storage.js

An abstraction (over localStorage) of per-tab and client storage.

• ¶

  /* This Source Code Form is subject to the terms of the Mozilla Public
   * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   * You can obtain one at http://mozilla.org/MPL/2.0/. */
  
  define(["util"], function (util) {
    var assert = util.assert;
    var Deferred = util.Deferred;
    var DEFAULT_SETTINGS = {
      name: "",
      defaultName: "",
      avatar: null,
      stickyShare: null,
      color: null,
      seenIntroDialog: false,
      seenWalkthrough: false,
      dontShowRtcInfo: false
    };
  
    var DEBUG_STORAGE = false;
  
    var Storage = util.Class({
      constructor: function (name, storage, prefix) {
        this.name = name;
        this.storage = storage;
        this.prefix = prefix;
      },
  
      get: function (key, defaultValue) {
        var self = this;
        return Deferred(function (def) {

• ¶

  Strictly this isn't necessary, but eventually I want to move to something more async for the storage, and this simulates that much better.

          setTimeout(util.resolver(def, function () {
            key = self.prefix + key;
            var value = self.storage.getItem(key);
            if (! value) {
              value = defaultValue;
              if (DEBUG_STORAGE) {
                console.debug("Get storage", key, "defaults to", value);
              }
            } else {
              value = JSON.parse(value);
              if (DEBUG_STORAGE) {
                console.debug("Get storage", key, "=", value);
              }
            }
            return value;
          }));
        });
      },
  
      set: function (key, value) {
        var self = this;
        if (value !== undefined) {
          value = JSON.stringify(value);
        }
        return Deferred(function (def) {
          setTimeout(util.resolver(def, function () {
            key = self.prefix + key;
            if (value === undefined) {
              self.storage.removeItem(key);
              if (DEBUG_STORAGE) {
                console.debug("Delete storage", key);
              }
            } else {
              self.storage.setItem(key, value);
              if (DEBUG_STORAGE) {
                console.debug("Set storage", key, value);
              }
            }
          }));
        });
      },
  
      clear: function () {
        var self = this;
        var promises = [];
        return Deferred((function (def) {
          this.keys().then(function (keys) {
            keys.forEach(function (key) {

• ¶

  FIXME: technically we're ignoring the promise returned by all these sets:

              promises.push(self.set(key, undefined));
            });
            util.resolveMany(promises).then(function () {
              def.resolve();
            });
          });
        }).bind(this));
      },
  
      keys: function (prefix, excludePrefix) {

• ¶

  Returns a list of keys, potentially with the given prefix

        var self = this;
        return Deferred(function (def) {
          setTimeout(util.resolver(def, function () {
            prefix = prefix || "";
            var result = [];
            for (var i=0; i<self.storage.length; i++) {
              var key = self.storage.key(i);
              if (key.indexOf(self.prefix + prefix) === 0) {
                var shortKey = key.substr(self.prefix.length);
                if (excludePrefix) {
                  shortKey = shortKey.substr(prefix.length);
                }
                result.push(shortKey);
              }
            }
            return result;
          }));
        });
      },
  
      toString: function () {
        return '[storage for ' + this.name + ']';
      }
  
    });
  
    var namePrefix = TogetherJS.getConfig("storagePrefix");
  
    var storage = Storage('localStorage', localStorage, namePrefix + ".");
  
    storage.settings = util.mixinEvents({
      defaults: DEFAULT_SETTINGS,
  
      get: function (name) {
        assert(storage.settings.defaults.hasOwnProperty(name), "Unknown setting:", name);
        return storage.get("settings." + name, storage.settings.defaults[name]);
      },
  
      set: function (name, value) {
        assert(storage.settings.defaults.hasOwnProperty(name), "Unknown setting:", name);
        return storage.set("settings." + name, value);
      }
  
    });
  
    storage.tab = Storage('sessionStorage', sessionStorage, namePrefix + "-session.");
  
    return storage;
  });