use UUIDs instead of millisecond timestamp for file name

Author: striezel

export-server/package.json

@@ -21,6 +21,7 @@
   "author": "Dirk Stolle <striezel-dev@web.de>",
   "license": "GPL-3.0",
   "dependencies": {
-    "phantomjs-prebuilt": "^2.1.16"
+    "phantomjs-prebuilt": "^2.1.16",
+    "uuid": "^3.4.0"
   }
 }

export-server/phantomize.js

@@ -1,6 +1,6 @@
 /*
     Plotly.js offline image export server with Node.js
-    Copyright (C) 2018  Dirk Stolle
+    Copyright (C) 2018, 2021  Dirk Stolle
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -21,7 +21,7 @@
 var child_process = require('child_process');
 var fs = require('fs');
 const paths = require('./paths.js');
-
+const uuidv4 = require('uuid/v4');
 
 /* Renders JSON data for a Plotly.js plot into a PNG file.
 
@@ -38,8 +38,10 @@ const paths = require('./paths.js');
                  rendering, may be cryptic and is not necessarily human-friendly
 */
 exports.render = function(jsonData, filename) {
+  const unique_id = uuidv4();
+
   if (!filename) {
-    filename = 'phantom-render-' + Date.now() + '.png';
+    filename = 'phantom-render-' + unique_id + '.png';
   }
   if (typeof jsonData !== 'string') {
     return {
@@ -54,7 +56,7 @@ exports.render = function(jsonData, filename) {
     };
   }
 
-  const plotDataFile = 'plot-data-' + Date.now() + '.json';
+  const plotDataFile = 'plot-data-' + unique_id + '.json';
   fs.writeFileSync(plotDataFile, jsonData, {mode: 0o644, flag: 'w'});
 
   console.log("Starting PhantomJS ...\n(This might take one or two seconds.)");

export-server/server.js

@@ -1,6 +1,6 @@
 /*
     Plotly.js offline image export server with Node.js
-    Copyright (C) 2018, 2020  Dirk Stolle
+    Copyright (C) 2018, 2020, 2021  Dirk Stolle
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -24,6 +24,7 @@ const path = require('path');
 const paths = require('./paths.js');
 const phantomize = require('./phantomize.js');
 const url = require('url');
+const uuidv4 = require('uuid/v4');
 
 const hostname = 'localhost';
 const port = 3000;
@@ -178,7 +179,7 @@ const server = http.createServer(function(req, res) {
       return;
     }
     // Render file with PhantomJS.
-    const filename = 'graph-' + Date.now() + '.png';
+    const filename = 'graph-' + uuidv4() + '.png';
     const result = phantomize.render(body, filename);
     if (result.success) {
       res.statusCode = 200; // 200 == OK