Event Sourced Content Repository Collection

This is the package bundle you can install alongside a plain Neos to play around with the event-sourced CR.

Feature comparison

✅ Done

⏩ Currently worked on

🚫 Will not be supported

Feature	Current CR	Event Sourced CR
Basics
Create/ Edit / Delete Nodes	✅	✅
Shortcut Handling	✅	⏩
Query Nodes	✅	✅
Cut / Copy / Paste	✅	✅
Move Nodes	✅	✅
Hide Nodes	✅	✅
History	(✅)
Basic Workspaces	✅	✅
Workspace Module	✅	⏩
Nested Workspaces	✅
Undo / Redo	🚫
Setting Start / End time	✅	EASY
Resolving Referencing Nodes	🚫	✅
Menu Rendering	✅	✅
Dimension Menu Rendering	✅	✅
Supporting "not in menu"	✅	✅
Change node type	✅	✅
Advanced
Dimensions	✅	✅
Dimension Fallback	✅	✅
Multiple Sites	✅	✅
Permissions / Policy	✅
Maintenance
Export / Import	✅	✅⏩
Node Migrations	✅	⏩ (MEDIUM)
Node Repair	✅	✅
Integrity Checks	🚫	⏩
API
Separate Read and Write API	🚫	✅
More convenient write API
FlowQuery is compatible	✅	✅
Advanced test cases	🚫	✅
Don't use ORM, but direct SQL queries	🚫	✅
Asynchronous operations possible	🚫	✅
performant node moving	🚫	✅
performant node deletion	🚫	✅
near-constant read performance	🚫	✅
User Interface
Ensure node deletion can be published in UI	✅
Support Dimension Constraints	✅
Publish Workspace	✅	✅
Publish Current Page	✅	✅
Discard all	✅	✅
Discard Current Page	✅	✅

Requirements

DB

The Event Sourced Content Repository relies on a feature called (Recursive) Common Table Expressions (CTE) that require

• MySQL: 8.0+
• MariaDB: 10.2.2+

Lateron, we will also support PostgreSQL. (We know it will work, but we did not create migrations or did testing yet).

PHP

The new code should be compatible with PHP 7.4

Getting Started / Installation

See https://github.com/neos/neos-development-distribution/tree/event-sourced

Road to first running beta

• create standalone package collection instead of branches
• command to import from NodeData to events
• make it work with Neos.ContentRepository.DimensionSpace package
• ensure Behavioral Tests run again
• Update CR for Neos 5
• Update EventSourcedNeosAdjustments for Neos 5
• Content Cache (#103)
• ensure Functional Tests run again
• figure out how/if to use event sourced Site/Domain (!possibly difficult!) -> fixed; won't use event sourced site/domain
• change RoutePart Handler when using event-sourced mode
• adjust NodeController when using event-sourced mode
• add switch to use event-sourced read model in Fusion rendering (!possibly difficult due to method signatures!)
• allow to open User Interface based on Event-Sourced read model
• implement Show/Hide of nodes (recursively)
• create Commands in response to UI interaction
  • SetProperty command
  • CreateNode
  • MoveNode
  • ShowNode
  • DisableNode
• create feature list in this README, detailing what is supported and what not yet.
• support empty content dimension values in URL; e.g. "/de/..." for german, and "/..." for english
• absolute node referencing for ContentCollection (e.g. shared footer in Demo Site)
• fix Policy handling to configure permissions for various UI parts
• fix structure tree
• show correct workspace state after reload (top publish button)
• [?] fix inline linking
• fix node tree search
• [?] fix node tree filter
• Implement Node Repair
• (further TODOs here; this list is not complete yet)

Technical Description (for developers)

This section should give an overview about the different involved packages, to ease understanding the different moving parts.

Neos.ContentRepository

see https://github.com/neos/neos-development-collection/pull/2202 for the Pull Request.

• in namespace Domain\Projection\Content, the new NodeInterface and TraversableNodeInterface are defined.
• in namespace Domain\ValueObject, corresponding value objects are defined.
• the old Neos\ContentRepository\Domain\Model\Node implements the full new NodeInterface and most of TraversableNodeInterface. This is needed to ensure we can build FlowQuery implementations which can work with old and new API at once.
• adjusted FlowQuery operations to TraversableNodeInterface (TODO not yet all of them)

Neos.Neos

see https://github.com/neos/neos-development-collection/pull/2202 for the Pull Request.

• various detail improvements to use TraversableNodeInterface in the core (e.g. FusionView)

Neos.ContentRepository.DimensionSpace

APIs to query the configured dimension space

CR / Neos.EventSourcedContentRepository

Transition package implementing the event sourced CR core. In the longer run, will probably be merged into Neos.ContentRepository.

• Domain\Context\* implements Commands, Command Handlers, Events for Workspace, Content Stream, Nodes
• Domain\Projection\* implements projections for changes, workspace listing; and contains the definition for the main Content Graph projection (ContentGraphInterface and ContentSubgraphInterface)

CR / Neos.ContentGraph.DoctrineDbalAdapter

implementation of the ContentGraphInterface and ContentSubgraphInterface using MySQL queries.

CR / Neos.EventSourcedNeosAdjustments

It turns out that there are numerous changes needed to the details of Neos.Neos - so this package hooks into various places in the Neos lifecycle to override certain Neos functionality.

We often completely override certain classes / behaviors from the Neos core completely; so that should make merging the changes back to the Neos.Neos package at some point a lot easier because we can then replace full classes instead of only individual pieces.

This package consists of the following bounded contexts, listed in their order during request processing:

NodeImportFromLegacyCR

This contains a CommandController and a service to generate events from reading NodeData. It can be activated using the new CLI command.

EventSourcedRouting

We replace the default FrontendNodeRoutePartHandler by providing an extra implementation of FrontendNodeRoutePartHandlerInterface.

Activation: We replace the implementation of FrontendNodeRoutePartHandlerInterface in Objects.yaml.

• internally, the Http and Routing namespaces are used for behaviours internal to the routing.

EventSourcedFrontController

This is a replacement for Frontend\NodeController of Neos.Neos.

Activation: We trigger this controller by AOP (in NodeControllerAspect): We call the new controller when processRequest() is called for the Neos controller.

Fusion

• We replace certain Fusion implementations which are already re-implemented to work more efficiently with the ContentGraph API; and which implement linking (because this API also changed). This includes:

  • Menu / DimensionMenu
  • NodeUri, ConvertUris
  • ContentElementEditable / ContentElementWrapping (because the ContentElementWrapping service has changed quite a lot)
  • Activation: using fusion autoInclude in Settings.yaml, we load the Fusion file resource://Neos.EventSourcedNeosAdjustments/Private/Fusion/Root.fusion. This Root.fusion replaces the implementations for the aforementioned Fusion objects, so things work as expected for integrators (without new namespaces).

• Eel NodeHelper and WorkspaceHelper

  • Activation: These helpers are registered under the names Neos.EventSourcedNeosAdjustments.*; so a separate name. These helpers are explicitely used in the Root.fusion mentioned a few lines above.

• custom ExceptionHandler because this also needs the replacement ContentElementWrappingService.

  • Activation: This helper is used as exception handlers in the Root.fusion mentioned a few lines above.
  • If people used these exception handlers themselves, they need to reconfigure them to the new implementations.

Fluid

• We replace Linking and Content Element Wrapping ViewHelpers, because Node Linking has changed and ContentElementWrapping has changed as well.
  • Activation: Using AOP, the ViewHelperReplacementAspect implements aliasing of ViewHelper classes; effectively returning the VHs in this namespace instead of the default ones.

ContentElementWrapping

We implement a completely new ContentElementWrappingService and ContentElementWrappingService; mainly because they change quite a bit and their interfaces now require TraversableNodeInterface instead of the legacy NodeInterface.

The new services are used in the overridden ViewHelpers (see section Fluid above); and in overridden Fusion implementations (see section Fusion above).

NodeAddress (Domain\Context\Content)

A NodeAddress is an external representation of a node (used in routing). TODO: Move to Neos.EventSourcedContentRepository.

Ui

• BackendController is an alternative implementation for Neos.Neos.Ui BackendController.
  • Activation: We trigger this controller by AOP (in BackendControllerAspect): We call the new controller when processRequest() is called for the Neos backend controller.
• We create Content Streams on backend login using the EditorContentStreamZookeeper (TODO change name maybe?).
  • Activation: We trigger this service by Signal/Slot in Package.php.
• Fusion (for backend)
  • Activation: We load a custom resource://Neos.EventSourcedNeosAdjustments/Private/Fusion/Backend/Root.fusion using Views.yaml.
  • custom NodeInfoHelper, calling to a custom NodePropertyConverterService
• adjust the DimensionSwitcher JS component in Resources/Private/UiAdapter
• TODO: this is not everything yet.