Programming Social Applications

Looping Content

When you’re working with large quantities of user social data, one question naturally arises in the context of OpenSocial templating: how do you handle repeating content, such as a list of friends or any measure of activity data? We certainly won’t be creating a markup definition for each repeating node in the template, will we? The short answer is no.

Content looping in OpenSocial allows a developer to define a block of markup to be used to render a series of repeating elements, without having to resort to handling each repeating node as a separate instance of markup. There are a few ways to define a loop structure within an OpenSocial template specification, which we’ll go over next.

Method 1: Escaped values

The first method is to build a loop structure that outputs the value of a piece of data as an escaped string, much like we saw with conditional statements. Let’s say that we have a customized subset of activity data that is returned to us through a data pipe request:

activities: [
   {
      title: "Jonathan just added a new comment on Twitter",
      body: "See what Jonathan is saying by adding him to Twitter",
      url: "http://www.twitter.com/jcleblanc"
   },
   {
      title: "Michael updated his profile",
      body: "See more about what Michael is doing",
      url: "http://www.container.com/profiles/michael"
   },
   {
      title: "Diane just posted a comment on your wall",
      body: "Reply to Diane's message",
      url: "http://www.container.com/messages"
   }
];

This content structure has several repeating nodes within ...