How can I return a draft Entity using CAP Node.JS?

[gregorw]

Hello CAP Friends,

the SAPUI5 documentation at Configuring Custom Actions that Create New Objects describes this behaviour of the UI:

"If a user triggers the action, note the following behavior in a draft application: if the back-end system returns a draft object as the result of the action, the front-end system automatically navigates to the object page where the new draft object is opened in edit mode."

This is exactly the behaviour I want to achieve. I've implemented an example in my bookshop-demo which can be tested via: http://localhost:4004/webapp/fiori-latest.html#V4Role-manageUI5latest. When you click there the action button "createDraftRole" you will be asked to enter the role name and description. When you then click the createDraftRole button of the pop-up the Entity is created using this code:

srv.on(["createDraftRole"], async (req) => {
  const adminService = await cds.connect.to("AdminService");
  const { Roles } = adminService.entities;
  console.log("createDraftRole - Request Parameters:", req.data);
  const insertRes = await cds.run(
    INSERT.into(Roles).entries([
      {
        ID: cds.utils.uuid(),
        rolename: req.data.rolename,
        description: req.data.description,
      },
    ])
  );
  const keyFields = [...insertRes][0];
  delete keyFields.IsActiveEntity;
  const roles = await cds.run(SELECT.from(Roles).where(keyFields));
  const role = roles[0];
  return role;
});

The UI navigates also the the created entity. But unfortuantely not in Edit mode. That due to the fact that I haven't found any documentation how to create a draft Entity in the CAP Node.JS documentation about Built-in Draft Support. It seems that for CAP Java this is already possible: Consuming Draft Services.

Would be great to know what is planned in this direction.

Best Regards
Gregor

[OlenaT · Accepted solution]

Hi gregorw,

In Node.js stack we are currently have no plans to provide Draft API similar to the one impemented by Java.

In your case you can try to register a handler not for a function but for a 'NEW' event, where a new draft is created. In the custom code you can access a draft entity as follows:

await SELECT.from(Books.drafts)

Also I'm not sure about cds.run. Most of our draft handling is implemented on service layer, so calling a handler on db layer will skip all of it. Maybe try srv.run (send)? If it not helps, please ask UI colleagues, if one can get a pop-up for some data in edit mode with some UI annotations.

Sorry for such a vague answer, building a custom draft implementation is really tricky.

Best regards,

Olena

[gregorw · Accepted solution]

Hi Olena,

thanks to your answer to Cannot create draft for Node.js CAP Service in custom handler I was able to update my bookshop-demo with this code for my action implementation:

  srv.on(["createDraftRole"], async (req) => {
    const adminService = await cds.connect.to("AdminService");
    const { Roles } = adminService.entities;
    console.log("createDraftRole - Request Parameters:", req.data);
    const role = await srv.send({
      query: INSERT.into(Roles).entries([
        {
          ID: cds.utils.uuid(),
          rolename: req.data.rolename,
          description: req.data.description,
        },
      ]),
      event: "NEW",
    });
    return role;
  });

When I trigger this action via the Fiori UI the new entity is returned as a Draft and so the behaviour documented in Configuring Custom Actions that Create New Objects works and the entity is shown in edit mode.

Best Regards
Gregor

[sergei-u-niq]

Thanks gregorw !