Bring back the screenshot handler code

lib/screenshotHandler.js

@@ -0,0 +1,118 @@
+var debug       = require('debug')('ylt:screenshotHandler');
+var Jimp        = require('jimp');
+var Q           = require('q');
+var fs          = require('fs');
+var path        = require('path');
+
+
+var screenshotHandler = function() {
+
+    var tmpFolderPath = 'tmp';
+    var tmpFolderFullPath = path.join(__dirname, '..', tmpFolderPath);
+    var tmpFileName = 'temp-screenshot.png';
+    var tmpFileFullPath = path.join(tmpFolderFullPath, tmpFileName);
+
+
+    this.findAndOptimizeScreenshot = function(width) {
+        var that = this;
+
+        debug('Starting screenshot transformation');
+
+        return this.openImage(tmpFileFullPath)
+
+            .then(function(image) {
+                that.deleteTmpFile(tmpFileFullPath);
+                return that.resizeImage(image, width);
+            })
+
+            .then(this.toBuffer);
+    };
+
+
+    this.openImage = function(imagePath) {
+        var deferred = Q.defer();
+
+        Jimp.read(imagePath, function(err, image){
+            if (err) {
+                debug('Could not open imagePath %s', imagePath);
+                debug(err);
+
+                deferred.reject(err);
+            } else {
+                debug('Image correctly open');
+                deferred.resolve(image);
+            }
+        });
+
+        return deferred.promise;
+    };
+
+
+    this.resizeImage = function(image, newWidth) {
+        var deferred = Q.defer();
+
+        var currentWidth = image.bitmap.width;
+
+        if (currentWidth > 0) {
+            var ratio = newWidth / currentWidth;
+
+            image.scale(ratio, function(err, image){
+                if (err) {
+                    debug('Could not resize image');
+                    debug(err);
+
+                    deferred.reject(err);
+                } else {
+                    debug('Image correctly resized');
+                    deferred.resolve(image);
+                }
+            });
+        } else {
+            deferred.reject('Could not resize an empty image');
+        }
+
+        return deferred.promise;        
+    };
+
+
+    this.toBuffer = function(image) {
+        var deferred = Q.defer();
+
+        image.quality(85).getBuffer(Jimp.MIME_JPEG, function(err, buffer){
+            if (err) {
+                debug('Could not save image to buffer');
+                debug(err);
+
+                deferred.reject(err);
+            } else {
+                debug('Image correctly transformed to buffer');
+                deferred.resolve(buffer);
+            }
+        });
+
+        return deferred.promise;
+    };
+
+
+    this.deleteTmpFile = function(tmpFilePath) {
+        var deferred = Q.defer();
+
+        fs.unlink(tmpFilePath, function (err) {
+            if (err) {
+                debug('Screenshot temporary file not found, could not be deleted. But it is not a problem.');
+            } else {
+                debug('Screenshot temporary file deleted.');
+            }
+
+            deferred.resolve();
+        });
+
+        return deferred.promise;
+    };
+
+    this.getTmpFileRelativePath = function() {
+        return tmpFolderPath + '/' + tmpFileName;
+    };
+};
+
+module.exports = new screenshotHandler();

package.json

@@ -45,6 +45,7 @@
     "is-webp": "1.0.1",
     "is-woff": "1.0.3",
     "is-woff2": "1.0.0",
+    "jimp": "0.6.0",
     "md5": "2.2.1",
     "meow": "5.0.0",
     "parse-color": "1.0.0",