首次提交

2026-07-13 12:06:16 +08:00
commit e3c810b1a6
1690 changed files with 228324 additions and 0 deletions
@@ -0,0 +1,255 @@
+'use strict'
+
+const fastfall = require('fastfall')
+const Packet = require('aedes-packet')
+const { through } = require('../utils')
+const { validateTopic, $SYS_PREFIX } = require('../utils')
+const write = require('../write')
+
+const subscribeTopicActions = fastfall([
+  authorize,
+  storeSubscriptions,
+  addSubs
+])
+const restoreTopicActions = fastfall([
+  authorize,
+  addSubs
+])
+
+function SubAck (packet, granted) {
+  this.cmd = 'suback'
+  this.messageId = packet.messageId
+  // the qos granted
+  this.granted = granted
+}
+
+function Subscription (qos, func, rh, rap, nl) {
+  this.qos = qos
+  this.func = func
+
+  // retain-handling indicates how retained messages should be
+  // handled when a new subscription is created
+  // (see [MQTT-3.3.1-9] through [MQTT-3.3.1-11])
+  this.rh = rh
+
+  // retain-as-published indicates whether to leave the retain flag as-is (true)
+  // or to clear it before sending to subscriptions (false) default false
+  // (see [MQTT-3.3.1-12] through [MQTT-3.3.1-13])
+  this.rap = rap
+
+  // no-local indicates that a client should not receive its own
+  // messages (see [MQTT-3.8.3-3])
+  this.nl = nl
+}
+
+function SubscribeState (client, packet, restore, finish) {
+  this.client = client
+  this.packet = packet
+  this.actions = restore ? restoreTopicActions : subscribeTopicActions
+  this.finish = finish
+  this.subState = []
+}
+
+function SubState (client, packet, granted, rh, rap, nl) {
+  this.client = client
+  this.packet = packet
+  this.granted = granted
+  this.rh = rh
+  this.rap = rap
+  this.nl = nl
+}
+
+// if same subscribed topic in subs array, we pick up the last one
+function _dedupe (subs) {
+  const dedupeSubs = {}
+  for (let i = 0; i < subs.length; i++) {
+    const sub = subs[i]
+    dedupeSubs[sub.topic] = sub
+  }
+  const ret = []
+  for (const key in dedupeSubs) {
+    ret.push(dedupeSubs[key])
+  }
+  return ret
+}
+
+function handleSubscribe (client, packet, restore, done) {
+  packet.subscriptions = packet.subscriptions.length === 1 ? packet.subscriptions : _dedupe(packet.subscriptions)
+  client.broker._parallel(
+    new SubscribeState(client, packet, restore, done), // what will be this in the functions
+    doSubscribe, // function to call
+    packet.subscriptions, // first argument of the function
+    restore ? done : completeSubscribe // the function to be called when the parallel ends
+  )
+}
+
+function doSubscribe (sub, done) {
+  const s = new SubState(this.client, this.packet, sub.qos, sub.rh, sub.rap, sub.nl)
+  this.subState.push(s)
+  this.actions.call(s, sub, done)
+}
+
+function authorize (sub, done) {
+  const err = validateTopic(sub.topic, 'SUBSCRIBE')
+  if (err) {
+    return done(err)
+  }
+  const client = this.client
+  client.broker.authorizeSubscribe(client, sub, done)
+}
+
+function blockDollarSignTopics (func) {
+  return function deliverSharp (packet, cb) {
+    // '$' is 36
+    if (packet.topic.charCodeAt(0) === 36) {
+      cb()
+    } else {
+      func(packet, cb)
+    }
+  }
+}
+
+function storeSubscriptions (sub, done) {
+  if (!sub || typeof sub !== 'object') {
+    // means failure: MQTT 3.1.1 specs > 3.9.3 Payload
+    this.granted = 128
+    return done(null, null)
+  }
+
+  const packet = this.packet
+  const client = this.client
+
+  if (client.clean) {
+    return done(null, sub)
+  }
+
+  client.broker.persistence.addSubscriptions(client, packet.subscriptions, function addSub (err) {
+    done(err, sub)
+  })
+}
+
+function addSubs (sub, done) {
+  if (!sub || typeof sub !== 'object') {
+    return done()
+  }
+
+  const client = this.client
+  const broker = client.broker
+  const topic = sub.topic
+  const qos = sub.qos
+  const rh = this.rh
+  const rap = this.rap
+  const nl = this.nl
+  let func = qos > 0 ? client.deliverQoS : client.deliver0
+
+  const deliverFunc = func
+  func = function handlePacketSubscription (_packet, cb) {
+    _packet = new Packet(_packet, broker)
+    _packet.nl = nl
+    if (!rap) _packet.retain = false
+    deliverFunc(_packet, cb)
+  }
+
+  // [MQTT-4.7.2-1]
+  if (isStartsWithWildcard(topic)) {
+    func = blockDollarSignTopics(func)
+  }
+
+  if (client.closed || client.broker.closed) {
+    // a hack, sometimes client.close() or broker.close() happened
+    // before authenticate() comes back
+    // we don't continue subscription here
+    return
+  }
+
+  if (!client.subscriptions[topic]) {
+    client.subscriptions[topic] = new Subscription(qos, func, rh, rap, nl)
+    broker.subscribe(topic, func, done)
+  } else if (client.subscriptions[topic].qos !== qos || client.subscriptions[topic].rh !== rh || client.subscriptions[topic].rap !== rap || client.subscriptions[topic].nl !== nl) {
+    broker.unsubscribe(topic, client.subscriptions[topic].func)
+    client.subscriptions[topic] = new Subscription(qos, func, rh, rap, nl)
+    broker.subscribe(topic, func, done)
+  } else {
+    done()
+  }
+}
+
+// + is 43
+// # is 35
+function isStartsWithWildcard (topic) {
+  const code = topic.charCodeAt(0)
+  return code === 43 || code === 35
+}
+
+function completeSubscribe (err) {
+  const done = this.finish
+
+  if (err) {
+    return done(err)
+  }
+
+  const packet = this.packet
+  const client = this.client
+
+  if (packet.messageId !== undefined) {
+    // [MQTT-3.9.3-1]
+    write(client,
+      new SubAck(packet, this.subState.map(obj => obj.granted)),
+      done)
+  } else {
+    done()
+  }
+
+  const broker = client.broker
+
+  // subscriptions array to return as result in 'subscribe' event and $SYS
+  const subs = packet.subscriptions
+
+  // topics we need to retrieve retain values from
+  const topics = []
+
+  for (let i = 0; i < subs.length; i++) {
+    // skip topics that are not allowed
+    if (this.subState[i].granted !== 128) {
+      topics.push(subs[i].topic)
+    }
+    // set granted qos to subscriptions
+    subs[i].qos = this.subState[i].granted
+  }
+
+  this.subState = []
+
+  broker.emit('subscribe', subs, client)
+  broker.publish({
+    topic: $SYS_PREFIX + broker.id + '/new/subscribes',
+    payload: Buffer.from(JSON.stringify({
+      clientId: client.id,
+      subs
+    }), 'utf8')
+  }, noop)
+
+  // Conform to MQTT 3.1.1 section 3.1.2.4
+  // Restored sessions should not contain any retained message.
+  // Retained message should be only fetched from SUBSCRIBE.
+
+  if (topics.length > 0) {
+    const persistence = broker.persistence
+    const stream = persistence.createRetainedStreamCombi(topics)
+    stream.pipe(through(function sendRetained (packet, enc, cb) {
+      packet = new Packet({
+        cmd: packet.cmd,
+        qos: packet.qos,
+        topic: packet.topic,
+        payload: packet.payload,
+        retain: true
+      }, broker)
+      // this should not be deduped
+      packet.brokerId = null
+      client.deliverQoS(packet, cb)
+    }))
+  }
+}
+
+function noop () { }
+
+module.exports = handleSubscribe