Programming Social Applications

Saving State with User Preferences

In many instances, you may need to persistently store small amounts of personalization information for a user. One of the features available within the OpenSocial gadgets JavaScript libraries provides a facility to help you do just that.

To integrate this feature, you need to take a few steps:

1. Within the ModulePrefs node of the gadget spec file, add a Require element including setprefs to enable the flash JavaScript library.

   • Include: <Require feature="setprefs"/>

2. Add a UserPref node with the value matching the user preference element you wish to persistently store.

3. When you wish to set a new user preference, you will need to call the set() method of the gadgets.Prefs object.

   • Method call: set(...);

There are several methods available that provide user preference getting and setting abilities, listed in Table 4-3.

Table 4-3. User preference methods

Method	Description
set	Allows you to set the persistent state of a user preference variable. Parameters include: Variable name (string) The name of the UserPref variable to set for the current user Value (mixed) The value of the UserPref variable
getString	Obtains a UserPref string. Parameters include: Variable name (string) The name of the UserPref variable to get for the current user
getInt	Obtains a UserPref integer. Parameters are the same as the getString method.
getBool	Obtains a UserPref Boolean. Parameters are the same as the getString method.

<Module> <ModulePrefs> <Require feature="setprefs" /> </ModulePrefs> <UserPref ...