1 files changed, 54 insertions, 0 deletions
diff --git a/actionpack/lib/action_dispatch/testing/request_encoder.rb b/actionpack/lib/action_dispatch/testing/request_encoder.rb
new file mode 100644
index 0000000000..b0b994b2d0
--- /dev/null
+++ b/actionpack/lib/action_dispatch/testing/request_encoder.rb
@@ -0,0 +1,54 @@
+module ActionDispatch
+  class RequestEncoder # :nodoc:
+    @encoders = {}
+
+    attr_reader :response_parser
+
+    def initialize(mime_name, param_encoder, response_parser, url_encoded_form = false)
+      @mime = Mime[mime_name]
+
+      unless @mime
+        raise ArgumentError, "Can't register a request encoder for " \
+          "unregistered MIME Type: #{mime_name}. See `Mime::Type.register`."
+      end
+
+      @url_encoded_form = url_encoded_form
+      @path_format      = ".#{@mime.symbol}" unless @url_encoded_form
+      @response_parser  = response_parser || -> body { body }
+      @param_encoder    = param_encoder   || :"to_#{@mime.symbol}".to_proc
+    end
+
+    def append_format_to(path)
+      if @url_encoded_form
+        path
+      else
+        path + @path_format
+      end
+    end
+
+    def content_type
+      @mime.to_s
+    end
+
+    def encode_params(params)
+      @param_encoder.call(params)
+    end
+
+    def self.parser(content_type)
+      mime = Mime::Type.lookup(content_type)
+      encoder(mime ? mime.ref : nil).response_parser
+    end
+
+    def self.encoder(name)
+      @encoders[name] || WWWFormEncoder
+    end
+
+    def self.register_encoder(mime_name, param_encoder: nil, response_parser: nil)
+      @encoders[mime_name] = new(mime_name, param_encoder, response_parser)
+    end
+
+    register_encoder :json, response_parser: -> body { JSON.parse(body) }
+
+    WWWFormEncoder = new(:url_encoded_form, -> params { params }, nil, true)
+  end
+end