This proof of concept (POC) is an minimum implementation of middleware in C# .NET 7.0. The purpose of this POC is to demonstrate the various ways to build middleware and how the order of the middleware can affect the overall functionality of the application.
Please note that this POC is not intended to show best practices, but rather to communicate a specific feature or implementation of middleware.
- Demonstrates multiple ways to build middleware, including using the built-in Use method and the Map method.
- Shows how the order of the middleware can affect the overall functionality of the application.
Middleware is a software layer that sits between the application and the underlying infrastructure. It acts as a bridge, allowing different parts of the application to communicate and interact with each other. In the context of a web application, middleware can handle tasks such as routing, authentication, and authorization.
The imagination is the limit of use cases for your own custom middleware, but here is a list of use cases that fit the middleware model well:
- Caching
- Error handling
- Logging
- Authentication
- Authorization
- Routing
- Compression
- Encryption
- Session management
- File handling
- Caching
- File system caching
- Distributed caching
- In-memory caching
- Authentication
- Authorization
- Token-based authentication
- OAuth and OpenID Connect
- CORS handling
- Data encryption and decryption
- Email sending
- SMS sending
- Push notifications
- Real-time communication
- WebSocket handling
- Event-based communication
- Service discovery
- Error handling
- Health check
- Circuit breaker pattern
- Retry policies
- Input validation
- Output formatting
- Image processing
- File upload and download
- Content negotiation
- File handling
- Routing
- Redirect handling
- Reverse proxy
- Logging and Monitoring:
- Logging
- Health check
- Rate limiting
For our app we will create the following Middleware Implementations to use for demonstration
The GlobalExceptionHandling must be the very first at the beginning of the pipeline.
Creates a trace identifier that can be used to track and aggregate requests in a system.
Returns a summary of the health of the service.
Does a simple Authentication and return Authentication error on failure
Allows the Client to Hash the request based on selected values...ex. Headers, body, etc... and store the SHA256 in a Header and the Middleware will verify this and on failure return some Auth Verification error.
Demonstrates stuffing items into the Request Collection and reading the items further down in the pipeline.
Allows the Trace Collector (ex. Prometheus) to call into the server to pull the Trace Metrics. Keep in mind this is only mock example.
The elegant beauty of a middleware pipeline is that it allows for modular and flexible software construction. Each middleware component can handle a specific task and can be added, removed, or reordered as needed. This is made possible by the builder pattern, which allows for easy and clear configuration of the pipeline.
Using middleware in your project can also make it easier to maintain and scale your application. By breaking down the application into smaller, more manageable components, it becomes easier to identify and fix issues, and to add new features.
In summary, middleware is a powerful tool for software construction that allows for modularity, flexibility, and scalability. This POC demonstrates the basic concepts of middleware and how to use it in a C# .NET 7.0 application.