How PHP gets the city based on the IP address

This article mainly to share with you how PHP based on IP address to obtain the city, this article mainly in the form of code, I hope to help everyone.

<?phpheader (' content-type:text/html;    Charset=utf-8 '); function GetIP () {$realip = ';    $unknown = ' unknown '; if (Isset ($_server)) {if (Isset ($_server[' http_x_forwarded_for ')) &&!empty ($_server[' http_x_forwarded_for ') ]) && strcasecmp ($_server[' http_x_forwarded_for '), $unknown)) {$arr = explode (', ', $_server[' http_x_for            Warded_for ']);                foreach ($arr as $ip) {$ip = Trim ($IP);                    if ($ip! = ' Unknown ') {$realip = $ip;                Break }}}else if (Isset ($_server[' http_client_ip ') &&!empty ($_server[' http_client_ip ']) &&        STRCASECMP ($_server[' http_client_ip '), $unknown)) {$realip = $_server[' http_client_ip ']; }else if (isset ($_server[' remote_addr ") &&!empty ($_server[' remote_addr ']) && strcasecmp ($_server[')        Remote_addr '], $unknown)) {$realip = $_server[' remote_addr '); }else{$reaLip = $unknown;            }}else{if (getenv (' http_x_forwarded_for ') && strcasecmp (getenv (' http_x_forwarded_for '), $unknown)) {        $realip = getenv ("Http_x_forwarded_for"); }else if (getenv (' http_client_ip ') && strcasecmp (getenv (' http_client_ip '), $unknown)) {$realip = getenv (        "Http_client_ip"); }else if (getenv (' remote_addr ') && strcasecmp (getenv (' remote_addr '), $unknown)) {$realip = getenv ("Remot        E_addr ");        }else{$realip = $unknown; }} $realip = Preg_match ("/[\d\.") {7,15}/", $realip, $matches)?    $matches [0]: $unknown; return $realip;}    function Getiplookup ($ip = ") {if (empty ($ip)) {$ip = GetIP ();    } $res = @file_get_contents (' http://int.dpool.sina.com.cn/iplookup/iplookup.php?format=js&ip= '. $ip);    if (empty ($res)) {return false;}    $jsonMatches = Array ();    Preg_match (' #\{.+?\}# ', $res, $jsonMatches);    if (!isset ($jsonMatches [0])) {return false;} $json = Json_decode ($jsonMatches [0], true);        if (Isset ($json [' ret ']) && $json [' ret '] = = 1) {$json [' IP '] = $IP;    unset ($json [' ret ']);    }else{return false; } return $json;} $ipInfos = Getiplookup (' 123.125.114.144 '); Baidu.com IP 鍦 Board from Var_dump ($ipInfos);? >