packBytes Discussion

[e3dio]

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[jcbbb]

Hey, do you use this library with uWebsockets.js?

I am using it the following way instead of using json for communication between servers;

// Node.js server
import WebSocket from 'websocket';
import { PackBytes, string } from 'packBytes';

const encoder = new PackBytes({ op: string, payload: string });

const ws = WebSocket('ws://localhost:3020');

ws.on('open', () => {
  const msg = encoder.encode({ op: "subscribe", payload: "some-topic" });
  ws.send(msg);
});

// uWebsockets.js server
import { App } from 'uWebsockets.js';

const app = App({ }).ws('/*', {
  open: (ws) => {
    const ping = encoder.encode({ op: "ping", payload: "connected" })
    ws.send(ping);
  },
  message: (ws, message) => {
    const decoded = encoder.decode(Buffer.from(message));
    console.log(decoded); // { op: "subscribe", payload: "some-topic" }
  }
})

What do you think about this? Any recommendations to improve this would be greatly appreciated.

Thanks for this library, I love it.

[e3dio]

I refactored the code and added new features:

• new schemas type as discussed above
• JSON serialize any schema with JSON.stringify(schema) and open with new PackBytes(json)
• string added auto-map to integers feature string('str1', 'str2')
• array added size() method to specify exact size if known

I ran it through the tests and is working well, I will be testing more in production, let me know if you need anything else

[e3dio]

I added API section to the README so it is clear how everything works and all options: https://github.com/e3dio/packBytes#api

[jcbbb]

Hey, thank you very much for adding these. I tested yesterday and today and it's working great. One question I have now is how do you send just an op without any data? For example, I want to ask my server for a new QR-code every 2 minutes, and I don't need to send any data except the op. I tried the following:

const encoder = new PackBytes(schemas({
  auth_init: null, // I don't know what to put here to just send the `op`
  auth_pending: string,
  auth_scan: { topic: string, name: string, profile_photo: string } 
}))

[e3dio]

Makes sense in that case to allow a null schema, I added that in latest commit, should work for you now as expected. Good feature, let me know if you need anything else

[jcbbb]

Thank you, it's working now :)

[jcbbb]

Hey, I was trying to encode object that has the following shape:

{
  createdBy: 12,
  id: 2,
  posting: {
    id: 2,
    title: "Hello world"
  },
  members: [{name: "a", id: 2}]
}

and the schema I used is the following:

let schema = schemas({
  new_chat: {
    createdBy: bits(32),
    id: bits(32),
    posting: {
      id: bits(32),
      title: string    
    },
    members: array({name: string, id: bits(32)})
  }
})

But this gives me varInt max exceeded error.

I tried to wrap that nested posting object in new PackBytes like this

let schema = schemas({
  new_chat: {
    // other stuff
    posting: new PackBytes({
       id: bits(32),
       title: string
    })
  }
})

Getting same error as above. Do you know how to write schema for objects like this? :) Thank you

[e3dio]

Your code works fine for me, the only thing missing in your post is encoder.encode('new_chat', data) here is in full:

import { bool, bits, string, array, float, blob, schemas, PackBytes } from 'packbytes';

const data = {
  createdBy: 12,
  id: 2,
  posting: {
    id: 2,
    title: "Hello world"
  },
  members: [{name: "a", id: 2}]
}

const schema = schemas({
  new_chat: {
    createdBy: bits(32),
    id: bits(32),
    posting: {
      id: bits(32),
      title: string    
    },
    members: array({name: string, id: bits(32)})
  }
})

const encoder = new PackBytes(schema);

const buf = encoder.encode('new_chat', data);

console.log(buf);

const [ type, data ] = encoder.decode(buf);

console.log(type, data);

[jcbbb]

Oh shit, forgot I to pass that new_chat op as first argument :(
This whole time I have just been passing only the data. Sorry to bother you with this nonsense