FFI calls > Support generators for async message

[tienvx]

These scenarios in compatibility suite indicate that generators are supported for async message on consumer side:

• Supports the use of generators with the message body
• Supports the use of generators with message metadata

But currently I think generators are not working when using this pactffi_message_reify FFI call.

[mefellows]

Reify doesn't support synchronous messages and a bunch of things. I think you're best using the message-related iterators to extract these values. The method should probably be marked as deprecated.

[tienvx]

I don't know how to use those iterators methods yet. I can't find any example code. Look like there are no language using those methods yet?

btw thanks for the suggestion.

[mefellows]

No worries!

Btw I use it in Go here: https://github.com/pact-foundation/pact-go/blob/master/internal/native/message_server.go#L397-L519.

[tienvx]

Using these methods:

• pactffi_pact_handle_get_message_iter
• pactffi_pact_message_iter_next
• pactffi_message_get_contents

I'm able to get the message content, but it's exactly the same with the result from pactffi_message_reify, which doesn't have any values generated by generators.

Plus I have a panic Caught panic with error: iter past the end of metadata while using these methods (there is no way I can handle it from php side):

• pactffi_message_get_metadata_iter
• pactffi_message_metadata_iter_next

[tienvx]

I'm able to use those iterator methods, but there 2 small problems:

• The code is too long for me (15 lines of code vs 1 when using pactffi_message_reify)
• An annoying issue related to panic "Iterator past the end ..." panics #344

I also updated pactffi_message_reify with this PR #342, so for now I will continue using it.

[tienvx]

Closed as implemented

[mefellows]

Nice one! I'm interested - does this work on synchronous messages also (both the request and/or response side)?

[tienvx]

I didn't touch on synchronous message FFI calls. But I have a quick look at synchronous_messages_iter and I think it is already implemented:

• https://github.com/pact-foundation/pact-reference/blob/master/rust/pact_consumer/src/builders/message_iter.rs#L56
• https://github.com/pact-foundation/pact-reference/blob/master/rust/pact_consumer/src/builders/message_iter.rs#L76

Currently I can't implement synchronous message in compatibility suite in PHP so I can't test it.

[mefellows]

oh yes, I know they support generators. I guess I was asking if you could use pactffi_message_reify on a sync message. I can look at code, I was being lazy :P

[tienvx]

if you could use pactffi_message_reify on a sync message

No, I don't think so.