diff -r 22f027da67ec -r 9c968d0de9a0 progs/scala/Application4.scala
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/progs/scala/Application4.scala	Sat Oct 04 12:46:04 2014 +0100
@@ -0,0 +1,52 @@
+package controllers
+
+import play.api.mvc._
+import java.security.MessageDigest
+
+/*
+ * Application sets a cookie in plain ASCII on the
+ * clients browser recording the visits of a page.
+ *
+ * The cookie data is hashed and salted with a
+ * secret key.
+ */
+
+
+object Application extends Controller {
+
+  //secret key for salting 
+  val salt = "my secret key"
+
+  //SHA-1 + salt
+  def mk_hash(s: String) : String = {
+    val hash_fun = MessageDigest.getInstance("SHA-1")
+    hash_fun.digest((s + salt).getBytes).map{ "%02x".format(_) }.mkString
+  }
+
+  def gt_cookie(c: Cookie) : Int = c.value.split("/") match {
+    case Array(s, h) if (s.forall(_.isDigit) && mk_hash(s) == h) => s.toInt 
+    case _ => 0
+  }
+
+  def mk_cookie(i: Int) : Cookie = {
+    val hash = mk_hash(i.toString)
+    Cookie("visits", s"$i/$hash")
+  }
+   
+  def index = Action { request =>
+
+    val visits_cookie = request.cookies.get("visits")
+    val visits = visits_cookie.map(gt_cookie).getOrElse(0)
+
+    val msg = 
+      if (visits >= 10)
+        s"You are a valued customer who has visited this site $visits times."               
+      else s"You have visited this site $visits times."
+    
+    Ok(msg).withCookies(mk_cookie(visits + 1))
+  }     
+}
+
+
+
+