Follow RFC 7807: Problem Details for HTTP APIs

[Frikki]

Is your feature request related to a problem? Please describe. When all HTTP APIs define their own “error” JSON objects, it becomes a nightmare for developers to remember or find which members are available. And it’s hard for machines to read them.

Describe the solution you'd like RFC 7807: Problem Details for HTTP APIs already reached consensus in the IETF community on how to define a “problem detail” as a way to carry machine-readable details of errors in an HTTP response to avoid the need to define new error response formats for HTTP APIs, not to replace existing domain-specific formats.

It would be super if Eventuous would follow the standard and be a role model like it is for Event Sourcing. Section 3 details the members of a Problem Detail Object.

Describe alternatives you've considered

• Stay with the format already defined if it’s a more appropriate way of carrying the error.
• Adopt a significant player’s (e.g., Google Cloud) custom error object.

Additional context

Here is an example of what the current 400 Bad Request response looks like:

HTTP/1.1 400 Bad Request
   Content-Type: application/json
   Content-Language: en

{
  "errorMessage": "Unable to append events to Booking-123: Type RoomBooked is not registered in the type map",
  "message": "Error handling command BookRoom",
  "state": null,
  "success": false,
  "changes": null
}

Here is an example of what a 400 Bad Request response with problem details would look like:

HTTP/1.1 400 Bad Request
   Content-Type: application/problem+json
   Content-Language: en

{
    "type": "https://eventuous.dev/errors/unable-to-handle-command",
    "title": "Unable to handle command",
    "status": 400,
    "detail": "Unable to append events to Booking-123: Type RoomBooked is not registered in the type map. See https://eventuous.dev/docs/persistence/serialisation/#type-map",
    "instance": "/bookings/book",
    "success": false,
    "state": null,
    "changes": null
}

[makp0]

@Frikki, could you please include before for ease of comparison?

[Frikki]

Sure thing, @makp0. Updated OP.

[Frikki]

While inspecting the Eventuous source code, I noticed that Eventuous.AspNetCore.Web’s ResultExtension uses ProblemDetails from Microsoft.AspNetCore.Web.

An article at CodeMaze also addresses the issue and the standard implemented in ASP.NET Core Web API.

[alexeyzimarev]

Does the latest preview version cover these needs?