bindings: support rabbitmq send any content types (#1147)

Signed-off-by: Long <long0dai@foxmail.com>

bindings/rabbitmq/rabbitmq.go

@@ -99,6 +99,12 @@ func (r *RabbitMQ) Invoke(req *bindings.InvokeRequest) (*bindings.InvokeResponse
 		Body:         req.Data,
 	}
 
+	contentType, ok := contrib_metadata.TryGetContentType(req.Metadata)
+
+	if ok {
+		pub.ContentType = contentType
+	}
+
 	ttl, ok, err := contrib_metadata.TryGetTTL(req.Metadata)
 	if err != nil {
 		return nil, err

bindings/requests.go

@@ -42,7 +42,7 @@ func (r *InvokeRequest) GetMetadataAsBool(key string) (bool, error) {
 	return false, nil
 }
 
-// GetMetadataAsBool parses metadata as int64
+// GetMetadataAsInt64 parses metadata as int64
 func (r *InvokeRequest) GetMetadataAsInt64(key string, bitSize int) (int64, error) {
 	if val, ok := r.Metadata[key]; ok {
 		intVal, err := strconv.ParseInt(val, 10, bitSize)

metadata/utils.go

@@ -23,6 +23,9 @@ const (
 
 	// PriorityMetadataKey defines the metadata key for setting a priority
 	PriorityMetadataKey = "priority"
+
+	// ContentType defines the metadata key for the content type
+	ContentType = "contentType"
 )
 
 // TryGetTTL tries to get the ttl as a time.Duration value for pubsub, binding and any other building block.
@@ -83,3 +86,11 @@ func IsRawPayload(props map[string]string) (bool, error) {
 
 	return false, nil
 }
+
+func TryGetContentType(props map[string]string) (string, bool) {
+	if val, ok := props[ContentType]; ok && val != "" {
+		return val, true
+	}
+
+	return "", false
+}

metadata/utils_test.go

@@ -55,3 +55,31 @@ func TestIsRawPayload(t *testing.T) {
 		assert.Nil(t, err)
 	})
 }
+
+func TestTryGetContentType(t *testing.T) {
+	t.Run("Metadata without content type", func(t *testing.T) {
+		val, ok := TryGetContentType(map[string]string{})
+
+		assert.Equal(t, "", val)
+		assert.Equal(t, false, ok)
+	})
+
+	t.Run("Metadata with empty content type", func(t *testing.T) {
+		val, ok := TryGetContentType(map[string]string{
+			"contentType": "",
+		})
+
+		assert.Equal(t, "", val)
+		assert.Equal(t, false, ok)
+	})
+
+	t.Run("Metadata with corrent content type", func(t *testing.T) {
+		const contentType = "application/cloudevent+json"
+		val, ok := TryGetContentType(map[string]string{
+			"contentType": contentType,
+		})
+
+		assert.Equal(t, contentType, val)
+		assert.Equal(t, true, ok)
+	})
+}