What You’ll Learn in This Hour:
• What Middleware is
• How you can use Middleware with Connect and Express
• What you can use Middleware for in Connect and Express applications
• What Middleware can offer developers
In the context of Node.js, Middleware is a way to filter a request and response in your application by adding a thin layer between the client and your application logic (see Figure 23.1). It provides a simple way to separate concerns within your application and can lead to more maintainable code, a better security model, and code reuse across projects. The idea is relatively simple, but it offers a great deal of power and flexibility to developers.