Message subtypes relevant for Connector to Connector communication
There are three Subclasses of the abstract ids:Message class. Namely the ids:RequestMessage, ids:ResponseMessage and ids:NotificationMessage. Each subclass itself has subclasses that fulfill a specific purpose in the communication process.
For communication in the IDS, usually the more specific subclasses of the three mentioned ones are used. The message classes relevant for the Connector to Connector communication are listed below. The entire Collection of Messages available in the Information Model can be found here.
Client-generated message initiating a communication, motivated by a certain reason and with an answer expected.
Message requesting metadata. If no URI is supplied via the ids:requestedElement field, this messages is treated like a self-description request and the recipient should return its self-description via an ids:DescriptionResponseMessage. However, if a URI is supplied, the Connector should either return metadata about the requested element via an ids:DescriptionResponseMessage, or send an ids:RejectionMessage, e.g., because the element was not found
Parent: ids:RequestMessage
Additional Message Properties:
| Properties /Fields | Description |
|---|---|
| requestedElement | The element whose metadata is requested. |
Implementations:
| List of Implementations |
|---|
| IDS-REST |
| idscp2 |
| multipart |
Message asking for retrieving the specified Artifact inside an ArtifactResponse message.
Parent: ids:RequestMessage
Additional Message Properties:
| Properties /Fields | Description |
|---|---|
| requestedArtifact* | References an ids:Artifact. |
Implementations:
| List of Implementations |
|---|
| IDS-REST |
| idscp2 |
| multipart |
Message containing a suggested content contract (as offered by the data consumer to the data provider)(which is an instance of ids:ContractRequest).
Parent: ids:RequestMessage
Additional Message Properties: None
Implementations:
| List of Implementations |
|---|
| IDS-REST |
| idscp2 |
| multipart |
Response messages hold information about the reaction of a recipient to a formerly sent command or event. They must be correlated to this message.
Message containing the metadata, which a Connector previously requested via the ids:DescriptionRequestMessage.
Parent: ids:ResponseMessage
Additional Message Properties: None
Implementations:
| List of Implementations |
|---|
| IDS-REST |
| idscp2 |
| multipart |
Message that follows up a ArtifactRequestMessage and contains the Artifact's data.
Parent: ids:ResponseMessage
Additional Message Properties: None
Implementations:
| List of Implementations |
|---|
| IDS-REST |
| idscp2 |
| multipart |
Message containing a contract, as an instance of ids:ContractAgreement, with resource access modalities on which two parties have agreed.
Parent: ids:ResponseMessage
Additional Message Properties: None
Implementations:
| List of Implementations |
|---|
| IDS-REST |
| idscp2 |
| multipart |
Rejection messages are specialized response messages that notify the sender of a message that processing of this message has failed.
Parent: ids:ResponseMessage
Additional Message Properties:
| Properties /Fields | Description |
|---|---|
| RejectionReason | Code describing the Rejection Reason, e.g., idsc:NOT_FOUND. (see ids:RejectionReason class) |
Implementations:
| List of Implementations |
|---|
| IDS-REST |
| idscp2 |
| multipart |
Message indicating rejection of a contract.
Parent: ids:ResponseMessage
Additional Message Properties:
| Properties /Fields | Description |
|---|---|
| contractRejectionReason | Human-readable text describing the reason for contract rejection |
Implementations:
| List of Implementations |
|---|
| IDS-REST |
| idscp2 |
| multipart |
Event messages are informative and no response is expected by the sender.
Message containing a offered content contract in the associated payload (which is an instance of ContractOffer).
Parent: ids:NotificationMessage
Additional Message Properties: None
Implementations:
| List of Implementations |
|---|
| IDS-REST |
| idscp2 |
| multipart |
Notification that a message has been successfully processed (i.e., not ignored or rejected).
Parent: ids:NotificationMessage
Additional Message Properties: None
Implementations:
| List of Implementations |
|---|
| IDS-REST |
| idscp2 |
| multipart |
See Connector to Metadata Broker Communication for information how to work with the Metadata Broker.
Will be added in the future (TODO).