goshort/internal/server/errors.go

package server

import (
	"net/http"

	"github.com/go-chi/render"
)

// ErrResponse renderer type for handling all sorts of errors.
//
// In the best case scenario, the excellent github.com/pkg/errors package
// helps reveal information on the error, setting it on Err, and in the Render()
// method, using it to set the application-specific error code in AppCode.
type ErrResponse struct {
	Err            error `json:"-"` // low-level runtime error
	HTTPStatusCode int   `json:"-"` // http response status code

	StatusText string `json:"status"`          // user-level status message
	ErrorText  string `json:"error,omitempty"` // application-level error message, for debugging
}

func (e *ErrResponse) Render(_ http.ResponseWriter, r *http.Request) error {
	render.Status(r, e.HTTPStatusCode)

	return nil
}

func ErrBasic(status int) *ErrResponse {
	return &ErrResponse{
		HTTPStatusCode: status,
		StatusText:     http.StatusText(status),
	}
}

func ErrGeneric(err error, status int) *ErrResponse {
	resp := ErrBasic(status)
	resp.Err = err
	resp.ErrorText = err.Error()

	return resp
}

func ErrBadRequest(err error) *ErrResponse {
	return ErrGeneric(err, http.StatusBadRequest)
}

func ErrNotFound() *ErrResponse {
	return ErrBasic(http.StatusNotFound)
}

func ErrUnauthorized() *ErrResponse {
	return ErrBasic(http.StatusUnauthorized)
}

func ErrForbidden() *ErrResponse {
	return ErrBasic(http.StatusForbidden)
}

func ErrRendering(err error) *ErrResponse {
	return &ErrResponse{
		Err:            err,
		HTTPStatusCode: http.StatusUnprocessableEntity,
		StatusText:     "Error rendering response.",
		ErrorText:      err.Error(),
	}
}

func RenderRender(w http.ResponseWriter, r *http.Request, resp render.Renderer) {
	// Try to render the response
	if err := render.Render(w, r, resp); err != nil {
		// If error, try to render that an error occurred
		if err := render.Render(w, r, ErrRendering(err)); err != nil {
			// If error, panic
			panic(err)
		}
	}
}

func RenderBadRequest(w http.ResponseWriter, r *http.Request, err error) {
	RenderRender(w, r, ErrBadRequest(err))
}

func RenderServerError(_ http.ResponseWriter, _ *http.Request, err error) {
	// Panic so the stack trace is printed
	panic(err)
}

func RenderNotFound(w http.ResponseWriter, r *http.Request) {
	RenderRender(w, r, ErrNotFound())
}

func RenderUnauthorized(w http.ResponseWriter, r *http.Request) {
	RenderRender(w, r, ErrUnauthorized())
}

func RenderForbidden(w http.ResponseWriter, r *http.Request) {
	RenderRender(w, r, ErrForbidden())
}