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Workshop Rights & Roles 2017-11

see also #7089 for details on Project specific requirements, TODOs for open questions, etc,

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

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


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.

private-entity-graphs.JPG

As long as as private entity graph is completely disconnected from the rest of the world the case is quite simple. But it is getting more difficult 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. Updated by can't be changed back to the creator as the creator does not have update rights on something he/she currently does not own.

In both cases 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. An 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 B in turn of the two cases described above.

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

Strategy 1 - "Publish View"

A "view" has associations to all entities which are included into the view.

Views potentially can replace general UPDATE & READ permissions. In this case Users are participants of specific views by being associated with it.

The views strategy opens a mechanism to handle those events when a private entity graph is becoming connected to a non private entity which causes the graph or parts of being blocked:

strategy_1.jpg

  1. The private entity graph get associated with a non private entitiy
  2. The formerly entity TypeD is now blocked and can in principle no longer be edited by the user having only the CREATE authority.
  3. depending on the project preferences the entity TypeD is
    • made public automatically by asscoiating it with the 'PublishView'
    • is put into the 'PublishView' manually in an editorial, curatorial process

As noted in point 2) editing of TypeD is only blocks in principal but can be allowed as long it is not incorporated into the 'PublishView'. So this strategy can replace the strategy 2b) which also allows to continue to edit blocked private entity graphs.

Different views can exist 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.

Strategy 2 - "Per property permissions"

strategy_2.jpg

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 a 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. can be replaced by strategy 1)

Strategy 3 - "Unpublished Entities - general READ rights"

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

strategy_3.jpg

In publication tools we need different possibilities to filter:
Filtered DTOs to provide DTOs containing only information 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 information (undisclosed entities)

Strategy 4

Managing referencing objects information in the referenced CDM entity.

strategy_4.JPG

Implementing this strategy involves a model change. CDM classes will be extended by adding the below fields for each collection of CDM entities. These can either go 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 hold of the referencing 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 one 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_5.jpg

Introduction of two new method level java annotations by which the blocking nature of a property can be expresses (see above for more details on blocking):

  • @isBlockedBy: Annotation for the arrow end, head, of the directed edge.
  • @isBlocking : Annotation for the tail of the the directed edge.

These annotations are being interpreted by business logic classes which implement the propagation of blocking events in the private entity graphs. This propagation can lead to an decision to

  • A. implicit deny editing of the entities in the subgraph
  • B. withdraw previously granted per entity permissions (see strategy 6)

Strategy 6

strategy_6.jpg

Explicitly grant and withdraw per entity granted authorities as currently implemented for the phycobank registry (see #6867 & #4305)

per_entity_permissions_and_groups.jpg

The per entity granted authorities are either directly associated with the user or could be assigned to per user permission groups. The idea of per user permission groups is lend from unix where a group is being created by default for each user.

Strategy 7

strategy_7.jpg

This is the concept of having an explicit workflow state information for an entity type as it is implemented for the Registration class. We might want to implement workflow states for each CDM type. By this is would for example become possible to create a new Term, use it immediately even if not yet published. The term will undergo a review process during which the decision is being made whether to publish it or not.

  • This strategy implies strategy 5
  • This strategy can be replaced by strategy 1

(BTW: The flowers are artwork painted by AMs' daughters)

Use Cases

Usecases.JPG

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.

Table 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 be 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 does not involve the creation of a private entity graph.
  • TODO ... to be continued

Combing GrantedAuthorities

GrantedAuthorities_1.jpg

  • The class CdmAuthority needs to become a cdm model class which replaces, extends GrantedAutorityImpl.

GrantedAuthorities_2.jpg

GrantedAuthorities_2.jpg View (844 KB) Andreas Kohlbecker, 11/29/2017 02:12 PM

strategy_2.jpg View (258 KB) Andreas Kohlbecker, 11/29/2017 02:12 PM

per_entity_permissions_and_groups.jpg View (688 KB) Andreas Kohlbecker, 11/29/2017 02:12 PM

strategy_3.jpg View (162 KB) Andreas Kohlbecker, 11/29/2017 02:12 PM

strategy_4.JPG View (471 KB) Andreas Kohlbecker, 11/29/2017 02:12 PM

strategy_5.jpg View (180 KB) Andreas Kohlbecker, 11/29/2017 02:12 PM

strategy_7.jpg View (278 KB) Andreas Kohlbecker, 11/29/2017 02:12 PM

Usecases.JPG View (923 KB) Andreas Kohlbecker, 11/29/2017 02:12 PM

private-entity-graphs.JPG View (1020 KB) Andreas Kohlbecker, 11/29/2017 02:13 PM

strategy_1.jpg View (207 KB) Andreas Kohlbecker, 11/29/2017 02:22 PM

strategy_6.jpg View (101 KB) Andreas Kohlbecker, 11/29/2017 02:23 PM

GrantedAuthorities_1.jpg View (739 KB) Andreas Kohlbecker, 11/30/2017 10:19 AM

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