Solution Overview

After some doodling on napkins, we came up with the system flowchart shown in Figure 24.1.

Figure 24.1. This diagram shows the possible paths through the PHPBookmark system.

We'll build a module for each box on this diagram—some will need one script and others, two. We'll also set up function libraries for

• User authentication.

• Bookmark storage and retrieval.

• Data validation.

• Database connections.

• Output to the browser. We'll confine all the HTML production to this function library, ensuring that visual presentation is consistent throughout the site. (This is the function API approach to separating logic and content.).

We'll also need to build a back-end database for the system.

We'll go through the solution in some detail, but all of the code for this application can be found on the CD-ROM in the chapter24 directory. A summary of included files is shown in Table 24.1.

Table 24.1. Files in the PHPBookmark Application

Filename	Description
bookmarks.sql	SQL statements to create the PHPBookmark database
login.php	Front page with login form for system
register_form.php	Form for users to register in the system
register_new.php	Script to process new registrations
forgot_form.php	Form for users to fill out if they've forgotten their passwords
forgot_passwd.php	Script to reset forgotten passwords
member.php	A user's main page, with a view of all his current bookmarks
add_bm_form.php	Form for adding new bookmarks
add_bms.php	Script to actually add new bookmarks to the database
delete_bms.php	Script to delete selected bookmarks from the user's list
recommend.php	Script to suggest recommendations to a user, based on users with similar interests
change_passwd_form.php	Form for members to fill out if they want to change their passwords
change_passwd.php	Script to change the user's password in the database
logout.php	Script to log a user out of the application
bookmark_fns.php	A collection of includes for the application
data_valid_fns.php	Functions to validate user-input data
db_fns.php	Functions to connect to the database
user_auth_fns.php	Functions for user authentication
url_fns.php	Functions for adding and deleting bookmarks and for making recommendations
output_fns.php	Functions that format output as HTML
bookmark.gif	Logo for PHPBookmark

We will begin by implementing the MySQL database for this application as it will be required for virtually all the other functionality to work.

Then we will work through the code in the order it was written, starting from the front page, going through the user authentication, to bookmark storage and retrieval, and finally to recommendations. This order is fairly logical—it's just a question of working out the dependencies and building first the things that will be required for later modules.