datasore.js

'use strict';

// A very simple, key/value-based IndexedDB library for storing binary data
// in IndexedDB. Used because Podcasts needs to store large binary files (
// podcast image covers and audio files) but can't use Appcache or localStorage.
// Because most data is manipulated with Backbone.js and stored in localStorage
// though, we just use IndexedDB as blob storage.
//
// This library lets a user store arbitrary "big data" in IndexedDB with a
// stupid simple API:
//
//     // To get a blob:
//     DataStore.get('some-key', callback)
//
//     // To set a key:
//     DataStore.set('some-key', blobData, callback)
//
//     // And to destroy data:
//     DataStore.destroy('some-key', callback)
define(function(require) {
    // Create/open database.
    var deviceStorage = window.navigator.getDeviceStorage('podcasts');
    window.alert(deviceStorage);

    // Connect to the database; should be fired on app start, with the app
    // initialization running after the database is ensured to be working.
    function load(callback) {
        callback();
    }

    // Utility function to destroy everything in the datastore. Probably not
    // useful.
    function clearAll() {
        window.alert('TODO');
    }

    // Destroy a blob based on its id key.
    function destroy(id, callback) {
        var deleteRequest = deviceStorage.delete(id);

        if (callback) {
            deleteRequest.onsuccess = callback;
        }

        return deleteRequest;
    }

    // Get blob data based on a simple, string key. Sends the request event
    // and the blob data (if it exists) as the two arguments to a callback.
    // TODO: Supply event data to callback.
    function get(id, callback) {
        var request = deviceStorage.get(id);

        request.onsuccess = function(event) {
            callback(request.result);
        }
    }

    // Save data based on a key to IndexedDB. This can take some time, be warned.
    function set(id, blob, callback) {
        var request = deviceStorage.addNamed(blob, id);

        request.onerror = function() {
            window.alert('SET FAILED ' + id);
        }

        if (callback) {
            request.onsuccess = callback;
        }
    }

    return {
        destroy: destroy,
        get: get,
        load: load,
        set: set
    };
});

manifest.webapp

{
  "version": "0.1",
  "name": "Podcasts",
  "description": "Listen to your favourite podcasts on your HTML5-powered device or browser.",
  "icons": {
    "16": "/img/icon-16.png",
    "30": "/img/icon-30.png",
    "32": "/img/icon-32.png",
    "48": "/img/icon-48.png",
    "60": "/img/icon-60.png",
    "64": "/img/icon-64.png",
    "128": "/img/icon-128.png",
    "256": "/img/icon-256.png"
  },
  "developer": {
    "name": "Mozilla",
    "url": "http://mozilla.org/"
  },
  "launch_path": "/index.html",
  "installs_allowed_from": ["https://marketplace.firefox.com", "*"],
  "type": "privileged",
  "permissions": {
    "device-storage:sdcard": {
      "access": "readcreate",
      "description": "Required to store podcast audio files."
    },
    "storage": {
      "description": "Required to store podcast images."
    },  
    "systemXHR": {
      "description": "Required to download podcasts."
    }
  }
}