Tags are used to describe the status of an object within a process chain independently of the object's metadata, which means no need of definition in the schema and no triggering of new versions.

Introduction

In document lifecycle management, multi-stage and asynchronous processes are not uncommon—quite the contrary. The first process steps are carried out with the highest priority. More complex and currently not absolutely essential process steps are carried out asynchronously with a lower priority. This saves time, and carrying out operations in parallel lets you distribute resources more evenly. To resume a process chain, additional information about the current status of the process is necessary. In order to not mix an object's metadata with its status data, there is the possibility to tag objects. 

Objects can be searched by tags and selected for the next process step. All tagging activities are recorded by the yuuvis® system in the object history (Audit Trail). Thanks to this, you can always retrace who has done what and when. Trouble shooting, reporting on the process status or general issues are made easy by this centrally stored history.

Characteristics of Tags

• Tags describe the status of an object in a process chain.
• Tags can be added to any object. They are stored together with the object.
• Multiple tags can be added to one object.
• The tags specify the status information via an integer value. Additionally, tags have a unique process number that can be set during the tag creation or will be randomly set after any tag operation.
• Any tag operation is documented in the object audit trail.
• Tags do not belong to the metadata and thus do not need to be defined in the schema. Moreover, tag operations do not lead to the creation of a new object version.
• Tags are always available for the current object version.
• The properties of tags are included in the searchable data.

The special feature of tags is the independence of versioning and schema definitions. The tags of an object are always attached to the current version, whereas previous versions cannot have tags. For version-specific information, metadata provide the suitable options. They have to be defined in the Schema.

Tag Management

Endpoints

Tags can be set in any object creation body in the system property system:tags. In the same way, it is also possible to set tags for the new version of an object in any POST/PATCH update call. A POST update without the explicit specification of already existing tags will remove them from the corresponding object.

Furthermore, there are endpoints for pure tag operations that do not trigger a new version of the corresponding object, but only a new entry in the audit trail:

• Retrieve object tags by ID – GET /api/dms/objects/{objectId}/tags
• Add object tag by ID – POST /api/dms/objects/{objectId}/tags/{name}/state/{state}
• Update object tag by ID – POST /api/dms/objects/{objectId}/tags/{name}/state/{state}?overwrite=true
• Delete object tag by ID – DELETE /api/dms/objects/{objectId}/tags/{name}
• Add/update object tag by search query – POST /api/dms/objects/tags/{name}/state/{state}?query=<SQL>

Tag Properties

Tags are defined by the following properties:

In a request, the corresponding properties are included directly in the URL for the call of the endpoint. In contrast, if tags are displayed in a response body, their properties are listed as a part of a JSON structure in the value of the property system:tags.

Handling of the traceid

The traceid is a unique process number that provides the possibility to retrace tag operations and tune the update or deletion permissions for the tag.  In the HTTP header, the request parameter traceIdMustMatch can be changed from its default value false to true. Thus, two different scenarios are possible:

• Call with traceIdMustMatch=false (default)
The endpoint either sets the used-defined value or a random string as new traceid for the tag.
  In case of a tag deletion, the endpoint removes the tag from the corresponding object without checking the current traceid of the tag to be deleted.
• Call with traceidMustMath=true
  An update or deletion endpoint takes the traceid from the request and compares it to the current traceid of the requested tag. The update or deletion operation will be performed only if the values are matching. Thus, the tag can only be updated or deleted if the previous traceid is known to the caller.
  In case of a tag creation, this condition would never match and should therefore not be used.

Summary

This article gave an introduction into the handling of tags as a feature of the lifecycle management of objects in yuuvis® Momentum. In the "Tagging Objects for Processing" tutorial, an exemplary use case is explained.