Description
bool
session_set_save_handler ( callback open, callback close, callback read, callback write, callback destroy, callback gc )
session_set_save_handler() sets the user-level
session storage functions which are used for storing and
retrieving data associated with a session. This is most useful
when a storage method other than those supplied by PHP sessions
is preferred. i.e. Storing the session data in a local database.
Returns TRUE on success or FALSE on failure.
Note:
The "write" handler is not executed until after the output
stream is closed. Thus, output from debugging statements in the
"write" handler will never be seen in the browser. If debugging
output is necessary, it is suggested that the debug output be
written to a file instead.
The following example provides file based session
storage similar to the PHP sessions default save handler
files. This example could easily be
extended to cover database storage using your favorite PHP
supported database engine.
Read function must return string value always to make save
handler work as expected. Return empty string if there is no data
to read. Return values from other handlers are converted to
boolean expression. TRUE for success, FALSE for failure.
| Warning |
Write and Close handlers are called after destructing objects since PHP
5.0.5. Thus destructors can use sessions but session handler can't use
objects. In prior versions, they were called in the opposite order. It
is possible to call session_write_close() from the
destructor to solve this chicken and egg problem.
|
Example 1.
session_set_save_handler() example
<?php
function open($save_path, $session_name)
{
global $sess_save_path, $sess_session_name;
$sess_save_path = $save_path;
$sess_session_name = $session_name;
return(true);
}
function close()
{
return(true);
}
function read($id)
{
global $sess_save_path, $sess_session_name;
$sess_file = "$sess_save_path/sess_$id";
if ($fp = @fopen($sess_file, "r")) {
$sess_data = fread($fp, filesize($sess_file));
return($sess_data);
} else {
return(""); // Must return "" here.
}
}
function write($id, $sess_data)
{
global $sess_save_path, $sess_session_name;
$sess_file = "$sess_save_path/sess_$id";
if ($fp = @fopen($sess_file, "w")) {
return(fwrite($fp, $sess_data));
} else {
return(false);
}
}
function destroy($id)
{
global $sess_save_path, $sess_session_name;
$sess_file = "$sess_save_path/sess_$id";
return(@unlink($sess_file));
}
/*********************************************
* WARNING - You will need to implement some *
* sort of garbage collection routine here. *
*********************************************/
function gc($maxlifetime)
{
return true;
}
session_set_save_handler("open", "close", "read", "write", "destroy", "gc");
session_start();
// proceed to use sessions normally
?>
|
|
See also the session.save_handler
configuration directive.
