Payload format about vmq_webhooks

[larshesel]

Hi - thanks for bringing this issue up - to be honest it's an oversight on my part and your suspicion is entirely correct: the current code cannot handle arbitrary binary payloads, only the subset that consists of utf8 encoded strings.

As you mentioned in vernemq/vernemq#210 the payload would have to be base64 encoded to be a valid json structure - so to support this I suppose we should automatically base64 encode the payload data and let the webhook implementors decode it. This would of course be a breaking change for existing users of the webhooks plugin but I think a necessary one. What do you think @dergraf ?

[dergraf]

Could we detect if the payload is UTF-8 encoded and pass it as a String or base64 encode it if required?

Another option would be to make some encoders configurable.

[larshesel]

@dergraf I don't think automatic detection would be a good idea. It would be expensive to do and also it would be confusing for the clients to handle.

I think the only real way forward is to base64 encode by default and maybe add a way to disable it for those that don't need it (which is probably a special case).