原生

Urlencoded Form

即content-type 為 x-www-form-urlencode的數據。

r.Form["param"]
r.PostForm["param"]
r.FormValue("param")
r.PostFormValue("param")

其中r.Form和r.PostForm必須在調用ParseForm之后，才會有數據，否則則是空數組。
而r.FormValue和r.PostFormValue("lang")無需ParseForm的調用就能讀取數據。

MutilpartFrom

即content-type為form-data的數據使用ParseMutilpartFrom方法解析參數，但是不會解析url query的參數的

r.Form["param"]
r.PostForm["param"]
r.FormValue("param")
r.PostFormValue("param")
r.MultipartForm.Value["param"]

r.MultipartForm.File包含圖片數據
r.FormFile可以直接讀取上傳文件數據

gin

Parameters in path

func main() {
    router := gin.Default()

    // This handler will match /user/john but will not match neither /user/ or /user
    router.GET("/user/:name", func(c *gin.Context) {
        name := c.Param("name")
        c.String(http.StatusOK, "Hello %s", name)
    })

    // However, this one will match /user/john/ and also /user/john/send
    // If no other routers match /user/john, it will redirect to /user/john/
    router.GET("/user/:name/*action", func(c *gin.Context) {
        name := c.Param("name")
        action := c.Param("action")
        message := name + " is " + action
        c.String(http.StatusOK, message)
    })

    router.Run(":8080")
}

Querystring parameters

func main() {
    router := gin.Default()

    // Query string parameters are parsed using the existing underlying request object.
    // The request responds to a url matching:  /welcome?firstname=Jane&lastname=Doe
    router.GET("/welcome", func(c *gin.Context) {
        firstname := c.DefaultQuery("firstname", "Guest")
        lastname := c.Query("lastname") // shortcut for c.Request.URL.Query().Get("lastname")

        c.String(http.StatusOK, "Hello %s %s", firstname, lastname)
    })
    router.Run(":8080")
}

Multipart/Urlencoded Form

func main() {
    router := gin.Default()

    router.POST("/form_post", func(c *gin.Context) {
        message := c.PostForm("message")
        nick := c.DefaultPostForm("nick", "anonymous")

        c.JSON(200, gin.H{
            "status":  "posted",
            "message": message,
            "nick":    nick,
        })
    })
    router.Run(":8080")
}

query + post form

func main() {
    router := gin.Default()

    router.POST("/post", func(c *gin.Context) {

        id := c.Query("id")
        page := c.DefaultQuery("page", "0")
        name := c.PostForm("name")
        message := c.PostForm("message")

        fmt.Printf("id: %s; page: %s; name: %s; message: %s", id, page, name, message)
    })
    router.Run(":8080")
}