Cannot create draft for Node.js CAP Service in custom handler

[#1]

I have created a simple project to showcase the issue that I am having at repo: draft-concern.

In this example repo, I have created a very simple service with entity project that has been annotated with @odata.draft.enabled. In the same service, I have created an additional action (createDraft) to add my custom handler code.

using { Customers as schemaCustomers } from '../db/schema';

service CustomerService{
  entity Customers as projection on schemaCustomers;
  annotate Customers with @odata.draft.enabled;

  action createDraft() returns {ID: UUID};
  
}

If I run a simple post command to the Customer entity set, a draft is created as expected:

curl -X POST -H "Content-Type:application/json" -d '{}' http://localhost:4004/customer/Customers
{"@odata.context":"$metadata#Customers/$entity","ID":"1a8b20eb-c044-422e-a137-d7c724c6f91d","CustomerID":null,"CustomerName":null,"IsActiveEntity":false,"HasActiveEntity":false,"HasDraftEntity":false}%

Specifically, you will see that the IsActiveEntity field is set to false since the draft has not been activated yet.

The issue I am running into in my project is when I try to replicate this behavior in a custom handler. In this case I have a very simple handler for the "createDrafts" action defined on the service.

const cds = require("@sap/cds")

module.exports = cds.service.impl( async (srv) => {
  srv.on('createDraft', async (req) => {
    const { Customers } = srv.entities
    const { ID } =  await srv.post(Customers, {})
    return { ID }
  })
})

When I call this action against the service, the behavior is not as expected:

curl -X POST -H "Content-Type:application/json" -d '{}' http://localhost:4004/customer/createDraft
{"@odata.context":"$metadata#CustomerService.return_CustomerService_createDraft","ID":"9d552f07-275c-4a7f-a79f-0fb7e59d94f9"}%

curl -X GET http://localhost:4004/customer/Customers
{"@odata.context":"$metadata#Customers","value":[{"ID":"9d552f07-275c-4a7f-a79f-0fb7e59d94f9","CustomerID":null,"CustomerName":null,"IsActiveEntity":true,"HasActiveEntity":false,"HasDraftEntity":false}]}%
                                         

Here you will see that the IsActiveEntity field has been set to true even though the draft has not been activated.

While in this example, I am using the post convenience method for a CAP service in my custom handler, the same results have occurred regardless of the way I have attempted a post on the Customer entity set via a custom handler.

This appears broken to me due to the fact that an direct POST command to the Customers entity set is not behaving in the same manner as the post method within the custom action of the service.

Any help on how to properly mimic the POST command within a custom handler where a draft entry gets created (with IsActiveEntity is set to false) would be truly appreciated!

cds -v
@sap/cds: 6.3.2
@sap/cds-compiler: 3.4.2
@sap/cds-dk: 4.1.5
@sap/cds-foss: 4.0.0
@sap/cds-mtx: -- missing --
Node.js: v16.18.1
draft-concern: 1.0.0
home: /Users/stevenmason/dev/cap/draft-concern/node_modules/@sap/cds<br>

[OlenaT]

Hi the_mason_abides,

Could you please check if this question and answer related to your issue?https://answers.sap.com/answers/13768341/view.html

Best regards,

Olena

[Steven-Mason]

Hello Olena,

Thank you very much for your response. Unfortunately that question is similar, but does not answer my question. I have tried both the srv.post statement (which I am including in my example repo above) and I have also tried the srv.send statement as well. When I have used the srv.send method, I actually receive an error message in inside the cds crud.js source file. Here is the code when attempting to use the srv.send method:

const cds = require("@sap/cds")

module.exports = cds.service.impl( async (srv) => {
  srv.on('createDraft', async (req) => {
    const { Customers } = srv.entities
    //const { ID } =  await srv.post(Customers, {})
    const ID = await srv.send('POST', Customers, {})
    return { ID }
  })
})

When I do this, I get the following error message:

[INTERNAL ERROR] TypeError: Cannot read properties of undefined (reading 'INSERT')
    at ApplicationService.<anonymous> (/Users/stevenmason/dev/cap/draft-concern/node_modules/@sap/cds/libx/_runtime/common/generic/crud.js:46:32)
    at next (/Users/stevenmason/dev/cap/draft-concern/node_modules/@sap/cds/lib/srv/srv-dispatch.js:75:36)
    at ApplicationService.handle (/Users/stevenmason/dev/cap/draft-concern/node_modules/@sap/cds/lib/srv/srv-dispatch.js:79:6)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at async ApplicationService.<anonymous> (/Users/stevenmason/dev/cap/draft-concern/srv/customer-service.js:7:16)
    at async next (/Users/stevenmason/dev/cap/draft-concern/node_modules/@sap/cds/lib/srv/srv-dispatch.js:75:17)
    at async ApplicationService.handle (/Users/stevenmason/dev/cap/draft-concern/node_modules/@sap/cds/lib/srv/srv-dispatch.js:73:10)
    at async /Users/stevenmason/dev/cap/draft-concern/node_modules/@sap/cds/libx/_runtime/cds-services/adapter/odata-v4/handlers/action.js:52:16<br>

Here you can see where that error is occurring within crud.js:

It is possible I am calling the srv.send method incorrectly, but I am following the example set in the CAP documentation here.

As mentioned in my previous post, if I call this service directly with a POST method via a HTTP client, I have no issues and draft works correctly. All I am wanting to do is programmatically replicated the POST request in my code. Any suggestions on how to accomplish this is greatly be appreciated!