你可以使用ipstack地理API获取访问者国家和城市。你需要获得自己的ipstack API，然后使用下面的代码:

<?php
 $ip = $_SERVER['REMOTE_ADDR']; 
 $api_key = "YOUR_API_KEY";
 $freegeoipjson = file_get_contents("http://api.ipstack.com/".$ip."?access_key=".$api_key."");
 $jsondata = json_decode($freegeoipjson);
 $countryfromip = $jsondata->country_name;
 echo "Country: ". $countryfromip ."";
?>

来源:使用ipstack API在PHP中获取访问者国家和城市

我根据“Chandra Nakka”的答案写了一个类。希望它能帮助人们，它将信息从geoplugin保存到会话中，以便在调用信息时加载得更快。它还将值保存到一个私有数组中，因此在相同的代码中调用是最快的。

class Geo {
private $_ip = null;
private $_useSession = true;
private $_sessionNameData = 'GEO_SESSION_DATA';
private $_hasError = false;
private $_geoData = [];

const PURPOSE_SUPPORT = [
    "all", "*", "location",
    "request",
    "latitude", 
    "longitude",
    "accuracy",
    "timezonde",
    "currencycode",
    "currencysymbol",
    "currencysymbolutf8",
    "country", 
    "countrycode", 
    "state", "region", 
    "city", 
    "address",
    "continent", 
    "continentcode"
];
const CONTINENTS = [
    "AF" => "Africa",
    "AN" => "Antarctica",
    "AS" => "Asia",
    "EU" => "Europe",
    "OC" => "Australia (Oceania)",
    "NA" => "North America",
    "SA" => "South America"
];

function __construct($ip = null, $deepDetect = true, $useSession = true)
{
    // define the session useage within this class
    $this->_useSession = $useSession;
    $this->_startSession();

    // define a ip as far as possible
    $this->_ip = $this->_defineIP($ip, $deepDetect);

    // check if the ip was set
    if (!$this->_ip) {
        $this->_hasError = true;
        return $this;
    }

    // define the geoData
    $this->_geoData = $this->_fetchGeoData();

    return $this;
}

function get($purpose)
{
    // making sure its lowercase
    $purpose = strtolower($purpose);

    // makeing sure there are no error and the geodata is not empty
    if ($this->_hasError || !count($this->_geoData) && !in_array($purpose, self::PURPOSE_SUPPORT)) {
        return 'error';
    }

    if (in_array($purpose, ['*', 'all', 'location']))  {
        return $this->_geoData;
    }

    if ($purpose === 'state') $purpose = 'region';

    return (isset($this->_geoData[$purpose]) ? $this->_geoData[$purpose] : 'missing: '.$purpose);
}

private function _fetchGeoData()
{
    // check if geo data was set before
    if (count($this->_geoData)) {
        return $this->_geoData;
    }

    // check possible session
    if ($this->_useSession && ($sessionData = $this->_getSession($this->_sessionNameData))) {
        return $sessionData;
    }

    // making sure we have a valid ip
    if (!$this->_ip || $this->_ip === '127.0.0.1') {
        return [];
    }

    // fetch the information from geoplusing
    $ipdata = @json_decode($this->curl("http://www.geoplugin.net/json.gp?ip=" . $this->_ip));

    // check if the data was fetched
    if (!@strlen(trim($ipdata->geoplugin_countryCode)) === 2) {
        return [];
    }

    // make a address array
    $address = [$ipdata->geoplugin_countryName];
    if (@strlen($ipdata->geoplugin_regionName) >= 1)
        $address[] = $ipdata->geoplugin_regionName;
    if (@strlen($ipdata->geoplugin_city) >= 1)
        $address[] = $ipdata->geoplugin_city;

    // makeing sure the continentCode is upper case
    $continentCode = strtoupper(@$ipdata->geoplugin_continentCode);

    $geoData = [
        'request' => @$ipdata->geoplugin_request,
        'latitude' => @$ipdata->geoplugin_latitude,
        'longitude' => @$ipdata->geoplugin_longitude,
        'accuracy' => @$ipdata->geoplugin_locationAccuracyRadius,
        'timezonde' => @$ipdata->geoplugin_timezone,
        'currencycode' => @$ipdata->geoplugin_currencyCode,
        'currencysymbol' => @$ipdata->geoplugin_currencySymbol,
        'currencysymbolutf8' => @$ipdata->geoplugin_currencySymbol_UTF8,
        'city' => @$ipdata->geoplugin_city,
        'region' => @$ipdata->geoplugin_regionName,
        'country' => @$ipdata->geoplugin_countryName,
        'countrycode' => @$ipdata->geoplugin_countryCode,
        'continent' => self::CONTINENTS[$continentCode],
        'continentcode' => $continentCode,
        'address' => implode(", ", array_reverse($address))
    ];

    if ($this->_useSession) {
        $this->_setSession($this->_sessionNameData, $geoData);
    }

    return $geoData;
}

private function _startSession()
{
    // only start a new session when the status is 'none' and the class
    // requires a session
    if ($this->_useSession && session_status() === PHP_SESSION_NONE) {
        session_start();
    }
}

private function _defineIP($ip, $deepDetect)
{
    // check if the ip was set before
    if ($this->_ip) {
        return $this->_ip;
    }

    // check if the ip given is valid
    if (filter_var($ip, FILTER_VALIDATE_IP)) {
        return $ip;
    }

    // try to get the ip from the REMOTE_ADDR
    $ip = filter_input(INPUT_SERVER, 'REMOTE_ADDR', FILTER_VALIDATE_IP);

    // check if we need to end the search for a IP if the REMOTE_ADDR did not
    // return a valid and the deepDetect is false
    if (!$deepDetect) {
        return $ip;
    }

    // try to get the ip from HTTP_X_FORWARDED_FOR
    if (($ip = filter_input(INPUT_SERVER, 'HTTP_X_FORWARDED_FOR', FILTER_VALIDATE_IP))) {
        return $ip;
    }

    // try to get the ip from the HTTP_CLIENT_IP
    if (($ip = filter_input(INPUT_SERVER, 'HTTP_CLIENT_IP', FILTER_VALIDATE_IP))) {
        return $ip;
    }

    return $ip;
}

private function _hasSession($key, $filter = FILTER_DEFAULT) 
{
    return (isset($_SESSION[$key]) ? (bool)filter_var($_SESSION[$key], $filter) : false);
}

private function _getSession($key, $filter = FILTER_DEFAULT)
{
    if ($this->_hasSession($key, $filter)) {
        $value = filter_var($_SESSION[$key], $filter);

        if (@json_decode($value)) {
            return json_decode($value, true);
        }

        return filter_var($_SESSION[$key], $filter);
    } else {
        return false;
    }
}

private function _setSession($key, $value) 
{
    if (is_array($value)) {
        $value = json_encode($value);
    }

    $_SESSION[$key] = $value;
}

function emptySession($key) {
    if (!$this->_hasSession($key)) {
        return;
    }

    $_SESSION[$key] = null;
    unset($_SESSION[$key]);

}

function curl($url) 
{
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    $output = curl_exec($ch);
    curl_close($ch);
    return $output;
}
}

用这个你可以调用的类来回答“op”问题

$country = (new \Geo())->get('country'); // United Kingdom

其他可用的属性是:

$geo = new \Geo('185.35.50.4');
var_dump($geo->get('*')); // allias all / location
var_dump($geo->get('country'));
var_dump($geo->get('countrycode'));
var_dump($geo->get('state')); // allias region
var_dump($geo->get('city')); 
var_dump($geo->get('address')); 
var_dump($geo->get('continent')); 
var_dump($geo->get('continentcode'));   
var_dump($geo->get('request'));
var_dump($geo->get('latitude'));
var_dump($geo->get('longitude'));
var_dump($geo->get('accuracy'));
var_dump($geo->get('timezonde'));
var_dump($geo->get('currencyCode'));
var_dump($geo->get('currencySymbol'));
var_dump($geo->get('currencySymbolUTF8'));

返回

array(15) {
  ["request"]=>
  string(11) "185.35.50.4"
  ["latitude"]=>
  string(7) "51.4439"
  ["longitude"]=>
  string(7) "-0.1854"
  ["accuracy"]=>
  string(2) "50"
  ["timezonde"]=>
  string(13) "Europe/London"
  ["currencycode"]=>
  string(3) "GBP"
  ["currencysymbol"]=>
  string(2) "£"
  ["currencysymbolutf8"]=>
  string(2) "£"
  ["city"]=>
  string(10) "Wandsworth"
  ["region"]=>
  string(10) "Wandsworth"
  ["country"]=>
  string(14) "United Kingdom"
  ["countrycode"]=>
  string(2) "GB"
  ["continent"]=>
  string(6) "Europe"
  ["continentcode"]=>
  string(2) "EU"
  ["address"]=>
  string(38) "Wandsworth, Wandsworth, United Kingdom"
}
string(14) "United Kingdom"
string(2) "GB"
string(10) "Wandsworth"
string(10) "Wandsworth"
string(38) "Wandsworth, Wandsworth, United Kingdom"
string(6) "Europe"
string(2) "EU"
string(11) "185.35.50.4"
string(7) "51.4439"
string(7) "-0.1854"
string(2) "50"
string(13) "Europe/London"
string(3) "GBP"
string(2) "£"
string(2) "£"

我尝试了Chandra的答案，但我的服务器配置不允许file_get_contents()

PHP警告:file_get_contents() URL文件访问在服务器配置中被禁用

我修改了Chandra的代码，使它也适用于使用cURL的服务器:

function ip_visitor_country()
{

    $client  = @$_SERVER['HTTP_CLIENT_IP'];
    $forward = @$_SERVER['HTTP_X_FORWARDED_FOR'];
    $remote  = $_SERVER['REMOTE_ADDR'];
    $country  = "Unknown";

    if(filter_var($client, FILTER_VALIDATE_IP))
    {
        $ip = $client;
    }
    elseif(filter_var($forward, FILTER_VALIDATE_IP))
    {
        $ip = $forward;
    }
    else
    {
        $ip = $remote;
    }
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, "http://www.geoplugin.net/json.gp?ip=".$ip);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
    $ip_data_in = curl_exec($ch); // string
    curl_close($ch);

    $ip_data = json_decode($ip_data_in,true);
    $ip_data = str_replace('"', '"', $ip_data); // for PHP 5.2 see stackoverflow.com/questions/3110487/

    if($ip_data && $ip_data['geoplugin_countryName'] != null) {
        $country = $ip_data['geoplugin_countryName'];
    }

    return 'IP: '.$ip.' # Country: '.$country;
}

echo ip_visitor_country(); // output Coutry name

?>

希望能有所帮助;-)

截至2022年，MaxMind国家数据库可如下使用:

<?php
require_once 'vendor/autoload.php';
use MaxMind\Db\Reader;
$databaseFile = 'GeoIP2-Country.mmdb';
$reader = new Reader($databaseFile);
$cc = $reader->get($_SERVER['REMOTE_ADDR'])['country']['iso_code'] # US/GB...
$reader->close();

来源: https://github.com/maxmind/MaxMind-DB-Reader-php

你可以使用http://ipinfo.io/获取ip地址的详细信息。

<?php
    function ip_details($ip)
    {
    $json = file_get_contents("http://ipinfo.io/{$ip}");
    $details = json_decode($json);
    return $details;
    }

    $details = ip_details(YoUR IP ADDRESS); 

    echo $details->city;
    echo "<br>".$details->country; 
    echo "<br>".$details->org; 
    echo "<br>".$details->hostname; /

    ?>

使用以下服务

1) http://api.hostip.info/get_html.php?ip=12.215.42.19

2)

$json = file_get_contents('http://freegeoip.appspot.com/json/66.102.13.106');
$expression = json_decode($json);
print_r($expression);

3) http://ipinfodb.com/ip_location_api.php