Key-value pair error when using a custom ChangeBoundsHandler in GLSP server GModelDiagramModule.

[david-pa]

I'm trying to use a custom ChangeBoundsHandler in my GLSP server, but I'm getting a strange error I'm not sure how to interpret.

For reference, my ChangeBoundsHandler is like so:

@injectable()
export class CustomChangeBoundsHandler extends OperationHandler {
  readonly operationType = ChangeBoundsOperation.KIND;

  @inject(ProjectModelState)
  protected modelState: CustomModelState;

  // execute(operation: ChangeBoundsOperation): MaybePromise<void> {
  //   for (const element of operation.newBounds) {
  //     this.changeElementBounds(element.elementId, element.newSize, element.newPosition);
  //   }
  // }

  override createCommand(operation: ChangeBoundsOperation): MaybePromise<Command | undefined> {
    const { index } = this.modelState;
    const oldPositions: {
      [key: string]: Point;
    } = {};
    const newPositions: {
      [key: string]: Point;
    } = {};
    const command: Command = {
      execute: function (): MaybePromise<void> {
        for (const element of operation.newBounds) {
          let indexElement: CustomNode | CustomNode2 | CustomNode3 | undefined;
          const { elementId, newPosition } = element;

          // find index element with ID
          if (elementId.includes('-container')) {
            indexElement = index.findByClass(elementId, CustomNode);
          } else if (elementId.includes('-input')) {
            indexElement = index.findByClass(elementId, CustomNode2);
          } else if (elementId.includes('-output')) {
            indexElement = index.findByClass(elementId, CustomNode3);
          }

          if (newPosition) {
            oldPositions[indexElement!.id] = indexElement!.position;
            newPositions[indexElement!.id] = newPosition;
            indexElement!.position = newPosition!;
          }
        }
      },
      undo: function (): MaybePromise<void> {
        for (const element of operation.newBounds) {
          let indexElement: CustomNode | CustomNode2 | CustomNode3 | undefined;
          const { elementId } = element;

          if (elementId.includes('-container')) {
            indexElement = index.findByClass(elementId, CustomNode);
          } else if (elementId.includes('-input')) {
            indexElement = index.findByClass(elementId, CustomNode2);
          } else if (elementId.includes('-output')) {
            indexElement = index.findByClass(elementId, CustomNode3);
          }

          indexElement!.position = oldPositions[indexElement!.id];
        }
      },
      redo: function (): MaybePromise<void> {
        for (const element of operation.newBounds) {
          let indexElement: CustomNode | CustomNode2 | CustomNode3 | undefined;
          const { elementId } = element;

          if (elementId.includes('-container')) {
            indexElement = index.findByClass(elementId, CustomNode);
          } else if (elementId.includes('-input')) {
            indexElement = index.findByClass(elementId, CustomNode2);
          } else if (elementId.includes('-output')) {
            indexElement = index.findByClass(elementId, CustomNode3);
          }

          indexElement!.position = newPositions[indexElement!.id];
        }
      }
    };
    return command;
  }
}

I am also attempting to use this handler here:

@injectable()
export class CustomDiagramModule extends GModelDiagramModule {
    ...
    protected override configureOperationHandlers(binding: InstanceMultiBinding<OperationHandlerConstructor>): void {
      binding.add(CustomChangeBoundsHandler);
      super.configureOperationHandlers(binding);
    }
}

I'm receiving the following error when starting up the GLSP server, however:

11:38:20 AM warn -  [OperationHandlerRegistry] Could not register key-value pair. Key is already registered {
    "key": "changeBounds",
    "value": {
        "operationType": "changeBounds",
        "serializer": {
            "reservedKeys": [
                "children",
                "parent",
                "index",
                "source",
                "target"
            ],
            "diagramConfiguration": {
                "layoutKind": 1,
                "needsClientLayout": true,
                "animatedUpdate": true
            }
        },
        "modelState": {
            "properties": {},
            "editMode": "editable",
            "index": {
                "idToElement": {},
                "typeToElements": {}
            },
            "serializer": {
                "reservedKeys": [
                    "children",
                    "parent",
                    "index",
                    "source",
                    "target"
                ],
                "diagramConfiguration": {
                    "layoutKind": 1,
                    "needsClientLayout": true,
                    "animatedUpdate": true
                }
            },
            "clientId": "tempId"
        }
    }
}

I know that the method of implementing custom handlers has changed, as it used to be as simple as

export class CustomChangeBoundsHandler implements OperationHandler {
  readonly operationType = ChangeBoundsOperation.KIND;

  @inject(CustomModelState)
  protected modelState: CustomModelState;

  execute(operation: ChangeBoundsOperation): MaybePromise<void> {
    for (const element of operation.newBounds) {
      this.changeElementBounds(element.elementId, element.newSize, element.newPosition);
    }
  }

  protected changeElementBounds(elementId: string, newSize: Dimension, newPosition?: Point): void {
      ...
  }

and now requires a different setup, but I'm not sure what this error is trying to tell me, either.

[tortmayr]

Hi @david-pa,

the error is telling you that there is already another OperationHandler registered for the same operation kind ("changeBounds").
The problem is in your diagram module:

@injectable()
export class CustomDiagramModule extends GModelDiagramModule {
    ...
    protected override configureOperationHandlers(binding: InstanceMultiBinding<OperationHandlerConstructor>): void {
      binding.add(CustomChangeBoundsHandler);
      super.configureOperationHandlers(binding);
    }
}

The super.configureOperationHandlers also adds a ChangeBoundsOperationHandler implementation.
You have to use binding.rebind instead of add:

@injectable()
export class CustomDiagramModule extends GModelDiagramModule {
    ...
    protected override configureOperationHandlers(binding: InstanceMultiBinding<OperationHandlerConstructor>): void {
      super.configureOperationHandlers(binding);
      binding.rebind(GModelChangeBoundsOperationHandler, CustomChangeBoundsHandler);

    }
}