contentType SNS attribute required to deserialize JSON with @NotificationMessage: bug or not?

[hertzsprung]

Using Spring Cloud AWS 2.4.2, publishing a JSON message to an SNS topic leads to this SqsListener receiving a null payload:

@SqsListener(value = "myQueue")
public void process(@NotificationMessage MyJsonPayload payload) {
    // ...
}

After some source diving I realised the SNS message must specify an attribute contentType: application/json to be recognised by the MappingJackson2MessageConverter.

Is this intentional (undocumented?) behaviour or a bug?

I worked around the problem by declaring my own MappingJackson2MessageConverter bean:

@Bean
MappingJackson2MessageConverter converter() {
    return new MappingJackson2MessageConverter(new MimeType[]{});
}

[maciejwalkowiak]

@hertzsprung which version of Spring Cloud AWS are you using?

Edit:

Enforcing content type match is already fixed in 3.0 M2 (#213). You can follow the discussion there for more details.

[hertzsprung]

2.4.2 (I've edited my post, too)

[hertzsprung]

Aha, thank you! Perhaps verging off topic, but should a @SqsListener method reasonably expect to handle a null payload? Less surprising if Spring Cloud AWS threw an exception without invoking the listener method. But perhaps this is already being fixed in 3.0? 🙂

[maciejwalkowiak]

I think framework shouldn't try to be too smart about it. Payload can be null but headers can be there. I think I prefer to leave it to the user space.