Predefined variables of php

Predefined variable SERVER variable: $ _ SERVER Note: Used in PHP4.1.0 and later versions. In earlier versions, $ HTTP_SERVER_VARS is used. $ _ SERVER is an array containing headers, paths, and scriptlocations. The object of the array is created by the web server. It cannot be guaranteed that all servers can generate all Predefined variables
SERVER variable: $ _ SERVER
Note: PHP 4.1.0 and later versions are used. In earlier versions, $ HTTP_SERVER_VARS is used.

$ _ SERVER is an array containing headers, paths, and script locations. The object of the array is created by the web server. It is not guaranteed that all servers can generate all information. the server may ignore some information or generate new information not listed below. This means that a large number of these variables are described in CGI 1.1 specification, so you should study it carefully.

This is a "superglobal", or it can be described as an automatic global variable. This only means that it is valid in all scripts. You do not need to use global $ _ SERVER; to access a function or method, just like using $ HTTP_SERVER_VARS.

$ HTTP_SERVER_VARS contains the same information, but it is not an automatic global variable. (Note: $ HTTP_SERVER_VARS and $ _ SERVER are different variables. PHP processes them differently .)

If the register_globals command is set, these variables are also available in all scripts; that is, the $ _ SERVER and $ HTTP_SERVER_VARS arrays are separated. For more information, see the security section using Register Globals. These independent global variables are not automatic global variables.

You may find that some $ _ SERVER elements listed below are not available. Note: If you run PHP in the command line mode, the elements listed below are hardly valid (or have no practical significance ).



"PHP_SELF"
The file name of the script being executed, which is related to document root. For example, using $ _ SERVER ['php _ SELF '] in a script with a URL address of http://example.com/test.php/foo.bar will get the result of/test. PHP/foo. bar.

If PHP is run as a command line, the variable is invalid.

"Argv"
Parameters passed to the script. When the script runs in the command line mode, the argv variable is passed to the command line parameters in the C language style of the program. When the GET method is called, the variable contains the requested data.

"Argc"
Contains the number of command line parameters passed to the program (if it is in command line mode ).

"GATEWAY_INTERFACE"
The CGI specification version used by the server. For example, "CGI/1.1 ".

'Server _ name'
Name of the server host where the script is currently running. If the script runs on a VM, the name is determined by the value set by that VM.

'Server _ soft'
The string identified by the server, which is in the header of the response request.

"SERVER_PROTOCOL"
The name and version of the communication protocol on the request page. For example, "HTTP/1.0 ".

"REQUEST_METHOD"
The request method used to access the page. For example, "GET", "HEAD", "POST", and "PUT ".

"QUERY_STRING"
Query string.

"DOCUMENT_ROOT"
The document root directory where the script is currently running. Defined in the server configuration file.

"HTTP_ACCEPT"
The Accept of the current request: the content in the header.

"HTTP_ACCEPT_CHARSET"
Accept-Charset of the current request: content in the header. Example: "ISO-8859-1, *, UTF-8 ".

"HTTP_ACCEPT_ENCODING"
Accept-Encoding of the current request: content in the header. For example, "gzip ".

"HTTP_ACCEPT_LANGUAGE"
The Accept-Language of the current request: the content in the header. For example, "en ".

"HTTP_CONNECTION"
Connection of the current request: content in the header. For example, "Keep-Alive ".

"HTTP_HOST"
Host of the current request: content in the header.

"HTTP_REFERER"
The URL of the previous page that is linked to the current page. Not all user proxies (browsers) will set this variable, and some can also manually modify HTTP_REFERER. Therefore, this variable is not always true.

"HTTP_USER_AGENT"
User_Agent of the current request: content in the header. This string indicates the information of the user agent accessing the page. A typical example is Mozilla/4.5 [en] (X11; U; Linux 2.2.9 i586 ). You can also use get_browser () to obtain this information.

"REMOTE_ADDR"
Browsing the IP address of the user on the current page.

"REMOTE_PORT"
The port used by the user to connect to the server.

"SCRIPT_FILENAME"
The absolute path name of the currently executed script.

"SERVER_ADMIN"
This value specifies the SERVER_ADMIN parameter in the Apache server configuration file. If the script runs on a VM, this value is the value of that VM.

"SERVER_PORT"
The port used by the server. The default value is "80 ". If you use an SSL secure connection, this value is the HTTP port you set.

"SERVER_SIGNATURE"
A string containing the server version and virtual host name.

"PATH_TRANSLATED"
The basic path of the file system (not the document root directory) where the current script is located. This is the result of a virtual image to a real path on the server.

"SCRIPT_NAME"
The path that contains the current script. This is useful when the page needs to point to itself.

"REQUEST_URI"
The URI required to access this page. For example, "/index.html ".

"PHP_AUTH_USER"
When PHP runs in the Apache module mode and uses the HTTP authentication function, this variable is the user name entered by the user.

"PHP_AUTH_PW"
When PHP runs in the Apache module mode and is using the HTTP authentication function, this variable is the password entered by the user.

"PHP_AUTH_TYPE"
When PHP runs in the Apache module mode and uses the HTTP authentication function, this variable is the authentication type.


Environment variable: $ _ ENV
Note: PHP 4.1.0 and later versions are used. In earlier versions, $ HTTP_ENV_VARS is used.

When the parser is running, these variables change from environment variables to PHP global variable namespace ). Many of them are determined by the system running PHP. A complete list is impossible. Check your system documentation to determine its specific environment variables.

Other environment variables (including CGI variables), whether PHP is run as a server module or as a CGI, are listed here.

This is a "superglobal", or it can be described as an automatic global variable. This only means that it is valid in all scripts. You do not need to use global $ _ ENV; to access a function or method, just like using $ HTTP_ENV_VARS.

$ HTTP_ENV_VARS contains the same information, but it is not an automatic global variable. (Note: HTTP_ENV_VARS and $ _ ENV are different variables. PHP processes them differently .)

If the register_globals command is set, these variables are also available in all scripts; that is, the $ _ ENV and $ HTTP_ENV_VARS arrays are separated. For more information, see the security section using Register Globals. These independent global variables are not automatic global variables.

HTTP Cookies: $ _ COOKIE
Note: PHP 4.1.0 and later versions are used. In earlier versions, $ HTTP_COOKIE_VARS is used.

An array composed of variables passed through HTTP cookies. Is an automatic global variable.

This is a "superglobal", or it can be described as an automatic global variable. This only means that it is valid in all scripts. You do not need to use global $ _ COOKIE; to access a function or method, just like using $ HTTP_COOKIE_VARS.

$ HTTP_COOKIE_VARS contains the same information, but it is not an automatic global variable. (Note: HTTP_COOKIE_VARS and $ _ COOKIE are different variables. PHP processes them differently .)

If the register_globals command is set, these variables are also available in all scripts; that is, the $ _ COOKIE and $ HTTP_COOKIE_VARS arrays are separated. For more information, see the security section using Register Globals. These independent global variables are not automatic global variables.

Http get variable: $ _ GET
Note: PHP 4.1.0 and later versions are used. In earlier versions, $ HTTP_GET_VARS is used.

An array composed of variables passed through the http get method. Is an automatic global variable.

This is a "superglobal", or it can be described as an automatic global variable. This only means that it is valid in all scripts. You do not need to use global $ _ GET; to access a function or method, just like using $ HTTP_GET_VARS.

$ HTTP_GET_VARS contains the same information, but it is not an automatic global variable. (Note: HTTP_GET_VARS and $ _ GET are different variables. PHP processes them differently .)

If the register_globals command is set, these variables are also available in all scripts; that is, the $ _ GET and $ HTTP_GET_VARS arrays are separated. For more information, see the security section using Register Globals. These independent global variables are not automatic global variables.

Http post variable: $ _ POST
Note: PHP 4.1.0 and later versions are used. In earlier versions, $ HTTP_POST_VARS is used.

An array composed of variables passed through the http post method. Is an automatic global variable.

This is a "superglobal", or it can be described as an automatic global variable. This only means that it is valid in all scripts. You do not need to use global $ _ POST; to access a function or method, just like using $ HTTP_POST_VARS.

$ HTTP_POST_VARS contains the same information, but it is not an automatic global variable. (Note: HTTP_POST_VARS and $ _ POST are different variables. PHP processes them differently .)

If the register_globals command is set, these variables are also available in all scripts; that is, the $ _ POST and $ HTTP_POST_VARS arrays are separated. For more information, see the security section using Register Globals. These independent global variables are not automatic global variables.

HTTP file Upload variable: $ _ FILES
Note: PHP 4.1.0 and later versions are used. In earlier versions, $ HTTP_POST_FILES is used.

An array composed of uploaded File items passed through the http post method. Is an automatic global variable.

This is a "superglobal", or it can be described as an automatic global variable. This only means that it is valid in all scripts. You do not need to use global $ _ FILES; to access a function or method, just like using $ HTTP_POST_FILES.

$ HTTP_POST_FILES contains the same information, but it is not an automatic global variable.

If the register_globals command is set, these variables are also available in all scripts; that is, the $ _ FILES and $ HTTP_POST_FILES arrays are separated. For more information, see the security section using Register Globals. These independent global variables are not automatic global variables.

Request variable: $ _ REQUEST
Note: PHP 4.1.0 and later versions are used. In earlier versions, there is no equivalent array.

An array consisting of $ _ GET, $ _ POST, and $ _ COOKIE content.

Note: Before PHP 4.3.0, $ _ FILES were included in the $ _ REQUEST array.

This is a "superglobal", or it can be described as an automatic global variable. This only means that it is valid in all scripts. You do not need to use global $ _ REQUEST; to access a function or method.

If the register_globals command is set, these variables are also available in all scripts; that is, the $ _ REQUEST array is separated. For more information, see the security section using Register Globals. These independent global variables are not automatic global variables.

Session variable: $ _ SESSION
Note: PHP 4.1.0 and later versions are used. In earlier versions, $ HTTP_SESSION_VARS is used.

An array containing the session variables in the current script. See the Session function documentation for more information.

This is a "superglobal", or it can be described as an automatic global variable. This only means that it is valid in all scripts. You do not need to use global $ _ SESSION; to access a function or method, just like using $ HTTP_SESSION_VARS.

$ HTTP_SESSION_VARS contains the same information, but it is not an automatic global variable.

If the register_globals command is set, these variables are also available in all scripts; that is, the $ _ SESSION and $ HTTP_SESSION_VARS arrays are separated. For more information, see the security section using Register Globals. These independent global variables are not automatic global variables.

Global variable: $ GLOBALS
Note: $ GLOBALS is applicable to PHP 3.0.0 and later versions.

An array composed of all defined global variables. The variable name is the index of the array.

This is a "superglobal", or it can be described as an automatic global variable. This only means that it is valid in all scripts. You do not need to use global $ GLOBALS; to access a function or method.

Previous error message: $ php_errormsg
$ Php_errormsg is a variable that contains the content of the previous error message generated by PHP. This variable is valid only when an error occurs and the track_errors option is enabled (disabled by default.