Allow multiple values for a single parameter key.

src/kemal/param_parser.cr

@@ -11,8 +11,8 @@ class Kemal::ParamParser
 
   def initialize(@request : HTTP::Request)
     @url = {} of String => String
-    @query = {} of String => String
-    @body = {} of String => String
+    @query = {} of String => String | Array(String)
+    @body = {} of String => String | Array(String)
     @json = {} of String => AllParamTypes
     @url_parsed = false
     @query_parsed = false
@@ -68,12 +68,26 @@ class Kemal::ParamParser
   end
 
   def parse_part(part)
-    part_params = {} of String => String
+    part_params = {} of String => String | Array(String)
+
     if part
       HTTP::Params.parse(part) do |key, value|
-        part_params[key as String] ||= value as String
+        key_string = key as String
+        value_string = value as String
+        current_value = part_params[key_string]?
+
+        part_params[key_string] = if current_value
+                                    if current_value.is_a?(Array)
+                                      current_value << value_string
+                                    else
+                                      [current_value, value_string]
+                                    end
+                                  else
+                                    value_string
+                                  end
       end
     end
+
     part_params
   end
 end

src/kemal/request.cr

@@ -10,18 +10,29 @@ class HTTP::Request
   # Checks if request params contain _method param to override request incoming method
   private def check_for_method_override!
     @override_method = @method
+
     if @method == "POST"
       params = Kemal::ParamParser.new(self).body
+
       if params.has_key?("_method") && HTTP::Request.override_method_valid?(params["_method"])
-        @override_method = params["_method"]
+	_method = params["_method"]
+
+        @override_method = if _method.is_a?(Array)
+          _method.last
+        else
+          _method
+        end
       end
     end
+
     @override_method
   end
 
   # Checks if method contained in _method param is valid one
   def self.override_method_valid?(override_method)
-    return false unless override_method.is_a?(String)
+    return false unless override_method.is_a?(String) || override_method.is_a?(Array(String))
+
+    override_method = override_method.last if override_method.is_a?(Array(String))
     override_method = override_method.upcase
     override_method == "PUT" || override_method == "PATCH" || override_method == "DELETE"
   end