Middleware¶
Middlewares can be executed before or after a request, usually handled by the handlers. This will be useful for cases where an action is required prior to reaching the handler, or when an action is required to execute prior to the returning of the response.
Middlewares require the Middy NPM package to work.
Middlewares should be written in the src/middlewares/ directory.
Available Middlewares¶
Lesgo! comes with a few pre-existing middlewares that you can use right away.
You may also import other ready-made middlewares from the Middy repository.
- HTTP Middleware
- HTTP Response Middleware
- SQS Middleware
- Invoke Command Middleware
- Disconnect Middleware
- Verify Basic Auth Middleware
- Verify JWT Middleware
Nesting Middlewares¶
Middlewares can be nested together to achieve the desired results.
For example, the HttpMiddleware consists of the following middlewares:
- @middy/do-not-wait-for-empty-event-loop
- @middy/http-event-normalizer
- @middy/http-header-normalizer
- @middy/http-json-body-parser
- lesgo/middlewares/disconnectMiddleware
- lesgo/middlewares/httpResponseMiddleware
Custom Middlewares¶
You can write your own custom middleware with Middy.
Middleware Ordering¶
Middy implements the classic onion-like middleware pattern, with some peculiar details.
The first middleware.before() will always be executed first with its middleware.after() being the last in that order.
See https://middy.js.org/docs/intro/how-it-works/ for more info.