Merge pull request #109 from cloudflare/sven/fix-duplicate-follow

ignore duplicated follow

backend/src/activitypub/activities/handle.ts

@@ -224,12 +224,10 @@ export async function handle(
 				const originalActor = await actors.getAndCache(new URL(actorId), db)
 				const receiverAcct = `${receiver.preferredUsername}@${domain}`
 
-				await Promise.all([
-					addFollowing(db, originalActor, receiver, receiverAcct),
-					acceptFollowing(db, originalActor, receiver),
-				])
+				await addFollowing(db, originalActor, receiver, receiverAcct)
 
 				// Automatically send the Accept reply
+				await acceptFollowing(db, originalActor, receiver)
 				const reply = accept.create(receiver, activity)
 				const signingKey = await getSigningKey(userKEK, db, receiver)
 				await deliverToActor(signingKey, receiver, originalActor, reply)

backend/src/mastodon/follow.ts

@@ -9,7 +9,7 @@ export async function addFollowing(db: D1Database, actor: Actor, target: Actor,
 	const id = crypto.randomUUID()
 
 	const query = `
-		INSERT INTO actor_following (id, actor_id, target_actor_id, state, target_actor_acct)
+		INSERT OR IGNORE INTO actor_following (id, actor_id, target_actor_id, state, target_actor_acct)
 		VALUES (?, ?, ?, ?, ?)
 	`
 

backend/test/activitypub/follow.spec.ts

@@ -149,5 +149,26 @@ describe('ActivityPub', () => {
 			assert.equal(entry.actor_id.toString(), actor.id.toString())
 			assert.equal(entry.from_actor_id.toString(), actor2.id.toString())
 		})
+
+		test('ignore when trying to follow multiple times', async () => {
+			const db = await makeDB()
+			const actor = await createPerson(domain, db, userKEK, 'sven@cloudflare.com')
+			const actor2 = await createPerson(domain, db, userKEK, 'sven2@cloudflare.com')
+
+			const activity = {
+				'@context': 'https://www.w3.org/ns/activitystreams',
+				type: 'Follow',
+				actor: actor2.id,
+				object: actor.id,
+			}
+
+			await activityHandler.handle(domain, activity, db, userKEK, adminEmail, vapidKeys)
+			await activityHandler.handle(domain, activity, db, userKEK, adminEmail, vapidKeys)
+			await activityHandler.handle(domain, activity, db, userKEK, adminEmail, vapidKeys)
+
+			// Even if we followed multiple times, only one row should be present.
+			const { count } = await db.prepare(`SELECT count(*) as count FROM actor_following`).first()
+			assert.equal(count, 1)
+		})
 	})
 })

backend/test/utils.ts

@@ -3,6 +3,7 @@ import type { Queue } from 'wildebeest/backend/src/types/queue'
 import { createClient } from 'wildebeest/backend/src/mastodon/client'
 import type { Client } from 'wildebeest/backend/src/mastodon/client'
 import { promises as fs } from 'fs'
+import * as path from 'path'
 import { BetaDatabase } from '@miniflare/d1'
 import * as Database from 'better-sqlite3'
 
@@ -21,8 +22,12 @@ export async function makeDB(): Promise<any> {
 	const db2 = new BetaDatabase(db)!
 
 	// Manually run our migrations since @miniflare/d1 doesn't support it (yet).
-	const initial = await fs.readFile('./migrations/0000_initial.sql', 'utf-8')
-	await db.exec(initial)
+	const migrations = await fs.readdir('./migrations/')
+
+	for (let i = 0, len = migrations.length; i < len; i++) {
+		const content = await fs.readFile(path.join('migrations', migrations[i]), 'utf-8')
+		await db.exec(content)
+	}
 
 	return db2
 }

migrations/0001_add-unique-following.sql

@@ -0,0 +1,3 @@
+-- Migration number: 0001 	 2023-01-16T13:09:04.033Z
+
+CREATE UNIQUE INDEX unique_actor_following ON actor_following (actor_id, target_actor_id);