Previous Values with Hooks

Help me!
1

Hi,

I have a special use case for @forestadmin/agent:1.12.0, which I am not able to solve with the docs.

Desired behaviour: Send out an event to a 3rd-party service over HTTP, after editing a record & persistence to the database, with the previous values of the edited record.

As I understand:

  • I can only generate previous values in the Update-Before hook
  • I can only send out a http request upon database persistence using an After-hook.
  • I can’t pass data from a Before to its corresponding After hook.

Are these observations correct? Then I’m stuck. Do you see another way to achieve the desired behaviour?

Thanks in advance.

2

You are indeed stuck.

Let me make a PR around that

1 Like
3

I just made a PR (in review) to add a caller.requestId value so that you can reconcile calls to multiple hooks on the same request.

Once merged, you should be able to do the following:

  agent.customizeCollection('hubspot_contacts', collection => {
    // Use a weak map to avoid leaking memory if updates fail.
    const recordsBeforeByRequestId = new WeakMap();
    const hookColumns = ['the', 'columns', 'you', 'need', 'for', 'the', 'api'];

    collection.addHook('Before', 'Update', async context => {
      const recordsBefore = await context.collection.list(context.filter, hookColumns);

      recordsBeforeByRequestId.set(context.caller.requestId, recordsBefore);
    });

    collection.addHook('After', 'Update', context => {
      const recordsBefore = recordsBeforeByRequestId.get(context.caller.requestId);
      const recordsAfter = await context.collection.list(context.filter, hookColumns);

      // Call API here

    });
  });

PR URL: fix(agent): add request identifier to context.caller by romain-gilliotte · Pull Request #753 · ForestAdmin/agent-nodejs · GitHub

4

PR was merged

You should be good to go.
I added a ticket to our tracker so that we document that in the hooks documentation page

5

Thanks for the quick action! I upgraded to @forestadmin/agent:1.13.1, and the requestId is there.

But something went missing. From your example above:

  agent.customizeCollection('hubspot_contacts', collection => {
    // Use a weak map to avoid leaking memory if updates fail.
    const recordsBeforeByRequestId = new WeakMap();
    const hookColumns = ['the', 'columns', 'you', 'need', 'for', 'the', 'api'];

    collection.addHook('Before', 'Update', async context => {
      const recordsBefore = await context.collection.list...

The list and other functions are missing, when I debug. Typescript doesn’t complain.

6

Sorry, never mind. I’m wrong, it’s there.