spike: Add pain text responses

lib/apia/rack.rb

@@ -152,6 +152,20 @@ def triplet_for_exception(exception)
 
     class << self
 
+      # Return a triplet for the given body.
+      #
+      # @param body [Hash, Array]
+      # @param status [Integer]
+      # @param headers [Hash]
+      # @return [Array]
+      def plain_triplet(body, status: 200, headers: {})
+        [
+          status,
+          headers.merge('content-type' => 'text/plain', 'content-length' => body.bytesize.to_s),
+          [body]
+        ]
+      end
+
       # Return a JSON-ready triplet for the given body.
       #
       # @param body [Hash, Array]

lib/apia/response.rb

@@ -10,6 +10,7 @@ class Response
     attr_reader :fields
     attr_reader :headers
     attr_writer :body
+    attr_writer :type
 
     def initialize(request, endpoint)
       @request = request
@@ -53,11 +54,18 @@ def body
       @body || hash
     end
 
+    def type
+      @type || :json
+    end
+
     # Return the rack triplet for this response
     #
     # @return [Array]
     def rack_triplet
-      Rack.json_triplet(body, headers: @headers, status: @status)
+      return Rack.json_triplet(body, headers: @headers, status: @status) if type == :json
+      return Rack.plain_triplet(body, headers: @headers, status: @status) if type == :plain
+
+      raise "Unknown response type '#{type}'"
     end
 
   end