HTTP支持跨域请求

go版本跨域请求方案：

package main

import (
	"net/http"

	"github.com/gin-gonic/gin"
)

func main() {
	router := gin.Default()
	router.Use(Cors())
	router.POST("/login", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{
			"message": "login",
		})
	})
	router.Run(":8080")
}

func Cors() gin.HandlerFunc {
	return func(c *gin.Context) {
		method := c.Request.Method
		origin := c.Request.Header.Get("Origin")
		c.Header("Access-Control-Allow-Origin", origin)
		c.Header("Access-Control-Allow-Headers", "Content-Type,AccessToken,X-CSRF-Token, Authorization, Token,X-Token,X-User-Id")
		c.Header("Access-Control-Allow-Methods", "POST, GET, OPTIONS,DELETE,PUT")
		c.Header("Access-Control-Expose-Headers", "Content-Length, Access-Control-Allow-Origin, Access-Control-Allow-Headers, Content-Type, New-Token, New-Expires-At")
		c.Header("Access-Control-Allow-Credentials", "true")

		// 放行所有OPTIONS方法
		if method == "OPTIONS" {
			c.AbortWithStatus(http.StatusNoContent)
		}
		// 处理请求
		c.Next()
	}
}

修改上述条件，通过在浏览器控制台中输入下述代码，以验证跨域问题。

var xhr = new XMLHttpRequest();
xhr.open("POST","http://localhost:8080/login",true);
xhr.setRequestHeader("Content-Type","application/json");
xhr.send("aaaaaaaaa")

修改响应的请求头，具体修改详见代码：

private void httpPostRequestHandle()
        {
            while (true)
            {
                try
                {
                    //等待请求连接,没有请求则GetContext处于阻塞状态
                    HttpListenerContext requestContext = verifyHttplisten.GetContext();
                    Thread m_threadsub = new Thread(new ParameterizedThreadStart((requestcontext) =>
                    {
                        ResponseEntity<Hashtable> result = new ResponseEntity<Hashtable>();
                        //客户端发送过来的信息
                        HttpListenerContext request = (HttpListenerContext)requestcontext;
                        //获取HTTPRequest的帮助类
                        HttpListenerHelper httppost = new HttpListenerHelper(request);
                        try
                        {
                            lock (listenLocker)
                            {
                                result.Message = "No such method";
                                switch (request.Request.HttpMethod)
                                {
                                    case "GET":
                                        if (request.Request.RawUrl == "/api/v1/idcard/last")
                                        {
                                            result.Code = 0;
                                            result.Message = "读卡成功";
                                            result.Data = cardinfo;
                                        }
                                        break;
                                }
                            }
                        }
                        catch (Exception ex)
                        {
                            result.Message = ex.Message;
                            LogHelper.CreateErrorLogTxt("verifyhttplistern", ex.Source.ToString(), ex.Message);
                        }
                        //Response  
                        request.Response.StatusCode = 200;
                        //添加如下的响应的请求头，即可解决跨域问题
                        request.Response.Headers.Add("Access-Control-Allow-Origin", "*");
                        request.Response.Headers.Add("Access-Control-Allow-Headers", "*");  
                        request.Response.Headers.Add("Access-Control-Allow-Methods", "GET,POST");
                        request.Response.ContentType = "application/json";
                        request.Response.ContentEncoding = Encoding.UTF8;
                      
                        byte[] buffer = Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(result));
                        request.Response.ContentLength64 = buffer.Length;
                        var output = request.Response.OutputStream;
                        output.Write(buffer, 0, buffer.Length);
                        output.Close();
                    }));
                    m_threadsub.IsBackground = true;
                    m_threadsub.Start(requestContext);
                }
                catch (Exception ex)
                {
                    LogHelper.CreateErrorLogTxt("httpRequestHandle", ex.Source, ex.Message);
                }
            }
        }