PHP 的一些路径变量

PHP 中有许多路径变量，先来认识清楚。假定浏览器中输入的 URL 地址为

http://example.com:8000/aaa/index.php/bbb/ccc?q=ddd

利用下面这些变量可以得到所访问服务器的基本信息：

$_SERVER['SERVER_PROTOCOL']	'HTTP 1.0'
$_SERVER['HTTP_HOST']	'example.com'
$_SERVER['SERVER_PORT']	'8000'

利用下面这些变量可以得到所访问路径的基本信息：

$_SERVER['REQUEST_URI']	'/aaa/index.php/bbb/ccc?q=ddd'
$_SERVER['PHP_SELF"']	'/aaa/index.php/bbb/ccc'
$_SERVER['SCRIPT_NAME']	'/aaa/index.php'
$_SERVER['PATH_INFO']	'/bbb/ccc'
$_SERVER['QUERY_STRING']	'q=ddd'

利用下面这些变量可以得到 PHP 文件在服务器的路径信息：

__FILE__	'/home/example/public_html/aaa/index.php'
$_SERVER['SCRIPT_FILENAME']	'/home/example/public_html/aaa/index.php'
$_SERVER['PATH_TRANSLATED']	'/home/example/public_html/aaa/index.php'
$_SERVER['DOCUMENT_ROOT']	'/home/example/public_html'

如果有 URL rewrite，情况将有所不同。比如 Apache 将 /aaa/index.php 重定向到 /aaa/error.php 时，$_SERVER['SCRIPT_NAME'] 将变成 '/aaa/error.php'。

参考资料：
[1] PHP: $_SERVER - Manual
[2] RFC 3875 - The Common Gateway Interface (CGI) Version 1.1
[3] http - PHP_SELF vs PATH_INFO vs SCRIPT_NAME vs REQUEST_URI - Stack Overflow
[4] url rewriting - Pros/cons of using index.php?q=path/ instead of index.php/path/? - Stack Overflow
[5] How to create friendly URL in php? - Stack Overflow
[6] PHP Get the Full URL - Stack Overflow
[7] PHP get current page URL
[8] URL Rewriting for Beginners - Web Development in Brighton - Added Bytes