HTTP error handlers per Party (docs and details in progress)

Former-commit-id: 7092ebed556b56d9f1769b9b23f2340c2a3a18f7

core/router/party.go

@@ -33,6 +33,22 @@ type Party interface {
 	// Learn more at:  https://github.com/kataras/iris/tree/master/_examples/routing/dynamic-path
 	Macros() *macro.Macros
 
+	// OnErrorCode registers an error http status code
+	// based on the "statusCode" < 200 || >= 400 (came from `context.StatusCodeNotSuccessful`).
+	// The handler is being wrapped by a generic
+	// handler which will try to reset
+	// the body if recorder was enabled
+	// and/or disable the gzip if gzip response recorder
+	// was active.
+	OnErrorCode(statusCode int, handlers ...context.Handler)
+	// OnAnyErrorCode registers a handler which called when error status code written.
+	// Same as `OnErrorCode` but registers all http error codes based on the `context.StatusCodeNotSuccessful`
+	// which defaults to < 200 || >= 400 for an error code, any previous error code will be overridden,
+	// so call it first if you want to use any custom handler for a specific error status code.
+	//
+	// Read more at: http://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml
+	OnAnyErrorCode(handlers ...context.Handler)
+
 	// Party groups routes which may have the same prefix and share same handlers,
 	// returns that new rich subrouter.
 	//