AgileConfig/docs/application-layer.md

Application layer

AgileConfig.Server.Application contains transport-independent application use cases. Both the legacy MVC controllers and the REST API controllers call this layer so that business behavior is implemented once.

Dependency direction

Apisite controllers
        |
        v
AgileConfig.Server.Application
        |
        v
AgileConfig.Server.IService / domain events
        |
        v
repositories

The Application project must not reference ASP.NET Core MVC, Apisite request models, controllers, or HTTP result types.

Responsibilities

Controllers own:

• authentication and authorization filters;
• HTTP request and response models;
• status codes, headers, routes, and ProblemDetails;
• compatibility mapping for legacy response envelopes.

Application services own:

• use-case validation and conflict detection;
• entity creation and state transitions;
• orchestration of the existing business services;
• current-user audit values and timestamps;
• domain-event publication and other required side effects.

The existing services in AgileConfig.Server.IService and AgileConfig.Server.Service continue to own persistence-oriented operations, queries, caches, and lower-level domain behavior.

Expected business failures are returned as ApplicationResult values. Application services do not return IActionResult, select HTTP status codes, or format user-facing HTTP payloads.

Compatibility

Legacy and v2 controllers deliberately map the same application result differently:

• legacy controllers preserve their existing { success, message, data } envelopes and status-code behavior;
• v2 controllers use resource responses, standard status codes, and ProblemDetails.

Any application-service migration must keep integration coverage for both contracts.