修复动态发布与互动问题

cloudfunctions/followToggle/index.js

@@ -3,12 +3,25 @@ const cloud = require('wx-server-sdk')
 cloud.init({ env: cloud.DYNAMIC_CURRENT_ENV })
 const db = cloud.database()
 
+// Reading a collection that was never created throws in WeChat 云开发, and this
+// function reads `follows` before it ever adds to it — so on a fresh database the
+// first follow would always fail. Create it up-front (no-op if it already exists).
+async function ensureCollection(name) {
+  try {
+    await db.createCollection(name)
+  } catch (e) {
+    // Already-exists error is expected on every call after the first.
+  }
+}
+
 exports.main = async event => {
   const { OPENID } = cloud.getWXContext()
   if (!OPENID) throw new Error('no openid in wx context')
   const { targetUserId, follow } = event
   if (!targetUserId) throw new Error('targetUserId is required')
 
+  await ensureCollection('follows')
+
   const meRes = await db.collection('users').where({ openid: OPENID }).limit(1).get()
   if (!meRes.data.length) throw new Error('user not found')
   const meId = meRes.data[0]._id