通常我们与第三方交互使用的是 json,但偶尔也会遇到要求使用表单方式来提交数据,故今天我们就一起来学习下如何在 Go 中发送表单请求。
准备工作
首先我们有这样一段测试代码来接收 POST 请求,并返回其接收到的字段信息。
package main import ( "fmt" "log" "net/http" ) func urlencodedHandler(w http.ResponseWriter, r *http.Request) { err := r.ParseForm() if err != nil { log.Printf("r.ParseForm(): %v", err) return } result := "" for k, v := range r.Form { result += fmt.Sprintf("%s:%v\n", k, v) } fmt.Fprintf(w, result) } func multipartHandler(w http.ResponseWriter, r *http.Request) { err := r.ParseMultipartForm(4 * 1024 * 1024) if err != nil { log.Printf("r.ParseForm(): %v", err) return } result := "" for k, v := range r.MultipartForm.Value { result += fmt.Sprintf("%s:%v\n", k, v) } for k, v := range r.MultipartForm.File { result += fmt.Sprintf("%s:%v\n", k, v) } fmt.Fprintf(w, result) } func main() { http.HandleFunc("/urlencoded", urlencodedHandler) http.HandleFunc("/multipart", multipartHandler) log.Fatal(http.ListenAndServe(":8080", nil)) }
发送 urlencoded 请求
urlencoded 主要用于纯文本请求,代码如下:
package main import ( "fmt" "io/ioutil" "net/http" "net/url" "strings" ) func main() { payload := url.Values{} payload.Set("foo", "a") payload.Add("foo", "b") payload.Set("foo2", "c") req, err := http.NewRequest(http.MethodPost, "http://localhost:8080/urlencoded", strings.NewReader(payload.Encode())) if err != nil { return } req.Header.Add("Content-Type", "application/x-www-form-urlencoded; param=value") resp, err := http.DefaultClient.Do(req) if err != nil { return } defer resp.Body.Close() data, _ := ioutil.ReadAll(resp.Body) fmt.Println(string(data)) }
运行 go run urlencoded.go 输出结果为:
foo2:[c] foo:[a b]
发送 multipart 请求
multipart 主要用于发送文件上传的请求,代码如下:
package main import ( "bytes" "fmt" "io/ioutil" "log" "mime/multipart" "net/http" ) func main() { buf := new(bytes.Buffer) writer := multipart.NewWriter(buf) writer.WriteField("foo", "a") writer.WriteField("foo", "b") part, err := writer.CreateFormFile("tmp.png", "tmp.png") if err != nil { return } fileData := []byte("hello,world") // 此处内容可以来自本地文件读取或云存储 part.Write(fileData) if err = writer.Close(); err != nil { return } req, err := http.NewRequest(http.MethodPost, "http://localhost:8080/multipart", buf) if err != nil { return } req.Header.Add("Content-Type", writer.FormDataContentType()) resp, err := http.DefaultClient.Do(req) if err != nil { return } defer resp.Body.Close() data, _ := ioutil.ReadAll(resp.Body) fmt.Println(string(data)) }
运行 go run multipart.go 输出结果为:
foo:[a b] tmp.png:[0xc420082410]
作者:songjiayang golang 微信交流群请+微信17812796384
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