src/IpAddress.php
protected function normalizeProxyHeader( $header )
    {
        $header = strtoupper( $header );
        $header = str_replace( '-', '_', $header );
        if ( 0 !== strpos( $header, 'HTTP_' ) )
        {
            $header = 'HTTP_' . $header;
        }
        return $header;
    }
protected function normalizeProxyHeader( $header )
    {
        $header = strtoupper( $header );
        $header = str_replace( '-', '_', $header );
        if ( 0 !== strpos( $header, 'HTTP_' ) )
        {
            $header = 'HTTP_' . $header;
        }
        return $header;
    }
protected function normalizeProxyHeader ( $ header ) { $ header = strtoupper ( $ header ) ; $ header = str_replace ( '-' , '_' , $ header ) ; if ( 0 !== strpos ( $ header , 'HTTP_' ) ) { $ header = 'HTTP_' . $ header ; } return $ header ; }
Normalize a header string

Normalizes a header string to a format that is compatible with
$_SERVER

@param  string $header
@return string
Normalize a header string