PHP Predefined
Variables
PHP provides a large number of predefined variables
to any script which it runs. PHP provides an additional set of predefined
arrays containing variables from the web server the environment, and user
input. These new arrays are called superglobals −
All the following variables are automatically
available in every scope.
PHP Superglobals
Sr.No |
Variable & Description |
1 |
$GLOBALS Contains a reference to every variable which is
currently available within the global scope of the script. The keys of this
array are the names of the global variables. |
2 |
$_SERVER This is an array containing information such as
headers, paths, and script locations. The entries in this array are created
by the web server. There is no guarantee that every web server will provide
any of these. See next section for a complete list of all the SERVER
variables. |
3 |
$_GET An associative array of variables passed to the
current script via the HTTP GET method. |
4 |
$_POST An associative array of variables passed to the
current script via the HTTP POST method. |
5 |
$_FILES An associative array of items uploaded to the
current script via the HTTP POST method. |
6 |
$_REQUEST An associative array consisting of the contents
of $_GET, $_POST, and $_COOKIE. |
7 |
$_COOKIE An associative array of variables passed to the
current script via HTTP cookies. |
8 |
$_SESSION An associative array containing session variables
available to the current script. |
9 |
$_PHP_SELF A string containing PHP script file name in which
it is called. |
10 |
$php_errormsg $php_errormsg is a
variable containing the text of the last error message generated by PHP. |
Server
variables: $_SERVER
$_SERVER is an array containing information such as
headers, paths, and script locations. The entries in this array are created by
the web server. There is no guarantee that every web server will provide any of
these.
Sr.No |
Variable & Description |
1 |
$_SERVER['PHP_SELF'] The filename of the currently executing script,
relative to the document root |
2 |
$_SERVER['argv'] Array of arguments passed to the script. When the
script is run on the command line, this gives C-style access to the command
line parameters. When called via the GET method, this will contain the query
string. |
3 |
$_SERVER['argc'] Contains the number of command line parameters
passed to the script if run on the command line. |
4 |
$_SERVER['GATEWAY_INTERFACE'] What revision of the CGI specification the server
is using; i.e. 'CGI/1.1'. |
5 |
$_SERVER['SERVER_ADDR'] The IP address of the server under which the
current script is executing. |
6 |
$_SERVER['SERVER_NAME'] The name of the server host under which the
current script is executing. If the script is running on a virtual host, this
will be the value defined for that virtual host. |
7 |
$_SERVER['SERVER_SOFTWARE'] Server identification string, given in the
headers when responding to requests. |
8 |
$_SERVER['SERVER_PROTOCOL'] Name and revision of the information protocol via
which the page was requested; i.e. 'HTTP/1.0'; |
9 |
$_SERVER['REQUEST_METHOD'] Which request method was used to access the page;
i.e. 'GET', 'HEAD', 'POST', 'PUT'. |
10 |
$_SERVER['REQUEST_TIME'] The timestamp of the start of the request.
Available since PHP 5.1.0. |
11 |
$_SERVER['QUERY_STRING'] The query string, if any, via which the page was
accessed. |
12 |
$_SERVER['DOCUMENT_ROOT'] The document root directory under which the
current script is executing, as defined in the server's configuration file. |
13 |
$_SERVER['HTTP_ACCEPT'] Contents of the Accept: header from the current
request, if there is one. |
14 |
$_SERVER['HTTP_ACCEPT_CHARSET'] Contents of the Accept-Charset: header from the
current request, if there is one. Example: 'iso-8859-1,*,utf-8'. |
15 |
$_SERVER['HTTP_ACCEPT_ENCODING'] Contents of the Accept-Encoding: header from the
current request, if there is one. Example: 'gzip'. |
16 |
$_SERVER['HTTP_ACCEPT_LANGUAGE'] Contents of the Accept-Language: header from the
current request, if there is one. Example: 'en'. |
17 |
$_SERVER['HTTP_CONNECTION'] Contents of the Connection: header from the
current request, if there is one. Example: 'Keep-Alive'. |
18 |
$_SERVER['HTTP_HOST'] Contents of the Host: header from the current
request, if there is one. |
19 |
$_SERVER['HTTP_REFERER'] The address of the page (if any) which referred
the user agent to the current page. |
20 |
$_SERVER['HTTP_USER_AGENT'] This is a string denoting the user agent being
which is accessing the page. A typical example is: Mozilla/4.5 [en] (X11; U;
Linux 2.2.9 i586). |
21 |
$_SERVER['HTTPS'] Set to a non-empty value if the script was
queried through the HTTPS protocol. |
22 |
$_SERVER['REMOTE_ADDR'] The IP address from which the user is viewing the
current page. |
23 |
$_SERVER['REMOTE_HOST'] The Host name from which the user is viewing the
current page. The reverse dns lookup is based off
the REMOTE_ADDR of the user. |
24 |
$_SERVER['REMOTE_PORT'] The port being used on the user's machine to
communicate with the web server. |
25 |
$_SERVER['SCRIPT_FILENAME'] The absolute pathname of the currently executing
script. |
26 |
$_SERVER['SERVER_ADMIN'] The value given to the SERVER_ADMIN (for Apache)
directive in the web server configuration file. |
27 |
$_SERVER['SERVER_PORT'] The port on the server machine being used by the
web server for communication. For default setups, this will be '80'. |
28 |
$_SERVER['SERVER_SIGNATURE'] String containing the server version and virtual
host name which are added to server-generated pages, if enabled. |
29 |
$_SERVER['PATH_TRANSLATED'] Filesystem based path to the current script. |
30 |
$_SERVER['SCRIPT_NAME'] Contains the current script's path. This is
useful for pages which need to point to themselves. |
31 |
$_SERVER['REQUEST_URI'] The URI which was given in order to access this
page; for instance, '/index.html'. |
32 |
$_SERVER['PHP_AUTH_DIGEST'] When running under Apache as module doing Digest
HTTP authentication this variable is set to the 'Authorization' header sent
by the client. |
33 |
$_SERVER['PHP_AUTH_USER'] When running under Apache or IIS (ISAPI on PHP 5)
as module doing HTTP authentication this variable is set to the username
provided by the user. |
34 |
$_SERVER['PHP_AUTH_PW'] When running under Apache or IIS (ISAPI on PHP 5)
as module doing HTTP authentication this variable is set to the password
provided by the user. |
35 |
$_SERVER['AUTH_TYPE'] When running under Apache as module doing HTTP
authenticated this variable is set to the authentication type. |