Add support for range of media types in Accept header

routes.go

@@ -99,7 +99,7 @@ func (m *RouteMux) AddRoute(method string, pattern string, handler http.HandlerF
 		if strings.HasPrefix(part, ":") {
 			expr := "([^/]+)"
 			//a user may choose to override the defult expression
-			// similar to expressjs: ‘/user/:id([0-9]+)’ 
+			// similar to expressjs: ‘/user/:id([0-9]+)’
 			if index := strings.Index(part, "("); index != -1 {
 				expr = part[index:]
 				part = part[:index]
@@ -138,13 +138,15 @@ func (m *RouteMux) Filter(filter http.HandlerFunc) {
 
 // FilterParam adds the middleware filter iff the REST URL parameter exists.
 func (m *RouteMux) FilterParam(param string, filter http.HandlerFunc) {
-	if !strings.HasPrefix(param,":") {
-		param = ":"+param
+	if !strings.HasPrefix(param, ":") {
+		param = ":" + param
 	}
 
 	m.Filter(func(w http.ResponseWriter, r *http.Request) {
 		p := r.URL.Query().Get(param)
-		if len(p) > 0 { filter(w, r) }
+		if len(p) > 0 {
+			filter(w, r)
+		}
 	})
 }
 
@@ -248,6 +250,14 @@ func (w *responseWriter) WriteHeader(code int) {
 // code that serializes resources and writes to the
 // http response.
 
+type contentSeralizer func(w http.ResponseWriter, v interface{})
+
+var contentHandler = map[string]contentSeralizer{
+	applicationJson: ServeJson,
+	applicationXml:  ServeXml,
+	textXml:         ServeXml,
+}
+
 // ServeJson replies to the request with a JSON
 // representation of resource v.
 func ServeJson(w http.ResponseWriter, v interface{}) {
@@ -304,14 +314,10 @@ func ReadXml(r *http.Request, v interface{}) error {
 // Accept header.
 func ServeFormatted(w http.ResponseWriter, r *http.Request, v interface{}) {
 	accept := r.Header.Get("Accept")
-	switch accept {
-	case applicationJson:
-		ServeJson(w, v)
-	case applicationXml, textXml:
-		ServeXml(w, v)
-	default:
-		ServeJson(w, v)
+	for header, handler := range contentHandler {
+		if strings.Contains(accept, header) {
+			handler(w, v)
+			return
+		}
 	}
-
-	return
 }

routes_test.go

@@ -32,6 +32,51 @@ var FilterId = func(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+// Test data used for ServeFormatted
+type testData struct {
+	SomeField string
+	Number    int
+	Test      float64
+}
+
+// contentTest describes a test for ServerFormatted
+type contentTest struct {
+	Header   string
+	Expected string
+}
+
+// The correct formatted data for use by TestContentFormatted
+var dataJSON = "{\n  \"SomeField\": \"Hi\",\n  \"Number\": 20,\n  \"Test\": 2.5\n}"
+var dataXML = "<testData><SomeField>Hi</SomeField><Number>20</Number><Test>2.5</Test></testData>"
+
+// Various test cases for TestContentFormatted
+var contentTester = []contentTest{
+	contentTest{
+		"",
+		dataJSON,
+	},
+	contentTest{
+		"application/json",
+		dataJSON,
+	},
+	contentTest{
+		"application/xml",
+		dataXML,
+	},
+	contentTest{
+		"text/xml",
+		dataXML,
+	},
+	contentTest{
+		"text/plain; q=0.5, text/html,\ntext/xml; q=0.8, text/x-c",
+		dataXML,
+	},
+	contentTest{
+		"text/html;\ntext/json;",
+		dataJSON,
+	},
+}
+
 // TestAuthOk tests that an Auth handler will append the
 // username and password to to the request URL, and will
 // continue processing the request by invoking the handler.
@@ -148,6 +193,28 @@ func TestFilterParam(t *testing.T) {
 
 }
 
+// TestContentFormatted tests the basic Accept-Header content matching.
+func TestContentFormatted(t *testing.T) {
+	recorder := httptest.NewRecorder()
+	response, _ := http.NewRequest("GET", "localhost/does/not/matter", nil)
+
+	data := testData{
+		SomeField: "Hi",
+		Number:    20,
+		Test:      2.5,
+	}
+
+	for _, test := range contentTester {
+		response.Header.Set("Accept", test.Header)
+		ServeFormatted(recorder, response, data)
+		if recorder.Body.String() != test.Expected {
+			t.Fatalf("Sent %q header, expected %q. Got %q", test.Header, test.Expected, recorder.Body.String())
+		}
+		recorder.Body.Reset()
+	}
+
+}
+
 // Benchmark_RoutedHandler runs a benchmark against
 // the RouteMux using the default settings.
 func Benchmark_RoutedHandler(b *testing.B) {