PHP超全局变量实现原理及代码解析

PHP è¶å¨å±åé

è¿äºè¶å¨å±åéæ¯ï¼

$GLOBALS
$_SERVER
$_REQUEST
$_POST
$_GET
$_FILES
$_ENV
$_COOKIE
$_SESSION

$GLOBALS â å¼ç¨å¨å±ä½ç¨åä¸å¯ç¨çå¨é¨åé

PHP å¨åä¸º $GLOBALS[index] çæ°ç»ä¸åå¨äºææå¨å±åéãåéçååå°±æ¯æ°ç»çé®ã

ä¸é¢çä¾åå±ç¤ºäºå¦ä½ä½¿ç¨è¶çº§å¨å±åé $GLOBALSï¼

å®ä¾

<?php 
$x = 75; 
$y = 25;
 
function addition() { 
 $GLOBALS['z'] = $GLOBALS['x'] + $GLOBALS['y']; 
}
 
addition(); 
echo $z; 
?>

PHP $_SERVER

ä¸é¢çä¾åå±ç¤ºäºå¦ä½ä½¿ç¨ $_SERVER ä¸çæäºåç´ ï¼

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<?php 
echo $_SERVER['PHP_SELF'];
echo "<br>";
echo $_SERVER['SERVER_NAME'];
echo "<br>";
echo $_SERVER['HTTP_HOST'];
echo "<br>";
echo $_SERVER['HTTP_REFERER'];
echo "<br>";
echo $_SERVER['HTTP_USER_AGENT'];
echo "<br>";
echo $_SERVER['SCRIPT_NAME'];
?>

ä¸è¡¨ååºäºæ¨è½å¤å¨ $_SERVER ä¸è®¿é®çæéè¦çåç´ ï¼

åç´ /ä»£ç	æè¿°
$_SERVER['PHP_SELF']	è¿åå½åæ§è¡èæ¬çæä»¶åã
$_SERVER['GATEWAY_INTERFACE']	è¿åæå¡å¨ä½¿ç¨ç CGI è§èççæ¬ã
$_SERVER['SERVER_ADDR']	è¿åå½åè¿è¡èæ¬æå¨çæå¡å¨ç IP å°åã
$_SERVER['SERVER_NAME']	è¿åå½åè¿è¡èæ¬æå¨çæå¡å¨çä¸»æºåï¼æ¯å¦ www.w3school.com.cnï¼ã
$_SERVER['SERVER_SOFTWARE']	è¿åæå¡å¨æ è¯åç¬¦ä¸²ï¼æ¯å¦ Apache/2.2.24ï¼ã
$_SERVER['SERVER_PROTOCOL']	è¿åè¯·æ±é¡µé¢æ¶éä¿¡åè®®çåç§°åçæ¬ï¼ä¾å¦ï¼âHTTP/1.0âï¼ã
$_SERVER['REQUEST_METHOD']	è¿åè®¿é®é¡µé¢ä½¿ç¨çè¯·æ±æ¹æ³ï¼ä¾å¦ POSTï¼ã
$_SERVER['REQUEST_TIME']	è¿åè¯·æ±å¼å§æ¶çæ¶é´æ³ï¼ä¾å¦ 1577687494ï¼ã
$_SERVER['QUERY_STRING']	è¿åæ¥è¯¢åç¬¦ä¸²ï¼å¦ææ¯éè¿æ¥è¯¢åç¬¦ä¸²è®¿é®æ¤é¡µé¢ã
$_SERVER['HTTP_ACCEPT']	è¿åæ¥èªå½åè¯·æ±çè¯·æ±å¤´ã
$_SERVER['HTTP_ACCEPT_CHARSET']	è¿åæ¥èªå½åè¯·æ±ç Accept_Charset å¤´ï¼ ä¾å¦ utf-8,ISO-8859-1ï¼
$_SERVER['HTTP_HOST']	è¿åæ¥èªå½åè¯·æ±ç Host å¤´ã
$_SERVER['HTTP_REFERER']	è¿åå½åé¡µé¢çå®æ´ URLï¼ä¸å¯é ï¼å ä¸ºä¸æ¯ææç¨æ·ä»£çé½æ¯æï¼ã
$_SERVER['HTTPS']	æ¯å¦éè¿å®å¨ HTTP åè®®æ¥è¯¢èæ¬ã
$_SERVER['REMOTE_ADDR']	è¿åæµè§å½åé¡µé¢çç¨æ·ç IP å°åã
$_SERVER['REMOTE_HOST']	è¿åæµè§å½åé¡µé¢çç¨æ·çä¸»æºåã
$_SERVER['REMOTE_PORT']	è¿åç¨æ·æºå¨ä¸è¿æ¥å° Web æå¡å¨æä½¿ç¨çç«¯å£å·ã
$_SERVER['SCRIPT_FILENAME']	è¿åå½åæ§è¡èæ¬çç»å¯¹è·¯å¾ã
$_SERVER['SERVER_ADMIN']	è¯¥å¼ææäº Apache æå¡å¨éç½®æä»¶ä¸ç SERVER_ADMIN åæ°ã
$_SERVER['SERVER_PORT']	Web æå¡å¨ä½¿ç¨çç«¯å£ãé»è®¤å¼ä¸º â80âã
$_SERVER['SERVER_SIGNATURE']	è¿åæå¡å¨çæ¬åèæä¸»æºåã
$_SERVER['PATH_TRANSLATED']	å½åèæ¬æå¨æä»¶ç³»ç»ï¼éææ¡£æ ¹ç®å½ï¼çåºæ¬è·¯å¾ã
$_SERVER['SCRIPT_NAME']	è¿åå½åèæ¬çè·¯å¾ã
$_SERVER['SCRIPT_URI']	è¿åå½åé¡µé¢ç URIã

PHP $_REQUEST

PHP $_REQUEST ç¨äºæ¶é HTML è¡¨åæäº¤çæ°æ®ã

å®ä¾

<html>
<body>

<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">
Name: <input type="text" name="fname">
<input type="submit">
</form>

<?php 
$name = $_REQUEST['fname']; 
echo $name; 
?>

</body>
</html>

PHP $_POST

PHP $_POST å¹¿æ³ç¨äºæ¶éæäº¤ method="post" ç HTML è¡¨ååçè¡¨åæ°æ®ã$_POST ä¹å¸¸ç¨äºä¼ éåéã

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<html>
<body>

<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">
Name: <input type="text" name="fname">
<input type="submit">
</form>

<?php 
$name = $_POST['fname'];
echo $name; 
?>

</body>
</html>

PHP $_GET

PHP $_GET ä¹å¯ç¨äºæ¶éæäº¤ HTML è¡¨å (method="get") ä¹åçè¡¨åæ°æ®ã

$_GET ä¹å¯ä»¥æ¶é URL ä¸çåéçæ°æ®ã

åè®¾æä»¬æä¸å¼ é¡µé¢å«æå¸¦åæ°çè¶é¾æ¥ï¼

<html>
<body>

<a href="test_get.php?subject=PHP&web=W3school.com.cn" rel="external nofollow" >æµè¯ $GET</a>

</body>
</html>

å½ç¨æ·ç¹å»é¾æ¥ "æµè¯ $GET"ï¼åæ° "subject" å "web" è¢«åéå° "test_get.php"ï¼ç¶åæ¨å°±è½å¤éè¿ $_GET å¨ "test_get.php" ä¸è®¿é®è¿äºå¼äºã

ä¸é¢çä¾åæ¯ "test_get.php" ä¸çä»£ç ï¼

å®ä¾

<html>
<body>

<?php 
echo "å¨ " . $_GET['web'] . " å¦ä¹  " . $_GET['subject'];
?>

</body>
</html>

PHP超全局变量实现原理及代码解析

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