Refactor route caching to use configurable max size

Author: sdogruyol

spec/spec_helper.cr

@@ -93,6 +93,6 @@ Spec.after_each do
   Kemal.config.clear
   Kemal::FilterHandler::INSTANCE.tree = Radix::Tree(Array(Kemal::FilterHandler::FilterBlock)).new
   Kemal::RouteHandler::INSTANCE.routes = Radix::Tree(Route).new
-  Kemal::RouteHandler::INSTANCE.cached_routes = Kemal::LRUCache(String, Radix::Result(Kemal::Route)).new(1024)
+  Kemal::RouteHandler::INSTANCE.cached_routes = Kemal::LRUCache(String, Radix::Result(Kemal::Route)).new(Kemal.config.max_route_cache_size)
   Kemal::WebSocketHandler::INSTANCE.routes = Radix::Tree(WebSocket).new
 end

src/kemal/config.cr

@@ -26,6 +26,7 @@ module Kemal
     property serve_static : (Bool | Hash(String, Bool))
     property static_headers : (HTTP::Server::Context, String, File::Info -> Void)?
     property? powered_by_header : Bool = true
+    property max_route_cache_size : Int32
 
     def initialize
       @app_name = "Kemal"
@@ -43,6 +44,7 @@ module Kemal
       @running = false
       @shutdown_message = true
       @handler_position = 0
+      @max_route_cache_size = 1024
     end
 
     @[Deprecated("Use standard library Log")]
@@ -69,6 +71,7 @@ module Kemal
       @router_included = false
       @handler_position = 0
       @default_handlers_setup = false
+      @max_route_cache_size = 1024
       HANDLERS.clear
       CUSTOM_HANDLERS.clear
       FILTER_HANDLERS.clear

src/kemal/route_handler.cr

@@ -57,7 +57,7 @@ module Kemal
     private def insert_front(node : Node(K, V))
       node.prev = nil
       node.next = @head
-      @head.try { |h| h.prev = node }
+      @head.try(&.prev=(node))
       @head = node
       @tail = node if @tail.nil?
     end
@@ -68,8 +68,8 @@ module Kemal
       # unlink
       prev = node.prev
       nxt = node.next
-      prev.try { |p| p.next = nxt }
-      nxt.try { |n| n.prev = prev }
+      prev.try(&.next=(nxt))
+      nxt.try(&.prev=(prev))
 
       # fix tail if needed
       if node == @tail
@@ -79,7 +79,7 @@ module Kemal
       # insert at head
       node.prev = nil
       node.next = @head
-      @head.try { |h| h.prev = node }
+      @head.try(&.prev=(node))
       @head = node
     end
 
@@ -105,13 +105,12 @@ module Kemal
   class RouteHandler
     include HTTP::Handler
 
-    INSTANCE            = new
-    CACHED_ROUTES_LIMIT = 1024
+    INSTANCE = new
     property routes, cached_routes
 
     def initialize
       @routes = Radix::Tree(Route).new
-      @cached_routes = LRUCache(String, Radix::Result(Route)).new(CACHED_ROUTES_LIMIT)
+      @cached_routes = LRUCache(String, Radix::Result(Route)).new(Kemal.config.max_route_cache_size)
     end
 
     def call(context : HTTP::Server::Context)