HTTP Server Response

httpserver.go

package httpserver

import (
	"encoding/json"
	"net/http"
)

func CreateTodo(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()

	if !can.I(ctx, "create-todo") {
		ErrUnauthorized().Render(w, r)
		return
	}

	var reqBody todo.Todo
	if err := json.NewDecoder(r.Body).Decode(&reqBody); err != nil {
		ErrBadRequest(err).Render(w, r)
		return
	}

	createdTodo, err := todo.Create(ctx, reqBody)
	if err != nil {
		ErrInternalServerError(err).Render(w, r)
		return
	}

	TodoCreatedResponse(createdTodo).Render(w, r)
}

response.go

package httpserver

import (
	"encoding/json"
	"net/http"
)

type ErrResponse struct {
	Err            error `json:"-"`
	HTTPStatusCode int   `json:"-"`

	StatusText string `json:"status"`
	ErrorText  string `json:"error,omitempty"`
}

func (e *ErrResponse) Render(w http.ResponseWriter, r *http.Request) error {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(e.HTTPStatusCode)
	return json.NewEncoder(w).Encode(e)
}

func ErrBadRequest(err error) *ErrResponse {
	return &ErrResponse{
		Err:            err,
		HTTPStatusCode: http.StatusBadRequest,

		StatusText: "Bad Request",
		ErrorText:  err.Error(),
	}
}

func ErrUnauthorized() *ErrResponse {
	return &ErrResponse{
		HTTPStatusCode: http.StatusUnauthorized,

		StatusText: "Unauthorized",
		ErrorText:  "You are not authorized to perform this action.",
	}
}

func ErrInternalServerError(err error) *ErrResponse {
	return &ErrResponse{
		Err:            err,
		HTTPStatusCode: http.StatusInternalServerError,

		StatusText: "Internal Server Error",
		ErrorText:  err.Error(),
	}
}

type TodoResponse struct {
	HTTPStatusCode int `json:"-"`

	todo.Todo
}

func (e *TodoResponse) Render(w http.ResponseWriter, r *http.Request) error {
	w.Header().Set("Content-Type", "application/json")

	if e.HTTPStatusCode == 0 {
		e.HTTPStatusCode = http.StatusOK
	}
	w.WriteHeader(e.HTTPStatusCode)

	return json.NewEncoder(w).Encode(e)
}

func TodoCreatedResponse(t todo.Todo) *TodoResponse {
	return &TodoResponse{
		HTTPStatusCode: http.StatusCreated,
		Todo:           t,
	}
}