reload when file is changed

tools/PollingSimulator/app.js

@@ -4,12 +4,14 @@ const url = require('url');
 const fs = require('fs');
 const request = require('request');
 const moment = require('moment');
+const md5 = require('md5');
 
 var myArgs = require('optimist').argv,
     help = 'node app.js -p port -f file-path/directory [-d delay-between-samples --postUrl http url to post instead of websocket]';
 
 var config = {};
 var jsonFilesMap = [];
+var filesMD5 = [];
 
 //const twoDaysAgoMs = 1000 * 3600 * 47;
 /**
@@ -198,3 +200,29 @@ fs.stat(config.file, (err, stats) => {
     }
 });
 
+let fsWait = false;
+fs.watch(config.file, (event, filename) => {
+    if (filename) {
+        // avoid temp editing files
+        if (filename.startsWith(".")) return;
+        // avoid multiple events
+        if (fsWait) return;
+        fsWait = setTimeout(() => {
+            fsWait = false;
+        }, 100);
+        try {
+            const fileUrl = config.file + '/' + filename;
+            const md5Current = md5(fs.readFileSync(fileUrl));
+            if (filesMD5[filename] && filesMD5[filename] === md5Current){
+                return;
+            }
+            // else file was really changed
+            console.log(`${filename} file Changed`);
+            let filePrefix = getFilePrefix(filename);
+            handleReadFile(fileUrl,filePrefix);
+        } catch (error) {
+            console.log(error);
+        }
+
+    }
+  });
\ No newline at end of file

tools/PollingSimulator/package.json

@@ -17,11 +17,12 @@
     "express": "^4.16.2",
     "fs": "0.0.1-security",
     "http": "0.0.0",
+    "md5": "^2.2.1",
     "moment": "^2.22.2",
     "optimist": "^0.6.1",
     "request": "^2.83.0"
   },
   "bin": {
-    "ws-event-emulator": "./app.js"
+    "polling-simulator": "./app.js"
   }
 }