fix conflict in engine

lib/core/engine.js

@@ -10,6 +10,7 @@ const Watch = require('../pipeline/watch.js');
 const LibraryManager = require('../versions/library_manager.js');
 const Pipeline = require('../pipeline/pipeline.js');
 const async = require('async');
+const Provider = require('./provider');
 
 class Engine {
   constructor(options) {
@@ -271,8 +272,8 @@ class Engine {
     if (this.web3 === undefined) {
       this.web3 = new Web3();
       if (this.config.contractsConfig.deployment.type === "rpc") {
-        let web3Endpoint = 'http://' + this.config.contractsConfig.deployment.host + ':' + this.config.contractsConfig.deployment.port;
-        this.web3.setProvider(new this.web3.providers.HttpProvider(web3Endpoint));
+        const web3Endpoint = 'http://' + this.config.contractsConfig.deployment.host + ':' + this.config.contractsConfig.deployment.port;
+        this.web3.setProvider(new Provider(web3Endpoint));
       } else {
         throw new Error("contracts config error: unknown deployment type " + this.config.contractsConfig.deployment.type);
       }

lib/core/provider.js

@@ -0,0 +1,37 @@
+const ProviderEngine = require('web3-provider-engine');
+// const ProviderSubprovider = require("web3-provider-engine/subproviders/provider.js");
+const RpcSubprovider = require('web3-provider-engine/subproviders/rpc.js');
+
+class Provider {
+  constructor(web3Endpoint) {
+    this.engine = new ProviderEngine();
+    // this.web3 = new Web3(engine);
+
+    this.engine.addProvider(new RpcSubprovider({
+      rpcUrl: web3Endpoint
+    }));
+
+    this.engine.on('block', function (block) {
+      console.log('================================');
+      console.log('BLOCK CHANGED:', '#' + block.number.toString('hex'), '0x' + block.hash.toString('hex'));
+      console.log('================================');
+    });
+
+    // network connectivity error
+    this.engine.on('error', function (err) {
+      // report connectivity errors
+      console.error(err.stack);
+    });
+    this.engine.start();
+  }
+
+  sendAsync() {
+    this.engine.sendAsync.apply(this.engine, arguments);
+  }
+
+  send() {
+    return this.engine.send.apply(this.engine, arguments);
+  }
+}
+
+module.exports = Provider;

package.json

@@ -67,6 +67,7 @@
     "url-loader": "^0.6.2",
     "viz.js": "^1.8.1",
     "web3": "1.0.0-beta.34",
+    "web3-provider-engine": "^14.0.5",
     "webpack": "^3.10.0",
     "window-size": "^1.1.0"
   },