How to serve up a JSON response using Go?
Other users were commenting that the Content-Type
is plain/text
when encoding.
You have to set the content type with w.Header().Set()
first, then write the HTTP response code with w.WriteHeader()
.
If you call w.WriteHeader()
first, then call w.Header().Set()
after you will get plain/text
.
An example handler might look like this:
func SomeHandler(w http.ResponseWriter, r *http.Request) {
data := SomeStruct{}
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(http.StatusCreated)
json.NewEncoder(w).Encode(data)
}
In gobuffalo.io framework I got it to work like this:
// say we are in some resource Show action
// some code is omitted
user := &models.User{}
if c.Request().Header.Get("Content-type") == "application/json" {
return c.Render(200, r.JSON(user))
} else {
// Make user available inside the html template
c.Set("user", user)
return c.Render(200, r.HTML("users/show.html"))
}
and then when I want to get JSON response for that resource I have to set "Content-type" to "application/json" and it works.
I think Rails has more convenient way to handle multiple response types, I didn't see the same in gobuffalo so far.
You can set your content-type header so clients know to expect json
w.Header().Set("Content-Type", "application/json")
Another way to marshal a struct to json is to build an encoder using the http.ResponseWriter
// get a payload p := Payload{d}
json.NewEncoder(w).Encode(p)
You can do something like this in you getJsonResponse
function -
jData, err := json.Marshal(Data)
if err != nil {
// handle error
}
w.Header().Set("Content-Type", "application/json")
w.Write(jData)