How list all available Apache webserver variables

How list all available Apache webserver variables
Networking Web Servers

Is it possible to output any or all available apache variables ?

Yes, we can use a perl or php script and cgi and php apache module:

Perl

  • create test domain config for apache virtual host e.g. var.mybluelinux.com.conf and enable it in apache configuration
  • in DocumentRoot for your apache virtual host config file create directory cgi
  • create in directory cgi file e.g. echo.pl
  • copy to echo.pl file this perl code:
#!/usr/bin/perl

print "Content-type: text/html\n\n";
print "<pre>\n";

foreach $key (sort keys(%ENV)) {
  print "$key = $ENV{$key}<p>";
}
print "</pre>\n";
  • change permission to echo.pl file to executable
]$ chmod 755 echo.pl
  • enable module cgi in your apache configuration and reload configuration
/etc/apache2/mods-enabled]$ ln -s ../mods-available/cgi.load .
/etc/apache2/mods-enabled]$ systemd reload apache2.service
  • to your apache virtual host config add this code:
ScriptAlias "/cgi/" "/path-to-your-DocumentRoot-virtual-host/cgi/"

  • create file .htaccess in your /path-to-your-DocumentRoot-virtual-host/cgi/ directory (You have to enable .htaccess files in your apache virtual host config)

  • copy to .htacess file this mod rewrite rules:

RewriteEngine On

RewriteCond %{REQUEST_URI} !echo.pl
RewriteRule .* echo.pl?ua=%{HTTP_USER_AGENT}&https=%{HTTPS} [L]
  • And call from web browser any url e.g https://your_virtual_host_domain/cgi/dir/subdir/any-text.html

Example:

When I call from web browser url https://var.mybluelinux.com/cgi/subdir/subsubdir/index.html?my-question&id=45:

CONTEXT_DOCUMENT_ROOT = /var/www/html/var.mybluelinux.com/data/cgi/
CONTEXT_PREFIX = /cgi/
DOCUMENT_ROOT = /var/www/html/var.mybluelinux.com/data
GATEWAY_INTERFACE = CGI/1.1
HTTPS = on
HTTP_ACCEPT = text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
HTTP_ACCEPT_ENCODING = gzip, deflate, br
HTTP_ACCEPT_LANGUAGE = en-US,en;q=0.7,cs;q=0.3
HTTP_CONNECTION = keep-alive
HTTP_COOKIE = _ga=GA1.2.998553010.1519138107; _gid=GA1.2.578630594.1519138107
HTTP_HOST = var.mybluelinux.com
HTTP_UPGRADE_INSECURE_REQUESTS = 1
HTTP_USER_AGENT = Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0
PATH = /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
QUERY_STRING = ua=Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0&https=on
REDIRECT_HTTPS = on
REDIRECT_QUERY_STRING = ua=Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0&https=on
REDIRECT_SSL_TLS_SNI = var.mybluelinux.com
REDIRECT_STATUS = 200
REDIRECT_URL = /cgi/subdir/subsubdir/index.html
REMOTE_ADDR = 212.158.133.35
REMOTE_PORT = 49854
REQUEST_METHOD = GET
REQUEST_SCHEME = https
REQUEST_URI = /cgi/subdir/subsubdir/index.html?my-question&id=45
SCRIPT_FILENAME = /var/www/html/var.mybluelinux.com/data/cgi/echo.pl
SCRIPT_NAME = /cgi/echo.pl
SERVER_ADDR = 84.244.68.54
SERVER_ADMIN = [no address given]
SERVER_NAME = var.mybluelinux.com
SERVER_PORT = 443
SERVER_PROTOCOL = HTTP/1.1
SERVER_SIGNATURE = 
Apache/2.4.25 (Debian) Server at var.mybluelinux.com Port 443
SERVER_SOFTWARE = Apache/2.4.25 (Debian)
SSL_TLS_SNI = var.mybluelinux.com

PHP

  • create test domain config for apache virtual host e.g. var.mybluelinux.com.conf and enable it in apache configuration
  • in DocumentRoot for your apache virtual host config file create directory php
  • create in directory php file e.g. echo.php
  • copy to echo.php file this php code:
<?php
phpinfo(INFO_VARIABLES);
?>
  • enable module php in your apache configuration and reload configuration
/etc/apache2/mods-enabled]$ ln -s ../mods-enabled/php7.0.load .
/etc/apache2/mods-enabled]$ ln -s ../mods-enabled/php7.0.conf .
/etc/apache2/mods-enabled]$ systemd reload apache2.service

  • create file .htaccess in your /path-to-your-DocumentRoot-virtual-host/php/ directory (You have to enable .htaccess files in your apache virtual host config)

  • copy to .htaccess file this mod rewrite rules:

RewriteEngine On

RewriteCond %{REQUEST_URI} !echo.pl
RewriteRule .* echo.php?ua=%{HTTP_USER_AGENT}&https=%{HTTPS} [L]
  • And call from web browser any url e.g https://your_virtual_host_domain/php/dir/subdir/any-text.html

Example:

When I call from web browser url e.g. https://var.mybluelinux.com/php/dir1/subdir1/subsubdir1/my-file.php?myquestion&my-parameter=45

$_REQUEST['ua']	Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0
$_REQUEST['https']	on
$_GET['ua']	Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0
$_GET['https']	on
$_COOKIE['_ga']	GA1.2.998553010.1519138107
$_COOKIE['_gid']	GA1.2.578630594.1519138107
$_SERVER['REDIRECT_HTTPS']	on
$_SERVER['REDIRECT_SSL_TLS_SNI']	var.mybluelinux.com
$_SERVER['REDIRECT_STATUS']	200
$_SERVER['HTTPS']	on
$_SERVER['SSL_TLS_SNI']	var.mybluelinux.com
$_SERVER['HTTP_HOST']	var.mybluelinux.com
$_SERVER['HTTP_USER_AGENT']	Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0
$_SERVER['HTTP_ACCEPT']	text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
$_SERVER['HTTP_ACCEPT_LANGUAGE']	en-US,en;q=0.7,cs;q=0.3
$_SERVER['HTTP_ACCEPT_ENCODING']	gzip, deflate, br
$_SERVER['HTTP_COOKIE']	_ga=GA1.2.998553010.1519138107; _gid=GA1.2.578630594.1519138107
$_SERVER['HTTP_CONNECTION']	keep-alive
$_SERVER['HTTP_UPGRADE_INSECURE_REQUESTS']	1
$_SERVER['PATH']	/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
$_SERVER['SERVER_SIGNATURE']	<address>Apache/2.4.25 (Debian) Server at var.mybluelinux.com Port 443</address>
$_SERVER['SERVER_SOFTWARE']	Apache/2.4.25 (Debian)
$_SERVER['SERVER_NAME']	var.mybluelinux.com
$_SERVER['SERVER_ADDR']	84.244.68.54
$_SERVER['SERVER_PORT']	443
$_SERVER['REMOTE_ADDR']	212.158.133.35
$_SERVER['DOCUMENT_ROOT']	/var/www/html/var.mybluelinux.com/data
$_SERVER['REQUEST_SCHEME']	https
$_SERVER['CONTEXT_PREFIX']	no value
$_SERVER['CONTEXT_DOCUMENT_ROOT']	/var/www/html/var.mybluelinux.com/data
$_SERVER['SERVER_ADMIN']	[no address given]
$_SERVER['SCRIPT_FILENAME']	/var/www/html/var.mybluelinux.com/data/php/echo.php
$_SERVER['REMOTE_PORT']	50049
$_SERVER['REDIRECT_URL']	/php/dir1/subdir1/subsubdir1/my-file.php
$_SERVER['REDIRECT_QUERY_STRING']	ua=Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0&https=on
$_SERVER['GATEWAY_INTERFACE']	CGI/1.1
$_SERVER['SERVER_PROTOCOL']	HTTP/1.1
$_SERVER['REQUEST_METHOD']	GET
$_SERVER['QUERY_STRING']	ua=Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0&https=on
$_SERVER['REQUEST_URI']	/php/dir1/subdir1/subsubdir1/my-file.php?myquestion&my-parameter=45
$_SERVER['SCRIPT_NAME']	/php/echo.php
$_SERVER['PHP_SELF']	/php/echo.php
$_SERVER['REQUEST_TIME_FLOAT']	1519214657.127
$_SERVER['REQUEST_TIME']	1519214657

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