Decodes url parameters (#229)

Decode url parameters

spec/param_parser_spec.cr

@@ -33,6 +33,23 @@ describe "ParamParser" do
     url_params["hasan"].should eq "cemal"
   end
 
+  it "decodes url params" do
+    kemal = Kemal::RouteHandler::INSTANCE
+    kemal.add_route "POST", "/hello/:email/:money/:spanish" do |env|
+      email = env.params.url["email"]
+      money = env.params.url["money"]
+      spanish = env.params.url["spanish"]
+      "Hello, #{email}. You have #{money}. The spanish word of the day is #{spanish}."
+    end
+    request = HTTP::Request.new("POST", "/hello/sam%2Bspec%40gmail.com/%2419.99/a%C3%B1o")
+    # Radix tree MUST be run to parse url params.
+    io_with_context = create_request_and_return_io(kemal, request)
+    url_params = Kemal::ParamParser.new(request).url
+    url_params["email"].should eq "sam+spec@gmail.com"
+    url_params["money"].should eq "$19.99"
+    url_params["spanish"].should eq "año"
+  end
+
   it "parses request body" do
     route = Route.new "POST", "/" do |env|
       name = env.params.query["name"]

src/kemal/param_parser.cr

@@ -21,6 +21,10 @@ module Kemal
       @json_parsed = false
     end
 
+    private def decode_url_param(value : String)
+      value.size == 0 ? value : HTTP::Params.parse(value).first[0]?
+    end
+
     {% for method in %w(url query body json) %}
     def {{method.id}}
       # check memoization
@@ -45,7 +49,7 @@ module Kemal
     def parse_url
       if params = @request.url_params
         params.each do |key, value|
-          @url[key.as(String)] = value.as(String)
+          @url[key.as(String)] = decode_url_param(value).as(String)
         end
       end
     end