Kompass.OData

A modular OData library suite for .NET, built around a schema-first philosophy. You define your data model in CSDL; the framework derives handler registrations from that schema and validates them for completeness—flagging entity sets or contained navigations that lack handlers before the service starts. Internally, the library cleanly separates a syntactic CSDL tree (where type references are plain strings) from a semantic EDM model (where every reference is resolved to a direct object link). A two-pass resolver bridges the two: the first pass registers all named elements, the second resolves every cross-reference—base types, navigation targets, partners, and bindings—into typed object pointers. Handler contexts form a small hierarchy (CollectionContext, EntityContext, ContainedCollectionContext, ContainedEntityContext) so each handler receives exactly the information its URL shape implies—keys, parent keys, navigation property, query options—without manual parsing. Each assembly is independently usable and focused on a single responsibility; see ARCHITECTURE.md for a deeper walkthrough.

Quick Example

var csdl = File.ReadAllText("rooms.csdl.xml");

var service = ODataServiceBuilder.FromCsdl<RoomsRepository>(csdl)
    .EntitySet("Rooms", es => es
        .OnList(ListRooms)                   // GET /Rooms
        .OnGet(GetRoom)                      // GET /Rooms/{id}
        .ContainedCollection("Printers", nav => nav
            .OnList(ListPrinters)            // GET /Rooms/{id}/Printers
            .OnGet(GetPrinter)));            // GET /Rooms/{id}/Printers/{id}

service.MapODataEndpoints(app);

Handlers receive a typed context and the TState dependency from DI:

static async Task<IResult> ListRooms(CollectionContext ctx, RoomsRepository repo)
{
    var (items, count) = await repo.GetRoomsAsync(
        skip: (int?)ctx.Query.Page.Skip,
        top:  (int?)ctx.Query.Page.Top);
    return ctx.Ok(items.Cast<object>(), ctx.Query.Count == true ? count : null);
}

See samples/ for complete runnable examples.

Assemblies

Assembly	Responsibility
Kompass.CsdlEdm	CSDL XML/JSON reader, syntactic model, resolver, resolved EDM model, and validator.
Kompass.OData.Url	OData URL and query-string parser ($filter, $select, $expand, $orderby, $top/$skip).
Kompass.OData.Routing	ASP.NET middleware that rewrites OData subsegment-key URLs into segment form for standard routing.
Kompass.OData.Service	Service builder, handler context types, and endpoint registration via EDM constructs (ASP.NET Minimal API).
Kompass.OData.ResponseShaping	OData-aware JSON response envelope construction, $select projection, and system annotations (@odata.context, @odata.count, @odata.nextLink).
Kompass.OData	Umbrella meta-package referencing all sub-assemblies.

Getting Started

Prerequisites

• .NET 9 SDK or later

Build

dotnet build

Run Tests

dotnet test

Run Benchmarks

dotnet run --project benchmarks/Kompass.CsdlEdm.Benchmarks -c Release

Solution Layout

Kompass.OData/
├── src/
│   ├── Kompass.CsdlEdm/
│   ├── Kompass.OData/
│   ├── Kompass.OData.ResponseShaping/
│   ├── Kompass.OData.Routing/
│   ├── Kompass.OData.Service/
│   └── Kompass.OData.Url/
├── tests/
│   ├── Kompass.CsdlEdm.Tests/
│   ├── Kompass.OData.Routing.Tests/
│   ├── Kompass.OData.Service.Tests/
│   └── Kompass.OData.Url.Tests/
├── benchmarks/
│   └── Kompass.CsdlEdm.Benchmarks/
└── samples/
    ├── Kompass.OData.Samples.Graph/
    └── Kompass.OData.Samples.Rooms/

License

This project is licensed under the GNU Lesser General Public License v3.0.