feat(http): 添加HTTP重定向和表单处理功能- 新增main8函数处理HTTP重定向请求

- 新增main9函数自定义重定向逻辑并打印请求链
- 新增main10函数实现multipart表单数据发送- 添加server_forms.go文件处理multipart表单解析
- 添加server_redirects.go文件处理重定向路由
- 引入bytes和mime/multipart包支持表单数据构造
- 在main函数中调用新增的三个测试函数

25-httpclient/httpclient/main.go

@@ -1,8 +1,10 @@
 package main
 
 import (
+	"bytes"
 	"encoding/json"
 	"io"
+	"mime/multipart"
 	"net/http"
 	"net/http/cookiejar"
 	"net/url"
@@ -20,6 +22,9 @@ func main() {
 	main5()
 	main6()
 	main7()
+	main8()
+	main9()
+	main10()
 }
 
 func mainInit() {
@@ -206,3 +211,109 @@ func main7() {
 		}
 	}
 }
+
+func main8() {
+	Printfln("\n\nmain8:")
+
+	req, err := http.NewRequest(http.MethodGet, "http://localhost:5000/redirect1", nil)
+	if err != nil {
+		Printfln("Request Init Error: %v", err.Error())
+		return
+	}
+	response, err := http.DefaultClient.Do(req)
+	if err != nil {
+		Printfln("Response Error: %v", err.Error())
+		return
+	}
+	defer response.Body.Close()
+	if response.StatusCode != http.StatusOK {
+		Printfln("Status Code: %v", response.StatusCode)
+		return
+	}
+	io.Copy(os.Stdout, response.Body)
+}
+
+func main9() {
+	Printfln("\n\nmain9:")
+	defer func() {
+		http.DefaultClient.CheckRedirect = nil
+	}()
+	http.DefaultClient.CheckRedirect = func(req *http.Request, previous []*http.Request) error {
+		if len(previous) == 3 {
+			for _, r := range previous {
+				Printfln("Previous Request: %v", r.URL.String())
+			}
+			Printfln("Now Request: %v", req.URL.String())
+			u, _ := url.Parse("http://localhost:5000/html")
+			req.URL = u
+		}
+		return nil
+	}
+	req, err := http.NewRequest(http.MethodGet, "http://localhost:5000/redirect1", nil)
+	if err != nil {
+		Printfln("Request Init Error: %v", err.Error())
+		return
+	}
+	response, err := http.DefaultClient.Do(req)
+	if err != nil {
+		Printfln("Response Error: %v", err.Error())
+		return
+	}
+	defer response.Body.Close()
+	if response.StatusCode != http.StatusOK {
+		Printfln("Status Code: %v", response.StatusCode)
+		return
+	}
+	io.Copy(os.Stdout, response.Body)
+}
+
+func main10() {
+	Printfln("\n\nmain10:")
+
+	var buffer bytes.Buffer
+	formWriter := multipart.NewWriter(&buffer)
+	fieldWriter, err := formWriter.CreateFormField("name")
+	if err == nil {
+		io.WriteString(fieldWriter, "Yanzuoguang")
+	}
+	fieldWriter, err = formWriter.CreateFormField("city")
+	if err == nil {
+		io.WriteString(fieldWriter, "重庆")
+		io.WriteString(fieldWriter, "渝北区")
+	}
+	fieldWriter, err = formWriter.CreateFormField("city")
+	if err == nil {
+		io.WriteString(fieldWriter, "上海")
+	}
+	fileWriter, err := formWriter.CreateFormFile("file", "printer.go")
+	if err == nil {
+		file, err := os.Open("printer.go")
+		if err == nil {
+			defer file.Close()
+			io.Copy(fileWriter, file)
+		}
+	}
+	fileWriter, err = formWriter.CreateFormFile("file", "go.mod")
+	if err == nil {
+		file, err := os.Open("go.mod")
+		if err == nil {
+			defer file.Close()
+			io.Copy(fileWriter, file)
+		}
+	}
+	formWriter.Close()
+
+	req, err := http.NewRequest(http.MethodPost, "http://localhost:5000/form", &buffer)
+	if err == nil {
+		req.Header.Add("Content-Type", formWriter.FormDataContentType())
+		response, err := http.DefaultClient.Do(req)
+		if err == nil {
+			io.Copy(os.Stdout, response.Body)
+		} else {
+			Printfln("Response Error: %v", err.Error())
+		}
+	} else {
+		Printfln("Request Init Error: %v", err.Error())
+	}
+
+}

25-httpclient/httpclient/server_forms.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+)
+
+func init() {
+	http.HandleFunc("/form", func(writer http.ResponseWriter, request *http.Request) {
+		err := request.ParseMultipartForm(10 * 60 * 1000)
+		if err != nil {
+			http.Error(writer, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		for key, values := range request.MultipartForm.Value {
+			Printfln("Field: %v : %v", key, values)
+		}
+		for name, files := range request.MultipartForm.File {
+			for _, file := range files {
+				fmt.Fprintf(writer, "File  %v : %v \n", name, file.Filename)
+				if f, err := file.Open(); err == nil {
+					defer f.Close()
+					io.Copy(writer, f)
+				}
+			}
+		}
+	})
+}

25-httpclient/httpclient/server_redirects.go

@@ -0,0 +1,12 @@
+package main
+
+import "net/http"
+
+func init() {
+	http.HandleFunc("/redirect1", func(writer http.ResponseWriter, request *http.Request) {
+		http.Redirect(writer, request, "/redirect2", http.StatusTemporaryRedirect)
+	})
+	http.HandleFunc("/redirect2", func(writer http.ResponseWriter, request *http.Request) {
+		http.Redirect(writer, request, "/redirect1", http.StatusTemporaryRedirect)
+	})
+}