Getting Clojure

In the Wild

A great way to get a feel for working with multiple threads in Clojure is to look at the Compojure library.^[30] Compojure helps you route the requests that come into your web application to a suitable response. Here, for example, is a simple placeholder web application for our book store, built with Compojure:

(ns storefront.handler
  (:require [compojure.core :refer :all]
            [compojure.handler :as handler]))

(defroutes main-routes
  (GET "/" [] "Welcome to Blotts Books!!")
  (GET "/book" [title author]
       (str "Sorry " title " By " author " is not available.")))

(def app (handler/site main-routes))

The key bit of code here is the call to defroutes, which allows you to associate a route—/book, for example—with ...