Golang http POST form data

Go http發送表單範例。

範例環境：

• Go 1.18

範例

下面範例有兩個API，一為GET|/send，一為POST|/employee。GET|/send中會將表單內容寫至http.Request.Body後透過http.Client.Do()發送請求給POST|/employee。

url.Values實為一個map，呼叫url.Values.Encode()則將值編碼為url參數(name=John&age=33&...)。

發送表單的請求頭(Request Header)的Content-Type設為application/x-www-form-urlencoded。

main.go

package main

import (
    "fmt"
    "io/ioutil"
    "net/http"
    "net/url"
    "strings"
)

func main() {
    http.HandleFunc("/send", func(w http.ResponseWriter, r *http.Request) {
        switch r.Method {
        case http.MethodGet:
            form := url.Values{}
            form.Add("name", "John")
            form.Add("age", "33")
            form.Add("lang", "en,ch,jp")

            req, err := http.NewRequest(http.MethodPost, "http://localhost:8080/employee", strings.NewReader(form.Encode()))
            if err != nil {
                panic(err)
            }
            req.Header.Set("Content-Type", "application/x-www-form-urlencoded")

            resp, err := http.DefaultClient.Do(req)
            if err != nil {
                panic(err)
            }
            defer resp.Body.Close()
            b, err := ioutil.ReadAll(resp.Body)

            fmt.Fprint(w, string(b))
        default:
            http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
        }
    })

    http.HandleFunc("/employee", func(w http.ResponseWriter, r *http.Request) {
        switch r.Method {
        case http.MethodPost:
            r.ParseForm()
            name := r.Form.Get("name")
            age := r.Form.Get("age")
            languages := r.Form["lang"]
            fmt.Fprint(w, fmt.Sprintf("name=%v\nage=%v\nlanguages=%v", name, age, languages))
        default:
            http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
        }
    })

    http.ListenAndServe(":8080", nil)
}

測試

使用curl輸入curl -X GET "http://localhost:8080/send"，執行結果如下

$ curl -X GET "http://localhost:8080/send"
name=John
age=33
languages=[en,ch,jp]

• Golang http POST form file
• Golang Web接收表單資料