No longer possible to use a non-TLS connection with Twisted 19.7.0+

[Juhaz]

As of Twisted 19.7.0, xmlstream.TLSInitiatingInitializer is required by default (as I'm sure you know since you pushed the changes yourself)

Unfortunately Wokkel doesn't expose the functionality in XMPPClient so it's no longer possible to make non-TLS connections at all.

[ralphm]

@Juhaz: looking into this, I seem to remember that was more or less intentional. In what circumstances would it be reasonable to have XMPPClient not use TLS?

[Juhaz]

@ralphm we are running a bunch of microservices that are perhaps semantically more like components than "normal" clients but for one reason or another didn't quite fit that mold either. They're running in same internal network as the XMPP server itself so TLS is necessary or helpful.

I understand that this is probably not a very common use-case.

[ralphm]

I guess the use-case itself is not that uncommon. However, for a while now, best practice is to have interconnecting (micro)services use transport encryption. Usually for regulatory compliance and privacy reasons. So I assumed nobody really did that anymore.