Here https://github.com/astaxie/build-web-application-with-golang/blob/master/en/11.1.md described how to enhance error handling with custom router and custom error type according to http package.
type appError struct {
Error error
Message string
Code int
}
type appHandler func(http.ResponseWriter, *http.Request) *appError
// custom handler catching errors
func (fn appHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if e := fn(w, r); e != nil { // e is *appError, not os.Error.
c := appengine.NewContext(r)
c.Errorf("%v", e.Error)
http.Error(w, e.Message, e.Code)
}
}
// fetch data or return *appError
func viewRecord(w http.ResponseWriter, r *http.Request) *appError {
c := appengine.NewContext(r)
key := datastore.NewKey(c, "Record", r.FormValue("id"), 0, nil)
record := new(Record)
if err := datastore.Get(c, key, record); err != nil {
return &appError{err, "Record not found", 404}
}
if err := viewTemplate.Execute(w, record); err != nil {
return &appError{err, "Can't display record", 500}
}
return nil
}
The aim is to make all the handlers returning *appError in case of error and write it into response in the router, so there is no need to call c.JSON(500, err) directly in the code of viewRecord
.
How to do the same with Gin?