Programming Social Applications

Defining User Preferences

You may need to save user preference variables persistently within an application’s OpenSocial gadget. This is where the UserPref element comes into play. It allows you to configure which variables you would like to store for a user. These configuration variables, along with JavaScript features we will talk about in later sections, provide simple key/value storage without requiring you to set up a database.

UserPref contains a number of configurable attributes, listed in Table 3-7.

Table 3-7. UserPref attributes

Attribute	Description
datatype	An optional string that denotes the date type present within the user preference variable. The value may be string (default value), bool, enum, hidden (not visible or user-editable), or list (dynamic array generated from user input).
default_value	An optional string that stores a default value for a user preference in the event that the user does not specify a variable configuration.
display_name	An optional string that represents the user preference during editing. This value must be unique.
name	The name of the user preference. This value is required and must be a unique value.
required	An optional Boolean value (true/false) indicating whether the user preference variable is required or not. The default value is false (not required).
urlparam	If a Content section within an XML gadget has the type set to url, signifying a separate file from which to load data, this optional parameter is passed along to that file as well if these ...