SliceR.Minimal

Adds Minimal API patterns for quickly adding endpoints to SliceR

Getting Started

This code extends the .NET Minimal API codebase with IEndpointBuilder. The idea is to define one or more endpoints in a set of classes that can be registered with DI.

register all your IEndpointBuilder classes in your assembly with

services.AddEndpointBuilders();

In program.cs make sure to use them in your WebApplication by calling AddEndpointBuilders

var builder = WebApplication.CreateBuilder(args);

//... more code

var app = builder.Build();

//... more code

app.AddEndpointBuilders();

app.Run();

IEndpointBuilder

There are several helper extensions:
MapRootRouteGroup

public IEndpointRouteBuilder Build(IEndpointRouteBuilder builder)
{
    var rootRouteBuilder = builder.MapRootRouteGroup<EntityType>();

    return builder;
}

This defines a Builder to add endpoints all with the same prefix. Overloads for group name, tag, and prefix.

Set ApiRouteGroupPrefix.Api to whatever constant you prefer on startup before building endpoints.

If you use standard Operations there are Map methods to simplify defining endpoints.
Examples are:
MapGetAsNoFilterQueryable<TDomain>
MapGetAsById<TDomain, TId>
MapGet<TRequest, TResult>
MapPostAsInsert<TDomainInsert, TDomain>
MapPost<TRequest, TResult>
MapPost<TRequest>
MapPutAsById<TDomainUpdate, TId, TDomain>
MapDeleteAsById<TDomain, TId>

If using entities then use MapEntityRouteGroup

public IEndpointRouteBuilder Build(IEndpointRouteBuilder builder)
{
    var entityRouteBuilder = builder.MapEntityRouteGroup<EntityType, KeyType>();

    return builder;
}

This returns EntityRouteGroupBuilder<TEntity, TKey> or EntityRouteGroupBuilder<TEntity, TKey, TDomain> depending on the overload called.

These have the same entity operation methods except now the Entity, Key, and Domain doesn't have to be repeated for each route.

For custom keys that select one property from a type then use EntityKeySelectorRouteGroupBuilder by calling MapEntityRouteGroup<TEntity, TKey, TKeyProperty> Any ..AsKey method uses the AsParameters attribute on the key in the minimal delegate so make sure the route pattern given has the property names from the key type in use.

Any EntityRouteGroupBuilder puts the EntityMetadata<TEntity> on the endpoint so when figuring out handlers that use a domain for a response, the default registered handler is one that know what entity to use for querying.

ValidatedResult

If you use MapRootRouteGroup then the ValidatedResultEndpointFilter is added by default. This simply turns a ValidatedResult into an IResult for the endpoint. This means the result gets translated to what the Http result required so if you do custom things make sure you either perform a ToHttpResult() on the ValidatedResult or add the endpoint filter to the endpoint manually. Same applies to MapEntityRouteGroup as well.

FileResponse

Use ValidatedResult<FileResponse> as the return value from a ValidatedHandler to get an endpoint to stream back a file from an endpoint.

Mapping Domain to Entity

If you use EF Core and want to have a DTO that is returned the basic scenarios are already handled by defining endpoints return the DTO type but then add the interface IDomainEntity<TEntity> to your DTO where TEntity is the entity type.

These default handlers can be registered by calling:

services.AddSliceREndpointDefaultValidatedHandlers();

The trick here is that the endpoint builders need to be registered first so the code can evaluate what default handler interfaces are being referenced. It then attempts to match the desired type to an entity, if not an entity then checks if the type implements the IEntityMetadata<TEntity>. If it all matches up then a default handler can be registered. If using EntityRouteGroupBuilder then the endpoint itself will already contain EntityMetadata so the DTO does not need the interface itself.

Debugging Note:

Code was added to log to the console on startup for any handlers that don't exist. The Microsoft developer exception page doesn't help with what type is missing when it can't be found in the services collection. So its helpful to log this specific missing handler type at the beginning of the console log.