$_REQUEST

HTTP Request 变量

说明

默认情况下包含了$_GET，$_POST和$_COOKIE的数组。

更新日志

注释

Note:

“Superglobal”也称为自动化的全局变量。这就表示其在脚本的所有作用域中都是可用的。不需要在函数或方法中用global $variable;来访问它。

Note:

以命令行方式运行时，将不包含argv和argc信息；它们将存在于$_SERVER数组。

Note:

由于$_REQUEST中的变量通过 GET，POST 和 COOKIE 输入机制传递给脚本文件，因此可以被远程用户篡改而并不可信。这个数组的项目及其顺序依赖于 PHP 的variables_order指令的配置。

参见

• import_request_variables()将 GET／POST／Cookie 变量导入到全局作用域中
• 处理外部变量
• 过滤器扩展

Don't forget, because $_REQUEST is a different variable than $_GET and $_POST, it is treated as such in PHP -- modifying $_GET or $_POST elements at runtime will not affect the ellements in $_REQUEST, nor vice versa.
e.g:
<?php
$_GET['foo'] = 'a';
$_POST['bar'] = 'b';
var_dump($_GET); // Element 'foo' is string(1) "a"
var_dump($_POST); // Element 'bar' is string(1) "b"
var_dump($_REQUEST); // Does not contain elements 'foo' or 'bar'
?>
If you want to evaluate $_GET and $_POST variables by a single token without including $_COOKIE in the mix, use $_SERVER['REQUEST_METHOD'] to identify the method used and set up a switch block accordingly, e.g:
<?php
switch($_SERVER['REQUEST_METHOD'])
{
case 'GET': $the_request = &$_GET; break;
case 'POST': $the_request = &$_POST; break;
.
. // Etc.
.
default:
}
?>

To access $_POST, $_GET, etc, use the function filter_input(TYPE, varname, filter) to ensure that your data is clean. 
Also, I was brought up to believe that modifying superglobals is a BAD idea. I stand by this belief and would recommend you do too

The default php.ini on your system as of in PHP 5.3.0 may exclude cookies from $_REQUEST. The request_order ini directive specifies what goes in the $_REQUEST array; if that does not exist, then the variables_order directive does. Your distribution's php.ini may exclude cookies by default, so beware.

I wrote a function because I found it inconvenient if I needed to change a particular parameter (get) while preserving the others. For example, I want to make a hyperlink on a web page with the URL http://www.example.com/script.php?id=1&blah=blah+blah&page=1 and change the value of "page" to 2 without getting rid of the other parameters.
<?php
 function add_or_change_parameter($parameter, $value)
 {
 $params = array();
 $output = "?";
 $firstRun = true;
 foreach($_GET as $key=>$val)
 {
  if($key != $parameter)
  {
  if(!$firstRun)
  {
   $output .= "&";
  }
  else
  {
   $firstRun = false;
  }
  $output .= $key."=".urlencode($val);
  }
 }
 if(!$firstRun)
  $output .= "&";
 $output .= $parameter."=".urlencode($value);
 return htmlentities($output);
 }
?>
Now, I can add a hyperlink to the page (http://www.example.com/script.php?id=1&blah=blah+blah&page=1) like this:
<a href="<?php echo add_or_change_parameter("page", "2"); ?>">Click to go to page 2</a>
The above code will output
<a href="?id=1&amp;blah=blah+blah&amp;page=2">Click to go to page 2</a>
Also, if I was setting "page" to a string rather than just "2", the value would be urlencode()'d.
<a href="<?php echo add_or_change_parameter("page", "banana+split!"); ?>">Click to go to page banana split!</a>
would become
<a href="?id=1&amp;blah=blah+blah&amp;page=banana+split%21">Click to go to page banana split!</a>
[EDIT BY danbrown AT php DOT net: Contains a bugfix provided by (theogony AT gmail DOT com), which adds missing `echo` instructions to the HREF tags.]