HTTP error handling

With BunRouter, you can and should use middlewares to handle all errors from a single place. BunRouter does not provide a built-in error handler, but you can easily create your own.

For example, let's create an error handler for a JSON API that generates responses like this whenever there is an error:

{ "code": "login_required", "message": "You must log in before continuing" } 

Let's start by defining a struct that will carry some information about an error:

type HTTPError struct {	statusCode int	Code string `json:"code"`	Message string `json:"message"` } func (e HTTPError) Error() string { return e.Message } 

Next, we need some logic to convert an error into a HTTPError:

func NewHTTPError(err error) HTTPError { switch err { case io.EOF: return HTTPError{	statusCode: http.StatusBadRequest,	Code: "eof",	Message: "EOF reading HTTP request body", } case sql.ErrNoRows: return HTTPError{	statusCode: http.StatusNotFound,	Code: "not_found",	Message: "Page Not Found", } } return HTTPError{	statusCode: http.StatusInternalServerError,	Code: "internal",	Message: "Internal server error", } } 

Lastly, we need a middleware that pulls everything together:

func errorHandler(next bunrouter.HandlerFunc) bunrouter.HandlerFunc { return func(w http.ResponseWriter, req bunrouter.Request) error { // Call the next handler on the chain to get the error.	err := next(w, req) switch err := err.(type) { case nil: // no error case HTTPError: // already a HTTPError	w.WriteHeader(err.statusCode) _ = bunrouter.JSON(w, err) default:	httpErr := NewHTTPError(err)	w.WriteHeader(httpErr.statusCode) _ = bunrouter.JSON(w, httpErr) } return err // return the err in case there other middlewares } } 

It is a good idea to isolate the API by creating a separate routing group and installing error handler only for that group:

api := router.NewGroup("/api", bunrouter.Use(errorHandler)) api.GET("/", indexHandler) 

You can find the source code on GitHub.