Workshop Rights & Roles 2017-11¶

see also #7089

Results of the Rights & Roles workshop held on November 27th - 30th at the BGBM.

Attendees: Andreas Kohlbecker, Katja Luther, Andreas Müller, Patrick Plitzner

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Continued create problem and private entity graphs¶

The "continued create" problem exists in cases when a user only is granted to perform CREATE operations for a specific entity type but misses having the UPDATE grant. Users may need to continue to edit the newly created entity and other new parts in the connected entity graph.

In consideration of this problem we introduced the concept of directed "private entity graphs". Private entity graphs are owned by the creator of all entities involved. An entity is owned by the creating user as long the createdBy and updatedBy are equal.

As long a private entity graph is completely disconnected from the rest of the world the case is quite simple. But it is getting fare more interesting once

A. the graph is becoming associated to other entities which are not owned by the creator of the private entity graph.
B. an entity inside this graph is being updated by another user. This changes the updatedBy property and this entity is no longer owned by the creator.

In both cases the this "ownership" change needs to propagate through the graph to other entities. This propagation travels along the directed edges of the graph. This directional property of the edges is expressed in the diagrams above by red arrow heads whereas the arrow head can be dashed. A dashed arrow head means that it is optional depending on the specific project requirements. A entity A which is connected by a directed edge with an entity B (A<----B) provides data for B from which B essentially depends. A cannot be changed without implicitly changing B. That B potentially blocks modifications of A. This blocking actually manifests when the "owning" user of A loses the exclusive ownership of in turn of the tow cases described above.

The blocking nature of an edge, that is of a entity class property, can be expressed in the model classes by introducing according annotations. See strategy 5).

Strategy 1 - "Publish View"¶

This strategy works with different views for published data and data in review (maybe there are more views if the project needs more states). Data which are "under constructions" can be updated by the original owner and are not visible to the public.
When the created/updated data are reviewed they are added to the "publish view". With this action the update rights can be removed from the creator, if they should not be editable by "normal" users.

Depending on the role of the creator or the workflow of the project the new created object can be added to the publish view immediately or managed.

Strategy 2 - "Per property permissions"¶

Grant authorities per entity class property.

2a)
For non cdm-entity properties this allows users to edit this and only this specific field.

2b)

For cdm-entity properties, this allows to express that a user can continue to edit an owned entity or private entity graph despite the fact that it is associated to an non-private entity which is connected via a "blocking" relation. Without this explicit per property permission the formerly private entity and subsequently parts of the private entity graph would be blocked by creating this relation.

Strategy 3 - "Unpublished Entities - general READ rights"¶

This strategy must be implemented in any case, since reneral READ permissions are a requirement in multiple projects. Euro+Med is an example.

In publication tools we need different possibilities to filter:
Filtered DTOs to provide DTOs containing only informations the user has the permissions to see.
For the case of collections of cdm entities the user has the permission to see them and cdm entities the user has no permission to see, we need filtered collections for the service layer.

The editor does not need filter but it should be possible to hide informations (undisclosed entities)

Strategy 4¶

Managing referencing objects information in the referenced cdm entity.

Implementing this strategy involves a model change. Cdm classes will be extended by adding the below fields for each collections of cdm entities. Theses can either got directly into the entity class or may be implemented by introducing a separate Class to hold this information. The benefit of the latter option is that updating the referencing objects information is not causing an update of the referenced entity record. In the first case it is needed to suppress auditing and changes of the updatedBy and updatedWhen fields of the referenced entity.

Explicitly managing and persisting the referencing objects information avoids excessive database querying in order to find the referencing objects via the ICdmGenericDao.getReferencingObjects(CdmBase referencedCdmBase) method. To determine the bounds of private entity graphs it is not needed to get old of the referecing objects, it merely is sufficient to know if there are more than one different users owning the referencing objects.

• User {collection_property_name}FirstReferencingObjectsUser: A reference to the the user which was the in the 'updatedBy' field of the first entity ever referencing this object.
  
• boolean {collection_property_name}IsMultiplyReferenced: true if there are more then one referencing objects (optionally as count value?)
• boolean {collection_property_name}IsReferencedByMultiplyOwnedEntities: true if the referencing objects are "owned" by multiple users. (optionally as count value?)

The semantics of "owned" in the context of this strategy refers to the user referenced in the updatedBy field. In case updatedBy is null it refers to createdBy. This semantics of ownership is different to that in the private entity graphs!

TODO: Why is {collection_property_name}FirstReferencingObjectsUser needed and how can this information be updated once the according referencing entity is updated by a different user?

Strategy 5¶

Strategy 6¶

Strategy 7¶

Use Cases¶

Table of use cases in which users which only CREATE authorities need to perform continued editing. That is these are use cases in which the private entity graphs are relevant which can be connected to non-private entities. The acronym DS used in here refers to the term Data Slave which has been used as jocular term for users which only CREATE authorities for specific entity types.

Tables columns:

• no review: The newly created entities are becoming immediately public
• in review/reviewed: The newly created entities are first being reviewed before becoming public. Maybe the publication is rejected by the reviewer.
  

In both columns the strategies required to realize the use case are noted. Often strategies need to combined, this is expressed by +, optionally strategies are in brackets (). || mean OR and expresses alternative combinations of strategies.

Use cases

• DS-non-entity: editing of a single non cdm entity property like a persistent ID, geo reference, etc. This is a special case since it not involves the creating of a private entity graph.
• TODO ... to be continued

Combing GrantedAuthorities¶