Miles more maintainable: building APIs with the middleware pattern

on YouTube ↗34m

" summary

Rails controllers with many before_action filters become tangled — a real controller at GoCardless grows to 12 filters with shared instance-variable state and hurting tests. The middleware pattern replaces filters with single‑purpose classes chained as a pipeline (implemented in a toy 25‑line simple middleware), passing an immutable state hash and returning Rack responses or delegating onward, which makes unit tests trivial. A production gem, Coach (github.com/gocardless/coach), adds middleware dependency declaration, config and boot‑time dependency checks so routes declare they require user and middleware reliably provide it.

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" chapters (8)

1. 0:00Introduction
2. 2:26The middleware pattern
3. 8:35Pain and maintainability
4. 10:00Hard to understand
5. 15:12Middleware pattern
6. 19:03Simple middleware
7. 23:15Refactor
8. 33:10Recap

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