Interception for object materialization (a.k.a. "ObjectMaterialized")

[ajcvickers]

Splitting this out as a separate issue as required on #626 so we can track it independently of other life-cycle hooks.

The ObjectMaterialized event will fire after an entity instance has been created and all it's non-navigation properties have been set.

[SidShetye]

@ajcvickers thanks for breaking this down into even smaller work items. Wasn't sure what granularity @divega was looking for.

Anyway, could this be promoted to 3.0.0 milestone just like #15910 ? The reason being we need hooks at both paths to and from the database - to preserve symmetry and avoid data corruption during data transformations. Having both ObjectMaterialized and SavingChanges is the bare minimum for us to unblock our EF Core customers who've been patiently asking us to support EF Core for a very long time. At our end, we can spotlight the 3.0.0 release as "fully supported" when it eventually comes out.

Thanks

[ajcvickers]

@SidShetye Can you give some details on how you intend to use ObjectMaterialized?

[SidShetye]

@ajcvickers : Sure. We basically use integration points in any ORM to enforce our data security pipeline.

Specifically, for data about to be written to the database we'd use something like SavingChanges in EF that results in encrypted data being sent to the database.

So on the reverse path, we again need our security pipeline to kick in that results in plaintext data being presented to the EF application. ObjectMaterialized in EF 6.x allows us that attach point and we'd like to use it similarly in EF Core too. As you can imagine, without anything like ObjectMaterialized on the reverse path, the data remains in an unusable state. For a visual, check out the very first figure on page 1.

[SidShetye]

@ajcvickers - will this be marked for the 3.0 release? Did my response address your question on usage? Thanks

[ajcvickers]

@SidShetye It's pretty unlikely to go into 3.0 at this point.

[SidShetye]

@ajcvickers Could we please have this for 3.1?

[optiks]

@SidShetye Have you considered using value conversions instead? Presumably you have a mechanism for flagging which properties need to be encrypted?

You could also consider introducing an Encrypted (potentially with an implicit operator) and expose that in your domain.

https://docs.microsoft.com/en-us/ef/core/modeling/value-conversions

[ajcvickers]

@SidShetye We haven't decided what will be in 3.1 yet.