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    Cannot get the WebSockets example working

    Posts: 1
    edited June 2024 in LFW111 Class Forum

    Hello,
    I'm running the LFW111 course examples on node 20.11.0 with

    1.   "dependencies": {
    2.     "@fastify/autoload": "^5.0.0",
    3.     "@fastify/cors": "^9.0.1",
    4.     "@fastify/sensible": "^5.0.0",
    5.     "@fastify/websocket": "^10.0.1",
    6.     "fastify": "^4.26.1",
    7.     "fastify-cli": "^6.2.1",
    8.     "fastify-plugin": "^4.0.0"
    9.   },

    The Web Sockets example in lesson 04 (Going Realtime) doesn't work for me. When I run the mock-service, and select a category in the static web page, the mock service of the routes/orders plugin throws an error complaining that the socket is undefined:

    1. [16:45:38.506] ERROR (369197): Cannot read properties of undefined (reading 'send')
    2.     reqId: "req-2"
    3.     err: {
    4.       "type": "TypeError",
    5.       "message": "Cannot read properties of undefined (reading 'send')",
    6.       "stack":
    7.           TypeError: Cannot read properties of undefined (reading 'send')
    8.               at Object.<anonymous> (file:///home/cfinis/workspace/jsnad/my-project-WS/mock-srv/routes/orders/index.mjs:9:16)
    9.               at /home/cfinis/workspace/jsnad/my-project-WS/mock-srv/node_modules/@fastify/websocket/index.js:185:34
    10. ...
    11. }

    Any idea what is going wrong?

    Thanks

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    Answers

    • Posts: 2

      I've got the same problem. Did you ever get it working?

    • Posts: 2

      @jonatasmello , thank you! That was the problem.

    • Posts: 1

      Saved my sanity with this, thanks!

    • Posts: 3

      Thanks @jonatasmello. Could the admins fix this? Also, there is a minor bug on the related page https://trainingportal.linuxfoundation.org/learn/course/introduction-to-nodejs-lfw111x/going-real-time/real-time-functionality?page=4 -> the static files should be served with command npx serve -p 5050 static

    • Posts: 1

      @jonatasmello Thanks it worked.

    • Posts: 1

      @jonatasmello said:
      Hi,
      here is what worked for me based on the official documentation

      async ({ socket }, request) => {

      use this instead:

      async ( socket, request) => {

      the parameter "socket" is just a variable, not an object (with {socket} )

      1. Let's also create an index.mjs file in our newly created folder with the following contents:
      2.  
      3. "use strict";
      4.  
      5. export default async function (fastify, opts) {
      6.   fastify.get(
      7.     "/:category",
      8.     { websocket: true },
      9.     async (socket, request) => {
      10.       socket.send(JSON.stringify({ id: "A1", total: 3 }));
      11.     }
      12.   )};

      This is the miracle working code!! A crack!!

    • Posts: 1

      Grazie!

    • Posts: 2

      Muchas gracias. Funciona correctamente con los datos originales, pero en cuanto añades nuevos registros estos quedan permanentemente sin definir. Entiendo que es lo normal dado que es un simple ejemplo.

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