Unity C# 之 使用 HttpWebRequest 基础知识/HttpWebRequest 进行异步Post 网络访问/数据流形式获取数据(Task/async/await)的代码简单实现

Unity C# 之使用 HttpWebRequest 基础知识/HttpWebRequest 进行异步Post 网络访问/数据流形式获取数据(Task/async/await)的代码简单实现

一、简单介绍

二、实现原理

三、注意事项

四、效果预览

五、关键代码

附录： HttpWebRequest 的一些基础知识

1、HttpWebRequest 常用属性

2、HttpWebRequest 中的 ContentType

3、HttpWebRequest 一般使用示例

4、HttpWebRequest json 文本 Post 请求示例

5、 HttpWebRequest multipart/form-data 文件上传示例

一、简单介绍

Unity 在开发中，网络访问：

可以使用 UnityWebRequest 访问，不过好似只能用协程的方式，并且访问只能在主线程中；

所以这里使用 C# 中的 HttpWebRequest，进行网络访问，而且 HttpWebRequest，允许在子线程中访问，在一些情况下可以大大减少主线程的网络访问压力；

这里使用 HttpWebRequest ，进行 Post 访问，并且Task 结合 async （await）的进行异步访问，最后使用 Stream 流式的形式获取数据，在这里做一个简单的记录，以便后期使用的时候参考。

二、实现原理

1、HttpWebRequest 创建 post 的请求

2、GetRequestStreamAsync 发起异步请求

3、GetResponseAsync 和 GetResponseStream 异步获取响应数据流

4、因为使用到异步，所以 async Task 返回异步获取的流数据

三、注意事项

1、获取更新的流数据打印是，注意每次更新下 buffer ，不然输出打印的结果可能不是预期的

    // 循环获取流式数据
    while ((bytesRead = await reader.ReadAsync(buffer, 0, buffer.Length)) > 0)
    {
         sb.Append(buffer, 0, bytesRead);
         Console.WriteLine(buffer);
         buffer = new char[1024];
     }

四、效果预览

五、关键代码

using System;
using System.Net;
using System.Text;
namespace TestHttpWebRequestPostStream
{
    internal class Program
    {
        static string m_Authorization = "Your_Authorization";
        static int TIMEOUT_TIME = 10000; // 超时时间
        static async Task Main(string[] args)
        {
            string url = "Your_STREAM_URL";
            string postData = "Your_POST_DATA";
            
            string content = await PostRequestStreamToStringAsync(url, postData);
            Console.WriteLine("Response content:");
            Console.WriteLine(content);
        }
        static async Task PostRequestStreamToStringAsync(string url, string postData)
        {
            try
            {
                HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
                request.ReadWriteTimeout = TIMEOUT_TIME;
                request.Timeout = TIMEOUT_TIME;
                request.Method = "POST";
                request.ContentType = "application/json"; // 根据需要设定
                request.Headers.Add("user-token", "xxxxxxxx");    // 根据需要设定
                request.Headers.Add("xxxx-authorization", m_Authorization); // 根据需要设定
                //流式发起请求
                using (Stream requestStream = await request.GetRequestStreamAsync())
                {
                    byte[] dataBytes = Encoding.UTF8.GetBytes(postData);
                    await requestStream.WriteAsync(dataBytes, 0, dataBytes.Length);
                }
                // 流式获取数据响应
                using (HttpWebResponse response = (HttpWebResponse)await request.GetResponseAsync())
                using (Stream responseStream = response.GetResponseStream())
                using (StreamReader reader = new StreamReader(responseStream))
                {
                    StringBuilder sb = new StringBuilder();
                    char[] buffer = new char[1024];
                    int bytesRead;
                    // 循环获取流式数据
                    while ((bytesRead = await reader.ReadAsync(buffer, 0, buffer.Length)) > 0)
                    {
                        sb.Append(buffer, 0, bytesRead);
                        Console.WriteLine(buffer);
                        buffer = new char[1024];
                    }
                    return sb.ToString();
                }
            }
            catch (Exception e)
            {
                return e.Message;
            }
            
        }
    }
}

附录： HttpWebRequest 的一些基础知识

1、HttpWebRequest 常用属性

AllowAutoRedirect：获取或设置一个值，该值指示请求是否应跟随重定向响应。
CookieContainer：获取或设置与此请求关联的cookie。
Credentials：获取或设置请求的身份验证信息。
KeepAlive：获取或设置一个值，该值指示是否与 Internet 资源建立持久性连接。
MaximumAutomaticRedirections：获取或设置请求将跟随的重定向的最大数目。
Proxy：获取或设置请求的代理信息。
SendChunked：获取或设置一个值，该值指示是否将数据分段发送到 Internet 资源。
Timeout：获取或设置请求的超时值。
UserAgent：获取或设置 User-agent HTTP 标头的值
ContentType：Http内容类型

Headers：指定组成 HTTP 标头的名称/值对的集合。

2、HttpWebRequest 中的 ContentType

普通文本: “text/plain”
JSON字符串: “application/json”
数据流类型(文件流): “application/octet-stream”
表单数据(键值对): “application/x-www-form-urlencoded”

多分部数据: “multipart/form-data”

3、HttpWebRequest 一般使用示例

//创建HttpWeb请求
HttpWebRequest request = (HttpWebRequest)WebRequest.Create (url);
//创建HttpWeb相应
HttpWebResponse response = (HttpWebResponse)request.GetResponse ();
Console.WriteLine ("Content length is {0}", response.ContentLength);
Console.WriteLine ("Content type is {0}", response.ContentType);
//获取response的流
Stream receiveStream = response.GetResponseStream ();
//使用streamReader读取流数据
StreamReader readStream = new StreamReader (receiveStream, Encoding.UTF8);
Console.WriteLine ("Response stream received.");
Console.WriteLine (readStream.ReadToEnd ());
response.Close ();
readStream.Close ();

4、HttpWebRequest json 文本 Post 请求示例

使用application/json作为请求头，用来告诉服务端消息主体是序列化的JSON字符串。

/*
*  url:POST请求地址
*  postData:json格式的请求报文,例如：{"key1":"value1","key2":"value2"}
*/
public static string PostUrl(string url, string postData)
{
    HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
    req.Method = "POST";
    req.TimeOut = "800";//设置请求超时时间，单位为毫秒
    req.ContentType = "application/json";
    byte[] data = Encoding.UTF8.GetBytes(postData);
    req.ContentLength = data.Length;
    using (Stream reqStream = req.GetRequestStream())
    {
        reqStream.Write(data, 0, data.Length);
        reqStream.Close();
    }
    HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
    Stream stream = resp.GetResponseStream();
    //获取响应内容
    string result = "";
    using (StreamReader reader = new StreamReader(stream, Encoding.UTF8))
    {
        result = reader.ReadToEnd();
    }
    return result;
}

5、 HttpWebRequest multipart/form-data 文件上传示例

使用multipart/form-data作为请求头，用来告诉服务器消息主体是多发文件格式

multipart/form-data格式使用一长串字符作为boundtry封装线对字段进行分割。这也很符合multipart多个部分的语义，包含了多个部分集，每一部分都包含了一个content-desposition头，其值为form-data,以及一个name属性，其值为表单的字段名，文件输入框还可以使用filename参数指定文件名。content-type非必须属性，其值会根据文件类型进行变化，默认值是text/plain。multipart的每一个part上方是边界线，最后一个part的下方添加一个边界线。

/// 
/// 上传文件请求
/// 
/// Url
/// 文件路径
/// 表单数据（字典格式）
/// 上传回调
public static void UploadRequest(string url, string filePath, Dictionary formDatas, Action callback)
{
    // 时间戳，用做boundary
    string timeStamp = DateTime.Now.Ticks.ToString("x");
    //根据uri创建HttpWebRequest对象
    HttpWebRequest httpReq = (HttpWebRequest) WebRequest.Create(new Uri(url));
    httpReq.Method = "POST";
    httpReq.AllowWriteStreamBuffering = false; //对发送的数据不使用缓存
    httpReq.Timeout = 300000; //设置获得响应的超时时间（300秒）
    httpReq.ContentType = "multipart/form-data; boundary=" + timeStamp;
    //读取file文件
    FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
    BinaryReader binaryReader = new BinaryReader(fileStream);
    
    //表单信息
    string boundary = "--" + timeStamp;
    string form = "";
    string formFormat = boundary + "\r\nContent-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}\r\n";
    string formEnd = boundary + "\r\nContent-Disposition: form-data; name=\"{0}\"; filename=\"{1}\";\r\nContent-Type:application/octet-stream\r\n\r\n";
    foreach (var pair in formDatas)
    {
        form += string.Format(formFormat, pair.Key, pair.Value);
    }
    form += string.Format(formEnd,"file", Path.GetFileName(filePath));
    byte[] postHeaderBytes = Encoding.UTF8.GetBytes(form);
    //结束边界
    byte[] boundaryBytes = Encoding.ASCII.GetBytes("\r\n--" + timeStamp + "--\r\n");
    long length = fileStream.Length + postHeaderBytes.Length + boundaryBytes.Length;
    httpReq.ContentLength = length; //请求内容长度
    try
    {
        //每次上传4k
        int bufferLength = 4096;
        byte[] buffer = new byte[bufferLength];
        //已上传的字节数
        long offset = 0;
        int size = binaryReader.Read(buffer, 0, bufferLength);
        Stream postStream = httpReq.GetRequestStream();
        //发送请求头部消息
        postStream.Write(postHeaderBytes, 0, postHeaderBytes.Length);
        while (size > 0)
        {
            postStream.Write(buffer, 0, size);
            offset += size;
            size = binaryReader.Read(buffer, 0, bufferLength);
        }
        //添加尾部边界
        postStream.Write(boundaryBytes, 0, boundaryBytes.Length);
        postStream.Close();
        //获取服务器端的响应
        using (HttpWebResponse response = (HttpWebResponse) httpReq.GetResponse())
        {
            Stream receiveStream = response.GetResponseStream();
            StreamReader readStream = new StreamReader(receiveStream, Encoding.UTF8);
            string returnValue = readStream.ReadToEnd();
            Debug.Log("upload result:"+returnValue);
            callback?.Invoke(returnValue);
            
            response.Close();
            readStream.Close();
        }
    }
    catch (Exception ex)
    {
        Debug.Log("文件传输异常： " + ex.Message);
    }
    finally
    {
        fileStream.Close();
        binaryReader.Close();
    }
}

Unity 上的简单的异步封装使用

1、HttpWebRequest 异步 Post 获取数据

using System;
using System.IO;
using System.Net;
using System.Text;
using System.Threading.Tasks;
using UnityEngine;
public class GptNormalWrapper : Singleton, IGptHttpWebRequestWrapper
{
    const string GPT_URL = "Your_URL";
    const string AUTHORIZATION = "Your_AUTHORIZATION";
    const string USER_TOKEN = "123456";
    const int TIMEOUT_TIME = 10000; // 超时时间
    public string GptUrl => GPT_URL;
    public async Task PostRequestToStringAsync(string postData) {
        return await PostRequestToStringAsync(GptUrl, postData);
    }
    public async Task PostRequestToStringAsync(string url, string postData)
    {
        try
        {
            HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
            request.ReadWriteTimeout = TIMEOUT_TIME;
            request.Timeout = TIMEOUT_TIME;
            request.Method = "POST";
            request.ContentType = "application/json";
            request.Headers.Add("user-token", USER_TOKEN);
            request.Headers.Add("xxx-authorization", AUTHORIZATION);
            Debug.Log("[GptNormalWrapper] PostRequestToStringAsync msg = " + postData);
            byte[] jsonBytes = Encoding.UTF8.GetBytes(postData);
            request.ContentLength = jsonBytes.Length;
            Stream strStream = request.GetRequestStream();
            strStream.Write(jsonBytes, 0, jsonBytes.Length);
            strStream.Close();
            HttpWebResponse respone = (HttpWebResponse)await request.GetResponseAsync();
            Stream ns = respone.GetResponseStream();
            string responseContent = new StreamReader(ns, Encoding.UTF8).ReadToEnd();
            Debug.Log("[GptNormalWrapper] PostRequestToStringAsync 消息返回:" + responseContent);
            MessageBack textback = JsonUtility.FromJson(responseContent);
            Debug.Log($"[GptNormalWrapper] PostRequestToStringAsync answer content {textback.data.choices[0].message.content} ");
            return new(textback.data.choices[0].message.content);
        }
        catch (Exception e)
        {
            Debug.LogError("[GptNormalWrapper] PostRequestToStringAsync error:" + e);
        }
        return new(GptChatCommonStringDefine.GPT_REQUEST_SERVER_FAILED);
    }
}

2、HttpWebRequest 异步 Post 流式的获取数据

using System.Net;
using System.Threading.Tasks;
using System.Text;
using System.IO;
using UnityEngine;
using System;
public class GptStreamWrapper : Singleton, IGptHttpWebRequestWrapper
{
    const string GPT_URL = "Your_URL";
    const string AUTHORIZATION = "Your_AUTHORIZATION";
    const string USER_TOKEN = "123456";
    const int TIMEOUT_TIME = 10000; // 超时时间
    public string GptUrl { get; } = GPT_URL;
    public async Task PostRequestToStringAsync(string postData) {
        return await PostRequestToStringAsync(GptUrl, postData);
    }
    public async Task PostRequestToStringAsync(string url, string postData)
    {
        try
        {
            HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
            request.ReadWriteTimeout = TIMEOUT_TIME;
            request.Timeout = TIMEOUT_TIME;
            request.Method = "POST";
            request.ContentType = "application/json";
            request.Headers.Add("user-token", USER_TOKEN);
            request.Headers.Add("xxx-authorization", AUTHORIZATION);
            //流式发起请求
            using (Stream requestStream = await request.GetRequestStreamAsync())
            {
                Debug.Log("[GptStreamWrapper] PostRequestStreamToStringAsync postData : " + postData);
                byte[] dataBytes = Encoding.UTF8.GetBytes(postData);
                await requestStream.WriteAsync(dataBytes, 0, dataBytes.Length);
            }
            // 流式获取数据响应
            using (HttpWebResponse response = (HttpWebResponse)await request.GetResponseAsync())
            using (Stream responseStream = response.GetResponseStream())
            using (StreamReader reader = new StreamReader(responseStream))
            {
                StringBuilder sb = new StringBuilder();
                char[] buffer = new char[1024];
                int bytesRead;
                // 循环获取流式数据
                while ((bytesRead = await reader.ReadAsync(buffer, 0, buffer.Length)) > 0)
                {
                    sb.Append(buffer, 0, bytesRead);
                    Debug.Log("[GptStreamWrapper] PostRequestStreamToStringAsync getting steam data : " + buffer);
                    buffer = new char[1024];
                }
                Debug.Log("[GptStreamWrapper] PostRequestStreamToStringAsync whole stream data : " + sb.ToString());
                return sb.ToString();
            }
        }
        catch (Exception e)
        {
            Debug.Log("[GptStreamWrapper] PostRequestStreamToStringAsync Exception Message data : " + e.Message);
            return new(GptChatCommonStringDefine.GPT_REQUEST_SERVER_FAILED);
        }
    }
}