C# HttpWebRequest使用结合Flask作为后端进行展示-白红宇的个人博客

C# HttpWebRequest使用结合Flask作为后端进行展示

发布日期：2021-05-14 15:07:19 浏览次数：21 分类：精选文章

本文共 5665 字，大约阅读时间需要 18 分钟。

在C#中发送HTTP请求可以通过HttpWebRequest类来实现。以下是详细说明：

不带参数的GET请求

创建请求：使用HttpWebRequest.Create方法创建请求对象。

设置方法：指定HTTP方法为GET。

发送请求：调用GetResponse方法获取WebResponse对象。

读取响应内容：使用StreamReader读取响应流内容。

using System;
using System.IO;
using System.Net;
namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create("http://127.0.0.1:8001/test/");
            req.Method = "GET";
            HttpWebResponse res;
            try
            {
                res = (HttpWebResponse)req.GetResponse();
            }
            catch (WebException ex)
            {
                res = (HttpWebResponse)ex.Response;
            }
            StreamReader sr = new StreamReader(res.GetResponseStream(), Encoding.UTF8);
            string content = sr.ReadToEnd();
            Console.WriteLine(content);
        }
    }
}

带参数的GET请求

创建参数字典：用于存储GET参数。

拼接URL：将参数按格式追加到URL末尾。

处理URL编码：确保特殊字符正确编码。

发送请求并读取响应：与不带参数的GET请求类似操作。

using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
namespace http_test
{
    class Program
    {
        static void Main(string[] args)
        {
            Dictionary
   
     param = new Dictionary
    
     ();
            param.Add("source", "D:/source/target.dicm");
            param.Add("operation", "1");
            param.Add("destination", "D:/destination/target.dicm");
            
            string url = "http://127.0.0.1:5000/test2";
            string result = HttpTest.GET(url, param);
            Console.WriteLine(result);
        }
    }
    
    public class HttpTest
    {
        public static string GET(string url, Dictionary
     
       param)
        {
            if (param != null)
            {
                StringBuilder queryBuilder = new StringBuilder(url.Contains("?") ? "" : "?");
                foreach (var item in param)
                {
                    queryBuilder.Append(item.Key);
                    queryBuilder.Append("=");
                    queryBuilder.Append(System.Uri.EscapeUriComponent(item.Value));
                    queryBuilder.Append("&");
                }
                url = queryBuilder.ToString().Substring(0, queryBuilder.Length - 1);
            }
            
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = "GET";
            HttpWebResponse res;
            try
            {
                res = (HttpWebResponse)request.GetResponse();
            }
            catch (WebException ex)
            {
                res = (HttpWebResponse)ex.Response;
            }
            StreamReader sr = new StreamReader(res.GetResponseStream(), Encoding.UTF8);
            return sr.ReadToEnd();
        }
    }
}

Flask后端示例

from flask import Flask, request, url_for
from flask_restful import Api, Resource, reqparse
import base64
app = Flask(__name__)
api = Api(app)
class TestView(Resource):
    def get(self):
        return {"message": "Testing GET method"}
    
    def post(self):
        data = request.get_json()
        # Process the data
        return {"success": True}
@app.route("/file", methods=["POST"])
def fileUpload():
    file = request.files.get("file")
    if file:
        file_path = " uploaded_file.jpg "
        # Save file
        return file_path

WinForm界面

设计界面：创建用户界面，包含按钮和输入框。

引用必要命名空间：确保所有必要的类被引用。

调用HTTP方法：在按钮点击事件中调用之前编写的GET或POST方法。

显示结果：在成功获取响应后显示结果。

client.cs:

using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Windows.Forms;
namespace WFM_Test001
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create("https://www.baidu.com");
            req.Method = HttpWebRequest.Method.Get;
            HttpWebResponse res;
            try
            {
                res = (HttpWebResponse)req.GetResponse();
            }
            catch (WebException ex)
            {
                res = (HttpWebResponse)ex.Response;
            }
            StreamReader sr = new StreamReader(res.GetResponseStream(), Encoding.UTF8);
            string result = sr.ReadToEnd();
            MessageBox.Show("结果：" + result);
        }
        private void button3_Click(object sender, EventArgs e)
        {
            string url = "http://127.0.0.1:5000/test";
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = HttpWebRequest.Method.Get;
            HttpWebResponse res;
            try
            {
                res = (HttpWebResponse)request.GetResponse();
            }
            catch (WebException ex)
            {
                res = (HttpWebResponse)ex.Response;
            }
            StreamReader sr = new StreamReader(res.GetResponseStream(), Encoding.UTF8);
            string content = sr.ReadToEnd();
            MessageBox.Show("结果：" + content);
        }
        private void button2_Click(object sender, EventArgs e)
        {
            Dictionary
   
     param = new Dictionary
    
     ();
            param.Add("source", "D:/test.dcm");
            param.Add("operation", "1");
            param.Add("destination", "D:/destination/test.dcm");
            string url = "http://127.0.0.1:5000/test";
            string result = HttpTest.POST(url, "D:/1.png");
            MessageBox.Show("上传结果：" + result);
        }
    }
}

总结

通过以上代码示例，可以在C#中实现与服务器交互的各种HTTP请求。理解每个步骤的目的和实现方式，是实现自定义API或脚本化任务的关键。建议根据具体需求调整请求方式和参数，确保URL编码的正确性和异常处理的有效性。

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