feat: support querying IP information

backend/getIP.php

@@ -0,0 +1,17 @@
+<?php
+
+function getClientIp() {
+    if (!empty($_SERVER['HTTP_CLIENT_IP'])) {
+        $ip = $_SERVER['HTTP_CLIENT_IP'];
+    } elseif (!empty($_SERVER['HTTP_X_REAL_IP'])) {
+        $ip = $_SERVER['HTTP_X_REAL_IP'];
+    } elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
+        $ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
+        $ip = preg_replace('/,.*/', '', $ip);
+    } else {
+        $ip = $_SERVER['REMOTE_ADDR'];
+    }
+    return preg_replace('/^::ffff:/', '', $ip);
+}
+
+?>

backend/getInfo.php

@@ -0,0 +1,107 @@
+<?php
+
+function getIPInfo($ip, $is_cli) {
+    $specialIpInfo = getSpecialIpInfo($ip);
+    if (is_string($specialIpInfo)) {
+        $info['ip'] = $ip;
+        $info['as'] = null;
+        $info['city'] = null;
+        $info['region'] = null;
+        $info['country'] = null;
+        $info['timezone'] = null;
+        $info['loc'] = null;
+        $info['isp'] = $specialIpInfo;
+    } else {
+        $rawIspInfo = getIspInfo($ip);
+
+        $info['ip'] = $ip;
+        $info['as'] = getAS($rawIspInfo);
+        $info['city'] = $rawIspInfo['city'];
+        $info['region'] = $rawIspInfo['region'];
+        $info['country'] = get_country($rawIspInfo['country'])['en'];
+        $info['timezone'] = $rawIspInfo['timezone'];
+        $info['loc'] = $rawIspInfo['loc'];
+        $info['isp'] = getIsp($rawIspInfo);
+    }
+
+    if ($is_cli == true) {
+        $cli = "IP: ".$info['ip'].PHP_EOL;
+        $cli = $cli."AS: ".$info['as'].PHP_EOL;
+        $cli = $cli."City: ".$info['city'].PHP_EOL;
+        $cli = $cli."Region: ".$info['region'].PHP_EOL;
+        $cli = $cli."Country: ".$info['country'].PHP_EOL;
+        $cli = $cli."Timezone: ".$info['timezone'].PHP_EOL;
+        $cli = $cli."Location: ".$info['loc'].PHP_EOL;
+        $cli = $cli."ISP: ".$info['isp'].PHP_EOL;
+        return $cli;
+    }
+
+    return json_encode($info);
+}
+
+function getSpecialIpInfo($ip) {
+    if ('::1' === $ip) {
+        return 'localhost IPv6 access';
+    }
+    if (stripos($ip, 'fe80:') === 0) {
+        return 'link-local IPv6 access';
+    }
+    if (strpos($ip, '127.') === 0) {
+        return 'localhost IPv4 access';
+    }
+    if (strpos($ip, '10.') === 0) {
+        return 'private IPv4 access';
+    }
+    if (preg_match('/^172\.(1[6-9]|2\d|3[01])\./', $ip) === 1) {
+        return 'private IPv4 access';
+    }
+    if (strpos($ip, '192.168.') === 0) {
+        return 'private IPv4 access';
+    }
+    if (strpos($ip, '169.254.') === 0) {
+        return 'link-local IPv4 access';
+    }
+    return null;
+}
+
+function getIspInfo($ip) {
+    $json = file_get_contents('https://ipinfo.io/'.$ip.'/json');
+    if (!is_string($json)) {
+        return null;
+    }
+
+    $data = json_decode($json, true);
+    if (!is_array($data)) {
+        return null;
+    }
+    return $data;
+}
+
+function getIsp($rawIspInfo) {
+    if (
+        !is_array($rawIspInfo)
+        || !array_key_exists('org', $rawIspInfo)
+        || !is_string($rawIspInfo['org'])
+        || empty($rawIspInfo['org'])
+    ) {
+        return 'Unknown ISP';
+    }
+    return preg_replace('/AS\\d+\\s/', '', $rawIspInfo['org']);
+}
+
+function getAS($rawIspInfo) {
+    if (
+        !is_array($rawIspInfo)
+        || !array_key_exists('org', $rawIspInfo)
+        || !is_string($rawIspInfo['org'])
+        || empty($rawIspInfo['org'])
+    ) {
+        return 'Unknown AS';
+    }
+    if (preg_match('/AS\\d+\\s/', $rawIspInfo['org'], $as) !== 1) {
+        return 'Unknown AS';
+    }
+    return trim($as['0']);
+}
+
+?>

backend/queryInfo.php

@@ -0,0 +1,30 @@
+<?php
+
+include("getInfo.php");
+include("getIP.php");
+
+function sendHeaders() {
+    header('Content-Type: application/json; charset=utf-8');
+    header('Cache-Control: no-store, no-cache, must-revalidate, max-age=0, s-maxage=0');
+    header('Cache-Control: post-check=0, pre-check=0', false);
+    header('Pragma: no-cache');
+}
+
+$ip = $_GET['ip'];
+if ($ip) {
+    if (!filter_var($ip, \FILTER_VALIDATE_IP)) {
+        echo "Illegal IP format".PHP_EOL;
+        exit;
+    }
+} else {
+    $ip = getClientIp();
+}
+
+if ($_GET['cli'] == "true") {
+    echo getIPInfo($ip, true);
+} else {
+    sendHeaders();
+    echo getIPInfo($ip, false);
+}
+
+?>