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

Implementing User Authentication
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As you can see, the only logic in the do_html_header() function is to add the
appropriate title and heading to the page.The other functions used in login.php are
similar.The function display_site_info() adds some general text about the site,
display_login_form() displays the gray form shown in Figure 27.3, and
do_html_footer() adds a standard HTML footer to the page.
The advantages to isolating or removing HTML from your main logic stream are discussed
in Chapter 25,“Using PHP and MySQL for Large Projects.”We use the function
API approach here.
Looking at Figure 27.3, you can see that this page has three options: A user can register,
log in if she has already registered, or reset her password if she has forgotten it.To
implement these modules, we move on to the next section, user authentication.
Implementing User Authentication
There are four main elements to the user authentication module: registering users, logging
in and logging out, changing passwords, and resetting passwords. In the following
sections, we look at each of these elements in turn.
Registering Users
To register a user, you need to get his details via a form and enter him in the database.
When a user clicks on the Not a member? link on the login.php page, he is taken to
a registration form produced by register_form.php.This script is shown in Listing 27.5.
Listing 27.5 register_form.php—This Form Gives Users the Opportunity to
Register with PHPbookmark
Again, you can see that this page is fairly simple and just calls functions from the output
library in output_fns.php.The output of this script is shown in Figure 27.4.
The gray form on this page is output by the function
display_registration_form(), contained in output_fns.php.When the user clicks on
the Register button, he is taken to the script register_new.php, shown in Listing 27.6.