$_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, therefore there is no guarantee that every web server will provide any of these; servers may omit some, or provide others not listed here. However, most of these variables are accounted for in the » CGI/1.1 specification, and are likely to be defined.
Note: When running PHP on the command line most of these entries will not be available or have any meaning.
In addition to the elements listed below, PHP will create additional elements with values from request headers. These entries will be named HTTP_ followed by the header name, capitalized and with underscores instead of hyphens. For example, the Accept-Language header would be available as $_SERVER[‘HTTP_ACCEPT_LANGUAGE’] .
Indices
‘ PHP_SELF ‘ The filename of the currently executing script, relative to the document root. For instance, $_SERVER[‘PHP_SELF’] in a script at the address http://example.com/foo/bar.php would be /foo/bar.php . The __FILE__ constant contains the full path and filename of the current (i.e. included) file. If PHP is running as a command-line processor this variable contains the script name. ‘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. ‘argc’ Contains the number of command line parameters passed to the script (if run on the command line). ‘ GATEWAY_INTERFACE ‘ What revision of the CGI specification the server is using; e.g. ‘CGI/1.1’ . ‘ SERVER_ADDR ‘ The IP address of the server under which the current script is executing. ‘ 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.
Note: Under Apache 2, UseCanonicalName = On and ServerName must be set. Otherwise, this value reflects the hostname supplied by the client, which can be spoofed. It is not safe to rely on this value in security-dependent contexts.
‘ SERVER_SOFTWARE ‘ Server identification string, given in the headers when responding to requests. ‘ SERVER_PROTOCOL ‘ Name and revision of the information protocol via which the page was requested; e.g. ‘HTTP/1.0’ ; ‘ REQUEST_METHOD ‘ Which request method was used to access the page; e.g. ‘GET’ , ‘HEAD’ , ‘POST’ , ‘PUT’ .
Note:
PHP script is terminated after sending headers (it means after producing any output without output buffering) if the request method was HEAD .
‘ REQUEST_TIME ‘ The timestamp of the start of the request. ‘ REQUEST_TIME_FLOAT ‘ The timestamp of the start of the request, with microsecond precision. ‘ QUERY_STRING ‘ The query string, if any, via which the page was accessed. ‘ DOCUMENT_ROOT ‘ The document root directory under which the current script is executing, as defined in the server’s configuration file. ‘ HTTPS ‘ Set to a non-empty value if the script was queried through the HTTPS protocol. ‘ REMOTE_ADDR ‘ The IP address from which the user is viewing the current page. ‘ REMOTE_HOST ‘ The Host name from which the user is viewing the current page. The reverse dns lookup is based on the REMOTE_ADDR of the user.
Note: The web server must be configured to create this variable. For example in Apache HostnameLookups On must be set inside httpd.conf for it to exist. See also gethostbyaddr() .
‘ REMOTE_PORT ‘ The port being used on the user’s machine to communicate with the web server. ‘ REMOTE_USER ‘ The authenticated user. ‘ REDIRECT_REMOTE_USER ‘ The authenticated user if the request is internally redirected. ‘ SCRIPT_FILENAME ‘
The absolute pathname of the currently executing script.
Note:
If a script is executed with the CLI, as a relative path, such as file.php or ../file.php , $_SERVER[‘SCRIPT_FILENAME’] will contain the relative path specified by the user.
‘ SERVER_ADMIN ‘ The value given to the SERVER_ADMIN (for Apache) directive in the web server configuration file. If the script is running on a virtual host, this will be the value defined for that virtual host. ‘ SERVER_PORT ‘ The port on the server machine being used by the web server for communication. For default setups, this will be ’80’ ; using SSL, for instance, will change this to whatever your defined secure HTTP port is.
Note: Under Apache 2, UseCanonicalName = On , as well as UseCanonicalPhysicalPort = On must be set in order to get the physical (real) port, otherwise, this value can be spoofed, and it may or may not return the physical port value. It is not safe to rely on this value in security-dependent contexts.
‘ SERVER_SIGNATURE ‘ String containing the server version and virtual host name which are added to server-generated pages, if enabled. ‘ PATH_TRANSLATED ‘ Filesystem- (not document root-) based path to the current script, after the server has done any virtual-to-real mapping.
Note: Apache 2 users may use AcceptPathInfo = On inside httpd.conf to define PATH_INFO .
‘ SCRIPT_NAME ‘ Contains the current script’s path. This is useful for pages which need to point to themselves. The __FILE__ constant contains the full path and filename of the current (i.e. included) file. ‘ REQUEST_URI ‘ The URI which was given in order to access this page; for instance, ‘ /index.html ‘. ‘ PHP_AUTH_DIGEST ‘ When doing Digest HTTP authentication this variable is set to the ‘Authorization’ header sent by the client (which you should then use to make the appropriate validation). ‘ PHP_AUTH_USER ‘ When doing HTTP authentication this variable is set to the username provided by the user. ‘ PHP_AUTH_PW ‘ When doing HTTP authentication this variable is set to the password provided by the user. ‘ AUTH_TYPE ‘ When doing HTTP authentication this variable is set to the authentication type. ‘ PATH_INFO ‘ Contains any client-provided pathname information trailing the actual script filename but preceding the query string, if available. For instance, if the current script was accessed via the URI http://www.example.com/php/path_info.php/some/stuff?foo=bar , then $_SERVER[‘PATH_INFO’] would contain /some/stuff . ‘ ORIG_PATH_INFO ‘ Original version of ‘ PATH_INFO ‘ before processed by PHP.
Examples
Example #1 $_SERVER example
PHP $_SERVER
$_SERVER is a superglobal that holds information regarding HTTP headers, path and script location etc. All the server and execution environment related information is available in this associative array. Most of the entries in this array are populated by web server.
PHP versions prior to 5.4.0 contained $HTTP_SERVER_VARS contained same information but has now been removed. Following are some prominent members of this array
PHP_SELF − stores filename of currently executing script. For example, a script in test folder of document root of a local server returns its path as follows −
Example
This results in following output in browser with http://localhost/test/testscript.php URL
SERVER_ADDR − This property of array returns The IP address of the server under which the current script is executing.
SERVER_NAME − Name of server hostunder which the current script is executing.In case of a erver running locally, localhost is returned
QUERY_STRING − A query string is the string of key=value pairs separated by & symbol and appended to URL after ? symbol. For example, http://localhost/testscript?name=xyz&age=20 URL returns trailing query string
REQUEST_METHOD − HTTP request method used for accessing a URL, such as POST, GET, POST, PUT or DELETE. In above query string example, a URL attached to query string wirh ? symbol requests the page with GET method
DOCUMENT_ROOT − returns name of directory on server that is configured as document root. On XAMPP apache server it returns htdocs as name of document root
DOCUMENT_ROOT − This is a string denoting the user agent (browser) being which is accessing the page.
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.116 Safari/537.36
REMOTE_ADDR − IP address of machine from which the user is viewing the current page.
SERVER_PORT − port number on which the web server is listening to incoming request. Default is 80
Following script invoked from document root of XAMPP server lists all server variables
Example
List of all server variables
MIBDIRS=>C:/xampp/php/extras/mibs MYSQL_HOME=>\xampp\mysql\bin OPENSSL_CONF=>C:/xampp/apache/bin/openssl.cnf PHP_PEAR_SYSCONF_DIR=>\xampp\php PHPRC=>\xampp\php TMP=>\xampp\tmp HTTP_HOST=>localhost HTTP_CONNECTION=>keep-alive HTTP_CACHE_CONTROL=>max-age=0 HTTP_DNT=>1 HTTP_UPGRADE_INSECURE_REQUESTS=>1 HTTP_USER_AGENT=>Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.135 Safari/537.36 HTTP_ACCEPT=>text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9 HTTP_SEC_FETCH_SITE=>none HTTP_SEC_FETCH_MODE=>navigate HTTP_SEC_FETCH_USER=>?1 HTTP_SEC_FETCH_DEST=>document HTTP_ACCEPT_ENCODING=>gzip, deflate, br HTTP_ACCEPT_LANGUAGE=>en-US,en;q=0.9,mr;q=0.8 PATH=>C:\python37\Scripts\;C:\python37\;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\Program Files (x86)\AMD\ATI.ACE\Core-Static;C:\python37\Scripts\;C:\python37\;C:\Users\User\AppData\Local\Microsoft\WindowsApps;C:\Users\User\AppData\Local\Programs\MiKTeX 2.9\miktex\bin\x64\;C:\MicrosoftVSCode\bin SystemRoot=>C:\Windows COMSPEC=>C:\Windows\system32\cmd.exe PATHEXT=>.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC;.PY;.PYW WINDIR=>C:\Windows SERVER_SIGNATURE=> Apache/2.4.41 (Win64) OpenSSL/1.0.2s PHP/7.1.32 Server at localhost Port 80 SERVER_SOFTWARE=>Apache/2.4.41 (Win64) OpenSSL/1.0.2s PHP/7.1.32 SERVER_NAME=>localhost SERVER_ADDR=>::1 SERVER_PORT=>80 REMOTE_ADDR=>::1 DOCUMENT_ROOT=>C:/xampp/htdocs REQUEST_SCHEME=>http CONTEXT_PREFIX=> CONTEXT_DOCUMENT_ROOT=>C:/xampp/htdocs SERVER_ADMIN=>postmaster@localhost SCRIPT_FILENAME=>C:/xampp/htdocs/testscript.php REMOTE_PORT=>49475 GATEWAY_INTERFACE=>CGI/1.1 SERVER_PROTOCOL=>HTTP/1.1 REQUEST_METHOD=>GET QUERY_STRING=> REQUEST_URI=>/testscript.php SCRIPT_NAME=>/testscript.php PHP_SELF=>/testscript.php REQUEST_TIME_FLOAT=>1599118525.327 REQUEST_TIME=>1599118525