return invalid url if feed url is different from user provided url

packages/api/src/generated/graphql.ts

@@ -2790,6 +2790,7 @@ export enum SubscribeErrorCode {
   AlreadySubscribed = 'ALREADY_SUBSCRIBED',
   BadRequest = 'BAD_REQUEST',
   ExceededMaxSubscriptions = 'EXCEEDED_MAX_SUBSCRIPTIONS',
+  InvalidUrl = 'INVALID_URL',
   NotFound = 'NOT_FOUND',
   Unauthorized = 'UNAUTHORIZED'
 }

packages/api/src/generated/schema.graphql

@@ -2190,6 +2190,7 @@ enum SubscribeErrorCode {
   ALREADY_SUBSCRIBED
   BAD_REQUEST
   EXCEEDED_MAX_SUBSCRIPTIONS
+  INVALID_URL
   NOT_FOUND
   UNAUTHORIZED
 }

packages/api/src/resolvers/subscriptions/index.ts

@@ -1,6 +1,6 @@
 import axios from 'axios'
 import { parseHTML } from 'linkedom'
-import { Brackets } from 'typeorm'
+import { Brackets, In } from 'typeorm'
 import {
   DEFAULT_SUBSCRIPTION_FOLDER,
   Subscription,
@@ -204,7 +204,7 @@ export const subscribeResolver = authorized<
 
     // find existing subscription
     const existingSubscription = await getRepository(Subscription).findOneBy({
-      url: feedUrl,
+      url: In([feedUrl, input.url]), // check both user provided url and parsed url
       user: { id: uid },
       type: SubscriptionType.Rss,
     })
@@ -241,6 +241,16 @@ export const subscribeResolver = authorized<
       }
     }
 
+    if (feedUrl !== input.url) {
+      log.info('feed url is different from user provided url', {
+        feedUrl,
+        inputUrl: input.url,
+      })
+      return {
+        errorCodes: [SubscribeErrorCode.InvalidUrl],
+      }
+    }
+
     // create new rss subscription
     const MAX_RSS_SUBSCRIPTIONS = env.subscription.feed.max
 

packages/api/src/schema.ts

@@ -1737,6 +1737,7 @@ const schema = gql`
     NOT_FOUND
     ALREADY_SUBSCRIBED
     EXCEEDED_MAX_SUBSCRIPTIONS
+    INVALID_URL
   }
 
   union AddPopularReadResult = AddPopularReadSuccess | AddPopularReadError