Chapter 15: E-campaign System 545 request (Mac os x web server) is considered
Chapter 15: E-campaign System 545 request is considered valid and the keepTrackAndRedirect() method is called to track and redirect the end-user to the target URL. computeCheckSum() This method implements a simple checksum algorithm using the URL ID ($u), USER ID ($uid), campaign ID ($c), and a random number stored in configuration file called $SECRET. This checksum value is compared with the campaign-execution-applicationgenerated checksum stored in the redirection link to check the validity of the redirection request. Using this checksum technique, we can avoid invalid requests from unfriendly users who want to distort the tracking data. keepTrackAndRedirect() This method tracks the URL request in the database and redirects the user to the target URL. It creates a URL Track object and calls the storeTrack() method to store the track data. It also creates a URL object and gets the URL for the given URL ID ($u) and redirects the user to the target URL via the HTTP location header. redirectTest() This method creates a URL object and redirects the user to the target URL by finding the target URL using the getURL() method and redirecting using the HTTP location header. Creating an Unsubscription Tracking Application When an end-user clicks on the unsubscription link sent by the campaign execution application, it is processed by the unsubscription process shown in Figure 15-9. The unsub.php, which can be found in ch15/apps directory in the CDROM, implements the unsubscription application using the following methods. run() This method first determines if the unsubscription redirection request mode is test or not. If the mode is test, which is true during message preview, the alert() method is used to display a message stating that the unsubscription request is a test and therefore it isn t tracked and stored in the database.