Refactor class level DSL with macros to convert blocks to instance-scoped methods

samples/app_squared.cr

@@ -0,0 +1,17 @@
+require "../src/kemal/base"
+
+class MyApp < Kemal::Application
+  get "/" do |env|
+    "Hello Kemal!"
+  end
+end
+
+class OtherApp < Kemal::Application
+  get "/" do |env|
+    "Hello World!"
+  end
+end
+
+spawn { MyApp.run(3002) }
+
+OtherApp.run(3001)

spec/application_mode_spec.cr

@@ -8,6 +8,10 @@ private class MyApp < Kemal::Application
   get "/route2" do |env|
     "Route 2"
   end
+
+  get "/file" do |env|
+    send_file env, "Serdar".to_slice
+  end
 end
 
 describe MyApp do
@@ -24,4 +28,23 @@ describe MyApp do
       end
     end
   end
+
+  it "sends file with binary stream" do
+    request = HTTP::Request.new("GET", "/file")
+    response = call_request_on_app(MyApp.new, request)
+    response.status_code.should eq(200)
+    response.headers["Content-Type"].should eq("application/octet-stream")
+    response.headers["Content-Length"].should eq("6")
+  end
+
+  it "responds to delayed route" do
+    app = MyApp.new
+    app.setup
+    app.get "/delayed" do |env|
+      "Happy addition!"
+    end
+    request = HTTP::Request.new("GET", "/delayed")
+    client_response = call_request_on_app(app, request)
+    client_response.body.should eq("Happy addition!")
+  end
 end

spec/helpers_spec.cr

@@ -42,7 +42,7 @@ describe "Macros" do
       client_response.body.should eq("world")
 
       app.get "/breaking" do |env|
-        halt env, 404, "hello"
+        Kemal::Macros.halt env, 404, "hello"
         "world"
       end
       request = HTTP::Request.new("GET", "/breaking")
@@ -54,7 +54,7 @@ describe "Macros" do
     it "can break block with halt macro using default values" do
       app = Kemal::Base.new
       app.get "/" do |env|
-        halt env
+        Kemal::Macros.halt env
         "world"
       end
       request = HTTP::Request.new("GET", "/")
@@ -69,7 +69,7 @@ describe "Macros" do
       app = Kemal::Base.new
       app.get "/headers" do |env|
         env.response.headers.add "Content-Type", "image/png"
-        headers env, {
+        app.headers env, {
           "Access-Control-Allow-Origin" => "*",
           "Content-Type"                => "text/plain",
         }
@@ -85,7 +85,7 @@ describe "Macros" do
     it "sends file with given path and default mime-type" do
       app = Kemal::Base.new
       app.get "/" do |env|
-        send_file env, "./spec/asset/hello.ecr"
+        app.send_file env, "./spec/asset/hello.ecr"
       end
 
       request = HTTP::Request.new("GET", "/")
@@ -98,7 +98,7 @@ describe "Macros" do
     it "sends file with given path and given mime-type" do
       app = Kemal::Base.new
       app.get "/" do |env|
-        send_file env, "./spec/asset/hello.ecr", "image/jpeg"
+        app.send_file env, "./spec/asset/hello.ecr", "image/jpeg"
       end
 
       request = HTTP::Request.new("GET", "/")
@@ -111,7 +111,7 @@ describe "Macros" do
     it "sends file with binary stream" do
       app = Kemal::Base.new
       app.get "/" do |env|
-        send_file env, "Serdar".to_slice
+        app.send_file env, "Serdar".to_slice
       end
 
       request = HTTP::Request.new("GET", "/")

src/kemal/application.cr

@@ -14,7 +14,7 @@ class Kemal::Application < Kemal::Base
     super
 
     unless error_handlers.has_key?(404)
-      error 404 do |env|
+      self.error 404 do |env|
         render_404
       end
     end
@@ -22,7 +22,7 @@ class Kemal::Application < Kemal::Base
     # Test environment doesn't need to have signal trap, built-in images, and logging.
     unless @config.env == "test"
       # This route serves the built-in images for not_found and exceptions.
-      get "/__kemal__/:image" do |env|
+      self.get "/__kemal__/:image" do |env|
         image = env.params.url["image"]
         file_path = File.expand_path("lib/kemal/images/#{image}", Dir.current)
         if File.exists? file_path

src/kemal/base.cr

@@ -13,7 +13,6 @@ class Kemal::Base
   include Macros
   include Base::DSL
   include Base::Builder
-  extend Base::ClassDSL
 
   # :nodoc:
   getter route_handler = Kemal::RouteHandler.new
@@ -41,9 +40,7 @@ class Kemal::Base
 
   # Overload of self.run with the default startup logging
   def run(port : Int32? = nil)
-    run port do
+    run(port) { }
-      log "[#{config.env}] Kemal is ready to lead at #{config.scheme}://#{config.host_binding}:#{config.port}"
-    end
   end
 
   # The command to run a `Kemal` application.

src/kemal/base/dsl.cr

@@ -1,31 +1,42 @@
 class Kemal::Base
+  private CUSTOM_METHODS_REGISTRY = {} of _ => _
+
+  macro inherited
+    {% CUSTOM_METHODS_REGISTRY[@type] = {
+         handlers: [] of _,
+         ws:       [] of _,
+         error:    [] of _,
+         filters:  [] of _,
+       } %}
+
+    include MacroDSL
+  end
+
   module DSL
     HTTP_METHODS   = %w(get post put patch delete options)
     FILTER_METHODS = %w(get post put patch delete options all)
 
-    macro included
-      # :nodoc:
-      DEFAULT_HANDLERS = [] of {String, String, (HTTP::Server::Context -> String)}
-      # :nodoc:
-      WEBSOCKET_HANDLERS = [] of {String, (HTTP::WebSocket, HTTP::Server::Context -> Void)}
-      # :nodoc:
-      DEFAULT_ERROR_HANDLERS = [] of {Int32, (HTTP::Server::Context, Exception -> String)}
-      # :nodoc:
-      DEFAULT_FILTERS = [] of {Symbol, String, String, (HTTP::Server::Context -> String)}
-    end
-
     {% for method in HTTP_METHODS %}
+      # Add a `{{method.id.upcase}}` handler.
+      #
+      # The block receives an `HTTP::Server::Context` as argument.
       def {{method.id}}(path, &block : HTTP::Server::Context -> _)
-        raise Kemal::Exceptions::InvalidPathStartException.new({{method}}, path) unless Kemal::Utils.path_starts_with_slash?(path)
+        raise Kemal::Exceptions::InvalidPathStartException.new({{method}}, path) unless path.starts_with?("/")
         route_handler.add_route({{method}}.upcase, path, &block)
       end
     {% end %}
 
+    # Add a webservice handler.
+    #
+    # The block receives `HTTP::WebSocket` and `HTTP::Server::Context` as arguments.
     def ws(path, &block : HTTP::WebSocket, HTTP::Server::Context -> Void)
-      raise Kemal::Exceptions::InvalidPathStartException.new("ws", path) unless Kemal::Utils.path_starts_with_slash?(path)
+      raise Kemal::Exceptions::InvalidPathStartException.new("ws", path) unless path.starts_with?("/")
       websocket_handler.add_route path, &block
     end
 
+    # Add an error handler for *status_code*.
+    #
+    # The block receives `HTTP::Server::Context` and `Exception` as arguments.
     def error(status_code, &block : HTTP::Server::Context, Exception -> _)
       add_error_handler status_code, &block
     end
@@ -35,57 +46,137 @@ class Kemal::Base
     #  - after_all, after_get, after_post, after_put, after_patch, after_delete, after_options
     {% for type in ["before", "after"] %}
       {% for method in FILTER_METHODS %}
+        # Add a filter for this class that runs {{type.id}} each `{{method.id.upcase}}` request (optionally limited to a specific *path*).
+        #
+        # The block receives an `HTTP::Server::Context` as argument.
         def {{type.id}}_{{method.id}}(path = "*", &block : HTTP::Server::Context -> _)
           filter_handler.{{type.id}}({{method}}.upcase, path, &block)
         end
       {% end %}
     {% end %}
 
-    private def initialize_defaults
+    private macro initialize_defaults
-      DEFAULT_HANDLERS.each do |method, path, block|
+      {% if CUSTOM_METHODS_REGISTRY[@type] %}
-        route_handler.add_route(method.upcase, path, &block)
+      {% for handler in CUSTOM_METHODS_REGISTRY[@type][:handlers] %}
-      end
+      self.{{handler[0].id}}({{handler[1]}}) do |context|
-
+        {{handler[2].id}}(context)
-      WEBSOCKET_HANDLERS.each do |path, block|
-        ws(path, &block)
-      end
-
-      DEFAULT_ERROR_HANDLERS.each do |status_code, block|
-        add_error_handler status_code, &block
-      end
-
-      DEFAULT_FILTERS.each do |type, method, path, block|
-        if type == :before
-          filter_handler.before(method, path, &block)
-        else
-          filter_handler.after(method, path, &block)
-        end
-      end
-    end
-  end
-
-  module ClassDSL
-    {% for method in DSL::HTTP_METHODS %}
-      def {{method.id}}(path, &block : HTTP::Server::Context -> _)
-        DEFAULT_HANDLERS << { {{method}}, path, block }
       end
       {% end %}
 
-    def ws(path, &block : HTTP::WebSocket, HTTP::Server::Context -> Void)
+      {% for ws in CUSTOM_METHODS_REGISTRY[@type][:ws] %}
-      WEBSOCKET_HANDLERS << {path, block}
+      self.ws({{handler[0]}}) do |websocket, context|
+        {{handler[1].id}}(websocket, context)
+      end
+      {% end %}
+
+      {% for ws in CUSTOM_METHODS_REGISTRY[@type][:error] %}
+      self.add_error_handler({{handler[0]}}) do |context|
+        {{handler[1].id}}(context)
+      end
+      {% end %}
+
+      {% for filter in CUSTOM_METHODS_REGISTRY[@type][:filters] %}
+        filter_handler.{{filter[0]}}({{filter[1]}}, {{filter[2]}}) do |context|
+          {{filter[3]}}(context)
+        end
+      {% end %}
+      {% end %}
+    end
   end
 
-    def error(status_code, &block : HTTP::Server::Context, Exception -> _)
+  module MacroDSL
-      DEFAULT_ERROR_HANDLERS << {status_code, block}
+    {% for method in DSL::HTTP_METHODS %}
+      # Define a `{{method.id.upcase}}` handler for this class.
+      #
+      # It will be initialized in every instance.
+      # The block receives an `HTTP::Server::Context` as argument and is scoped to the instance.
+      #
+      # Example:
+      # ```
+      # class MyClass < Kemal::Base
+      #   {{method.id}}("/route") do |context|
+      #     # ...
+      #   end
+      # end
+      # ```
+      # NOTE: This macro *must* be called from class scope as it expands to a custom method definition.
+      macro {{method.id}}(path, &block)
+        \{% raise "invalid path start for {{method.id}}: path must start with \"/\"" unless path.starts_with?("/") %}
+        \{% method_name = "__{{method.id}}_#{path.id.gsub(/[^a-zA-Z0-9]/,"_").gsub(/__+/, "_").gsub(/\A_|_\z/, "")}_#{CUSTOM_METHODS_REGISTRY[@type][:handlers].size}" %}
+        def \{{method_name.id}}(\{{block.args[0].id}})
+          \{{block.body}}
+        end
+        \{% CUSTOM_METHODS_REGISTRY[@type][:handlers] << { {{method}}, path, method_name } %}
+      end
+    {% end %}
+
+    # Define a webservice handler for this class.
+    #
+    # It will be initialized in every instance.
+    # The block receives `HTTP::WebSocket` and `HTTP::Server::Context` as arguments and is scoped to the instance.
+    #
+    # Example:
+    # ```
+    # class MyClass < Kemal::Base
+    #   ws("/wsroute") do |context|
+    #     # ...
+    #   end
+    # end
+    # ```
+    # NOTE: This macro *must* be called from class scope as it expands to a custom method definition.
+    macro ws(path, &block)
+        \{% raise "invalid path start for webservice: path must start with \"/\"" unless path.starts_with?("/") %}
+      \{% method_name = "__ws_#{path.id.gsub(/[^a-zA-Z0-9]/,"_").gsub(/__+/, "_").gsub(/\A_|_\z/, "")}_#{CUSTOM_METHODS_REGISTRY[@type][:ws].size}" %}
+      def \{{method_name.id}}(\{{block.args[0].id}}, \{{block.args[1].id}})
+        \{{block.body}}
+      end
+      \{% CUSTOM_METHODS_REGISTRY[@type][:ws] << { path, method_name } %}
     end
 
-    # All the helper methods available are:
+    # Define an error handler for this class.
-    #  - before_all, before_get, before_post, before_put, before_patch, before_delete, before_options
+    #
-    #  - after_all, after_get, after_post, after_put, after_patch, after_delete, after_options
+    # It will be initialized in every instance.
-    {% for type in [:before, :after] %}
+    # The block receives `HTTP::Server::Context` and `Exception` as arguments and is scoped to the instance.
+    #
+    # Example:
+    # ```
+    # class MyClass < Kemal::Base
+    #   error(403) do |context|
+    #     # ...
+    #   end
+    # end
+    # ```
+    # NOTE: This macro *must* be called from class scope as it expands to a custom method definition.
+    macro error(status_code)
+      \{% method_name = "__error_#{status_code}_#{CUSTOM_METHODS_REGISTRY[@type][:error].size}" %}
+      def \{{method_name.id}}(\{{block.args[0].id}})
+        \{{block.body}}
+      end
+      \{% CUSTOM_METHODS_REGISTRY[@type][:error] << { status_code, method_name } %}
+    end
+
+    {% for type in ["before", "after"] %}
       {% for method in DSL::FILTER_METHODS %}
-        def {{type.id}}_{{method.id}}(path = "*", &block : HTTP::Server::Context -> _)
+        # Define a filter for this class that runs {{type.id}} each `{{method.id.upcase}}` request (optionally limited to a specific *path*).
-          DEFAULT_FILTERS << { {{type}}, {{method}}, path, block }
+        #
+        # The filter will be initialized in every instance of this class.
+        # The block receives an `HTTP::Context` as argument and is scoped to the instance.
+        #
+        # Example:
+        # ```
+        # class MyClass < Kemal::Base
+        #   {{type.id}}_{{method.id}}("/route") do |context|
+        #     # ...
+        #   end
+        # end
+        # ```
+        # NOTE: This macro *must* be called from class scope as it expands to a custom method definition.
+        macro {{type.id}}_{{method.id}}(path = "*", &block)
+          \{% method_name = "__{{type.id}}_{{method.id}}_#{path.id.gsub(/[^a-zA-Z0-9]/,"_").gsub(/__+/, "_").gsub(/\A_|_\z/, "")}_#{CUSTOM_METHODS_REGISTRY[@type][:handlers].size}" %}
+          def \{{method_name.id}}(\{{block.args[0].id}})
+            \{{block.body}}
+          end
+          \{% CUSTOM_METHODS_REGISTRY[@type][:fitlers] << { {{type}}, {{method}}, path, method_name } %}
         end
       {% end %}
     {% end %}