Fiori Support ​

See Advanced > Draft-based Editing for an overview on SAP Fiori Draft support in CAP.

Lean Draft ​

Lean draft is a new approach which makes it easier to differentiate between drafts and active instances in your code. This new architecture drastically reduces the complexity and enables more features like storing active instances in remote systems while keeping the corresponding drafts in the local persistence.

Enablement ​

Lean draft is enabled by default. Add this to your cds configuration to disable the feature:

{
  "cds": {
    "fiori": {
      "lean_draft": false
    }
  }
}

Handlers Registration ​

Class ApplicationService provides built-in support for Fiori Draft. All CRUD events are supported for both, active and draft entities. Please note that draft-enabled entities must follow a specific draft choreography.

The examples are provided for on handlers, but the same is true for before and after handlers.

// only active entities
srv.on(['CREATE', 'READ', 'UPDATE', 'DELETE'], 'MyEntity', /*...*/)
// only draft entities
srv.on(['CREATE', 'READ', 'UPDATE', 'DELETE'], 'MyEntity.drafts', /*...*/)
// bound action/function on active entity
srv.on('boundActionOrFunction', 'MyEntity', /*...*/)
// bound action/function on draft entity
srv.on('boundActionOrFunction', 'MyEntity.drafts', /*...*/)

It's also possible to use the array variant to register a handler for both entities, for example: srv.on('boundActionOrFunction', ['MyEntity', 'MyEntity.drafts'], /*...*/).

Additionally, you can add your logic to the draft-specific events as follows:

// When a new draft is created
srv.on('NEW', 'MyEntity.drafts', /*...*/)
// When a draft is discarded
srv.on('CANCEL', 'MyEntity.drafts', /*...*/)
// When a new draft is created from an active instance
srv.on('EDIT', 'MyEntity', /*...*/)
// When the active entity is changed
srv.on('SAVE', 'MyEntity', /*...*/)

• The CANCEL event is triggered when you cancel the draft. In this case, the draft entity is deleted and the active entity isn't changed.
• The EDIT event is triggered when you start editing an active entity. As a result MyEntity.drafts is created.
• The SAVE event is just a shortcut for ['UPDATE', 'CREATE'] on an active entity. This event is also triggered when you press the SAVE button in UI after finishing editing your draft. Note, that composition children of the active entity will also be updated or created.

For compatibility to previous variants, set `cds.fiori.draft_compat` to `true`.

Draft Locks ​

To prevent inconsistency, the entities with draft are locked for modifications by other users. The lock is released when the draft is saved, canceled or a timeout is hit. The default timeout is 15 minutes. You can configure this timeout by the following application configuration property:

cds.drafts.cancellationTimeout=1h

Differences to Previous Version ​

• Draft-enabled entities have corresponding CSN entities for drafts:

  js

  const { MyEntity } = srv.entities
  MyEntity.drafts // points to model.definitions['MyEntity.drafts']

• Queries are now cleansed from draft-related properties (like IsActiveEntity)

• PATCH event isn't supported anymore.

• The target is resolved before the handler execution and points to either the active or draft entity:

  js

  srv.on('READ', 'MyEntity.drafts', (req, next) => {
    assert.equal(req.target.name, 'MyEntity.drafts')
    return next()
  })

  Special case: "Editing Status: All"

  In the special case of the Fiori Elements filter "Editing Status: All", two separate READ events are triggered for either the active or draft entity. The individual results are then combined behind the scenes. Draft entries are always positioned on top of active ones.

• Draft-related properties (with the exception of IsActiveEntity) are only computed for the target entity, not for expanded sub entities since this is not required by Fiori Elements.

• Manual filtering on draft-related properties is not allowed, only certain draft scenarios are supported.