使用数据库保存session的方法
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2022-11-25 14:55:14
php的session默认是以文件方式保存在服务器端,并且在客户端使用cookie保存变量,这就会出现一个问题,当一个用户由于某种安全原因关闭了浏览器的cookie,程序中...
php的session默认是以文件方式保存在服务器端,并且在客户端使用cookie保存变量,这就会出现一个问题,当一个用户由于某种安全原因关闭了浏览器的cookie,程序中的session相关操作将无法执行。因此,如果能以数据库保存session数据,将不受客户端设置的限制,并且在性能和扩展性等方面有一个飞跃。程序中使用关键函数是session_set_save_handler,同时要将php.ini里的session.save_handler = files 改为 user。这里我们讨论的环境是linux(freesd)+apache+mysql+php。
数据表结构:[sessions]
create table sessions (
sesskey char(32) not null,
expiry int(11) unsigned not null,
value text not null,
primary key (sesskey)
);
程序代码:[session_inc.php]
<?php
$sess_dbhost = "yourhost"; /* database server hostname */
$sess_dbname = "yourdb"; /* database name */
$sess_dbuser = "youruser"; /* database user */
$sess_dbpass = "yourpassword"; /* database password */
$sess_dbh = "";
$sess_life = get_cfg_var("session.gc_maxlifetime");
function sess_open($save_path, $session_name) {
global $sess_dbhost, $sess_dbname, $sess_dbuser, $sess_dbpass, $sess_dbh;
if (! $sess_dbh = mysql_pconnect($sess_dbhost, $sess_dbuser, $sess_dbpass)) {
echo "<li>can't connect to $sess_dbhost as $sess_dbuser";
echo "<li>mysql error: " . mysql_error();
die;
}
if (! mysql_select_db($sess_dbname, $sess_dbh)) {
echo "<li>unable to select database $sess_dbname";
die;
}
return true;
}
function sess_close() {
return true;
}
function sess_read($key) {
global $sess_dbh, $sess_life;
$qry = "select value from session_tbl where sesskey = '$key' and expiry > " . time();
$qid = mysql_query($qry, $sess_dbh);
if (list($value) = mysql_fetch_row($qid)) {
return $value;
}
return false;
}
function sess_write($key, $val) {
global $sess_dbh, $sess_life;
$expiry = time() + $sess_life; //过期时间
$value = addslashes($val);
$qry = "insert into session_tbl values ('$key', $expiry, '$value')";
$qid = mysql_query($qry, $sess_dbh);
if (! $qid) {
$qry = "update session_tbl set expiry = $expiry, value = '$value' where sesskey = '$key' and expiry > " . time();
$qid = mysql_query($qry, $sess_dbh);
}
return $qid;
}
function sess_destroy($key) {
global $sess_dbh;
$qry = "delete from session_tbl where sesskey = '$key'";
$qid = mysql_query($qry, $sess_dbh);
return $qid;
}
function sess_gc($maxlifetime) {
global $sess_dbh;
$qry = "delete from session_tbl where expiry < " . time();
$qid = mysql_query($qry, $sess_dbh);
return mysql_affected_rows($sess_dbh);
}
session_set_save_handler(
"sess_open",
"sess_close",
"sess_read",
"sess_write",
"sess_destroy",
"sess_gc");
session_start();
?>
完成以上步骤后,在程序中使用require("session_inc.php")来代替session_start()即可,其他的session函数还是象以前一样的方法调用。
【本文版权归作者与奥索网共同拥有,如需转载,请注明作者及出处】
数据表结构:[sessions]
create table sessions (
sesskey char(32) not null,
expiry int(11) unsigned not null,
value text not null,
primary key (sesskey)
);
程序代码:[session_inc.php]
<?php
$sess_dbhost = "yourhost"; /* database server hostname */
$sess_dbname = "yourdb"; /* database name */
$sess_dbuser = "youruser"; /* database user */
$sess_dbpass = "yourpassword"; /* database password */
$sess_dbh = "";
$sess_life = get_cfg_var("session.gc_maxlifetime");
function sess_open($save_path, $session_name) {
global $sess_dbhost, $sess_dbname, $sess_dbuser, $sess_dbpass, $sess_dbh;
if (! $sess_dbh = mysql_pconnect($sess_dbhost, $sess_dbuser, $sess_dbpass)) {
echo "<li>can't connect to $sess_dbhost as $sess_dbuser";
echo "<li>mysql error: " . mysql_error();
die;
}
if (! mysql_select_db($sess_dbname, $sess_dbh)) {
echo "<li>unable to select database $sess_dbname";
die;
}
return true;
}
function sess_close() {
return true;
}
function sess_read($key) {
global $sess_dbh, $sess_life;
$qry = "select value from session_tbl where sesskey = '$key' and expiry > " . time();
$qid = mysql_query($qry, $sess_dbh);
if (list($value) = mysql_fetch_row($qid)) {
return $value;
}
return false;
}
function sess_write($key, $val) {
global $sess_dbh, $sess_life;
$expiry = time() + $sess_life; //过期时间
$value = addslashes($val);
$qry = "insert into session_tbl values ('$key', $expiry, '$value')";
$qid = mysql_query($qry, $sess_dbh);
if (! $qid) {
$qry = "update session_tbl set expiry = $expiry, value = '$value' where sesskey = '$key' and expiry > " . time();
$qid = mysql_query($qry, $sess_dbh);
}
return $qid;
}
function sess_destroy($key) {
global $sess_dbh;
$qry = "delete from session_tbl where sesskey = '$key'";
$qid = mysql_query($qry, $sess_dbh);
return $qid;
}
function sess_gc($maxlifetime) {
global $sess_dbh;
$qry = "delete from session_tbl where expiry < " . time();
$qid = mysql_query($qry, $sess_dbh);
return mysql_affected_rows($sess_dbh);
}
session_set_save_handler(
"sess_open",
"sess_close",
"sess_read",
"sess_write",
"sess_destroy",
"sess_gc");
session_start();
?>
完成以上步骤后,在程序中使用require("session_inc.php")来代替session_start()即可,其他的session函数还是象以前一样的方法调用。
【本文版权归作者与奥索网共同拥有,如需转载,请注明作者及出处】
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