1 files changed, 31 insertions, 0 deletions

diff --git a/server/lib/activitypub/process/process-undo.ts b/server/lib/activitypub/process/process-undo.ts
new file mode 100644
index 000000000..5d09423e1
--- /dev/null
+++ b/server/lib/activitypub/process/process-undo.ts
@@ -0,0 +1,31 @@
+import { ActivityUndo } from '../../../../shared/models/activitypub/activity'
+import { logger } from '../../../helpers/logger'
+import { database as db } from '../../../initializers'
+
+async function processUndoActivity (activity: ActivityUndo) {
+  const activityToUndo = activity.object
+
+  if (activityToUndo.type === 'Follow') {
+    const follower = await db.Account.loadByUrl(activity.actor)
+    const following = await db.Account.loadByUrl(activityToUndo.object)
+    const accountFollow = await db.AccountFollow.loadByAccountAndTarget(follower.id, following.id)
+
+    if (!accountFollow) throw new Error(`'Unknown account follow (${follower.id} -> ${following.id}.`)
+
+    await accountFollow.destroy()
+
+    return undefined
+  }
+
+  logger.warn('Unknown activity object type %s -> %s when undo activity.', activityToUndo.type, { activity: activity.id })
+
+  return undefined
+}
+
+// ---------------------------------------------------------------------------
+
+export {
+  processUndoActivity
+}
+
+// ---------------------------------------------------------------------------