Golang-使用框架时在“ if”语句后提供返回

Question

It give error missing return at end of function. I've tried add return nil, return "", return c.String, and several others but none works.

package main

import (
    "github.com/hiteshmodha/goDevice"
    "github.com/labstack/echo"
    "net/http"
)

func main() {
    e := echo.New()

    e.Get("/", func(c *echo.Context, w http.ResponseWriter, r *http.Request) *echo.HTTPError {

        deviceType := goDevice.GetType(r)

        if deviceType == "Mobile" {
            return c.String(http.StatusOK, "Mobile!")
        } else if deviceType == "Web" {
            return c.String(http.StatusOK, "Desktop!")
        } else if deviceType == "Tab" {
            return c.String(http.StatusOK, "Tablet!")
        }

    })

    e.Run(":4444")
}

This one quite different that other case such as in here.

Without framework, it works fine.

Answer 1

Your handler here is not what echo.Get is waiting for that's why you're getting this: panic: echo: unknown handler. To get rid of this error change your handler to something like this: func(c *echo.Context) error If you need to access the http.Request from inside the handler you can do it by using the *echo.Context which also contains a *echo.Response.

Working solution:

e.Get("/", func(c *echo.Context) error {
    deviceType := goDevice.GetType(c.Request())

    if deviceType == "Mobile" {
        return echo.NewHTTPError(http.StatusOK, "Mobile!")
    } else if deviceType == "Web" {
        return echo.NewHTTPError(http.StatusOK, "Desktop!")
    } else if deviceType == "Tab" {
        return echo.NewHTTPError(http.StatusOK, "Tablet!")
    }

    return echo.NewHTTPError(http.StatusNoContent, "Alien probe")
})

Hope it helps