新增订阅消息额度记账表与模块

2026-08-15 17:34:46 +08:00
parent 68acbb3809
commit 8d63b47577
3 changed files with 119 additions and 0 deletions
@@ -0,0 +1,60 @@
+/**
+ * 订阅消息额度记账
+ *
+ * ⚠️ balance 是估算值，不是权威数据。真值只存在于微信服务器，且没有接口可查。
+ * 我们靠「前端授权成功上报 +1、发送成功 -1」维护，并在发送返回 43101 时归零校正。
+ * 任何地方都不要把 balance 当作可信的强校验依据。
+ *
+ * 额度是「每用户 × 每模板」维度的，所以以 openid 为主键；本项目只有一个模板，故不再分列。
+ */
+
+const db = require('./db')
+
+const MAX_GRANT_PER_CALL = 50 // 单次上报上限，防御异常入参
+
+function getBalance(openid) {
+  const row = db.prepare('SELECT balance FROM subscribe_quota WHERE openid = ?').get(openid)
+  return row ? row.balance : 0
+}
+
+// 把任意入参收敛成 1..MAX_GRANT_PER_CALL 的整数
+function _normalize(count) {
+  const n = parseInt(count, 10)
+  if (!Number.isFinite(n) || n < 1) return 1
+  return Math.min(n, MAX_GRANT_PER_CALL)
+}
+
+// 授权上报：纯累加、不去重——微信侧确实每次授权都 +1，如实记录即可
+function grant(openid, count = 1) {
+  const n = _normalize(count)
+  db.prepare(`
+    INSERT INTO subscribe_quota (openid, balance, grantedTotal, sentTotal, updateTime)
+    VALUES (@openid, @n, @n, 0, @now)
+    ON CONFLICT(openid) DO UPDATE SET
+      balance      = balance + @n,
+      grantedTotal = grantedTotal + @n,
+      updateTime   = @now
+  `).run({ openid, n, now: Date.now() })
+  return getBalance(openid)
+}
+
+function consume(openid, count = 1) {
+  const n = _normalize(count)
+  db.prepare(`
+    UPDATE subscribe_quota
+    SET balance = MAX(0, balance - @n), sentTotal = sentTotal + @n, updateTime = @now
+    WHERE openid = @openid
+  `).run({ openid, n, now: Date.now() })
+  return getBalance(openid)
+}
+
+// 余额归零：发送返回 43101 时调用，说明微信侧实际已无额度（或用户关了通知总开关）
+function reset(openid) {
+  db.prepare(`
+    INSERT INTO subscribe_quota (openid, balance, grantedTotal, sentTotal, updateTime)
+    VALUES (@openid, 0, 0, 0, @now)
+    ON CONFLICT(openid) DO UPDATE SET balance = 0, updateTime = @now
+  `).run({ openid, now: Date.now() })
+}
+
+module.exports = { getBalance, grant, consume, reset }