Unity接入移动解析HTTPDNS SDK最佳方案

一、概述

Unity是内容创作引擎。Unity可以开发：2D/3D游戏，2D/3D应用，VR，AR，甚至移动App，网页前端 ，电影实时渲染等，创作者可以借助Unity将创意变成现实。

为方便 Unity 开发者接入使用移动解析HTTPDNS SDK，我们提供了针对Unity场景下的PdnsUnityDemo源码供用户参考，源码中提供了移动解析HTTPDNS Unity插件。

4.1 原理说明

本示例展示了Unity中集成HTTPDNS的完整解决方案：

1. 跨平台统一接口：使用 AlipdnsHelper 提供统一的API接口

2. 平台特定实现：针对 iOS、Android、 SDK提供不同的底层实现

3. 自动DNS替换：在网络请求前自动将域名替换为解析的IP地址

4. Host头设置：确保HTTPS/SSL连接的SNI正确性

4.2 网络请求集成

当使用不同的网络模块发送请求时，需要相应地进行请求头配置等操作，下面对HttpClient、HttpWebRequest、UnityWebRequest三种类型分别给出示例：

4.2.1 HttpClient

using System;
using System.Net.Http;
using UnityEngine;

public class AlipdnsHttpClient : MonoBehaviour
{
    private static readonly HttpClient httpClient = new HttpClient();
    
    public async void MakeRequest(string url)
    {
        try
        {
            var uri = new Uri(url);
            string hostname = uri.Host;
            
            // 使用HTTPDNS解析域名
	    var result = AlipdnsHelper.getIpsByCacheWithDomain(host, true);
            if (result != null && result.Count > 0)
            {
                string resolvedIP = result[0];
                string newUrl = url.Replace(hostname, resolvedIP);
                
                using (var requestMessage = new HttpRequestMessage(HttpMethod.Get, newUrl))
                {
                    // 关键：设置Host头保证SSL/SNI正确性
                    requestMessage.Headers.Host = hostname;
                    
                    var response = await httpClient.SendAsync(requestMessage);
                    string content = await response.Content.ReadAsStringAsync();
                    
                    Debug.Log($"请求成功: {response.StatusCode}");
                }
            }
        }
        catch (Exception e)
        {
            Debug.LogError($"请求失败: {e.Message}");
        }
    }
}

4.2.2 HttpWebRequest

using System;
using System.IO;
using System.Net;
using UnityEngine;

public class AlipdnsWebRequest : MonoBehaviour
{
    public void MakeRequest(string url)
    {
        try
        {
            var uri = new Uri(url);
            string hostname = uri.Host;
            
            // 使用HTTPDNS解析域名
            var result = AlipdnsHelper.getIpsByCacheWithDomain(host, true);
            if (result != null && result.Count > 0)
            {
                string resolvedIP = result[0];
                string newUrl = url.Replace(hostname, resolvedIP);
                
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(newUrl);
                request.Method = "GET";
                // 关键：设置Host头保证SSL/SNI正确性
                request.Host = hostname;
                
                using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
                using (Stream stream = response.GetResponseStream())
                using (StreamReader reader = new StreamReader(stream))
                {
                    string content = reader.ReadToEnd();
                    Debug.Log($"请求成功: {response.StatusCode}");
                }
            }
        }
        catch (Exception e)
        {
            Debug.LogError($"请求失败: {e.Message}");
        }
    }
}

4.2.3 UnityWebRequest（不推荐）

using System;
using System.Collections;
using UnityEngine;
using UnityEngine.Networking;

public class AlipdnsUnityWebRequest : MonoBehaviour
{
    public IEnumerator MakeRequest(string url)
    {
        var uri = new Uri(url);
        string hostname = uri.Host;
        
        // 使用HTTPDNS解析域名
        var result = AlipdnsHelper.getIpsByCacheWithDomain(host, true);
        if (result != null && result.Count > 0)
        {
            string resolvedIP = result[0];
            string newUrl = url.Replace(hostname, resolvedIP);
            
            using (UnityWebRequest request = UnityWebRequest.Get(newUrl))
            {
                // 关键：设置Host头
                request.SetRequestHeader("Host", hostname);
                
                yield return request.SendWebRequest();
                
                if (request.result == UnityWebRequest.Result.Success)
                {
                    Debug.Log($"请求成功: {request.responseCode}");
                }
                else
                {
                    Debug.LogError($"请求失败: {request.error}");
                }
            }
        }
    }
}