Alibaba Cloud DNS：Unity接入移動解析HTTPDNS SDK最佳方案

一、概述

Unity是內容創作引擎。Unity可以開發：2D/3D遊戲，2D/3D應用，VR，AR，甚至移動App，網頁前端 ，電影即時渲染等，創作者可以藉助Unity將創意變成現實。

為方便 Unity 開發人員接入使用移動解析HTTPDNS SDK，我們提供了針對Unity情境下的PdnsUnityDemo源碼供使用者參考，源碼中提供了移動解析HTTPDNS Unity外掛程式。

4.1 原理說明

本樣本展示了Unity中整合HTTPDNS的完整解決方案：

1. 跨平台統一介面：使用 AlipdnsHelper 提供統一的API介面

2. 平台特定實現：針對 iOS、Android、 SDK提供不同的底層實現

3. 自動DNS替換：在網路請求前自動將網域名稱替換為解析的IP地址

4. Host頭設定：確保HTTPS/SSL串連的SNI正確性

4.2 網路請求整合

當使用不同的網路模組發送請求時，需要相應地進行要求標頭配置等操作，下面對HttpClient、HttpWebRequest、UnityWebRequest三種類型分別給出樣本：

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解析網域名稱
	    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))
                {
                    // 關鍵：設定Host頭保證SSL/SNI正確性
                    requestMessage.Headers.Host = hostname;
                    
                    var response = await httpClient.SendAsync(requestMessage);
                    string content = await response.Content.ReadAsStringAsync();
                    
                    Debug.Log($"請求成功: {response.StatusCode}");
                }
            }
        }
        catch (Exception e)
        {
            Debug.LogError($"請求失敗: {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解析網域名稱
            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";
                // 關鍵：設定Host頭保證SSL/SNI正確性
                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($"請求成功: {response.StatusCode}");
                }
            }
        }
        catch (Exception e)
        {
            Debug.LogError($"請求失敗: {e.Message}");
        }
    }
}

4.2.3 UnityWebRequest（不推薦）

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解析網域名稱
        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))
            {
                // 關鍵：設定Host頭
                request.SetRequestHeader("Host", hostname);
                
                yield return request.SendWebRequest();
                
                if (request.result == UnityWebRequest.Result.Success)
                {
                    Debug.Log($"請求成功: {request.responseCode}");
                }
                else
                {
                    Debug.LogError($"請求失敗: {request.error}");
                }
            }
        }
    }
}