Create and delete methods

pkg/models/error.go

@@ -1454,3 +1454,32 @@ func (err ErrUnknownSubscriptionEntityType) HTTPError() web.HTTPError {
 		Message:  "The subscription entity type is invalid.",
 	}
 }
+
+// ErrSubscriptionAlreadyExists represents an error where a subscription entity already exists
+type ErrSubscriptionAlreadyExists struct {
+	EntityID   int64
+	EntityType SubscriptionEntityType
+	UserID     int64
+}
+
+// IsErrSubscriptionAlreadyExists checks if an error is ErrSubscriptionAlreadyExists.
+func IsErrSubscriptionAlreadyExists(err error) bool {
+	_, ok := err.(*ErrSubscriptionAlreadyExists)
+	return ok
+}
+
+func (err *ErrSubscriptionAlreadyExists) Error() string {
+	return fmt.Sprintf("Subscription for this (entity_id, entity_type, user_id) already exists [EntityType: %d, EntityID: %d, UserID: %d]", err.EntityType, err.EntityID, err.UserID)
+}
+
+// ErrCodeSubscriptionAlreadyExists holds the unique world-error code of this error
+const ErrCodeSubscriptionAlreadyExists = 12002
+
+// HTTPError holds the http error description
+func (err ErrSubscriptionAlreadyExists) HTTPError() web.HTTPError {
+	return web.HTTPError{
+		HTTPCode: http.StatusPreconditionFailed,
+		Code:     ErrCodeSubscriptionAlreadyExists,
+		Message:  "You're already subscribed.",
+	}
+}

pkg/models/subscription.go

@@ -72,10 +72,30 @@ func getEntityTypeFromString(entityType string) SubscriptionEntityType {
 	return SubscriptionEntityUnknown
 }
 
-func (sb *Subscription) Create(s *xorm.Session, auth web.Auth) error {
+func (sb *Subscription) Create(s *xorm.Session, auth web.Auth) (err error) {
+	// Rights method alread does the validation of the entity type so we don't need to do that here
 
+	exists, err := s.
+		Where("entity_id = ? AND entity_type = ? AND user_id = ?", sb.EntityID, sb.EntityType, sb.UserID).
+		Exist(&Subscription{})
+	if err != nil {
+		return err
+	}
+	if exists {
+		return &ErrSubscriptionAlreadyExists{
+			EntityID:   sb.EntityID,
+			EntityType: sb.EntityType,
+			UserID:     sb.UserID,
+		}
+	}
+
+	_, err = s.Insert(sb)
+	return
 }
 
-func (sb *Subscription) Delete(s *xorm.Session, auth web.Auth) error {
-
+func (sb *Subscription) Delete(s *xorm.Session, auth web.Auth) (err error) {
+	_, err = s.
+		Where("entity_id = ? AND entity_type = ? AND user_id = ?", sb.EntityID, sb.EntityType, sb.UserID).
+		Delete(&Subscription{})
+	return
 }

pkg/models/subscription_test.go

@@ -18,7 +18,6 @@ package models
 
 import (
 	"code.vikunja.io/api/pkg/db"
-	"code.vikunja.io/api/pkg/user"
 	"github.com/stretchr/testify/assert"
 	"testing"
 )
@@ -86,7 +85,7 @@ func TestSubscription_Create(t *testing.T) {
 		defer s.Close()
 
 	})
-	t.Run("Subscription already exists for this entity", func(t *testing.T) {
+	t.Run("existing subscription for (entity_id, entity_type, user_id) ", func(t *testing.T) {
 		db.LoadAndAssertFixtures(t)
 		s := db.NewSession()
 		defer s.Close()