PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

694 Chapter 30 Building a Mailing List Manager
The mail table contains information about each email message that is sent through
the system. It stores a unique ID (mailid), the address the mail is sent from (email), the
subject line of the email (subject), and the listid of the list it has been sent to or will
be sent to.The actual text or HTML of the message could be a large file, so you need to
store the archive of the actual messages outside the database.You also track some general
status information: whether the message has been sent (status), when it was sent (sent),
and a timestamp to show when this record was last modified (modified).
Finally, you use the images table to track any images associated with HTML messages.
Again, these images can be large, so you store them outside the database for efficiency.You
need to keep track of the mailid they are associated with, the path to the
location where the image is actually stored, and the MIME type of the image
(mimetype)—for example, image/gif.
The SQL shown in Listing 30.1 also sets up a user for PHP to connect as and an
administrative user for the system.
Defining the Script Architecture
As in the preceding project, this project uses an event-driven approach.The backbone of
the application is in the file index.php.This script has the following four main segments:
1. Perform preprocessing. Do any processing that must be done before headers can be
sent.
2. Set up and send headers. Create and send the start of the HTML page.
3. Perform an action. Respond to the event that has been passed in. As in the preceding
example, the event is contained in the $action variable.
4. Send footers.
Almost all the application’s processing is done in this file.The application also uses the
function libraries listed in Table 30.1, as mentioned previously.
The full listing of the index.php script is shown in Listing 30.2.