session全教程(二)

(很抱歉，由于版权原因，我不能把以下代码中的英文去掉，只好加些注释了 
================================================================================== 
<? 
/* ------------------------------------------------------------------------ 
* session_mysql.php 
* ------------------------------------------------------------------------ 
* PHP4 MySQL Session Handler 
* Version 1.00 
* by Ying Zhang (ying@zippydesign.com) 
* Last Modified: May 21 2000 
* 
* ------------------------------------------------------------------------ 
* TERMS OF USAGE: 
* ------------------------------------------------------------------------ 
* You are free to use this library in any way you want, no warranties are 
* expressed or implied. This works for me, but I don't guarantee that it 
* works for you, USE AT YOUR OWN RISK. 

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* 
* While not required to do so, I would appreciate it if you would retain 
* this header information. If you make any modifications or improvements, 
* please send them via email to Ying Zhang <ying@zippydesign.com>. 
* 
* ------------------------------------------------------------------------ 
* DESCRIPTION: 
* ------------------------------------------------------------------------ 
* This library tells the PHP4 session handler to write to a MySQL database 
* instead of creating individual files for each session. 
* 
* Create a new database in MySQL called "sessions" like so: 
* 
* CREATE TABLE sessions ( 
* sesskey char(32) not null, 
* expiry int(11) unsigned not null, 
* value text not null, 
* PRIMARY KEY (sesskey) 
* ); 
* 
* ------------------------------------------------------------------------ 
* INSTALLATION: 
* ------------------------------------------------------------------------ 
* Make sure you have MySQL support compiled into PHP4. Then copy this 
* script to a directory that is accessible by the rest of your PHP 
* scripts. 
* 确信你的php4有mysql支持，然后把这个脚本拷贝到和你的php脚本有关的目录。 
* ------------------------------------------------------------------------ 
* USAGE:（使用方法） 
* ------------------------------------------------------------------------ 
* Include this file in your scripts before you call session_start(), you 
* don't have to do anything special after that. 
* 包含这个文件到你要使用session的文件中，必须在调用session_start()之前，否则, 
* 会很惨的，不要怪我没告诉你。 这样就不需要再做什么工作了,还和你以前用session的方法一样。 
*/ 

$SESS_DBHOST = "localhost"; /* database server hostname */ 
$SESS_DBNAME = "sessions"; /* database name */ 
$SESS_DBUSER = "phpsession"; /* database user */ 
$SESS_DBPASS = "phpsession"; /* database password */ 

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$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;  网管有家www.bitscn.net

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; 
}  网管论坛bbs_bitsCN_com

if (! mysql_select_db($SESS_DBNAME, $SESS_DBH)) { 
echo "<li>Unable to select database $SESS_DBNAME"; 
die; 
}  网管网www_bitscn_com

return true; 
} 

function sess_close() { 
return true; 
}  中国网管联盟bitsCN.com

function sess_read($key) { 
global $SESS_DBH, $SESS_LIFE;  网管有家www.bitscn.net

$qry = "SELECT value FROM sessions WHERE sesskey = '$key' AND expiry > " . time(); 
$qid = mysql_query($qry, $SESS_DBH); 

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if (list($value) = mysql_fetch_row($qid)) { 
return $value; 
}  网管u家u.bitscn@com

return false; 
} 

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function sess_write($key, $val) { 
global $SESS_DBH, $SESS_LIFE; 

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$expiry = time() + $SESS_LIFE; 
$value = addslashes($val);  网管网www_bitscn_com

$qry = "INSERT INTO sessions VALUES ('$key', $expiry, '$value')"; 
$qid = mysql_query($qry, $SESS_DBH);  网管朋友网www_bitscn_net

if (! $qid) { 
$qry = "UPDATE sessions SET expiry = $expiry, value = '$value' WHERE sesskey 
= '$key' AND expiry > " . time(); 
$qid = mysql_query($qry, $SESS_DBH); 
} 

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return $qid; 
}  网管u家u.bitsCN.com

function sess_destroy($key) { 
global $SESS_DBH;  中国网管联盟bitsCN.com

$qry = "DELETE FROM sessions WHERE sesskey = '$key'"; 
$qid = mysql_query($qry, $SESS_DBH); 

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return $qid; 
}  中国网管论坛bbs.bitsCN.com

function sess_gc($maxlifetime) { 
global $SESS_DBH; 

$qry = "DELETE FROM sessions WHERE expiry < " . time(); 
$qid = mysql_query($qry, $SESS_DBH);  中国网管论坛bbs.bitsCN.com

return mysql_affected_rows($SESS_DBH); 
}  网管联盟bitsCN@com

session_set_save_handler( 
"sess_open", 
"sess_close", 
"sess_read", 
"sess_write", 
"sess_destroy", 
"sess_gc"); 
?> 
================================================================= 
定制使用dbm文件时的接口 
================================================================= 
<? 
/* ------------------------------------------------------------------------ 
* session_dbm.php 
* ------------------------------------------------------------------------ 
* PHP4 DBM Session Handler 
* Version 1.00 
* by Ying Zhang (ying@zippydesign.com) 
* Last Modified: May 21 2000 
* 
* ------------------------------------------------------------------------ 
* TERMS OF USAGE: 
* ------------------------------------------------------------------------ 

* You are free to use this library in any way you want, no warranties are 
* expressed or implied. This works for me, but I don't guarantee that it 
* works for you, USE AT YOUR OWN RISK. 
* 
* While not required to do so, I would appreciate it if you would retain 
* this header information. If you make any modifications or improvements, 
* please send them via email to Ying Zhang <ying@zippydesign.com>. 
* 
* ------------------------------------------------------------------------ 
* DESCRIPTION: 
* ------------------------------------------------------------------------ 
* This library tells the PHP4 session handler to write to a DBM file 
* instead of creating individual files for each session. 
* 
* ------------------------------------------------------------------------ 
* INSTALLATION:  网管u家bitscn.net
* ------------------------------------------------------------------------ 
* Make sure you have DBM support compiled into PHP4. Then copy this 
* script to a directory that is accessible by the rest of your PHP 
* scripts. 
* 确信你的php4有DBM支持。拷贝这个文件在你的php脚本目录。 
* ------------------------------------------------------------------------ 
* USAGE: 
* ------------------------------------------------------------------------ 
* Include this file in your scripts before you call session_start(), you 
* don't have to do anything special after that. 
* 在调用session_start()之前请包含这个文件。之后就不需要作什么工作了。 
*/  网管u家www.bitscn.net

$SESS_DBM = ""; 
$SESS_LIFE = get_cfg_var("session.gc_maxlifetime");  网管u家www.bitscn.net

function sess_open($save_path, $session_name) { 
global $SESS_DBM; 

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$SESS_DBM = dbmopen("$save_path/$session_name", "c"); 
return ($SESS_DBM); 
}  网管bitscn_com

function sess_close() { 
global $SESS_DBM; 

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dbmclose($SESS_DBM); 
return true; 
} 

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function sess_read($key) { 
global $SESS_DBM, $SESS_LIFE; 

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$var = ""; 
if ($tmp = dbmfetch($SESS_DBM, $key)) { 
$expires_at = substr($tmp, 0, strpos($tmp, "│")); 

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if ($expires_at > time()) { 
$var = substr($tmp, strpos($tmp, "│") + 1); 
} 
} 

return $var; 
} 

function sess_write($key, $val) { 
global $SESS_DBM, $SESS_LIFE;  网管论坛bbs_bitsCN_com

dbmreplace($SESS_DBM, $key, time() + $SESS_LIFE . "│" . $val); 
return true; 
} 

function sess_destroy($key) { 
global $SESS_DBM; 

dbmdele($SESS_DBM, $key); 
return true; 
} 

function sess_gc($maxlifetime) { 
global $SESS_DBM; 

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$now = time(); 
$key = dbmfirstkey($SESS_DBM); 
while ($key) { 
if ($tmp = dbmfetch($SESS_DBM, $key)) { 
$expires_at = substr($tmp, 0, strpos($tmp, "│")); 
if ($now > $expires_at) { 
sess_destroy($key); 
} 
} 

$key = dbmnextkey($SESS_DBM, $key); 
} 
} 

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session_set_save_handler( 
"sess_open", 
"sess_close", 
"sess_read", 
"sess_write", 
"sess_destroy", 
"sess_gc"); 
?>

================================================================= 
具体怎么用就不用多说了，因为这些函数都是php引擎调用的，与我们无关的。我们只需照上述配
置后就行了，你用的还是以前的session函数。 
看看下面的代码就知道了：） 

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session定制的测试代码 
================================================================== 
<? 
/* ------------------------------------------------------------------------ 
* test.php 
* ------------------------------------------------------------------------ 
* PHP4 Customer Session Handler Test Script 
* Version 1.00 
* by Ying Zhang (ying@zippydesign.com) 
* Last Modified: May 21 2000 
*/ 

/* default to DBM handler */ 
if (! isset($handler)) { 
$handler = "dbm"; 
}  网管u家u.bitsCN.com

/* default action is increment */ 
if (! isset($action)) { 
$action = "increment"; 
}  网管朋友网www_bitscn_net

/* load up the appropriate session handling script, depending on the handler */ 
if ($handler == "dbm") { 
include("session_dbm.php");  网管有家bitscn.net

} elseif ($handler == "mysql") { 
include("session_mysql.php"); 

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} else { 
echo "<li>Unrecognized handler ($handler)"; 
die; 
} 

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/* start the session and register a simple counter */ 
session_start(); 
session_register("count");  网管u家u.bitsCN.com

/* figure out what we should do, depending on the action */ 
switch ($action) { 
case "increment" : 
$count = isset($count) ? $count + 1 : 0; 
break; 

case "destroy" : 
session_destroy(); 
break;  中国网管联盟bitsCN.com

case "gc" : 
$maxlife = get_cfg_var("session.gc_maxlifetime"); 
sess_gc($maxlife); 
break; 

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default: 
echo "<li>Unknown action ($action)"; 
break; 
} 
?> 

<h1>Session Test Script</h1> 
<ul> 
<li>Handler: <b><?=$handler?></b> 
<li>Action: <b><?=$action?></b> 
<li>Count: <b><?=$count?></b> 
</ul>  网管联盟bitsCN_com

<hr size=1> 
<form> 
<table> 
<tr> 
<td>Handler:</td> 
<td> 
<select name="handler"> 
<option value="dbm">DBM</option> 
<option value="mysql">MySQL</option> 
</select> 
</td> 
</tr> 
<tr> 
<td>Action:</td> 
<td> 
<select name="action"> 
<option value="increment">Increment</option> 
<option value="destroy">Session Destroy</option> 
<option value="gc">Force Garbage Collection</option> 
</select> 
</td> 
</tr> 
<tr> 
<td></td> 
<td><br><input type="submit"></td> 

</tr> 
</table> 
</form> 
======================================================================= 
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