broker: pass broker content type if message options not pass it

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

broker/memory/memory.go

@@ -159,6 +159,9 @@ func (b *Broker) Init(opts ...broker.Option) error {
 
 func (b *Broker) NewMessage(ctx context.Context, hdr metadata.Metadata, body interface{}, opts ...broker.PublishOption) (broker.Message, error) {
 	options := broker.NewPublishOptions(opts...)
+	if options.ContentType == "" {
+		options.ContentType = b.opts.ContentType
+	}
 	m := &memoryMessage{ctx: ctx, hdr: hdr, opts: options}
 	c, err := b.newCodec(m.opts.ContentType)
 	if err == nil {

broker/noop.go

@@ -128,6 +128,9 @@ func (m *noopMessage) Unmarshal(dst interface{}, opts ...codec.Option) error {
 
 func (b *NoopBroker) NewMessage(ctx context.Context, hdr metadata.Metadata, body interface{}, opts ...PublishOption) (Message, error) {
 	options := NewPublishOptions(opts...)
+	if options.ContentType == "" {
+		options.ContentType = b.opts.ContentType
+	}
 	m := &noopMessage{ctx: ctx, hdr: hdr, opts: options}
 	c, err := b.newCodec(m.opts.ContentType)
 	if err == nil {