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

142 Chapter 5 Reusing Code and Writing Functions
This approach gives you a consistent-looking website very easily, and you can make a
new page in the same style by typing something like this:
Here is the content for this page
Most importantly, even after you have created many pages using this header and footer,
you can easily change the header and footer files.Whether you are making a minor text
change or completely redesigning the look of the site, you need to make the change
only once.You do not need to separately alter every page in the site because each page is
loading in the header and footer files.
The example shown here uses only plain HTML in the body, header, and footer.This
need not be the case.Within these files, you could use PHP statements to dynamically
generate parts of the page.
If you want to be sure that a file will be treated as plain text or HTML, and not have
any PHP executed, you may want to use readfile() instead.This function echoes the
content of a file without parsing it.This can be an important safety precaution if you are
using user-provided text.
Using auto_prepend_file and auto_append_file
If you want to use require() or include() to add your header and footer to every
page, you can do it another way.Two of the configuration options in the php.ini file are
auto_prepend_file and auto_append_file. By setting these options to point to the
header and footer files, you ensure that they will be loaded before and after every page.
Files included using these directives behave as though they had been added using an
include() statement; that is, if the file is missing, a warning will be issued.
For Windows, the settings look like this:
auto_prepend_file = "c:/Program Files/Apache Software
Froundation/Apache2.2//include/header.php"
auto_append_file = "c:/Program Files/Apache Group/Apache2/include/footer.php"
For Unix, like this:
auto_prepend_file = “/home/username/include/header.php”
auto_append_file = “/home/username/include/footer.php”
If you use these directives, you do not need to type include() statements, but the headers
and footers will no longer be optional on pages.
If you are using an Apache web server, you can change various configuration options
like these for individual directories.To do this, you must have your server set up to allow
its main configuration file(s) to be overridden.To set up auto prepending and appending
for a directory, create a file called .htaccess in the directory.The file needs to contain
the following two lines:
php_value auto_prepend_file “/home/username/include/header.php”
php_value auto_append_file “/home/username/include/footer.php”