add websocket support for remix-sim

remix-simulator/package.json

@@ -22,6 +22,7 @@
     "body-parser": "^1.18.2",
     "color-support": "^1.1.3",
     "express": "^4.16.3",
+    "express-ws": "^4.0.0",
     "fast-async": "^6.3.7",
     "merge": "^1.2.0",
     "remix-lib": "0.3.13",

remix-simulator/src/server.js

 const express = require('express')
 const bodyParser = require('body-parser')
 const app = express()
+const expressWs = require('express-ws')(app)
 const Provider = require('./provider')
 const log = require('./utils/logs.js')
 
@@ -22,4 +23,15 @@ app.use(function (req, res) {
   })
 })
 
+app.ws('/', function(ws, req) {
+  ws.on('message', function(msg) {
+    provider.sendAsync(JSON.parse(msg), (err, jsonResponse) => {
+      if (err) {
+        ws.send({error: err});
+      }
+      ws.send(JSON.stringify(jsonResponse));
+    })
+  });
+});
+
 app.listen(8545, () => log('Remix Simulator listening on port 8545!'))