getenv

(PHP 4, PHP 5)

getenv — Gets the value of an environment variable

Description

string getenv ( string $varname )

Gets the value of an environment variable.

You can see a list of all the environmental variables by using phpinfo(). You can find out what many of them mean by taking a look at the » CGI specification, specifically the » page on environmental variables.

Parameters

varname: The variable name.

Return Values

Returns the value of the environment variable varname , or FALSE on an error.

Examples

Example #1 getenv() Example


<?php
// Example use of getenv()
$ip = getenv('REMOTE_ADDR');

// Or simply use a Superglobal ($_SERVER or $_ENV)
$ip = $_SERVER['REMOTE_ADDR'];
?>


A function returning the remote adress of the visiting browser could look like this:





<?php


function getIPfromXForwarded() {


    $ipString=@getenv("HTTP_X_FORWARDED_FOR");


    $addr = explode(",",$ipString);


    return $addr[sizeof($addr)-1];


}


?>





Note that some adresses are followed by a whitespace and ip2long(getIPfromXForwarded()) would not return the expected result.





Make use of trim() in your scripts, either in the function itself, or the surrounding space of the caller.





Greetings

estarapapax at gmail dot com
19-Feb-2009 06:19


This is a sample function for checking if your visitor comes from this certain country. This is especially useful for amateur webmasters who don't want to use sql databases.





Sample use of function:


<?php


if(check_coutry('http://www.domain.com/files/philippines.csv') === true)


      echo 'You are from the Philippines';


?>





Basically, you'll need CSV (or TXT) which lists the IP ranges of a certain country. Example (excerpt of the philippines.csv only):





58.69.0.0, 58.69.255.255


58.71.0.0, 58.71.127.255


61.9.0.0, 61.9.127.255


61.14.28.0, 61.14.28.63


61.14.41.136, 61.14.41.143


and so on until the end





You may obtain these CSV files in a number of websites out there. Be sure to update these CSV files regularly as these IP ranges change from time to time.





Here is the function:


<?php


function check_country($url_csv){


$curl_handle = curl_init();


curl_setopt($curl_handle, CURLOPT_URL, $url_csv);


curl_setopt($curl_handle, CURLOPT_RETURNTRANSFER, 1);


$str_fromfile = curl_exec($curl_handle);


curl_close($curl_handle);


$range = explode("\n", $str_fromfile);





$ip_addr = getenv(REMOTE_ADDR); //gets the IP of the visitor


$ip_byte = explode('.', $ip_addr);


$ip_number = (16777216 * (int) $ip_byte[0]) + (65536 * (int) $ip_byte[1]) + (256 * (int) $ip_byte[2]) + ((int) $ip_byte[3]);





for($i = 0; $range[$i] != NULL && $is_positive == NULL; $i++){ // the condition $line[$i] != NULL means that you should not put blank lines before the end of your CSV. The values should start at line 1.


    $range[$i] = rtrim(ltrim($range[$i])); //you may remove this if you are sure the CSV doesnt contain whitespaces


    $ends_addr = explode(',', $range[$i]); //for CSV (comma-separated values), comma is the separator. You may change this if your TXT uses different separator.


    $ends_addr[0] = rtrim($ends_addr[0]); //again, you may remove this if your CSV is free from whitespaces


    $ends_addr[1] = ltrim($ends_addr[1]); //yet, again


    $start_ip_byte = explode('.', $ends_addr[0]);


    $end_ip_byte = explode('.', $ends_addr[1]);


    $start_ip_number = (16777216 * (int) $start_ip_byte[0]) + (65536 * (int) $start_ip_byte[1]) + (256 * (int) $start_ip_byte[2]) + ((int) $start_ip_byte[3]);


    $end_ip_number = (16777216 * (int) $end_ip_byte[0]) + (65536 * (int) $end_ip_byte[1]) + (256 * (int) $end_ip_byte[2]) + ((int) $end_ip_byte[3]);


       


    if($ip_number >= $start_ip_number && $ip_number <= $end_ip_number)


            $is_positive = 1;


}


   


    if($is_positive == 1)


        return true;


    else


        return false;


}


?>

sam at sambarrow dot com
13-Mar-2008 02:32


SERVER_NAME is the name defined in the apache configuration.

HTTP_HOST is the host header sent by the client when using the more recent versions of the http protocol.

renko at <remove>virtual-life dot net
08-Nov-2004 03:40


The function 'getenv' does not work if your Server API is ASAPI (IIS).



So, try to don't use getenv('REMOTE_ADDR'), but $_SERVER["REMOTE_ADDR"].

kyong
04-Feb-2004 10:06


As you know, getenv('DOCUMENT_ROOT') is useful.

However, under CLI environment(I tend to do quick check

if it works or not), it doesn't work without modified php.ini

file. So I add "export DOCUMENT_ROOT=~" in my .bash_profile.

daman at SPAM_BlockERmralaska dot com
08-Sep-2002 03:37


Be careful using HTTP_X_FORWARDED_FOR in conditional statements collecting the IP address. Sometimes the user's LAN address will get forwarded, which of course is pretty worthless by itself.

alex at acid-edge dot net
23-Jul-2002 07:32


Note that some caches seem to send the client-ip header *backwards*. be careful :)

john-php at pc dot xs4all dot nl
16-Aug-2000 03:56


Note that the X-Forwarded for header might contain multiple addresses, comma separated, if the request was forwarded through multiple proxies.





Finally, note that any user can add an X-Forwarded-For header themselves. The header is only good for traceback information, never for authentication. If you use it for traceback, just log the entire X-Forwarded-For header, along with the REMOTE_ADDR.

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Last updated: Fri, 20 Nov 2009

getenv

Description

Parameters

Return Values

Examples

See Also