Mapping JsonMergePatchDocument when working with DTO

[manifoldhiker]

Thank you for this project!

I want to implement a partial update for my domain model, but I don't want to expose this model to the outside world and restrict what fields could be updated. It could be achieved with DTO.

As described in this stackoverflow answer, it is possible to use automapper to map JsonPatchDocument<AccountDTO> to JsonPatchDocument<Account>

It works when map JsonMergePatchDocument.JsonPatchDocument in such way - all operations are mapped.

But when I map JsonMergePatchDocument , operations are not mapped and lost.

I guess, I cant use JsonPatchDocument directly, because it needs to go through ClearAddOperation procedure.

Please, suggest how can I use JsonMergePatchDocument with DTOs and automapper?

[RoboBurned]

I am working on the same issue now.
I don't like the idea to add AutoMapper just for that reason. There is no reason for adding another layer of transformation. We just need to apply a set of changes described in one object our model.
I would like to have JsonMergePatchDocument.ApplyTo(Account) method. Is it possible?

[Morcatko]

I never thought about this use case. ApplyTo is based on duck typing. TModel is there only to have some type safety on the API level, but internally it can apply the operations to any object as long as it has correct property names.
These ideas came to my mind

1. add ApplyTo(object xxx)
2. expose JsonPatchDocument - most generic solution, but would still need AutoMapper or similar
3. same way to cast JsonMergePatchDocument<SomeType> to JsonMergePatchDocument<AnyOtherType> which would expose ApplyTo(AnyOtherType xxx) method. There could even be a helper/extension method that would allow JsonMergePatchDocument<SomeType>.ApplyTo<AnyOtherType>(AnyOtherType xx)

None of these solutions is thread safe, but I guess it is not a big deal since it is parsed from JSON anyway. I personally tend to implement option 3) but let me know if you have any other ideas.

[manifoldhiker]

Option 3 looks fine.

[Morcatko]

Implemented in 2.0.0-beta08