core.clj

## core.clj
(ns enlive-mw.core
  (:use compojure)
  (:require [net.cgrand.enlive-html :as e]))

(e/deftemplate simple-layout "enlive_mw/layout.html"
 [{:keys [title ps widget]}]
  #{[:title] [:h1]} (e/content title)
  [:p] (e/clone-for [p ps] (e/content p))
  [:#widget] (e/content widget))

(e/defsnippet widget "enlive_mw/widget.html" [:div] [s]
  [:b] (e/content s))

(defn welcome-page [req]
  {:body {:title "Layout through middleware: Demo"
          :ps ["Lorem ipsum dolor sit amet, consectetur adipiscing elit."
               "Ut hendrerit, nibh ac porttitor rhoncus, diam dolor
                vestibulum nisi, non suscipit urna est vitae est."]
          :widget (widget "Hello World")}})

(defn layout-with [handler layout]
  (fn [req]
    (let [{body :body :as resp} (handler req)]
      (if (map? body)
        (assoc resp :body (layout body))
        resp))))

(decorate welcome-page
  (layout-with simple-layout))

(defroutes app
  (GET "/" welcome-page)
  (ANY "*"
    [404 "Page Not Found"]))

(defn start-app
 ([] (start-app 8080))
 ([port] (start-app app port))
 ([app port]
  (run-server {:port port}
    "/*" (servlet app))))

## layout.html
<html>
  <head>
    <title>Title goes here</title>
  </head>
  <body>
    <h1>Title goes here too</h1>
    <p>A very intersting paragraph</p>
    <div id="widget">intentionally left blank</div>
  </body>
</html>

## sample-output.html
<html>
  <head>
    <title>Layout through middleware: Demo</title>
  </head>
  <body>
    <h1>Layout through middleware: Demo</h1>
    <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p><p>Ut hendrerit, nibh ac porttitor rhoncus, diam dolor
                vestibulum nisi, non suscipit urna est vitae est.</p>

    <div id="widget"><div style="background: #ccc; font: bold">I'm a wonderful widget which says <b>Hello World</b>!</div></div>
  </body>
</html>

## widget.html
<html>
  <body>
    <div style="background: #ccc; font: bold">I'm a wonderful widget which says <b>boo</b>!</div>
  </body>
</html>