Nodejs CoAP服务器未接收有效负载

Question

I just created CoAP Client using Arduino and am able to send payload("hello") to the coap browser(installed from mozilla browser). I can see it in browser, it receives.

Now I need to create my own |Nodejs server to receive my payload (say "hello") from Arduino client. How can I achieve it ?

server

var coap        = require('coap');
    var server      = coap.createServer();

// At this point, I checked from mozilla coap browser, sent "hello" and I am able to receive the HEX values. Same way, I tried to send it from Arduino, but did not print anything
    server.on('request', function(req, res) {
       console.log(req.payload);
    })

    // the default CoAP port is 5683
    server.listen(function() {
        var req = coap.request('coap://localhost');
        console.log('Listening on : 5683')

        req.on('response', function(res) {
            res.pipe(process.stdout);
        });

        req.end()
    });

arduino

void loop() {
  // send GET or PUT coap request to CoAP server.
  // To test, use libcoap, microcoap server...etc
   int msgid = coap.put(IPAddress(192,168,0,11), 5683, "light","1");
  Serial.println("Send Request");
  //int msgid1 = coap.get(IPAddress(192, 168, 0, 11), 5683, "time");

  delay(1000);
  coap.loop();
}

Answer 1

On the Arduino, you should implement a coap server in firmware (not in Node).

Are you using this library? If so then you should check out especially this example which reads from the ethernet peripheral, parses the packet, and then responds accordingly.

Pseudocode:

udp.setup()

while true
  p = udp.read()
  if(p == SUCCESSFUL_UDP_READ_FLAG)
    parsed = p.parse()
    if(parsed matches some condition)
      udp.respond(message regarding condition)

---

There's another example server with 2 endpoints here .

The important parts are:

Inside void setup() :

coap.add_resource(&aSensor);
coap.add_resource(&bSensor);

And then inside void loop() :

coap.handler();