Detailed explanation of the function of getting started with PHP session 2_PHP tutorial

There is no such thing as session in php3, but we need it, what should we do? Don't worry, there are many people who have done this for you, the most famous of which is phplib. You can download it abroad, and you can download it from most domestic PHP sites. The first thing we need to do is get phplib and php3 together to make it work. In order to achieve this function, we need to install phplib first. Follow me, it's very easy (the following method is passed on win2000 php3.0.16 apache1.3.12 phplib7.2c mysql3.23.21 for win32) The most basic functions of phplib include user authentication, Session management, permissions and database abstraction.

How to use phplib to implement the session function?
1. First, you unzip phplib. There is a directory called "php" in it. Copy this directory to the apache installation. directory. Take the author's machine as an example: My apache is installed in the d:/apache directory. I copied the "php" directory above to d:a/pache, and copied the files and directories in the pages directory under phplib to Under d:/apache/htdocs, be careful not to include the directory itself. The phplib class library needs to be initialized according to the system. You can modify the local.inc file, which contains some basic parameters. You can modify it according to the actual situation of your machine. The program in D: /APACHE/PHP/Prepend.php3 is changed to the following:
IF (! ISSET ($ _ phplib) or! Is_array ($ _ phplib)) {
$ _phplib ["libdir" ] = "d:/apache/php/"; //Change here to the path where you put the php directory under phplib
}
Then change the d:/apache/php/local.inc file as follows:
class DB_Example extends DB_Sql {
var $Host = "localhost";//The host name of your mysql database
var $Database = "test";//Database name
var $User = "root ";//Database user name
       var $Password = "";//Database user password
}
The last step is to execute the create_database.mysql file in the stuff directory in the unpacked phplib directory to generate the initial surface. Let’s explain how phplib works. Every page that uses phplib must first find the class library files necessary to run phplib. We can set the auto_prepend variable in php3.ini to support it. The phplib distribution package contains a prepend.php3 file. After specifying "d:/apache /php/prepend.php3" (with quotes) for auto_prepend, each page will automatically include the phplib class library. We can also add the directory where the phplib class library is located to the include variable so that these can be found. File, of course, the easiest way is to specify the absolute path of phplib. This is not a good idea, the portability is too poor!

Second step, in every page using phplib, you must first call the page_open function for initialization. This tells phplib that you will need to save the state now or in the future. A typical page_open example is as follows:
page_open(array("sess" => "Example_Session"));
?>
Array variable (sess) is used for initialization Some state saving objects, note: phplib built-in names (sess) must be used. These built-in names are defined by you in local.ini. The page_open function must be called before the page content is output to the browser. The php3 script should end with page_close(), which will write the relevant status data back to the database. If you forget, you should be able to think of the result, haha, all your variables are lost, don’t blame me for not telling you. ...Because phplib uses Cookies to save state information, the page_open() function must be called before the page content is output to the browser. The page content here can be any HTML information or blank lines. If you find the error "Oops - SetCookie called after header has been sent", this indicates what was output to the browser before page_open(). You should pay special attention to blank lines, because they are very difficult to find. Typical errors are in the and ? > tags If a blank line is output, you should check whether the local.inc and prepend.php3 files contain blank lines. This is also a very error-prone place. In order to reduce the possibility of errors, we can write the initialization program like this: ;
....