publishing-api: Decision Record: Include Content Block Change Notes in Downstream Payloads
Context
The content modelling team needs email alerts to be triggered when a major update is made to a content block, especially when that update affects other pieces of content that embed it.
This is challenging because changes to dependent content happen indirectly - when the embedding content is republished, it pulls in the updated content block. However, to users subscribed to email alerts for that content, these changes are invisible since no alert is triggered (even though the content has effectively changed).
To fix this, we need to ensure that change notes from content blocks are sent to the email-alert-service, so that subscribers receive notifications when embedded content is updated.
Solution
We will update the EditionPresenter to include change notes from embedded content blocks, in addition to the
change notes for the content itself.
This involves:
- Fetching all links of type
embedfrom the Publishing API - Retrieving change notes for those embedded content blocks
- Including these change notes in the payload alongside those of the host document
Consequences
Currently, the EditionPresenter returns the change_notes from the details hash of the edition if they are present,
as there are circumstances where we the change notes are contained within the details hash, and don't have Change Note
records stored within Publishing API, if a change_note hash is present we only fetch the change note for dependent
content blocks and merge the two together.
There are also soms discrepancies in time zones - specifically, Whitehall's Edition#details uses local time, whereas the Publishing API's presenter queries use UTC - so we will also ensure that all times change notes have UTC timestamps for consistency.