Home >Backend Development >PHP Tutorial >10 Tips for PHP Scripting (2)_PHP Tutorial
Session Usage
PHP 4.0 has a feature that has been long-awaited, which is PHP session support. In contrast, PHP 3.0 users have to use third-party libraries or do not have this functionality at all. The lack of session support is one of PHP's biggest flaws and its most criticized aspect. However, as session support has been part of PHP 4.0 since early beta versions, this obstacle has disappeared.
With session support, you can maintain user-specific variables during the user's visit to the website without having to set multiple cookies, use hidden form fields, or in a database that you may frequently connect to. Store information, etc.
Starting a session on a page tells the PHP engine that you either want to start a session (if there was none before) or continue the current session:
session_start();
Starting a session will send an identification string to the user through a cookie (for example, 940f8b05a40d5119c030c9c7745aead9); on the server side, a temporary file matching this will be created. In the above example, its name is like this: sess_940f8b05a40d5119c030c9c7745aead9. This file contains registered session variables and their assignments.
User access counters are the most common example of using sessions:
Start your PHP module and make sure the PHP code is the first line of the file: no whitespace, no HTML output, etc. This is because when the session function emits a file header, if you send blanks or HTML code before the session_start() function, the system will report an error.
// if a session does not yet exist for this user, start one
session_start();
Next, register a variable named count .
session_register('count');
Registering a variable is equivalent to telling PHP that as long as the session exists, a variable named count will also exist. This variable has not yet been assigned a value. However, if you add 1 to it, the value can be assigned to 1:
$count++;
Taking the above lines of code together, you have actually started a session (if there is no previous one), assign a session id to a user, register a variable named count and increment $count by 1 to indicate the user's first visit to the page:
To display that the user visited under the current session The number of pages, you just need to print out the value of $count:
echo "
You've been here $count times.
";You' ve been here $count times.
";