Validation endpoint and minor refactoring (#607)

backend/src/Squidex.Domain.Apps.Core.Operations/EventSynchronization/SchemaSynchronizer.cs

@@ -12,13 +12,12 @@ using Squidex.Domain.Apps.Core.Schemas;
 using Squidex.Domain.Apps.Events;
 using Squidex.Domain.Apps.Events.Schemas;
 using Squidex.Infrastructure;
-using Squidex.Infrastructure.EventSourcing;
 
 namespace Squidex.Domain.Apps.Core.EventSynchronization
 {
     public static class SchemaSynchronizer
     {
-        public static IEnumerable<IEvent> Synchronize(this Schema source, Schema? target, Func<long> idGenerator,
+        public static IEnumerable<SchemaEvent> Synchronize(this Schema source, Schema? target, Func<long> idGenerator,
             SchemaSynchronizationOptions? options = null)
         {
             Guard.NotNull(source, nameof(source));
@@ -32,76 +31,64 @@ namespace Squidex.Domain.Apps.Core.EventSynchronization
             {
                 options ??= new SchemaSynchronizationOptions();
 
-                static SchemaEvent E(SchemaEvent @event)
-                {
-                    return @event;
-                }
-
                 if (!source.Properties.Equals(target.Properties))
                 {
-                    yield return E(new SchemaUpdated { Properties = target.Properties });
+                    yield return new SchemaUpdated { Properties = target.Properties };
                 }
 
                 if (!source.Category.StringEquals(target.Category))
                 {
-                    yield return E(new SchemaCategoryChanged { Name = target.Category });
+                    yield return new SchemaCategoryChanged { Name = target.Category };
                 }
 
                 if (!source.Scripts.Equals(target.Scripts))
                 {
-                    yield return E(new SchemaScriptsConfigured { Scripts = target.Scripts });
+                    yield return new SchemaScriptsConfigured { Scripts = target.Scripts };
                 }
 
                 if (!source.PreviewUrls.EqualsDictionary(target.PreviewUrls))
                 {
-                    yield return E(new SchemaPreviewUrlsConfigured { PreviewUrls = target.PreviewUrls.ToDictionary() });
+                    yield return new SchemaPreviewUrlsConfigured { PreviewUrls = target.PreviewUrls.ToDictionary() };
                 }
 
                 if (source.IsPublished != target.IsPublished)
                 {
                     yield return target.IsPublished ?
-                        E(new SchemaPublished()) :
+                        new SchemaPublished() :
-                        E(new SchemaUnpublished());
+                        new SchemaUnpublished();
                 }
 
-                var events = SyncFields(source.FieldCollection, target.FieldCollection, idGenerator, CanUpdateRoot, null, options);
+                var events = SyncFields(source.FieldCollection, target.FieldCollection, idGenerator, CanUpdateRoot, options);
 
                 foreach (var @event in events)
                 {
-                    yield return E(@event);
+                    yield return @event;
                 }
 
                 if (!source.FieldsInLists.SequenceEqual(target.FieldsInLists))
                 {
-                    yield return E(new SchemaUIFieldsConfigured { FieldsInLists = target.FieldsInLists });
+                    yield return new SchemaUIFieldsConfigured { FieldsInLists = target.FieldsInLists };
                 }
 
                 if (!source.FieldsInReferences.SequenceEqual(target.FieldsInReferences))
                 {
-                    yield return E(new SchemaUIFieldsConfigured { FieldsInReferences = target.FieldsInReferences });
+                    yield return new SchemaUIFieldsConfigured { FieldsInReferences = target.FieldsInReferences };
                 }
 
                 if (!source.FieldRules.SetEquals(target.FieldRules))
                 {
-                    yield return E(new SchemaFieldRulesConfigured { FieldRules = target.FieldRules });
+                    yield return new SchemaFieldRulesConfigured { FieldRules = target.FieldRules };
                 }
             }
         }
 
-        private static IEnumerable<SchemaEvent> SyncFields<T>(
+        private static IEnumerable<ParentFieldEvent> SyncFields<T>(
             FieldCollection<T> source,
             FieldCollection<T> target,
             Func<long> idGenerator,
             Func<T, T, bool> canUpdate,
-            NamedId<long>? parentId, SchemaSynchronizationOptions options) where T : class, IField
+            SchemaSynchronizationOptions options) where T : class, IField
         {
-            FieldEvent E(FieldEvent @event)
-            {
-                @event.ParentFieldId = parentId;
-
-                return @event;
-            }
-
             var sourceIds = source.Ordered.Select(x => x.NamedId()).ToList();
 
             if (!options.NoFieldDeletion)
@@ -114,7 +101,7 @@ namespace Squidex.Domain.Apps.Core.EventSynchronization
 
                         sourceIds.Remove(id);
 
-                        yield return E(new FieldDeleted { FieldId = id });
+                        yield return new FieldDeleted { FieldId = id };
                     }
                 }
             }
@@ -135,7 +122,7 @@ namespace Squidex.Domain.Apps.Core.EventSynchronization
                     {
                         if (!sourceField.RawProperties.Equals(targetField.RawProperties as object))
                         {
-                            yield return E(new FieldUpdated { FieldId = id, Properties = targetField.RawProperties });
+                            yield return new FieldUpdated { FieldId = id, Properties = targetField.RawProperties };
                         }
                     }
                     else if (!sourceField.IsLocked && !options.NoFieldRecreation)
@@ -144,7 +131,7 @@ namespace Squidex.Domain.Apps.Core.EventSynchronization
 
                         sourceIds.Remove(id);
 
-                        yield return E(new FieldDeleted { FieldId = id });
+                        yield return new FieldDeleted { FieldId = id };
                     }
                 }
 
@@ -162,7 +149,6 @@ namespace Squidex.Domain.Apps.Core.EventSynchronization
                     yield return new FieldAdded
                     {
                         Name = targetField.Name,
-                        ParentFieldId = parentId,
                         Partitioning = partitioning,
                         Properties = targetField.RawProperties,
                         FieldId = id
@@ -175,31 +161,33 @@ namespace Squidex.Domain.Apps.Core.EventSynchronization
                 {
                     if (!targetField.IsLocked.BoolEquals(sourceField?.IsLocked))
                     {
-                        yield return E(new FieldLocked { FieldId = id });
+                        yield return new FieldLocked { FieldId = id };
                     }
 
                     if (!targetField.IsHidden.BoolEquals(sourceField?.IsHidden))
                     {
                         yield return targetField.IsHidden ?
-                            E(new FieldHidden { FieldId = id }) :
+                            new FieldHidden { FieldId = id } :
-                            E(new FieldShown { FieldId = id });
+                            new FieldShown { FieldId = id };
                     }
 
                     if (!targetField.IsDisabled.BoolEquals(sourceField?.IsDisabled))
                     {
                         yield return targetField.IsDisabled ?
-                            E(new FieldDisabled { FieldId = id }) :
+                            new FieldDisabled { FieldId = id } :
-                            E(new FieldEnabled { FieldId = id });
+                            new FieldEnabled { FieldId = id };
                     }
 
                     if ((sourceField == null || sourceField is IArrayField) && targetField is IArrayField targetArrayField)
                     {
                         var fields = (sourceField as IArrayField)?.FieldCollection ?? FieldCollection<NestedField>.Empty;
 
-                        var events = SyncFields(fields, targetArrayField.FieldCollection, idGenerator, CanUpdate, id, options);
+                        var events = SyncFields(fields, targetArrayField.FieldCollection, idGenerator, CanUpdate, options);
 
                         foreach (var @event in events)
                         {
+                            @event.ParentFieldId = id;
+
                             yield return @event;
                         }
                     }
@@ -215,7 +203,7 @@ namespace Squidex.Domain.Apps.Core.EventSynchronization
                 {
                     var fieldIds = targetNames.Select(x => sourceIds.Find(y => y.Name == x)!.Id).ToArray();
 
-                    yield return new SchemaFieldsReordered { FieldIds = fieldIds, ParentFieldId = parentId };
+                    yield return new SchemaFieldsReordered { FieldIds = fieldIds };
                 }
             }
         }

backend/src/Squidex.Domain.Apps.Entities/Apps/AppDomainObject.cs

@@ -345,10 +345,9 @@ namespace Squidex.Domain.Apps.Entities.Apps
 
             foreach (var @event in events)
             {
-                @event.Actor = command.Actor;
                 @event.AppId = appId;
 
-                RaiseEvent(@event);
+                Raise(command, @event);
             }
         }
 
@@ -356,121 +355,123 @@ namespace Squidex.Domain.Apps.Entities.Apps
         {
             if (string.Equals(appPlansProvider.GetFreePlan()?.Id, command.PlanId))
             {
-                RaiseEvent(SimpleMapper.Map(command, new AppPlanReset()));
+                Raise(command, new AppPlanReset());
             }
             else
             {
-                RaiseEvent(SimpleMapper.Map(command, new AppPlanChanged()));
+                Raise(command, new AppPlanChanged());
             }
         }
 
         public void Update(UpdateApp command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppUpdated()));
+            Raise(command, new AppUpdated());
         }
 
         public void UpdateClient(UpdateClient command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppClientUpdated()));
+            Raise(command, new AppClientUpdated());
         }
 
         public void UploadImage(UploadAppImage command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppImageUploaded { Image = new AppImage(command.File.MimeType) }));
+            Raise(command, new AppImageUploaded { Image = new AppImage(command.File.MimeType) });
         }
 
         public void RemoveImage(RemoveAppImage command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppImageRemoved()));
+            Raise(command, new AppImageRemoved());
         }
 
         public void UpdateLanguage(UpdateLanguage command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppLanguageUpdated()));
+            Raise(command, new AppLanguageUpdated());
         }
 
         public void AssignContributor(AssignContributor command, bool isAdded)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppContributorAssigned { IsAdded = isAdded }));
+            Raise(command, new AppContributorAssigned { IsAdded = isAdded });
         }
 
         public void RemoveContributor(RemoveContributor command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppContributorRemoved()));
+            Raise(command, new AppContributorRemoved());
         }
 
         public void AttachClient(AttachClient command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppClientAttached()));
+            Raise(command, new AppClientAttached());
         }
 
         public void RevokeClient(RevokeClient command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppClientRevoked()));
+            Raise(command, new AppClientRevoked());
         }
 
         public void AddWorkflow(AddWorkflow command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppWorkflowAdded()));
+            Raise(command, new AppWorkflowAdded());
         }
 
         public void UpdateWorkflow(UpdateWorkflow command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppWorkflowUpdated()));
+            Raise(command, new AppWorkflowUpdated());
         }
 
         public void DeleteWorkflow(DeleteWorkflow command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppWorkflowDeleted()));
+            Raise(command, new AppWorkflowDeleted());
         }
 
         public void AddLanguage(AddLanguage command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppLanguageAdded()));
+            Raise(command, new AppLanguageAdded());
         }
 
         public void RemoveLanguage(RemoveLanguage command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppLanguageRemoved()));
+            Raise(command, new AppLanguageRemoved());
         }
 
         public void AddPattern(AddPattern command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppPatternAdded()));
+            Raise(command, new AppPatternAdded());
         }
 
         public void DeletePattern(DeletePattern command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppPatternDeleted()));
+            Raise(command, new AppPatternDeleted());
         }
 
         public void UpdatePattern(UpdatePattern command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppPatternUpdated()));
+            Raise(command, new AppPatternUpdated());
         }
 
         public void AddRole(AddRole command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppRoleAdded()));
+            Raise(command, new AppRoleAdded());
         }
 
         public void DeleteRole(DeleteRole command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppRoleDeleted()));
+            Raise(command, new AppRoleDeleted());
         }
 
         public void UpdateRole(UpdateRole command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppRoleUpdated()));
+            Raise(command, new AppRoleUpdated());
         }
 
         public void ArchiveApp(ArchiveApp command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AppArchived()));
+            Raise(command, new AppArchived());
         }
 
-        private void RaiseEvent(AppEvent @event)
+        private void Raise<T, TEvent>(T command, TEvent @event) where T : class where TEvent : AppEvent
         {
+            SimpleMapper.Map(command, @event);
+
             @event.AppId ??= Snapshot.NamedId();
 
             RaiseEvent(Envelope.Create(@event));

backend/src/Squidex.Domain.Apps.Entities/Assets/AssetDomainObject.cs

@@ -72,9 +72,9 @@ namespace Squidex.Domain.Apps.Entities.Assets
                     {
                         await GuardAsset.CanCreate(c, assetQuery);
 
-                        var tagIds = await NormalizeTagsAsync(c.AppId.Id, c.Tags);
+                        c.Tags = await NormalizeTagsAsync(c.AppId.Id, c.Tags);
 
-                        Create(c, tagIds);
+                        Create(c);
 
                         return Snapshot;
                     });
@@ -92,9 +92,9 @@ namespace Squidex.Domain.Apps.Entities.Assets
                     {
                         GuardAsset.CanAnnotate(c);
 
-                        var tagIds = await NormalizeTagsAsync(Snapshot.AppId.Id, c.Tags);
+                        c.Tags = await NormalizeTagsAsync(Snapshot.AppId.Id, c.Tags);
 
-                        Annotate(c, tagIds);
+                        Annotate(c);
 
                         return Snapshot;
                     });
@@ -133,9 +133,9 @@ namespace Squidex.Domain.Apps.Entities.Assets
             return new HashSet<string>(normalized.Values);
         }
 
-        public void Create(CreateAsset command, HashSet<string>? tagIds)
+        public void Create(CreateAsset command)
         {
-            var @event = SimpleMapper.Map(command, new AssetCreated
+            Raise(command, new AssetCreated
             {
                 MimeType = command.File.MimeType,
                 FileName = command.File.FileName,
@@ -143,45 +143,37 @@ namespace Squidex.Domain.Apps.Entities.Assets
                 FileVersion = 0,
                 Slug = command.File.FileName.ToAssetSlug()
             });
-
-            @event.Tags = tagIds;
-
-            RaiseEvent(@event);
         }
 
         public void Update(UpdateAsset command)
         {
-            var @event = SimpleMapper.Map(command, new AssetUpdated
+            Raise(command, new AssetUpdated
             {
                 MimeType = command.File.MimeType,
                 FileVersion = Snapshot.FileVersion + 1,
                 FileSize = command.File.FileSize
             });
-
-            RaiseEvent(@event);
         }
 
-        public void Annotate(AnnotateAsset command, HashSet<string>? tagIds)
+        public void Annotate(AnnotateAsset command)
         {
-            var @event = SimpleMapper.Map(command, new AssetAnnotated());
+            Raise(command, new AssetAnnotated());
-
-            @event.Tags = tagIds;
-
-            RaiseEvent(@event);
         }
 
         public void Move(MoveAsset command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AssetMoved()));
+            Raise(command, new AssetMoved());
         }
 
         public void Delete(DeleteAsset command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AssetDeleted { DeletedSize = Snapshot.TotalSize }));
+            Raise(command, new AssetDeleted { DeletedSize = Snapshot.TotalSize });
         }
 
-        private void RaiseEvent(AppEvent @event)
+        private void Raise<T, TEvent>(T command, TEvent @event) where T : class where TEvent : AppEvent
         {
+            SimpleMapper.Map(command, @event);
+
             @event.AppId ??= Snapshot.AppId;
 
             RaiseEvent(Envelope.Create(@event));

backend/src/Squidex.Domain.Apps.Entities/Assets/AssetFolderDomainObject.cs

@@ -96,26 +96,28 @@ namespace Squidex.Domain.Apps.Entities.Assets
 
         public void Create(CreateAssetFolder command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AssetFolderCreated()));
+            Raise(command, new AssetFolderCreated());
         }
 
         public void Move(MoveAssetFolder command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AssetFolderMoved()));
+            Raise(command, new AssetFolderMoved());
         }
 
         public void Rename(RenameAssetFolder command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AssetFolderRenamed()));
+            Raise(command, new AssetFolderRenamed());
         }
 
         public void Delete(DeleteAssetFolder command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new AssetFolderDeleted()));
+            Raise(command, new AssetFolderDeleted());
         }
 
-        private void RaiseEvent(AppEvent @event)
+        private void Raise<T, TEvent>(T command, TEvent @event) where T : class where TEvent : AppEvent
         {
+            SimpleMapper.Map(command, @event);
+
             @event.AppId ??= Snapshot.AppId;
 
             RaiseEvent(Envelope.Create(@event));

backend/src/Squidex.Domain.Apps.Entities/Assets/Commands/CreateAsset.cs

@@ -14,7 +14,7 @@ namespace Squidex.Domain.Apps.Entities.Assets.Commands
     {
         public DomainId ParentId { get; set; }
 
-        public HashSet<string> Tags { get; } = new HashSet<string>();
+        public HashSet<string> Tags { get; set; } = new HashSet<string>();
 
         public bool Duplicate { get; set; }
 

backend/src/Squidex.Domain.Apps.Entities/Contents/Commands/ValidateContent.cs

@@ -0,0 +1,13 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+namespace Squidex.Domain.Apps.Entities.Contents.Commands
+{
+    public sealed class ValidateContent : ContentCommand
+    {
+    }
+}

backend/src/Squidex.Domain.Apps.Entities/Contents/ContentDomainObject.cs

@@ -6,6 +6,7 @@
 // ==========================================================================
 
 using System;
+using System.Linq;
 using System.Threading.Tasks;
 using NodaTime;
 using Squidex.Domain.Apps.Core.Contents;
@@ -79,7 +80,7 @@ namespace Squidex.Domain.Apps.Entities.Contents
                 case CreateContent createContent:
                     return CreateReturnAsync(createContent, async c =>
                     {
-                        await LoadContext(c.AppId, c.SchemaId, c, c.OptimizeValidation);
+                        await LoadContext(c, c.OptimizeValidation);
 
                         await GuardContent.CanCreate(c, context.Workflow, context.Schema);
 
@@ -126,10 +127,22 @@ namespace Squidex.Domain.Apps.Entities.Contents
                         return Snapshot;
                     });
 
+                case ValidateContent validateContent:
+                    return UpdateReturnAsync(validateContent, async c =>
+                    {
+                        await LoadContext(c);
+
+                        var errors = await context.GetErrorsAsync(Snapshot.Data);
+
+                        var result = new ValidationResult { Errors = errors.ToArray() };
+
+                        return result;
+                    });
+
                 case CreateContentDraft createContentDraft:
                     return UpdateReturnAsync(createContentDraft, async c =>
                     {
-                        await LoadContext(Snapshot.AppId, Snapshot.SchemaId, c);
+                        await LoadContext(c);
 
                         GuardContent.CanCreateDraft(c, Snapshot);
 
@@ -143,7 +156,7 @@ namespace Squidex.Domain.Apps.Entities.Contents
                 case DeleteContentDraft deleteContentDraft:
                     return UpdateReturnAsync(deleteContentDraft, async c =>
                     {
-                        await LoadContext(Snapshot.AppId, Snapshot.SchemaId, c);
+                        await LoadContext(c);
 
                         GuardContent.CanDeleteDraft(c, Snapshot);
 
@@ -173,7 +186,7 @@ namespace Squidex.Domain.Apps.Entities.Contents
                     {
                         try
                         {
-                            await LoadContext(Snapshot.AppId, Snapshot.SchemaId, c);
+                            await LoadContext(c);
 
                             await GuardContent.CanChangeStatus(c, Snapshot, context.Workflow, context.Repository, context.Schema);
 
@@ -183,7 +196,7 @@ namespace Squidex.Domain.Apps.Entities.Contents
                             }
                             else
                             {
-                                var change = GetChange(c);
+                                var change = GetChange(c.Status);
 
                                 if (!c.DoNotScript && context.HasScript(c => c.Change))
                                 {
@@ -232,7 +245,7 @@ namespace Squidex.Domain.Apps.Entities.Contents
                 case DeleteContent deleteContent:
                     return UpdateAsync(deleteContent, async c =>
                     {
-                        await LoadContext(Snapshot.AppId, Snapshot.SchemaId, c);
+                        await LoadContext(c);
 
                         await GuardContent.CanDelete(c, Snapshot, context.Repository, context.Schema);
 
@@ -264,7 +277,7 @@ namespace Squidex.Domain.Apps.Entities.Contents
 
             if (!currentData!.Equals(newData))
             {
-                await LoadContext(Snapshot.AppId, Snapshot.SchemaId, command, command.OptimizeValidation);
+                await LoadContext(command, command.OptimizeValidation);
 
                 if (!command.DoNotValidate)
                 {
@@ -304,76 +317,85 @@ namespace Squidex.Domain.Apps.Entities.Contents
 
         public void Create(CreateContent command, Status status)
         {
-            RaiseEvent(SimpleMapper.Map(command, new ContentCreated { Status = status }));
+            Raise(command, new ContentCreated { Status = status });
 
             if (command.Publish)
             {
-                RaiseEvent(SimpleMapper.Map(command, new ContentStatusChanged { Status = Status.Published, Change = StatusChange.Published }));
+                var published = Status.Published;
+
+                Raise(command, new ContentStatusChanged { Status = published, Change = GetChange(published) });
             }
         }
 
         public void CreateDraft(CreateContentDraft command, Status status)
         {
-            RaiseEvent(SimpleMapper.Map(command, new ContentDraftCreated { Status = status }));
+            Raise(command, new ContentDraftCreated { Status = status });
         }
 
         public void Delete(DeleteContent command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new ContentDeleted()));
+            Raise(command, new ContentDeleted());
         }
 
         public void DeleteDraft(DeleteContentDraft command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new ContentDraftDeleted()));
+            Raise(command, new ContentDraftDeleted());
         }
 
         public void Update(ContentCommand command, NamedContentData data)
         {
-            RaiseEvent(SimpleMapper.Map(command, new ContentUpdated { Data = data }));
+            Raise(command, new ContentUpdated { Data = data });
         }
 
         public void ChangeStatus(ChangeContentStatus command, StatusChange change)
         {
-            RaiseEvent(SimpleMapper.Map(command, new ContentStatusChanged { Change = change }));
+            Raise(command, new ContentStatusChanged { Change = change });
         }
 
         public void CancelChangeStatus(ChangeContentStatus command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new ContentSchedulingCancelled()));
+            Raise(command, new ContentSchedulingCancelled());
         }
 
         public void ScheduleStatus(ChangeContentStatus command, Instant dueTime)
         {
-            RaiseEvent(SimpleMapper.Map(command, new ContentStatusScheduled { DueTime = dueTime }));
+            Raise(command, new ContentStatusScheduled { DueTime = dueTime });
         }
 
-        private void RaiseEvent(SchemaEvent @event)
+        private void Raise<T, TEvent>(T command, TEvent @event) where TEvent : SchemaEvent where T : class
         {
+            SimpleMapper.Map(command, @event);
+
             @event.AppId ??= Snapshot.AppId;
             @event.SchemaId ??= Snapshot.SchemaId;
 
             RaiseEvent(Envelope.Create(@event));
         }
 
-        private StatusChange GetChange(ChangeContentStatus command)
+        private StatusChange GetChange(Status status)
         {
-            var change = StatusChange.Change;
+            if (status == Status.Published)
-
-            if (command.Status == Status.Published)
             {
-                change = StatusChange.Published;
+                return StatusChange.Published;
             }
             else if (Snapshot.EditingStatus == Status.Published)
             {
-                change = StatusChange.Unpublished;
+                return StatusChange.Unpublished;
+            }
+            else
+            {
+                return StatusChange.Change;
             }
+        }
 
-            return change;
+        private Task LoadContext(ContentCommand command, bool optimized = false)
+        {
+            return context.LoadAsync(Snapshot.AppId, Snapshot.SchemaId, command, optimized);
         }
 
-        private Task LoadContext(NamedId<DomainId> appId, NamedId<DomainId> schemaId, ContentCommand command, bool optimized = false)
+        private Task LoadContext(CreateContent command, bool optimized = false)
         {
-            return context.LoadAsync(appId, schemaId, command, optimized);
+            return context.LoadAsync(command.AppId, command.SchemaId, command, optimized);
         }
     }
 }

backend/src/Squidex.Domain.Apps.Entities/Contents/Operations/ContentOperationContext.cs

@@ -146,6 +146,18 @@ namespace Squidex.Domain.Apps.Entities.Contents.Operations
             CheckErrors(validator);
         }
 
+        public async Task<IEnumerable<ValidationError>> GetErrorsAsync(NamedContentData data)
+        {
+            var validator =
+                new ContentValidator(Partition(),
+                    validationContext, validators, log);
+
+            await validator.ValidateInputAsync(data);
+            await validator.ValidateContentAsync(data);
+
+            return validator.Errors;
+        }
+
         public async Task ValidateOnPublishAsync(NamedContentData data)
         {
             if (!schema.SchemaDef.Properties.ValidateOnPublish)

backend/src/Squidex.Domain.Apps.Entities/Contents/ValidationResult.cs

@@ -0,0 +1,16 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using Squidex.Infrastructure.Validation;
+
+namespace Squidex.Domain.Apps.Entities.Contents
+{
+    public sealed class ValidationResult
+    {
+        public ValidationError[] Errors { get; set; }
+    }
+}

backend/src/Squidex.Domain.Apps.Entities/Rules/RuleDomainObject.cs

@@ -121,31 +121,33 @@ namespace Squidex.Domain.Apps.Entities.Rules
 
         public void Create(CreateRule command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new RuleCreated()));
+            Raise(command, new RuleCreated());
         }
 
         public void Update(UpdateRule command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new RuleUpdated()));
+            Raise(command, new RuleUpdated());
         }
 
         public void Enable(EnableRule command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new RuleEnabled()));
+            Raise(command, new RuleEnabled());
         }
 
         public void Disable(DisableRule command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new RuleDisabled()));
+            Raise(command, new RuleDisabled());
         }
 
         public void Delete(DeleteRule command)
         {
-            RaiseEvent(SimpleMapper.Map(command, new RuleDeleted()));
+            Raise(command, new RuleDeleted());
         }
 
-        private void RaiseEvent(AppEvent @event)
+        private void Raise<T, TEvent>(T command, TEvent @event) where T : class where TEvent : AppEvent
         {
+            SimpleMapper.Map(command, @event);
+
             @event.AppId ??= Snapshot.AppId;
 
             RaiseEvent(Envelope.Create(@event));

backend/src/Squidex.Domain.Apps.Entities/Schemas/SchemaDomainObject.cs

@@ -270,106 +270,106 @@ namespace Squidex.Domain.Apps.Entities.Schemas
 
             foreach (var @event in events)
             {
-                RaiseEvent(SimpleMapper.Map(command, (SchemaEvent)@event));
+                Raise(command, @event);
             }
         }
 
         public void Create(CreateSchema command)
         {
-            RaiseEvent(command, new SchemaCreated { SchemaId = NamedId.Of(command.SchemaId, command.Name), Schema = command.BuildSchema() });
+            Raise(command, new SchemaCreated { SchemaId = NamedId.Of(command.SchemaId, command.Name), Schema = command.BuildSchema() });
         }
 
         public void Add(AddField command)
         {
-            RaiseEvent(command, new FieldAdded { FieldId = CreateFieldId(command) });
+            Raise(command, new FieldAdded { FieldId = CreateFieldId(command) });
         }
 
         public void UpdateField(UpdateField command)
         {
-            RaiseEvent(command, new FieldUpdated());
+            Raise(command, new FieldUpdated());
         }
 
         public void LockField(LockField command)
         {
-            RaiseEvent(command, new FieldLocked());
+            Raise(command, new FieldLocked());
         }
 
         public void HideField(HideField command)
         {
-            RaiseEvent(command, new FieldHidden());
+            Raise(command, new FieldHidden());
         }
 
         public void ShowField(ShowField command)
         {
-            RaiseEvent(command, new FieldShown());
+            Raise(command, new FieldShown());
         }
 
         public void DisableField(DisableField command)
         {
-            RaiseEvent(command, new FieldDisabled());
+            Raise(command, new FieldDisabled());
         }
 
         public void EnableField(EnableField command)
         {
-            RaiseEvent(command, new FieldEnabled());
+            Raise(command, new FieldEnabled());
         }
 
         public void DeleteField(DeleteField command)
         {
-            RaiseEvent(command, new FieldDeleted());
+            Raise(command, new FieldDeleted());
         }
 
         public void Reorder(ReorderFields command)
         {
-            RaiseEvent(command, new SchemaFieldsReordered());
+            Raise(command, new SchemaFieldsReordered());
         }
 
         public void Publish(PublishSchema command)
         {
-            RaiseEvent(command, new SchemaPublished());
+            Raise(command, new SchemaPublished());
         }
 
         public void Unpublish(UnpublishSchema command)
         {
-            RaiseEvent(command, new SchemaUnpublished());
+            Raise(command, new SchemaUnpublished());
         }
 
         public void ConfigureScripts(ConfigureScripts command)
         {
-            RaiseEvent(command, new SchemaScriptsConfigured());
+            Raise(command, new SchemaScriptsConfigured());
         }
 
         public void ConfigureFieldRules(ConfigureFieldRules command)
         {
-            RaiseEvent(command, new SchemaFieldRulesConfigured { FieldRules = command.ToFieldRules() });
+            Raise(command, new SchemaFieldRulesConfigured { FieldRules = command.ToFieldRules() });
         }
 
         public void ChangeCategory(ChangeCategory command)
         {
-            RaiseEvent(command, new SchemaCategoryChanged());
+            Raise(command, new SchemaCategoryChanged());
         }
 
         public void ConfigurePreviewUrls(ConfigurePreviewUrls command)
         {
-            RaiseEvent(command, new SchemaPreviewUrlsConfigured());
+            Raise(command, new SchemaPreviewUrlsConfigured());
         }
 
         public void ConfigureUIFields(ConfigureUIFields command)
         {
-            RaiseEvent(command, new SchemaUIFieldsConfigured());
+            Raise(command, new SchemaUIFieldsConfigured());
         }
 
         public void Update(UpdateSchema command)
         {
-            RaiseEvent(command, new SchemaUpdated());
+            Raise(command, new SchemaUpdated());
         }
 
         public void Delete(DeleteSchema command)
         {
-            RaiseEvent(command, new SchemaDeleted());
+            Raise(command, new SchemaDeleted());
         }
 
-        private void RaiseEvent<TCommand, TEvent>(TCommand command, TEvent @event) where TCommand : class where TEvent : SchemaEvent
+        private void Raise<T, TEvent>(T command, TEvent @event) where TEvent : SchemaEvent where T : class
         {
             SimpleMapper.Map(command, @event);
 
@@ -383,13 +383,13 @@ namespace Squidex.Domain.Apps.Entities.Schemas
                 return null;
             }
 
-            if (command is ParentFieldCommand pc && @event is ParentFieldEvent pe)
+            if (command is ParentFieldCommand parentField && @event is ParentFieldEvent parentFieldEvent)
             {
-                if (pc.ParentFieldId.HasValue)
+                if (parentField.ParentFieldId.HasValue)
                 {
-                    if (Snapshot.SchemaDef.FieldsById.TryGetValue(pc.ParentFieldId.Value, out var field))
+                    if (Snapshot.SchemaDef.FieldsById.TryGetValue(parentField.ParentFieldId.Value, out var field))
                     {
-                        pe.ParentFieldId = field.NamedId();
+                        parentFieldEvent.ParentFieldId = field.NamedId();
 
                         if (command is FieldCommand fc && @event is FieldEvent fe)
                         {
@@ -406,11 +406,8 @@ namespace Squidex.Domain.Apps.Entities.Schemas
                 }
             }
 
-            RaiseEvent(@event);
+            SimpleMapper.Map(command, @event);
-        }
 
-        private void RaiseEvent(SchemaEvent @event)
-        {
             @event.AppId ??= Snapshot.AppId;
             @event.SchemaId ??= Snapshot.NamedId();
 

backend/src/Squidex.Web/ApiExceptionConverter.cs

@@ -83,7 +83,7 @@ namespace Squidex.Web
             switch (exception)
             {
                 case ValidationException ex:
-                    return (CreateError(400, T.Get("common.httpValidationError"), ToDetails(ex)), true);
+                    return (CreateError(400, T.Get("common.httpValidationError"), ToErrors(ex.Errors).ToArray()), true);
 
                 case DomainObjectNotFoundException _:
                     return (CreateError(404), true);
@@ -121,7 +121,7 @@ namespace Squidex.Web
             return error;
         }
 
-        private static string[] ToDetails(ValidationException ex)
+        public static IEnumerable<string> ToErrors(IEnumerable<ValidationError> errors)
         {
             static string FixPropertyName(string property)
             {
@@ -155,7 +155,7 @@ namespace Squidex.Web
                 return builder.ToString();
             }
 
-            return ex.Errors.Select(e =>
+            return errors.Select(e =>
             {
                 if (e.PropertyNames?.Any() == true)
                 {
@@ -165,7 +165,7 @@ namespace Squidex.Web
                 {
                     return e.Message;
                 }
-            }).ToArray();
+            });
         }
     }
 }

backend/src/Squidex/Areas/Api/Controllers/Contents/ContentsController.cs

@@ -285,6 +285,36 @@ namespace Squidex.Areas.Api.Controllers.Contents
             return Ok(response);
         }
 
+        /// <summary>
+        /// Get a content item validity.
+        /// </summary>
+        /// <param name="app">The name of the app.</param>
+        /// <param name="name">The name of the schema.</param>
+        /// <param name="id">The id of the content to fetch.</param>
+        /// <returns>
+        /// 200 => Content validation result returned.
+        /// 404 => Content, schema or app not found.
+        /// </returns>
+        /// <remarks>
+        /// You can read the generated documentation for your app at /api/content/{appName}/docs.
+        /// </remarks>
+        [HttpGet]
+        [Route("content/{app}/{name}/{id}/validity")]
+        [ProducesResponseType(typeof(ValidationResultDto), 200)]
+        [ApiPermissionOrAnonymous]
+        [ApiCosts(1)]
+        public async Task<IActionResult> GetContentValidity(string app, string name, DomainId id)
+        {
+            var command = new ValidateContent { ContentId = id };
+
+            var context = await CommandBus.PublishAsync(command);
+
+            var result = context.Result<ValidationResult>();
+            var response = ValidationResultDto.FromResult(result);
+
+            return Ok(response);
+        }
+
         /// <summary>
         /// Get all references of a content.
         /// </summary>

backend/src/Squidex/Areas/Api/Controllers/Contents/Models/ValidationResultDto.cs

@@ -0,0 +1,29 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using System.Linq;
+using Squidex.Domain.Apps.Entities.Contents;
+using Squidex.Web;
+
+namespace Squidex.Areas.Api.Controllers.Contents.Models
+{
+    public class ValidationResultDto
+    {
+        /// <summary>
+        /// The validation errors.
+        /// </summary>
+        public string[] Errors { get; set; }
+
+        public static ValidationResultDto FromResult(ValidationResult result)
+        {
+            return new ValidationResultDto
+            {
+                Errors = ApiExceptionConverter.ToErrors(result.Errors).ToArray()
+            };
+        }
+    }
+}

backend/tests/Squidex.Domain.Apps.Entities.Tests/Contents/ContentDomainObjectTests.cs

@@ -5,6 +5,7 @@
 //  All rights reserved. Licensed under the MIT license.
 // ==========================================================================
 
+using System;
 using System.Linq;
 using System.Threading.Tasks;
 using FakeItEasy;
@@ -592,6 +593,20 @@ namespace Squidex.Domain.Apps.Entities.Contents
             await PublishAsync(command);
         }
 
+        [Fact]
+        public async Task Validate_should_not_update_state()
+        {
+            await ExecuteCreateAsync();
+
+            var command = new ValidateContent();
+
+            var result = await PublishAsync(command);
+
+            result.ShouldBeEquivalent(new ValidationResult { Errors = Array.Empty<ValidationError>() });
+
+            Assert.Equal(0, sut.Snapshot.Version);
+        }
+
         [Fact]
         public async Task Delete_should_create_events_and_update_deleted_flag()
         {