Go Iris Parameter Processing

This chapter introduces how to obtain GET, POST and other request parameters in the iris framework, including reading and writing cookies.

Parameters in the Path

func main() {
    app := iris.Default()

    // This handler will match /user/john, but not /user/ or /user
    app.Get("/user/{name}", func(ctx iris.Context) {
        name := ctx.Params().Get("name")
        ctx.Writef("Hello %s", name)
    })
    
    // However, this handler will match /user/john/ and /user/john/send
    // If no other router matches /user/john, it will redirect to /user/john/
    app.Get("/user/{name}/{action:path}", func(ctx iris.Context) {
        name := ctx.Params().Get("name")
        action := ctx.Params().Get("action")
        message := name + " is " + action
        ctx.WriteString(message)
    })
    
    // For each matched request, the context will keep the router's definition
    app.Post("/user/{name:string}/{action:path}", func(ctx iris.Context) {
        ctx.GetCurrentRoute().Tmpl().Src == "/user/{name:string}/{action:path}" // true
    })
    
    app.Listen(":8080")
}

Built-in available parameter types:

Getting Query Parameters

func main() {
    app := iris.Default()

    // Parse query string parameters using the existing low-level request object.
    // Request URL match: /welcome?firstname=Jane&lastname=Doe
    app.Get("/welcome", func(ctx iris.Context) {
        firstname := ctx.URLParamDefault("firstname", "Guest")
        lastname := ctx.URLParam("lastname") // Shortcut for ctx.Request().URL.Query().Get("lastname")

        ctx.Writef("Hello %s %s", firstname, lastname)
    })
    app.Listen(":8080")
}

Getting Form Parameters

func main() {
    app := iris.Default()

    app.Post("/form_post", func(ctx iris.Context) {
        message := ctx.PostValue("message")
        nick := ctx.PostValueDefault("nick", "Anonymous")

        ctx.JSON(iris.Map{
            "status":  "Published",
            "message": message,
            "nick":    nick,
        })
    })
    app.Listen(":8080")
}

Combined Example of Query + Form Parameters

POST /post?id=1234&page=1 HTTP/1.1
Content-Type: application/x-www-form-urlencoded

name=kataras&message=this_is_great

func main() {
    app := iris.Default()

    app.Post("/post", func(ctx iris.Context) {
        id, err := ctx.URLParamInt("id", 0)
        if err != nil {
            ctx.StopWithError(iris.StatusBadRequest, err)
            return
        }

        page := ctx.URLParamIntDefault("page", 0)
        name := ctx.PostValue("name")
        message := ctx.PostValue("message")

        ctx.Writef("id: %d; page: %d; name: %s; message: %s", id, page, name, message)
    })
    app.Listen(":8080")
}

id: 1234; page: 1; name: kataras; message: this_is_great

Retrieving Query Parameters in a POST Request

POST /post?id=a&id=b&id=c&name=john&name=doe&name=kataras
Content-Type: application/x-www-form-urlencoded

func main() {
    app := iris.Default()

    app.Post("/post", func(ctx iris.Context) {

        ids := ctx.URLParamSlice("id")
        names, err := ctx.PostValues("name")
        if err != nil {
            ctx.StopWithError(iris.StatusBadRequest, err)
            return
        }

        ctx.Writef("ids: %v; names: %v", ids, names)
    })
    app.Listen(":8080")
}

ids: [a b c], names: [john doe kataras]

Cookie Read/Write

import "github.com/kataras/iris/v12"

func main() {
    app := iris.Default()

    app.Get("/cookie", func(ctx iris.Context) {
        // Read cookie
        value := ctx.GetCookie("my_cookie")

        if value == "" {
            value = "NotSet"
            // Create cookie
            ctx.SetCookieKV("my_cookie", value)
            // Alternatively: ctx.SetCookie(&http.Cookie{...})
            // Create cookie
            ctx.SetCookie("", "test", 3600, "/", "localhost", false, true)
        }

        ctx.Writef("Cookie value: %s \n", value)
    })

    app.Listen(":8080")
}