ストーキング実装

Closes #1511

src/server/api/endpoints/following/stalk.ts

@@ -0,0 +1,36 @@
+import $ from 'cafy';
+import Following from '../../../../models/following';
+import { isLocalUser } from '../../../../models/user';
+
+/**
+ * Stalk a user
+ */
+module.exports = (params, user) => new Promise(async (res, rej) => {
+	const follower = user;
+
+	// Get 'userId' parameter
+	const [userId, userIdErr] = $(params.userId).id().$;
+	if (userIdErr) return rej('invalid userId param');
+
+	// Fetch following
+	const following = await Following.findOne({
+		followerId: follower._id,
+		followeeId: userId
+	});
+
+	if (following === null) {
+		return rej('following not found');
+	}
+
+	// Stalk
+	await Following.update({ _id: following._id }, {
+		$set: {
+			stalk: true
+		}
+	});
+
+	// Send response
+	res();
+
+	// TODO: イベント
+});