From 8fb028149b69f383cf5aabe782ed1029f2fc0a6a Mon Sep 17 00:00:00 2001
From: Serdar Dogruyol <dogruyolserdar@gmail.com>
Date: Sun, 16 Sep 2018 13:17:51 +0300
Subject: [PATCH 1/3] Cache http routes

---
 spec/spec_helper.cr        |  1 +
 src/kemal/route_handler.cr | 17 ++++++++++++++---
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/spec/spec_helper.cr b/spec/spec_helper.cr
index 4d27003..0bc127a 100644
--- a/spec/spec_helper.cr
+++ b/spec/spec_helper.cr
@@ -83,5 +83,6 @@ end
 Spec.after_each do
   Kemal.config.clear
   Kemal::RouteHandler::INSTANCE.routes = Radix::Tree(Route).new
+  Kemal::RouteHandler::INSTANCE.cached_routes = Hash(String, Radix::Result(Route)).new
   Kemal::WebSocketHandler::INSTANCE.routes = Radix::Tree(WebSocket).new
 end
diff --git a/src/kemal/route_handler.cr b/src/kemal/route_handler.cr
index 95f9050..2e3ea3b 100644
--- a/src/kemal/route_handler.cr
+++ b/src/kemal/route_handler.cr
@@ -5,10 +5,11 @@ module Kemal
     include HTTP::Handler
 
     INSTANCE = new
-    property routes
+    property routes, cached_routes
 
     def initialize
       @routes = Radix::Tree(Route).new
+      @cached_routes = Hash(String, Radix::Result(Route)).new
     end
 
     def call(context : HTTP::Server::Context)
@@ -22,9 +23,19 @@ module Kemal
       add_to_radix_tree("HEAD", path, Route.new("HEAD", path) { }) if method == "GET"
     end
 
-    # Check if a route is defined and returns the lookup
+    # Looks up the route from the Radix::Tree for the first time and caches to improve performance.
     def lookup_route(verb : String, path : String)
-      @routes.find radix_path(verb, path)
+      lookup_path = radix_path(verb, path)
+
+      if cached_route = @cached_routes[lookup_path]?
+        return cached_route
+      end
+
+      route = @routes.find(lookup_path)
+
+      @cached_routes[lookup_path] = route if route.found?
+
+      route
     end
 
     # Processes the route if it's a match. Otherwise renders 404.

From 1a8a3c5b1d8b8d0a73b021d597b65d8cf09cde72 Mon Sep 17 00:00:00 2001
From: Serdar Dogruyol <dogruyolserdar@gmail.com>
Date: Sun, 16 Sep 2018 15:34:43 +0300
Subject: [PATCH 2/3] Add cache size limit check to caching routes

---
 src/kemal/route_handler.cr | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/kemal/route_handler.cr b/src/kemal/route_handler.cr
index 2e3ea3b..233289e 100644
--- a/src/kemal/route_handler.cr
+++ b/src/kemal/route_handler.cr
@@ -4,7 +4,8 @@ module Kemal
   class RouteHandler
     include HTTP::Handler
 
-    INSTANCE = new
+    INSTANCE            = new
+    CACHED_ROUTES_LIMIT = 1024
     property routes, cached_routes
 
     def initialize
@@ -33,7 +34,11 @@ module Kemal
 
       route = @routes.find(lookup_path)
 
-      @cached_routes[lookup_path] = route if route.found?
+      if route.found? && @cached_routes.size < CACHED_ROUTES_LIMIT
+        @cached_routes[lookup_path] = route
+      else
+        @cached_routes.clear
+      end
 
       route
     end

From 4bb56d23768ce57a25b304d054e051bcc8df4c9a Mon Sep 17 00:00:00 2001
From: Serdar Dogruyol <dogruyolserdar@gmail.com>
Date: Mon, 17 Sep 2018 09:51:56 +0300
Subject: [PATCH 3/3] Only clear cached_routes if there's a route

---
 src/kemal/route_handler.cr | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/kemal/route_handler.cr b/src/kemal/route_handler.cr
index 233289e..b0476c6 100644
--- a/src/kemal/route_handler.cr
+++ b/src/kemal/route_handler.cr
@@ -34,10 +34,9 @@ module Kemal
 
       route = @routes.find(lookup_path)
 
-      if route.found? && @cached_routes.size < CACHED_ROUTES_LIMIT
+      if route.found?
+        @cached_routes.clear if @cached_routes.size == CACHED_ROUTES_LIMIT
         @cached_routes[lookup_path] = route
-      else
-        @cached_routes.clear
       end
 
       route