8 Useful server variables available in PHP

8 Useful server variables available in PHP

Set your Server Variable name in Dreamweaver as the part between the square brackets.
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Set your Server Variable name in Dreamweaver as the part between the square brackets.
e.g. $_SERVER['HTTP_HOST'] you need to set as HTTP_HOST

When you use it as a dynamic variable it will be entered into your script or email as {SERVER.HTTP_HOST}

  1. $_SERVER['REQUEST_URI']
    It returns the URL
    in to access the page which is executing the script.
    If you need to type http://www.example.com/product.php?id=5 to access the page then $_SERVER['REQUEST_URI'] returns /product.php?id=5″.
  2. $_SERVER['DOCUMENT_ROOT']
    Returns the root directory
    of the server which is specified in the configuration file of server.
    This variable usually returns the path like /usr/yoursite/www in Linux and D:/xamps/xampp/htdocs in windows.
  3. $_SERVER['HTTP_HOST']
    Returns the host’s name
    as found in the http header.
    This variable usually returns the path like example.com when you find http://example.com in browsers address-bar and return www.example.com when you see http://www.example.com in the address bar.
    This is quite useful when you've to preserve session while making an online payment using PHP since session stored for http://example.com is not same as for the http://www.example.com.
  4. $_SERVER['HTTP_USER_AGENT']
    Returns the user agents (browser)
    detail accessing the web page.
    We can use strpos($_SERVER["HTTP_USER_AGENT"],MSIE) to detect Microsoft Internet explorer or you can use strpos($_SERVER["HTTP_USER_AGENT"], Firefox) to detect firefox browser in PHP.
  5. $_SERVER['PHP_SELF']
    Returns the file-name of the currently executing script
    .
    Let’s suppose that you’re accessing the URL http://www.example.com/product.php?id=5 then $_SERVER['PHP_SELF'] returns /product.php in your script.
  6. $_SERVER['QUERY_STRING']
    Returns the query string if query string is used to access the script currently executing.
    Query strings are those string which is available after the ? sign. If you use $_SERVER['QUERY_STRING'] in the script executing the following URL http://www.example.com/index.php?id=5&page=product then it returns id=5&page=product in your script.
  7. $_SERVER['REMOTE_ADDR']
    Returns the IP address of remote machine
    accessing the current page.
    But you can’t relie on $_SERVER['REMOTE_ADDR'] to get the real IP address of client’s machine.
  8. $_SERVER['SCRIPT_FILENAME']
    Returns the absolute path of the file which is currently executing.
    It returns path like var/example.com/www/product.php in Linux and path like D:/xampp/xampp/htdocs/test/example.php in windows.
Written by:  - 6 Jul, 2010