Extending Ring

Ring stack consists of a chain of middleware function. We can write our own middleware functions or we can use libraries that include these middleware functions. There are three popular libraries that are used for this purpose:

• ring-defaults https://github.com/ring-clojure/ring-defaults
• ring-http-response https://github.com/metosin/ring-http-response
• muuntaja https://github.com/metosin/muuntaja

ring-defaults

This library provides sensible and secure default configurations of Ring middleware for both websites and APIs. It provides:

• api-defaults - support for urlencoded parameters
• site-defaults - support for parameters, cookies, sessions, static resources, file uploads and browser security headers
• secure-api-defaults and secure-site-defaults - same support + forced SSL

ring-http-response

This library provides an easier way to write code that returns meaningful responses that map to specific HTTP status codes. For example ok maps to 200, found - 302, and so on.

1(require [ring.util.http-response :refer :all])
2
3(ok "<p>Hello</p>")
4; => {:status 200, :headers {}, :body "<p>Hello</p>"}
5
6(internal-server-error "<p>failed</p>")
7; => {:status 500, :headers {}, :body "<p>failed</p>"}

muuntaja

Muuntaja is used for automatic serializing and deserializing of different data formats used in Ring applications. These formats include JSON and YAML as weel as Clojure-specific formats such as EDN and Transit. To work with this library we just need to include muuntaja.middleware/wrap-formats for automatic decoding based on request headers.