重定向后停止执行代码

Question

//main.go
func (self *GoodsController) GoodsEditGet(w http.ResponseWriter, r *http.Request) {
    vars := mux.Vars(r)
    tmpID, ok := vars["id"]
    sess := session.Instance(w, r)

    if !ok {
        tpl.Error("Invalid goods id")
    }

    id, _ := strconv.ParseInt(tmpID, 10, 64)

    goods, err := service.NewGoodsService(w, r).GetGoodsDetail(id)

    if err != nil {
        //This utility function will not stop the rest of the code being executed
        util.RedirectWithMessage(w, r, err.Error(), "/system/inventory/goods")
    }

    //This line will be executed even though the above line producing error
    goodsUom, err := service.NewGoodsService(w, r).GetGoodsUom(id)

    if err != nil {
        util.RedirectWithMessage(w, r, err.Error(), "/system/inventory/goods")
    }

}

//package utility
func RedirectWithMessage(w http.ResponseWriter, r *http.Request, errMsg string, redirect string) {
    sess := session.Instance(w, r)
    sess.FlashError(errMsg)
    sess.FlashForm(r)
    sess.Save(r, w)
    http.Redirect(w, r, redirect, http.StatusFound)
    return
}

May i know how to stop execution rest of the code after called to function RedirectWithMessage ?

Putting return at the end of that function didn't rest of the code being executed

Im looking the equivalent of Php version of redirect in Golang:

fuunction foo($location){
  header(“Location : $location”);
  exit();
}

 foo("/bar"):
 echo "blah"; //this will not be executed

Edited cause of overzealous down-vote.

Yes im fully aware that i can put return statement after a called to RedirectWithMessage. I just dont want to clutter my code with return statement all the place.Instead i just put once inside the function. I just wonder is there any better solution to that? Can i achieve the same behaviour like php code i show?

Answer 1

I was tempted to give you a panic defer way and warn you not to use it but then I realize it might be better to change the API.

You can focus the main logic of the function and return the error to the caller, and ask the caller to handle the error the way you want, e.g. redirect, log and so on.

func (self *GoodsController) GoodsEditGet(w http.ResponseWriter, r *http.Request) {
    err:=self.goodsEditGet(w,r)
    if err!=nil { //Note 1
        util.RedirectWithMessage(w, r, err.Error(), "/system/inventory/goods")
    }
}

func (self *GoodsController) goodsEditGet(w http.ResponsWriter, r *http.Request) {
    vars := mux.Vars(r)
    tmpID, ok := vars["id"]
    sess := session.Instance(w, r)

    if !ok {
        tpl.Error("Invalid goods id")
    }

    id, _ := strconv.ParseInt(tmpID, 10, 64)

    goods, err := service.NewGoodsService(w, r).GetGoodsDetail(id)

    if err != nil {
        //This utility function will not stop the rest of the code being executed
        return err //Note 2
    }

    goodsUom, err := service.NewGoodsService(w, r).GetGoodsUom(id)

    if err != nil {
        return err
    }
    return nil
}

Note 1: You would possibly want to handle more specified errors, not just dealing with nil and non-nil. In that case, type assertion may be a good idea.

Note 2: You would possibly want to wrap the error. You can try github/pkg/errors, a good package dealing with erros written by Dave Cheney.

Note 3: It is adviced against to use self as receiver name, as it is pretty ambiguous.