Handling http errors in Go

httperr.go

package httpresp

import (
	"context"
	"fmt"
	"net/http"

	"github.com/go-chi/render"
	"github.com/go-pg/pg/v9"

	"github.com/ribice/api/pkg/zlog"
)

// Response represents error response
type Response struct {
	Status  int    `json:"-"`
	Message string `json:"message,omitempty"`
}

// HTTP error statuses with message
var (
	NotFound    = &Response{Status: 404}
	Unauthorized = &Response{Status: 401, Message: "You are not authorized to access this resource"}
	Internal     = &Response{Status: 500, Message: "An error occurred. We're already working on it. Please try again later."}
)

// Render is the Renderer for Response struct
func (e *Response) Render(w http.ResponseWriter, r *http.Request) error {
	render.Status(r, e.Status)
	return nil
}

// Error implements the Error interface
func (e *Response) Error() string {
	return e.Message
}

// BadRequest returns http 400 with error message
func BadRequest(msg string) *Response {
	return &Response{Status: 400, Message: msg}
}

// BadRequest returns http 400 with error message
func BadRequestF(msg string, args ...interface{}) *Response {
	return &Response{Status: 400, Message: fmt.Sprintf(msg, args)}
}

// Respond wraps any error into httperr.Response and returns it for client
func Respond(ctx context.Context, err error) *Response {
	// Response writes an error response to client
	switch e := err.(type) {
	case *Response:
		return e
	default:
		if e == pg.ErrNoRows {
			return NotFound
		}

		zlog.FromContext(ctx).Err(e)
		return &Response{Status: 500, Message: e.Error()}
	}
}