Add Kemal::OverrideMethodHandler

src/kemal/override_method_handler.cr

@@ -0,0 +1,24 @@
+module Kemal
+  class OverrideMethodHandler
+    include HTTP::Handler
+    INSTANCE = new
+
+    ALLOWED_METHODS           = ["PUT", "PATCH", "DELETE"]
+    OVERRIDE_METHOD           = "POST"
+    OVERRIDE_METHOD_PARAM_KEY = "_method"
+
+    def call(context)
+      request = context.request
+      if request.method == OVERRIDE_METHOD
+        if context.params.body.has_key?(OVERRIDE_METHOD_PARAM_KEY) && override_method_valid?(context.params.body["_method"])
+          request.method = context.params.body["_method"].upcase
+        end
+      end
+      call_next(context)
+    end
+
+    def override_method_valid?(override_method : String)
+      ALLOWED_METHODS.includes?(override_method.upcase)
+    end
+  end
+end