javascript - 需要通过浏览器将 MQTT 与 Ably 结合使用的帮助

Question

我在 Chrome 中运行的 SPA 中使用 paho-mqtt 库，并使用示例代码调用连接，但收到两个交替的错误

var client = mqtt.connect('mqtts:mqtt.ably.io', {
  keepalive: 30,
  username: 'keyPartA1.artA2',
  password: 'keyPartB',
  port: 8883
});

错误重复出现，但顺序并不总是相同...

stream.js?553e:64 WebSocket connection to 'ws://mqtt.ably.io:8883/' failed: Connection closed before receiving a handshake response
    WebSocketStream @ stream.js?553e:64
    createWebSocket @ ws.js?fcb9:59
    buildBuilderBrowser @ ws.js?fcb9:85
    wrapper @ index.js?e7fc:148
    MqttClient._setupStream @ client.js?df86:263
    MqttClient._reconnect @ client.js?df86:847
    eval @ client.js?df86:862
stream.js?553e:64 WebSocket connection to 'wss://mqtt.ably.io:8883/' failed: Connection closed before receiving a handshake response
    WebSocketStream @ stream.js?553e:64
    createWebSocket @ ws.js?fcb9:59
    buildBuilderBrowser @ ws.js?fcb9:85
    wrapper @ index.js?e7fc:148
    MqttClient._setupStream @ client.js?df86:263
    MqttClient._reconnect @ client.js?df86:847
    eval @ client.js?df86:862
stream.js?553e:64 WebSocket connection to 'ws://mqtt.ably.io:8883/' failed: Error during WebSocket handshake: net::ERR_CONNECTION_RESET
    WebSocketStream @ stream.js?553e:64
    createWebSocket @ ws.js?fcb9:59
    buildBuilderBrowser @ ws.js?fcb9:85
    wrapper @ index.js?e7fc:148
    MqttClient._setupStream @ client.js?df86:263
    MqttClient._reconnect @ client.js?df86:847
    eval @ client.js?df86:862

Answer 1

首先，URI 应该以正确的模式开头，例如mqtts:// 不仅仅是 mqtts:

其次，这实际上是导致问题的原因，您只能从浏览器内连接到 websocket 或启用安全 websocket 的代理。您无法从页面内连接到 native MQTTS 代理。看起来 Ably 的代理期望端口 8883 上的 native MQTTS，而不是 Websockets 上的 MQTT。