Caching locally created files with imgcache.js

app.js

app.config(['$compileProvider',
function ($compileProvider) {
    $compileProvider.imgSrcSanitizationWhitelist(/^\s*(https?|local|data):/);
}]);

imgcache.js

// I manually pasted these lines into imgcache.js to that "Private" and "Helpers" could be "public"
// These go as the first lines after "(function ($) {"
ImgCache.getPrivate = function() { return Private; };
ImgCache.getHelpers = function() { return Helpers; };

imgcahe-local.js

(function() {

  Private = ImgCache.getPrivate();
  Helpers = ImgCache.getHelpers();

  Private.FileTransferWrapper.prototype.cacheLocal = function (imageData, localPath, success_callback, error_callback) {

    var blob = this.dataURItoBlob(imageData);

    var filesystem = this.filesystem;
    filesystem.root.getFile(localPath, { create:true }, function (fileEntry) {
        fileEntry.createWriter(function (writer) {
            writer.onerror = error_callback;
            writer.onwriteend = function () { success_callback(fileEntry);  };
            writer.write(blob, error_callback);
        }, error_callback);
    }, error_callback);

  };

  Private.FileTransferWrapper.prototype.dataURItoBlob = function (dataURI) {
    // convert base64/URLEncoded data component to raw binary data held in a string
    var byteString;
    if (dataURI.split(',')[0].indexOf('base64') >= 0)
        byteString = atob(dataURI.split(',')[1]);
    else
        byteString = unescape(dataURI.split(',')[1]);

    // separate out the mime component
    var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0];

    // write the bytes of the string to a typed array
    var ia = new Uint8Array(byteString.length);
    for (var i = 0; i < byteString.length; i++) {
        ia[i] = byteString.charCodeAt(i);
    }

    return new Blob([ia], {type:mimeString});
  }

  ImgCache.cacheLocalFile = function (key, img_data, success_callback, error_callback, on_progress) {

    if (!Private.isImgCacheLoaded() || !img_data) {
        return;
    }

    var filePath = Private.getCachedFileFullPath(key);

    var fileTransfer = new Private.FileTransferWrapper(ImgCache.attributes.filesystem);
    fileTransfer.cacheLocal(
        img_data,
        filePath,
        function (entry) {
            entry.getMetadata(function (metadata) {
                if (metadata && metadata.hasOwnProperty('size')) {
                    ImgCache.overridables.log('Cached file size: ' + metadata.size, LOG_LEVEL_INFO);
                    Private.setCurrentSize(ImgCache.getCurrentSize() + parseInt(metadata.size, 10));
                } else {
                    ImgCache.overridables.log('No metadata size property available', LOG_LEVEL_INFO);
                }
            });
            ImgCache.overridables.log('Download complete: ' + Helpers.EntryGetPath(entry), LOG_LEVEL_INFO);

            // iOS: the file should not be backed up in iCloud
            // new from cordova 1.8 only
            if (entry.setMetadata) {
                entry.setMetadata(
                    function () {
                    /* success*/
                        ImgCache.overridables.log('com.apple.MobileBackup metadata set', LOG_LEVEL_INFO);
                    },
                    function () {
                    /* failure */
                        ImgCache.overridables.log('com.apple.MobileBackup metadata could not be set', LOG_LEVEL_WARNING);
                    },
                    { 'com.apple.MobileBackup': 1 }
                    // 1=NO backup oddly enough..
                );
            }

            if (success_callback) { success_callback(); }
        },
        function (error) {
            if (error.source) { ImgCache.overridables.log('Download error source: ' + error.source, LOG_LEVEL_ERROR); }
            if (error.target) { ImgCache.overridables.log('Download error target: ' + error.target, LOG_LEVEL_ERROR); }
            ImgCache.overridables.log('Download error code: ' + error.code, LOG_LEVEL_ERROR);
            if (error_callback) { error_callback(); }
        },
        on_progress
    );
  };

})();