go - Terminating or aborting an HTTP request

Question

What's the way to abort my API serving with some error message?

Link to call my service:

http://creative.test.spoti.io/api/getVastPlayer?add=
    {"Json":Json}&host=api0.spoti.io&domain=domain&userAgent=userAgent&mobile=true

To call my service the client need to send a Json and some params.

I want to test if the params that I get are correct, if not I want send a error message.

The response should be a Json Code {"Result":"Result","Error":"error message"}

I tried log.fatal and os.Exit(1) they stop the service, not just the call request. panic aborts the call but it prevents me to send a http.ResponseWriter which is my error message.

I read something about panic, defer, recover but I don't really know how can I use them to solve this problem.

return works:

mobile :=query.Get("mobile")
if mobile=="mobile" {
            str:=`{"Resultt":"","Error":"No valide Var"}`
            fmt.Fprint(w, str)      
            fmt.Println("No successfull Operation!!")
            return}  

But I can use it just in the main function, because in the other functions it exits just the func not the caller function (request).

Answer 1

Waitting for answers