Sending JSON responses

The response.JSON() function in the internal/response package can be used to send a JSON response with a specific HTTP status code.

You can use it like this:

func (app *application) exampleHandler(w http.ResponseWriter, r *http.Request) {
    data := map[string]string{"hello":  "world"}

    err := response.JSON(w, http.StatusOK, data)
    if err != nil {
        app.serverError(w, r, err)
    }
}

Note that the data parameter does not have to be a map. You can pass any JSON-marshalable value – including structs, slices, or maps – as the final argument, and it will be encoded and sent as the response body.

The response.JSON() function also automatically sets a Content-Type: application/json header on the response.

If you need to include additional HTTP headers, you can use response.JSONWithHeaders() instead. This accepts an http.Header map as the final argument.

For example:

func (app *application) exampleHandler(w http.ResponseWriter, r *http.Request) {
    data := map[string]string{"hello":  "world"}

    headers := make(http.Header)
    headers.Set("X-Server", "Go")

    err := response.JSONWithHeaders(w, http.StatusOK, data, headers)
    if err != nil {
        app.serverError(w, r, err)
    }
}