Document JSON and Extended Fields

Nuxeo Platform 7.2 introduces the concept of Extended fields. See Field Constraints and Validation and How to Customize Document Validation.

This kind of document field are defined as reference to external object. For example, in the Dublin Core schema:

• dc:creator and dc:lastContributors are references to Nuxeo users
• dc:contributors contains references to Nuxeo users
• dc:subjects contains references to the "l10nsubjects" directory entries
• dc:coverage is a reference to the "l10ncoverage" directory entry
• dc:nature is a reference to the "nature" directory entry

Usage

The document marshalling provides a nice way to get the data referenced by one of its fields in-place.

For example, a call to get the JSON of a document which creator is the user "johnd" will return:

$ curl -X GET 'http://localhost:8080/nuxeo/site/api/v1/path/to/my/document?properties=dublincore'

{  
  "entity-type":"document",
  "properties":{  
    "dc:creator": "johnd",
    ...
  },
  ...
}

If we tell the document marshaller to load the dc:creator referenced value, it will return the user's JSON in-place:

$ curl -X GET 'http://localhost:8080/nuxeo/site/api/v1/path/to/my/document?properties=dublincore&fetch.document=dc:creator'

{  
  "entity-type":"document",
  "properties":{  
    "dc:creator":{  
      "entity-type":"user",
      "id":"johndoe",
      "properties":{  
        "firstName":"John",
        "lastName":"Doe",
        "password":"",
        "groups":[  
          "members"
        ],
        "company":"Nuxeo",
        "email":"[email protected]",
        "username":"johnd"
      },
      "extendedGroups":[  
        {  
          "name":"members",
          "label":"Members group",
          "url":"group/members"
        }
      ],
      "isAdministrator":false,
      "isAnonymous":false
    },
    ...
  },
  ...
}

To load every extended fields of a document, use fetch.document=properties.

The Nuxeo Platform provides resolver for document, directory entry, user and group. It also provides Java-to-JSON marshaller for those objects. Therefore, you can fetch any property based on built-in resolvers.

Updating Document Properties

If a field is defined as a reference and if you provide a JSON-to-Java marshaller for the referenced object, you can either update the document using the reference as usual or use the object's JSON to update the corresponding document property.

1. The Nuxeo Platform uses the ObjectResolver.getManagedClasses() method to get the expected type.
2. The Nuxeo Platform delegates the JSON-to-Java marshalling to the marshalling service.
3. The marshalling service delegates the JSON parsing to the registered marshaller.
4. The Nuxeo Platform uses the resolver to get the reference from the parsed object and update the property.

The platform also provides JSON-to-Java for document, directory entry, user and group. Therefore, you can update any field based on the corresponding resolvers using the referenced object JSON.

Custom Resolver

When you create a custom resolver, if you want to be able to load the JSON of a referenced object, you have to register a Java-to-JSON marshaller.

If you want to be able to update a field using the JSON rather than the reference, you have to register a JSON-to-Java marshaller and be sure the getManagedClasses() method of your resolver returns the expected Java type.