Page 533 - Beginning PHP 5.3

Chapter 16: PHP and the Outside World

Variable Description
$_SERVER[ “ DOCUMENT_ROOT “ The absolute path to the document root folder of the Web
]
site (for example: /home/matt/mysite/htdocs )
$_SERVER[ “ HTTP_REFERER “ The referring URL, as sent by the browser in the Referer
]
HTTP header. (See the “ Working with HTTP ” section in
this chapter for more details)
$_SERVER[ “ HTTP_USER_AGENT “ The visitor ’ s browser information, such as name and
]
version. (A nicer way to access this information is to use the
PEAR Net_UserAgent_Detect package, as described in
Chapter 15)

$_SERVER[ “ HTTPS “ true if the script was accessed via HTTPS; false if
]
accessed via HTTP
$_SERVER[ “ PATH_INFO “ Any extra info appended onto the URL. For example, if the
]
script is accessed via the URL http://www.example.com/
myscript.php/extra/info ) then $_SERVER[ “ PATH_
INFO “ contains /extra/info . (Not supported on all
]
servers)
$_SERVER[ “ PHP_SELF “ The URL of the currently running script, relative to the Web
]
site ’ s document root. For example: /about/index.php
$_SERVER[ “ QUERY_STRING “ The query string in the URL of the request, if present (this
]
is the string that appears after the ‘ ? ’ in the URL)
$_SERVER[ “ REMOTE_ADDR “ The IP address of the visitor ’ s computer (or proxy server if
]
the visitor is using one)
$_SERVER[ “ REMOTE_HOST “ The hostname of the visitor ’ s computer (or proxy server if
]
the visitor is using one). Because this involves making a
DNS lookup it can have a performance hit on the server, so
many Web server applications disable this option by
default. However, you can use gethostbyaddr() to
manually retrieve the hostname from the IP address as
follows: echo gethostbyaddr( $_SERVER[ “ REMOTE_
ADDR “ ] )
$_SERVER[ “ REQUEST_METHOD “ The request method used to access the script (such as GET ,
]
POST , or HEAD )

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