Does Medplum implement Update with No Changes?
I...
# devj
joshua_kelly
02/01/2024, 7:39 PMDoes Medplum implement Update with No Changes?
It's an interesting feature of Smile CDR: https://smilecdr.com/docs/fhir_standard/fhir_crud_operations.html#no-op
joshua_kelly
02/01/2024, 7:41 PMThe implementation seems to be in HAPI as well
It looks like they use a SHA in the schema to do this: https://github.com/hapifhir/hapi-fhir/blob/51a6ddad3ddd1bd77b15a70e8433a381925e9865/hapi-fhir-docs/src/main/resources/ca/uhn/hapi/fhir/docs/server_jpa/schema.md#columns
joshua_kelly
02/01/2024, 10:07 PM@reshma we can maybe put this one on our agenda, we have a use case here and could probably come up with a similar design
I think the loose idea would to add a column to each resource table that stores a sha256 hash of the resource content
Then, in Repository, check if the value matches on writes
r
reshma
02/01/2024, 10:14 PM@joshua_kelly - interesting, yeah - let's discuss.
reshma
02/01/2024, 10:15 PMwe do not currently support that - interesting to note that it is in use elsewhere
r
rahul1
02/02/2024, 1:24 AM@joshua_kelly what is the intended behavior for this feature? If you PUT a resource without changing it, we do not add an entry to the history.
rahul1
02/02/2024, 1:24 AMe.g.
medplum get Patient/:id | xargs -0 -n 1 medplum put 'Patient/:id'rahul1
02/02/2024, 1:35 AMIs there another functionality we should be implementing?
j
joshua_kelly
02/02/2024, 4:30 PM@rahul1 Oh, interesting - so, behaviourally, it actually is implemented? A no-op OperationOutcome would be nice (but not necessary for our use case)
joshua_kelly
02/02/2024, 4:31 PMIs there a sameness check in Repository or a deeper layer?
joshua_kelly
02/02/2024, 4:32 PMThe behavior is sort of two things in the Smile CDR implementation:
1. Don't create a new version, don't update meta values (lastUpdated etc) when PUTing a body that is exactly equal to the current content
2. Optionally, return an OperationOutcome that specifies that the response did not produce a change (not sure what the Smile CDR uses here as far as a code, but the docs suggest this is what they do)
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