Events ability to halt

events.go

@@ -1,6 +1,8 @@
 package authboss
 
 import (
+	"fmt"
+	"github.com/friendsofgo/errors"
 	"net/http"
 )
 
@@ -9,6 +11,8 @@ import (
 // Event type is for describing events
 type Event int
 
+var ErrHalt = fmt.Errorf("event halt")
+
 // Event kinds
 const (
 	EventRegister Event = iota
@@ -96,6 +100,13 @@ func (c *Events) call(evs []EventHandler, w http.ResponseWriter, r *http.Request
 	for _, fn := range evs {
 		interrupt, err := fn(w, r, handled)
 		if err != nil {
+			if errors.Is(err, ErrHalt) {
+				if interrupt {
+					handled = true
+				}
+				break
+			}
+
 			return false, err
 		}
 		if interrupt {

events_test.go

@@ -92,6 +92,94 @@ func TestEventsHandled(t *testing.T) {
 	}
 }
 
+func TestEventsHaltHandled(t *testing.T) {
+	t.Parallel()
+
+	ab := New()
+	firstCalled := false
+	secondCalled := false
+
+	firstHandled := false
+	secondHandled := false
+
+	ab.Events.Before(EventRegister, func(w http.ResponseWriter, r *http.Request, handled bool) (bool, error) {
+		firstCalled = true
+		firstHandled = handled
+		return true, ErrHalt
+	})
+	ab.Events.Before(EventRegister, func(w http.ResponseWriter, r *http.Request, handled bool) (bool, error) {
+		secondCalled = true
+		secondHandled = handled
+		return false, nil
+	})
+
+	handled, err := ab.Events.FireBefore(EventRegister, nil, nil)
+	if err != nil {
+		t.Error("Unexpected error:", err)
+	}
+	if !handled {
+		t.Error("it should have been handled")
+	}
+
+	if !firstCalled {
+		t.Error("expected first to have been called")
+	}
+	if firstHandled {
+		t.Error("first should not see the event as being handled")
+	}
+
+	if secondCalled {
+		t.Error("expected second to not have been called")
+	}
+	if secondHandled {
+		t.Error("second should not see the event as being handled (as second should not be running at all)")
+	}
+}
+
+func TestEventsHaltNotHandled(t *testing.T) {
+	t.Parallel()
+
+	ab := New()
+	firstCalled := false
+	secondCalled := false
+
+	firstHandled := false
+	secondHandled := false
+
+	ab.Events.Before(EventRegister, func(w http.ResponseWriter, r *http.Request, handled bool) (bool, error) {
+		firstCalled = true
+		firstHandled = handled
+		return false, ErrHalt
+	})
+	ab.Events.Before(EventRegister, func(w http.ResponseWriter, r *http.Request, handled bool) (bool, error) {
+		secondCalled = true
+		secondHandled = handled
+		return false, nil
+	})
+
+	handled, err := ab.Events.FireBefore(EventRegister, nil, nil)
+	if err != nil {
+		t.Error("Unexpected error:", err)
+	}
+	if handled {
+		t.Error("it should not have been handled")
+	}
+
+	if !firstCalled {
+		t.Error("expected first to have been called")
+	}
+	if firstHandled {
+		t.Error("first should not see the event as being handled")
+	}
+
+	if secondCalled {
+		t.Error("expected second to not have been called")
+	}
+	if secondHandled {
+		t.Error("second should not see the event as being handled (as second should not be running at all)")
+	}
+}
+
 func TestEventsErrors(t *testing.T) {
 	t.Parallel()