Plug

Composable web middleware specification and connection adapter for Elixir

Language / Topic

Elixir

Rules

Plug · balanced balanced

- Build request pipelines with `Plug.Builder` — each plug transforms the `%Plug.Conn{}` struct in sequence.

- Use `Plug.Router` for routing with `get/post/put/delete` macros — each route is a function that receives `conn` and `opts`.

- Call `Plug.Conn.send_resp/3` to send responses — always set status code and body. Use `put_resp_content_type/2` for JSON APIs.

- Use `Plug.Parsers` in your pipeline to automatically parse JSON, URL-encoded, and multipart request bodies.

- Implement `init/1` for compile-time option validation and `call/2` for runtime request handling.

- Use `Plug.Builder` to define reusable plug pipelines with `plug MyPlug, opts` macros.

- Use `Plug.Conn` functions (`put_resp_content_type`, `send_resp`, `assign`) to build responses.

- Chain plugs in order: parsing → auth → rate limiting → routing → response.