.contrib import messages
 from django.contrib.auth import login
 from django.http import HttpRequest, HttpResponseRedirect, JsonResponse, HttpResponse
@@ -6,14 +8,15 @@
 from django.views.decorators.csrf import csrf_exempt
 from django.views.decorators.http import require_POST
 from praw import Reddit
+from requests.models import PreparedRequest
 
-from sidewinder.identity.models import RedditApplication, User, RedditCredentials
+from sidewinder.identity.models import RedditApplication, DiscordApplication, User, RedditCredentials, DiscordCredentials
 from sidewinder.utils import generate_state_token
 
 def _build_reddit(request: HttpRequest) -> Reddit:
     app = RedditApplication.get_solo()
     return Reddit(client_id=app.client_id, client_secret=app.client_secret,
-                  redirect_uri=request.build_absolute_uri(reverse(authorize_callback)),
+                  redirect_uri=request.build_absolute_uri(reverse(reddit_authorize_callback)),
                   user_agent='Sidewinder/1.0.0')
 
 
@@ -30,8 +33,29 @@ def reddit_login(request: HttpRequest):
 
     return HttpResponseRedirect(redirect_url)
 
+def discord_login(request: HttpRequest):
+    app = DiscordApplication.get_solo()
+
+    state = generate_state_token()
+
+    redirect = PreparedRequest()
+    redirect.prepare_url("https://discord.com/api/oauth2/authorize", {
+        'response_type': 'code',
+        'client_id': app.client_id,
+        'scope': 'identify',
+        'state': state,
+        'redirect_uri': request.build_absolute_uri(reverse(discord_authorize_callback)),
+        'prompt': 'none'
+    })
+
+    if 'return_to' in request.GET:
+        request.session['return_to'] = request.GET['return_to']
+
+    request.session['state'] = state
+
+    return HttpResponseRedirect(redirect.url)
 
-def authorize_callback(request: HttpRequest):
+def reddit_authorize_callback(request: HttpRequest):
     reddit = _build_reddit(request)
     redirect_to = "/"
 
@@ -78,6 +102,87 @@ def authorize_callback(request: HttpRequest):
     return HttpResponseRedirect(redirect_to)
 
 
+def discord_authorize_callback(request: HttpRequest):
+    redirect_to = "/"
+
+    if 'return_to' in request.session:
+        redirect_to = request.session['return_to']
+    redirect_to = request.build_absolute_uri(redirect_to)
+
+    if not request.user.is_authenticated:
+        messages.error(request, 'Not signed in')
+
+        return HttpResponseRedirect(redirect_to)
+
+    if 'error' in request.GET:
+        error_msg = request.GET['error']
+        messages.error(request, f"Couldn't authorize you with Discord: {error_msg}")
+
+        return HttpResponseRedirect(redirect_to)
+
+    if request.GET['state'] != request.session['state']:
+        messages.error(request, "Couldn't authorize you with Discord: invalid state parameter")
+
+        return HttpResponseRedirect(redirect_to)
+
+    code = request.GET['code']
+
+    app = DiscordApplication.get_solo()
+
+    token_response = requests.post('https://discord.com/api/v10/oauth2/token', data={
+        'client_id': app.client_id,
+        'client_secret': app.client_secret,
+        'grant_type': 'authorization_code',
+        'code': code,
+        'redirect_uri': request.build_absolute_uri(reverse(discord_authorize_callback)),
+    }, headers={
+        'Content-Type': 'application/x-www-form-urlencoded',
+        'User-Agent': 'Sidewinder/1.0.0'
+    }).json()
+
+    if 'error' in token_response:
+        error_msg = token_response['error']
+        messages.error(request, f"Couldn't authorize you with Discord: failed to get token: {error_msg}")
+
+        return HttpResponseRedirect(redirect_to)
+
+    refresh_token = token_response['refresh_token']
+    access_token = token_response['access_token']
+
+    user_response = requests.get('https://discord.com/api/v10/users/@me', headers={
+        'Authorization': 'Bearer ' + access_token,
+        'User-Agent': 'Sidewinder/1.0.0'
+    }).json()
+
+    if 'error' in user_response:
+        error_msg = user_response['error']
+        messages.error(request, f"Couldn't authorize you with Discord: failed to identify user: {error_msg}")
+
+        return HttpResponseRedirect(redirect_to)
+
+    id = user_response['id']
+
+    if request.user.discord_id != '' and request.user.discord_id != id:
+        messages.error(request, f"Couldn't authorize you with Discord: mismatched user")
+
+        return HttpResponseRedirect(redirect_to)
+
+    request.user.discord_id = id
+    request.user.save(update_fields=['discord_id'])
+
+    creds, created = DiscordCredentials.objects.get_or_create(
+        user=request.user,
+        defaults=dict(access_token=access_token, refresh_token=refresh_token, last_refresh=timezone.now())
+    )
+
+    if not created:
+        creds.access_token = access_token
+        creds.refresh_token = refresh_token
+        creds.last_refresh = timezone.now()
+        creds.save()
+
+    return HttpResponseRedirect(redirect_to)
+
 def get_current_user(request):
     if request.user.is_authenticated:
         user: User = request.user
@@ -86,6 +191,7 @@ def get_current_user(request):
             "uid": user.uid,
             "username": user.username,
             "pronouns": user.pronouns,
+            "discord_id": user.discord_id,
             "is_staff": user.is_staff,
         })
     else: