Entra.EventHandlers.Abstractions 1.3.3

Entra.EventHandlers.Abstractions

License: MIT
Author: Jakub Szubarga (Szubarga.NET)
This package is free for all use cases, including commercial use.

This package contains the public abstractions, event types, and protocol definitions for building Microsoft Entra External ID Authentication Event Handlers.

It is intentionally lightweight, dependency‑free, and framework‑agnostic. You can reference it freely in open‑source or commercial projects.

All public types include full XML documentation for a first‑class developer experience.

✨ What This Package Provides

This package defines the public contract for the Entra Event Handlers ecosystem:

• Strongly‑typed event request models
• Strongly‑typed response models
• Action definitions and protocol constants
• Directory attribute primitives
• Handler interfaces, e.g.:

  public interface IAttributeCollectionStartHandler 
      : IEntraEventHandler<AttributeCollectionStartEvent, AttributeCollectionStartResponse> { }

• Enums and metadata types
• OData‑typed payload models
• Event type identifiers

These types represent the JSON protocol used by Entra External ID custom authentication flows.

The abstractions are stable, versioned, and safe to depend on in long‑term projects.

🧩 Supported Events

The abstractions package includes complete request/response models and handler interfaces for all currently supported External ID Authentication Event Handlers:

• AttributeCollectionStart
• AttributeCollectionSubmit
• EmailOtpSend
• PasswordSubmit (just‑in‑time password migration)
• TokenIssuanceStart

Each event includes:

• Request model
• Response model
• Payload types
• Action definitions
• Handler interface

🧩 Why a Separate Abstractions Package?

The abstractions are MIT‑licensed to maximize adoption and interoperability.

They allow you to:

• Build your own handlers
• Integrate with Entra External ID events
• Test locally without Azure
• Reference the protocol without pulling in implementation details
• Use the models in any hosting environment (Functions, ASP.NET Core, custom hosts)

The full implementation lives in separate packages under the Business Source License (BSL).

📦 Related Packages

These packages extend the abstractions with production‑ready functionality:

Entra.EventHandlers — implementation layer (BSL)

• Validation
• Response builders
• Logging & telemetry

Entra.EventHandlers.AzureFunctions — Azure Functions adapter (BSL)

• Automatic request/response handling
• DI wiring
• Minimal boilerplate for production deployments

Entra.EventHandlers.AspNetCore — ASP.NET Core adapter (BSL)

• Minimal API endpoint integration
• Router endpoint
• Single‑event endpoint classes

All packages are available on NuGet.

📄 License

This package is licensed under the MIT License.
See the LICENSE file for details.

The implementation and hosting adapters are available under the Business Source License (BSL) in the related packages.

📚 Documentation

Full documentation, examples, and production templates are available in the main repository.

📘 Further Reading

For a deeper look into Microsoft Entra External ID Authentication Event Handlers and the design of this ecosystem, see the full article:

➡️ Entra External ID — .NET Handlers Deep Dive
https://medium.com/@jakub.szubarga/entra-external-id-dotnet-handlers-a7447dc1e437