Tuesday, September 29, 2020

PHP Predefined Variables



Hello folks! welcome back to another section of my tutorial on PHP. In this tutorial guide, we are going to be discussing about the PHP Predefined Variables.

PHP provides a large number of predefined variables to any script which it runs. PHP also provides an additional set of arrays that contains variables from the web server, the environment, and the user input. This new arrays are called superglobals -

Every of the following variables are automatically available in every of the scope.



Superglobal Variables

The following below is the list of superglobal variables available in PHP -

Sr.NoVariable & 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 is an array containing informations such as the headers, the paths and script locations. The entries in this array are created by the server. There is no assurance that every web server is going to provide all these. The following below is the list of the $_Server variables available in PHP -

Sr.NoVariable & 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.



Alright guys! This is where we are rounding up for this tutorial post. In my next tutorial post, we will be studying about the PHP Regular Expressions.

Feel free to ask your questions where necessary and i will attend to them as soon as possible. If this tutorial was helpful to you, you can use the share button to share this tutorial.

Follow us on our various social media platforms to stay updated with our latest tutorials. You can also subscribe to our newsletter in order to get our tutorials delivered directly to your emails.

Thanks for reading and bye for now.
Share:

0 comments:

Post a Comment

Hello dear readers! Please kindly try your best to make sure your comments comply with our comment policy guidelines. You can visit our comment policy page to view these guidelines which are clearly stated. Thank you.