Minimal API (with EF Scaffolder) should be updated to handle PUT requests correctly

[vijayrkn]

Issue:

The current scaffolded code first tries to find the resouce (in a tracking way) and uses a different model to update the resource. Since the model updated is different from the model added to the context, the PUT operation fails.

Code block with the issue:

https://github.com/dotnet/Scaffolding/blob/main/src/Scaffolding/VS.Web.CG.Mvc/Templates/MinimalApi/MinimalApiEf.cshtml#L98-L110

Fix

There are 2 ways to fix this issue:

1. The find operation needs to change to a non-tracking form:
   model.AsNoTracking().FirstOrDefaultAsync(r => r.Id == Id)

2. Based on https://www.ietf.org/rfc/rfc2616.txt, the PUT operation is not required to check for the existence of the resource. If the provided model matches an existing resource it will be updated, else a new resource should be created.

   If the Request-URI does not point to an existing resource, and that URI is capable of being defined as a new resource by the requesting user agent, the origin server can create the resource with that URI.

Preference:

Since the API controller scaffolders follow 2, it would be preferable to match the behavior for both API end-point and API controller scaffolders.

Thanks @timheuer for identifying and tracking down the issue.

@DamianEdwards - Do you have a preference on how these should be updated to handle the error scenario here?

Related issue: #1964

[deepchoudhery]

#2269 addresses a lot of the concerns but does not address If the provided model matches an existing resource it will be updated, else a new resource should be created. in the fix suggested above. Any thoughts on that @DamianEdwards @sayedihashimi.

[vijayrkn]

Closing this since it is addressed with the new EF model of update.