Dynamic Reporting – Integrating the Force.com Analytics and Streaming APIs

Back in September, I explained how to use the Salesforce Analytics API on a Visualforce Page; this time, I’ll show you how to use the Force.com Streaming API to add life to your data.

Let’s say you’ve written a marvelous UI that leverages the Analytics API (or the REST API, or JavaScript Remoting) to present data in a brilliantly digestible format:

Now, this is a snapshot of your analysis – how do you know it’s still current? Enter the Streaming API – our page can subscribe for notifications on changes to the underlying data and prompt the user to rerun the report. Take a look at the page in action:

//www.youtube.com/watch?v=PHM4eycBDK0

Grab the source for the entire page here; I’ll walk through the changes to the static Analytics page from last time.

The Streaming API implements a publish/subscribe model. You (the developer) create a topic based on a SOQL query, and your client app can subscribe for notifications when the results of that query change. So, the first thing I did was to follow the instructions, in the Streaming API Developer’s Guide, on creating a PushTopic record for notifications on any change to Merchandise Name or Quantity fields – the raw data that feeds into my analysis.

This is the code I ran, in the ‘Execute Anonymous’ window of the Developer Console:

1PushTopic pushTopic = new PushTopic();
2pushTopic.Name = 'MerchandiseUpdates';
3pushTopic.Query = 'SELECT Id, Name, Quantity__c FROM Merchandise__c';
4pushTopic.ApiVersion = 29.0;
5pushTopic.NotifyForOperationCreate = true;
6pushTopic.NotifyForOperationUpdate = true;
7pushTopic.NotifyForOperationUndelete = true;
8pushTopic.NotifyForOperationDelete = true;
9pushTopic.NotifyForFields = 'Referenced';
10insert pushTopic;

I followed the instructions to test my PushTopic in Workbench. Updating a Merchandise record’s quantity correctly generates a notification:

The first thing my page needs to do is to include the CometD JavaScript libraries:

1<apex:includeScript value="{!$Resource.cometd}"/>
2<apex:includeScript value="{!$Resource.jquery_cometd}"/>

1// Initialize CometD
2$.cometd.init({
3    url: '/cometd/29.0/',
4    requestHeaders: { Authorization: 'Bearer {!$Api.Session_ID}'}
5});
6
7// Subscribe to a topic. JSON-encoded update will be returned
8// in the callback
9$.cometd.subscribe('/topic/MerchandiseUpdates', function(message) {
10    $('#output').append(JSON.stringify(message, null, '    ')+'nn');
11
12    // Prompt user to rerun report
13    $("#rerun").show();
14});

1// Rerun report on click
2$("#rerun").click(function(){
3    $("#rerun").hide();
4    runReport();
5});

Why do I show a button rather than simply running the report automatically? Well, running a report is relatively expensive, computationally speaking; it’s wasteful to run the report on every data change, regardless of whether the user is watching or not. So, to be good multi-tenant citizens, we prompt the user to rerun the report.

Are you using the Analytics API yet? Let us know in the comments…