angular service factory to use the Filesystem API. ONLY WORKS IN CHROME!!!

fileservices.js

/* Check the file content
    //var filename = FileHandler.getFileName();
    // FileHandler.checkRateFile();
    
    // current use:
    FileHandler.checkRateFile(function(counter) {
      $scope.counter = counter;
      console.log('$scope.counter: '+$scope.counter);
    });
*/

var fileServices = angular.module('App.fileServices', []);

fileServices.value('aFileName', '.filename');


fileServices.factory('FileHandler', [
  function() {
    var cb;
    var onError = function(err) {
      console.error(err.name+": "+err.message);
    }

    var fileInfo = function(file) {
      console.log(file.name+" - "+file.lastModifiedDate+" - "+file.size);

      return file.size;
    }

    var writeFile = function(fileEntry, content) {
      fileEntry.createWriter(function(writer) {
        writer.onwriteend = function(ev) {
          console.log('written '+content);
        };

        writer.onerror = function(err) {
          console.err(err.toString());
        };

        var blob = new Blob([content], {type: 'text/plain'});
        writer.write(blob);
      }, onError); // EO createWriter
    }


    var readFile = function(fileEntry) {
      var reader = new FileReader();

      fileEntry.file(function(file) {
        reader.readAsText(file);
        reader.onloadend = function(ev) {
          console.log("file content: '"+ev.target.result+"'");
          cb(ev.target.result);
        }
      });
    }

    var checkForFile = function(fileSystem) {
      // fileSystem.root.getFile('.oncosur', {create: true}, gotFileEntry, onError);
      fileSystem.root.getFile('.filename', {create: true, exclusive: false},
        function(fileEntry) {
          handleFile(fileEntry);
        }, onError
      );
    }

    var handleFile = function(fileEntry) {
      fileEntry.file(function(file) {
        var size = fileInfo(file);

        if (size == 0)
          writeFile(fileEntry, '1');

        else
          readFile(fileEntry);

      }, onError); // EO fileEntry.file
    }


    var factory = {};
    factory.checkRateFile = function(fn) {
      cb = fn;
      var PERSISTENT, TEMPORARY;
      if (typeof LocalFileSystem === 'undefined') {
        PERSISTENT = window.PERSISTENT;
        TEMPORARY = window.TEMPORARY;

      } else {
        PERSISTENT = LocalFileSystem.PERSISTENT ;
        TEMPORARY = LocalFileSystem.TEMPORARY;
      }

      window.requestFileSystem  = window.requestFileSystem || window.webkitRequestFileSystem;
      if (window.webkitStorageInfo) {
        window.webkitStorageInfo.requestQuota(PERSISTENT, 5*1024, function(grantSize){
          // navigator.webkitPersistentStorage.requestQuota(PERSISTENT, 5*1024, function(grantSize){
          window.requestFileSystem(PERSISTENT, grantSize, checkForFile, onError);
        }, function(err) {
          console.log(err.name+": "+err.message);
        })
      }
      else {
        // window.requestFileSystem(PERSISTENT, 256, createFile, onError);
        window.requestFileSystem(PERSISTENT, 256, checkForFile, onError);
      }

    };

    factory.getFileName = function() {
      return '.filename';
    }

    return factory;
  }
]);