Files
YellowLabTools/lib/screenshotHandler.js
T

123 lines
3.3 KiB
JavaScript

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() {
this.findAndOptimizeScreenshot = function(width) {
var that = this;
debug('Starting screenshot transformation');
return this.openImage(this.getTmpFileRelativePath())
.then(function(image) {
that.deleteTmpFile(that.getTmpFileRelativePath());
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(this.getTmpFileRelativePath(), 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() {
// Chrome saves a temporary file on the disk, which is then removed.
// Its default folder is /tmp, but it can be changed in server_config/settings.json
var serverSettings = require('../server_config/settings.json');
var tmpFolderPath = serverSettings.screenshotTempPath || '/tmp';
var tmpFileName = 'temp-chrome-screenshot.png';
var tmpFileFullPath = path.join(tmpFolderPath, tmpFileName);
return tmpFileFullPath;
};
};
module.exports = new screenshotHandler();