Avoid concurrency issues while the same file-version is created for multiple requests resulting in an overwrite of the files by the last request.

Author: Sebastian.Just

README.md

@@ -253,6 +253,7 @@ Other options and their default values:
     targetDir: uploadDir,
     targetUrl: uploadUrl,
     ssl: false,
+    prefixUuid: false, // Prefix every created file with a UUID. Important if there are multiple node processes working on the same folder (iisnode for example) serving requests
     hostname: null, // in case your reverse proxy doesn't set Host header
                     // eg 'google.com'
     maxPostSize: 11000000000, // 11 GB

lib/fileinfo.js

@@ -26,11 +26,17 @@ module.exports = function (options) {
         // Prevent directory traversal and creating hidden system files:
         this.name = require('path').basename(this.name).replace(/^\.+/, '');
         // Prevent overwriting existing files:
-        while (fs.existsSync(options.baseDir() + '/' + this.name)) {
-            this.name = this.name.replace(/(?:(?: \(([\d]+)\))?(\.[^.]+))?$/, function (s, index, ext) {
-                return ' (' + ((parseInt(index, 10) || 0) + 1) + ')' + (ext || '');
-            });
+        if (options.prefixUuid) {
+            this.name = require('uuid').v1() + '_' + this.name;
+        } else {
+            while (fs.existsSync(options.baseDir() + '/' + this.name)) {
+                this.name = this.name.replace(/(?:(?: \(([\d]+)\))?(\.[^.]+))?$/, function (s, index, ext) {
+                    return ' (' + ((parseInt(index, 10) || 0) + 1) + ')' + (ext || '');
+                });
+            }
         }
+        //Touch the file to be sure. Synchronous to have this done before the emit of 'begin' happens
+        fs.closeSync(fs.openSync(options.baseDir() + '/' + this.name, 'w'));
     };
 
     FileInfo.prototype.setUrl = function (type, baseUrl) {

package.json

@@ -14,6 +14,7 @@
     "imagemagick": ">=0.1.2",
     "lodash": ">= 0.9.2",
     "mkdirp": ">= 0.3.4",
+    "uuid": ">=2.0.1",
     "async": "*"
   },
   "engines": {