Outbound notification:

Not only how to do it, but how to do it without blowing things up!

Over here in Voxeo’s Extreme Support, we see a fair amount of tickets asking us how a user might implement their applications on a larger scale, or in what ways our platform could be leveraged to further business needs. ”Hello World” applications might impress your mom, but something has to pay to keep the lights on. One very common use of Voxeo’s technology is outbound notification, where a company sends hundreds, thousands, or even hundreds of thousands of notifications to their customers in an automated fashion. If you have always wanted your very own automated message delivery service, you have come to the right blog. Let’s build a small, but scaleable, one from scratch. The main focus of this posting is to give an overview of how an application like this might be developed. We will show you how several markups and scripting languages can be combined to perform this type of outbound campaign.

Our application will combine PHP and MySQL to launch CCXML/VoiceXML calls using a simple HTTP control mechanism through Voxeo’s hosted network. The control mechanism provides throttling intelligence to our application, ensuring a defined ceiling of concurrent calls will not be surpassed, but still allowing for maximum efficiency and duration. When running call campaigns through a telephony network shared with other customers, everyone wins by adhering to port boundaries.

In the example I am presenting we are using a hypothetical application developed for the ‘XYZ Corporation‘, their needs for their application are as follows:

• Call users and notify them of appointments
• Verify that intended callers got the notification
• If caller chooses to, allow them to change appointments
• Log results to a database so we can view call history’s and track any problematic sessions reported by users

The requirements are not to overwhelming, however in addition to the above we also want to give them a nice interface to ensure a pleasant user experience. We also want to ensure that this interface will allow for someone without a intimate knowledge of VoiceXML, or even any markup at all to operate our application. After all, our fictitious company ‘XYZ Corp’, is in the business of notifying people about appointments, not debugging application code.

So let me do a quick video run through of the final product before I go into detail on the relevant components below. Below you will see an embedded YouTube video that shows the interface and it’s functions, this might be helpful if you gave this a quick review prior to proceeding, as the rest of the posting is based off this example application and assumes that you have reviewed it:

So first off let me say that all this code is going to be attached for download at the end of this posting. So fear not you will have unfettered access to download, edit, and test any of this to your hearts content. If you wish to deploy this you will need to do so on your own Web Server since the majority is done in PHP. The reason for this is that Voxeo’s shared production network does not allow for server side scripting.

So lets get down and dirty into the components of this application: First off we have our interface which was done in HTML & PHP. The interface is driven by a MySQL database, from which we query for our list of callers and log session results. Now PHP generally falls outside of the scope of our support, so we will not dive to deep into this portion of the application code. It is for the reason we attached the code of the entire application to this posting. The portion I want to focus on here is the throttling mechanism for call launches, the methods we pass data into and out of our CCXML & VoiceXML application for our dialogs. Then finally I will show you how we get the data back from our VoiceXML dialog and log these results back into our database for post call review. At the very end I will have a link to the source code of this entire thing for you to download should you wish to do so. So with out further delay lets take a look at CPS.

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