# Status Handlers Since v2.4.0

# Introduction

Status handlers are regular handlers executed during the finalization step of the request's lifecycle if the response body is empty but a status code has been set. Status handler are mainly used to implement a custom behavior for user or server errors (400 and 500 status codes).

Goyave comes with a default error status handler. When a panic occurs or the Response.Error() method is called, the request's status is set to 500 Internal Server Error and the request error is set. The latter can be accessed using Response.GetError(). The error is printed in the console. If debugging is enabled in the config, the error is also written in the response using the JSON format, and the stacktrace is printed in the console. If debugging is not enabled, the following is returned:

{
    "error": "Internal Server Error"
}

The status handler covering all the other errors in the 400 and 500 status codes ranges has a similar behavior but doesn't print anything to the console. For example, if the user requests a route that doesn't exist, the following is returned:

{
    "error": "Not Found"
}

# Writing status handlers

As said earlier, status handlers are regular handlers. The only difference is that they are executed at the very end of the request's lifecycle. Ideally, create a new controller for your status handlers.

http/controller/status/status.go:

package status

import "github.com/System-Glitch/goyave/v2"

func NotFound(response *goyave.Response, request *goyave.Request) {
    response.RenderHTML(response.GetStatus(), "errors/404.html", nil)
}

# Registering status handlers

Status handlers are registered in the router.

# Router.StatusHandler

Set a handler for responses with an empty body. The handler will be automatically executed if the request's life-cycle reaches its end and nothing has been written in the response body.

Multiple status codes can be given. The handler will be executed if one of them matches.

Status handlers are inherited as a copy in sub-routers. Modifying a child's status handler will not modify its parent's. That means that you can define different status handlers for certain route groupes if you so desire.

Parameters Return
handler Handler void
status int
additionalStatuses ...int

Example:

func errorStatusHandler(response *Response, request *Request) {
	message := map[string]string{
		"error": http.StatusText(response.GetStatus()),
	}
	response.JSON(response.GetStatus(), message)
}

// Use "errorStatusHandler" for empty responses having status 404 or 405.
router.StatusHandler(errorStatusHandler, 404, 405)