Config sharp image preprocessing

app.js

@@ -413,10 +413,25 @@ app.post('/uploadimage', function (req, res) {
         form.uploadDir = "public/uploads";
     }
 
+    function preprocessImage(path) {
+        return new Promise((resolve) => {
+            var oldFile = `${path}-old`;
+            fs.rename(path, oldFile, function() {
+                var sharp = require('sharp');
+                sharp(oldFile).toFile(path).then(() => {
+                    fs.unlink(oldFile, function() {
+                        resolve(path);
+                    })
+                });
+            });
+        });
+    }
+
     form.parse(req, function (err, fields, files) {
         if (err || !files.image || !files.image.path) {
             response.errorForbidden(res);
         } else {
+            preprocessImage(files.image.path).then(() => {
                 if (config.debug)
                     logger.info('SERVER received uploadimage: ' + JSON.stringify(files.image));
 
@@ -478,6 +493,7 @@ app.post('/uploadimage', function (req, res) {
                     logger.error(err);
                     return res.status(500).end('upload image error');
                 }
+            });
         }
     });
 });

package.json

@@ -87,6 +87,7 @@
     "reveal.js": "^3.3.0",
     "sequelize": "^3.24.3",
     "sequelize-cli": "^2.4.0",
+    "sharp": "^0.16.2",
     "shortid": "2.2.6",
     "socket.io": "1.5.0",
     "socket.io-client": "^1.5.0",