DIDComm message handler breaks out of message handler flow

[rkreutzer]

Once a DIDComm v2 message is unpacked, no further messageHandlers are executed. Maybe this is intended behavior, but I was expecting to use subsequent message handlers to perform more processing on the message.

The fix would be easy, changing line 124 of the DidComm message-handler.ts from "return message" to "return super.handle(message, context)".

[mirceanis]

We found that our original message chaining design was confusing for a lot of folks and that's why we decided to try to change it.

We didn't actually get to change the behavior of the other message handlers, leading to this bug.

I think the fix you propose should be good to align the behavior of the handlers, but I'd still like to come up with a better solution for all.

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One of the ideas was to split message handlers into parsers and handlers

Parsers can be chained, just like the the handlers of today, and they should return a message as soon as a message type is decoded.

Then the message with a type can be broadcast to all the handlers, which can do further processing and rebroadcast a message with a different type, if for example there's a different layer that can be decoded.

This seemingly more complicated design should accommodate handlers that can handle multiple messages (like a message forwarding handler) and messages that can be interpreted by multiple handlers ( a jwt string can be both a final message as well as an envelope for another protocol)

Another reason for a redesign is the fact that our chaining logic today doesn't differentiate between an invalid signature and an exceptional failure (like failing to resolve a DID while trying to verify a signature) leading to very unhelpful "Unsupported message type“ errors.

Any feedback here is very welcome!

[rkreutzer]

I submitted a PR for this fix.

Maybe I've just gotten used to the current method of chaining, but I think that any confusion can be dealt with in more documentation and some more examples. Some apps may only need a few handlers, if they are working with a limited scope of messages, while other apps may need more handlers to process a wider variety of messages.

The broadcast/rebroadcast idea may add more complexity than is needed. I'd rather see a move to a single package for message handling, with the various handlers being within that, so each new handler doesn't require a unique package/plugin.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.