From 45c7b4596b1543db7166277146da02254661e2b1 Mon Sep 17 00:00:00 2001
From: Eric Schulte <schulte.eric@gmail.com>
Date: Mon, 19 Apr 2010 14:36:06 -0600
Subject: [PATCH] adding web-server example

---
 project.clj    |  3 ++-
 propagator.org | 41 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/project.clj b/project.clj
index ea5dd08..425c0a3 100644
--- a/project.clj
+++ b/project.clj
@@ -2,5 +2,6 @@
   :description "Concurrent propagator system"
   :dependencies [[org.clojure/clojure "1.1.0-alpha-SNAPSHOT"]
                  [org.clojure/clojure-contrib "1.0-SNAPSHOT"]
-                 [vijual "0.1.0-SNAPSHOT"]]
+                 [vijual "0.1.0-SNAPSHOT"]
+                 [ring "0.2.0"]]
   :dev-dependencies [[leiningen/lein-swank "1.0.0-SNAPSHOT"]])
\ No newline at end of file
diff --git a/propagator.org b/propagator.org
index 08bafc2..cd18043 100644
--- a/propagator.org
+++ b/propagator.org
@@ -123,6 +123,47 @@ pull a graph from a the propagators saved in the =prop-graph= variable
       (/ (+ guess (/ x guess)) 2.0)))
 #+end_src
 
+** web server
+Alright, this will use Clojure's [[http://github.com/mmcgrana/ring][Ring]] web server middle-ware.
+
+So, I guess the best demo here would be some reading/writing through a
+MVC setup.
+
+The =app= will dispatch the incoming data to input cell by the route
+at the end of the url, then there can be a couple of output cells
+which will render different views of the related data.
+
+#+begin_src clojure
+  (use 'ring.adapter.jetty)
+  (use 'clojure.contrib.list-utils)
+  (import 'java.util.Date 'java.text.SimpleDateFormat)
+  
+  ;; cells
+  (cell names '())
+  (cell input "")
+  
+  ;; propagator -- adds value of input to names
+  (propagator adder [input names] [names]
+     (when (count (seq input)) (set (cons input names))))
+  
+  ;; web wrapping
+  (let [out *out*]
+    (defn app [req]
+      (binding [*out* out] (println (:uri req)))
+      (or
+       ;; dump value into "input" cell
+       (when-let [matched (re-matches #"/add/(.+)" (:uri req))]
+         (set-cell input (second matched))
+         {:status 303 :headers {"Location" "../list"}})
+       ;; render the value of the "list" cell
+       (when-let [matched (re-matches #"/list" (:uri req))]
+         {:status  200
+          :headers {"Content-Type" "text/html"}
+          :body    (apply str (flatten (list "<ul>" (map #(str "<li>"%"</li>") @names) "</ul>")))}))))
+  
+  (run-jetty app {:port 3000})
+#+end_src
+
 * notes
 ** look at mutable data stores
 - http://clojure.org/agents
-- 
2.11.4.GIT