User blocking (Following part) (#3035)

* block wip

* UndoBlock

* UnBlock

* wip

* follow

* UI

* fix

src/remote/activitypub/kernel/undo/block.ts

@@ -0,0 +1,34 @@
+import * as mongo from 'mongodb';
+import User, { IRemoteUser } from '../../../../models/user';
+import config from '../../../../config';
+import * as debug from 'debug';
+import { IBlock } from '../../type';
+import unblock from '../../../../services/blocking/delete';
+
+const log = debug('misskey:activitypub');
+
+export default async (actor: IRemoteUser, activity: IBlock): Promise<void> => {
+	const id = typeof activity.object == 'string' ? activity.object : activity.object.id;
+
+	const uri = activity.id || activity;
+
+	log(`UnBlock: ${uri}`);
+
+	if (!id.startsWith(config.url + '/')) {
+		return null;
+	}
+
+	const blockee = await User.findOne({
+		_id: new mongo.ObjectID(id.split('/').pop())
+	});
+
+	if (blockee === null) {
+		throw new Error('blockee not found');
+	}
+
+	if (blockee.host != null) {
+		throw new Error('ブロック解除しようとしているユーザーはローカルユーザーではありません');
+	}
+
+	unblock(actor, blockee);
+};