fix paramter extraction with charset

This fixes a bug where a charset in the content type blocked the
extraction of the payload.
A browser may send a string like

  multipart/form-data; charset=UTF-8

which include? could not find the defined types. Now it gets split and
then checked against the defined types.

lib/zero/request/parameter.rb

@@ -16,6 +16,9 @@ module Zero
       ENV_KEY_CUSTOM = 'zero.params.custom'
       # the key for the content type
       ENV_KEY_CONTENT_TYPE = 'CONTENT_TYPE'
+      # the separator of the type and charset
+      #   for example multipart/form-data; charset=UTF-8
+      CONTENT_TYPE_SEPERATOR = ';'
       # all content types which used for using the body as a parameter input
       PAYLOAD_CONTENT_TYPES = [
         'application/x-www-form-urlencoded',
@@ -87,12 +90,20 @@ module Zero
       # extracts the key value pairs from the body
       # @return Hash all key value pairs from the payload
       def extract_payload_params(environment)
-        unless PAYLOAD_CONTENT_TYPES.include?(environment[ENV_KEY_CONTENT_TYPE])
+        unless matches_payload_types?(environment[ENV_KEY_CONTENT_TYPE])
           return {}
         end
         parse_string(environment[ENV_KEY_PAYLOAD].read)
       end
 
+      # check if the content-type matches one of the payload types
+      # @param [String] type - the content type string
+      # @return Boolean true if it matches
+      def matches_payload_types?(type)
+        return false if type.nil?
+        PAYLOAD_CONTENT_TYPES.include?(type.split(CONTENT_TYPE_SEPERATOR)[0])
+      end
+
       # parse the query string like input to a hash
       # @param query [String] the query string
       # @return [Hash] the key/valuie pairs

spec/unit/zero/request/parameter/payload_spec.rb

@@ -50,6 +50,16 @@ describe Zero::Request::Parameter, '#payload' do
     its(:payload) { should == {'bar[]' => ['foo', 'bar']} }
   end
 
+  context 'with encoding in the content type' do
+    let(:env) do
+      EnvGenerator.post('/foo', {
+        :input => 'foo=bar',
+        'CONTENT_TYPE' => 'multipart/form-data; charset=UTF-8'
+      })
+    end
+    its(:payload) { should == {'foo' => 'bar'} }
+  end
+
   # TODO behaves like this, but is this really good like this?
   context 'with a post body and content type application/json' do
     let(:env) do