KeyAuthWithConfig - how to call next handler with decoded user

[fundef1]

Hi,
I'm taking my first steps with echo (and go) so I'm possibly "doing this wrong" - hence my question ;-)

I'm trying to validate an API key, which encodes a username, and then use that username in a subsequent handler.
I was following the Key Auth example, with a custom validator to extract the username. (API keys are fixed and map directly to users) .

But then how to pass that user to the following handler?

thanks!

[aldas]

You can use echo.Context.Set and echo.Context.Get to store value in middleware into context and get that value from context in downstream middlewares or handler

const MyValueContextKey = "my-context-value"

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

	e.Use(middleware.Logger())
	e.Use(middleware.Recover())

	e.Use(func(next echo.HandlerFunc) echo.HandlerFunc {
		return func(c echo.Context) error {
			value := c.QueryParam("value")
			if value != "" {
				c.Set(MyValueContextKey, value) // store in context
			}
			return next(c)
		}
	})

	e.GET("/", func(c echo.Context) error {
		value, ok := c.Get(MyValueContextKey).(string) // get from context
		if !ok {
			value = "no value in context"
		}
		return c.String(http.StatusOK, value)
	})

	if err := e.Start(":8080"); err != http.ErrServerClosed {
		log.Fatal(err)
	}
}

Example:

x@x:~/code$ curl -v http://localhost:8080/?value=test
*   Trying 127.0.0.1:8080...
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET /?value=test HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.74.0
> Accept: */*
> 
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Content-Type: text/plain; charset=UTF-8
< Date: Mon, 07 Mar 2022 17:52:30 GMT
< Content-Length: 4
< 
* Connection #0 to host localhost left intact
test

x@x:~/code$ curl -v http://localhost:8080/?
*   Trying 127.0.0.1:8080...
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET /? HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.74.0
> Accept: */*
> 
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Content-Type: text/plain; charset=UTF-8
< Date: Mon, 07 Mar 2022 17:52:17 GMT
< Content-Length: 19
< 
* Connection #0 to host localhost left intact
no value in context

and for KeyAuth it would look something like that

	e.Use(middleware.KeyAuth(func(auth string, c echo.Context) (bool, error) {
		if auth == "mysecret" {
			user := auth  // FIXME: encode auth to user
			c.Set(MyValueContextKey, user) 
			return true, nil
		}
		return false, nil
	}))

[fundef1]

Yes! exactly what I was looking for. Thanks a bunch.