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Ubuntu 16.04 REP/REQ Over websockets question #193

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LionCoder4ever opened this issue Jan 22, 2018 · 6 comments
Open

Ubuntu 16.04 REP/REQ Over websockets question #193

LionCoder4ever opened this issue Jan 22, 2018 · 6 comments
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@LionCoder4ever
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LionCoder4ever commented Jan 22, 2018 •
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here is my server code:

const nanomsg = require('nanomsg');
const http = require('http');
const fs = require('fs');
const rep = nanomsg.socket('rep')
rep.bind('ws://127.0.0.1:7789');
rep.on('data', function(msg){
    console.log(msg)
    rep.send('received message');
})
http.createServer(function( req, res ){
  fs.createReadStream( 'index.html' ).pipe( res )
}).listen( 3000 )

and my front code:

<!DOCTYPE html>  
<html>  
<head></head>  
<body>  
   <div id="response"> 
      <span> </span> 
   </div> 
   <input type="text"> 
   <button>send</button> 
   <script> 

      var ws = new WebSocket('ws://127.0.0.1:7789',[
         'rep.sp.nanomsg.org'
      ])

      ws.onmessage = function( e ){
          var reader = new FileReader() // handle binary messages
          reader.addEventListener('loadend', function(){
             var result = reader.result;
             document.querySelector('span').textContent = result
          });
          reader.readAsText( e.data );
      }

       var button = document.querySelector('button');
       var input  = document.querySelector('input');
       button.addEventListener('click', function( e )
       {
           ws.send(input.value);
           input.value = '';
       })

   </script> 
</body>  
</html>

from the chrome devtools I see the upload msg,but the server client doesn't console or reply the msg .After that, i change the req/rep to pair and pub/sub, it works. Is there anything wrong in my req/rep code? Hope your help,Best wishes
@LionCoder4ever
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@reqshark could you help me solve the issue?

@reqshark
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hi @LionCoder4ever, yes happy to help

I will look into this tomorrow morning and we'll get to the bottom of it

thanks for your patience :)

@reqshark
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@LionCoder4ever I'm not sure if req/rep protocol works with websockets in the browser.

I was able to receive a req message in the browser by changing the server in your example code to req and inserting req.sp.nanomsg.org as the argument to the websocket constructor but I wasn't able to receive any further messages

@LionCoder4ever
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@reqshark follow your test, i tried and also can't receive any further messages. Maybe it just not support work in websocket.
Howerver,thanks to your help! Have a nice day!

@reqshark
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btw @LionCoder4ever if you're serious about using nanomsg pub/subs for websocket in the browser, I recommend using the wsopt() socketopt

seems like you already figured out that pair and req/rep sockets are useless for doing websocket msgs over the browser in nanomsg

and avoid messing with browser's FileReader to decode, b/c text frames are more convenient.

here's an update to server.js that we should probably fix in examples/ws:

const addr = 'ws://' + '127.0.0.1' // or do: + require('ip').address()
const pub = require('nanomsg').socket('pub')
const sub = require('nanomsg').socket('sub')

/* set the nanomsg websocket text frames option */
pub.wsopt('text')
sub.wsopt('text')

/* use case doesnt need buffers, set stream encoding to utf8 */
sub.setEncoding('utf8')

/* websocket connections with some random ports */
pub.bind(addr + ':7789')
sub.bind(addr + ':7790')

/* recv websocket msgs */
sub.on('data', recv)

function recv(msg) {
  console.log(msg)
  pub.send(`${msg} ... from node-nanomsg`)
}

/* delete/replace this with your browser server code */
require('http')
  .createServer(function( req, res ){
    require('fs')
      .createReadStream( 'index.html' )
      .pipe( res )
  })
  .listen( 3000 )

console.log('please check http://localhost:3000')

now with text frames sockopts set, your index.html javascript is a bit more reasonable:

<!DOCTYPE html>
<html>
<head></head>
<body>
  <div class='res'><span></span></div>
  <input type='text' />
  <button>send</button>
  <script>
    var addr = 'ws://127.0.0.1'
    var sub = new WebSocket(addr + ':7789', [ 'pub.sp.nanomsg.org' ])
    var pub = new WebSocket(addr + ':7790', [ 'sub.sp.nanomsg.org' ])

    /* recv websocket msgs */
    sub.onmessage = recv

    function recv(msg) {
      document
        .querySelector('span')
        .textContent = msg.data /* <-- an improvement from FileReader :) */
    }

    /* send websocket msgs w/ input button */
    var input = document.querySelector('input')
    document
      .querySelector('button')
      .addEventListener('click', send)

    function send( e ){
      pub.send(input.value)
      input.value = ''
    }

    /* call send() also if user hits return key */
    input.onkeydown = function hitreturn ( e ) {
      if (e.keyCode === 13 || e.which === 13)
        send()
    }
  </script>
</body>
</html>

@LionCoder4ever
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@reqshark thanks for your recommend advice , i solved my problem successfully!
Best wishes

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@reqshark @LionCoder4ever