feat: IP定位服务 #7

1，实现ip-api.com、ipapi.co、ipwhois.app、ip-api.io、ipinfo.io免费版API
2，实现ipip.net、纯真库API
3，实现ipip.net、纯真离线库

Author: Cyaim

Cyaim.WebSocketServer/Cyaim.WebSocketServer/Infrastructure/AccessControl/ChunZhenGeoLocationProvider.cs

@@ -0,0 +1,138 @@
+using System;
+using System.Net.Http;
+using System.Text.Json;
+using System.Threading.Tasks;
+using Microsoft.Extensions.Logging;
+
+namespace Cyaim.WebSocketServer.Infrastructure.AccessControl
+{
+    /// <summary>
+    /// Geographic location provider using ChunZhen (纯真) IP database online service
+    /// 使用纯真 IP 数据库在线服务的地理位置提供者
+    /// Note: This is a placeholder implementation. Actual API may vary / 注意：这是占位符实现，实际 API 可能不同
+    /// </summary>
+    public class ChunZhenGeoLocationProvider : IGeoLocationProvider
+    {
+        private readonly ILogger<ChunZhenGeoLocationProvider> _logger;
+        private readonly HttpClient _httpClient;
+        private readonly string _apiUrl;
+
+        /// <summary>
+        /// Constructor / 构造函数
+        /// </summary>
+        /// <param name="logger">Logger instance / 日志实例</param>
+        /// <param name="httpClient">HTTP client (optional, will create if null) / HTTP 客户端（可选，如果为 null 则创建）</param>
+        /// <param name="apiUrl">API URL (if available) / API URL（如果可用）</param>
+        public ChunZhenGeoLocationProvider(
+            ILogger<ChunZhenGeoLocationProvider> logger,
+            HttpClient httpClient = null,
+            string apiUrl = null)
+        {
+            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+            _httpClient = httpClient ?? new HttpClient();
+            // Note: ChunZhen may not have a public online API, this is a placeholder
+            // 注意：纯真可能没有公开的在线 API，这是占位符
+            _apiUrl = apiUrl;
+        }
+
+        /// <summary>
+        /// Get geographic location information for an IP address / 获取 IP 地址的地理位置信息
+        /// </summary>
+        /// <param name="ipAddress">IP address / IP 地址</param>
+        /// <returns>Geographic location information or null if not found / 地理位置信息，如果未找到则返回 null</returns>
+        public async Task<GeoLocationInfo> GetLocationAsync(string ipAddress)
+        {
+            if (string.IsNullOrEmpty(ipAddress))
+            {
+                return null;
+            }
+
+            try
+            {
+                // Skip local/private IPs / 跳过本地/私有 IP
+                if (IsLocalOrPrivateIp(ipAddress))
+                {
+                    _logger.LogDebug($"IP {ipAddress} is local/private, skipping geo lookup");
+                    return null;
+                }
+
+                // Note: ChunZhen typically uses offline database (qqwry.dat)
+                // For online service, you would need to implement the actual API call here
+                // 注意：纯真通常使用离线数据库（qqwry.dat）
+                // 对于在线服务，您需要在此处实现实际的 API 调用
+
+                if (string.IsNullOrEmpty(_apiUrl))
+                {
+                    _logger.LogWarning("ChunZhen online API URL is not configured. Please use ChunZhenOfflineGeoLocationProvider instead.");
+                    return null;
+                }
+
+                var url = _apiUrl.Replace("{ip}", ipAddress);
+                var response = await _httpClient.GetStringAsync(url);
+
+                if (string.IsNullOrEmpty(response))
+                {
+                    return null;
+                }
+
+                var jsonDoc = JsonDocument.Parse(response);
+                var root = jsonDoc.RootElement;
+
+                var geoInfo = new GeoLocationInfo
+                {
+                    CountryCode = root.TryGetProperty("country_code", out var countryCode)
+                        ? countryCode.GetString()
+                        : null,
+                    CountryName = root.TryGetProperty("country", out var country)
+                        ? country.GetString()
+                        : null,
+                    RegionName = root.TryGetProperty("region", out var region)
+                        ? region.GetString()
+                        : null,
+                    CityName = root.TryGetProperty("city", out var city)
+                        ? city.GetString()
+                        : null
+                };
+
+                _logger.LogDebug($"Geo lookup for IP {ipAddress}: {geoInfo.CountryCode}/{geoInfo.CityName}");
+                return geoInfo;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex, $"Error getting geographic location for IP {ipAddress}");
+                return null;
+            }
+        }
+
+        /// <summary>
+        /// Check if IP is local or private / 检查 IP 是否为本地或私有
+        /// </summary>
+        private bool IsLocalOrPrivateIp(string ipAddress)
+        {
+            if (string.IsNullOrEmpty(ipAddress))
+                return true;
+
+            if (ipAddress == "::1" || ipAddress == "127.0.0.1" || ipAddress == "localhost")
+                return true;
+
+            if (System.Net.IPAddress.TryParse(ipAddress, out var ip))
+            {
+                // Check for private IP ranges / 检查私有 IP 范围
+                if (ip.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
+                {
+                    var bytes = ip.GetAddressBytes();
+                    // 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16
+                    if (bytes[0] == 10 ||
+                        (bytes[0] == 172 && bytes[1] >= 16 && bytes[1] <= 31) ||
+                        (bytes[0] == 192 && bytes[1] == 168))
+                    {
+                        return true;
+                    }
+                }
+            }
+
+            return false;
+        }
+    }
+}
+