I can't understand the reasoning on putting everything behind HTTP these days. Personally, I think that if a project decides to go that route it's because poor design decisions. Separation of interests should exist in software solutions.
The only bit I see that talks about something similar is, "Salmon is designed to sit _behind a traditional mail server_ in the same way a web application sits behind Apache or Nginx", emphasis is mine.
> Salmon is best deployed behind another mailserver such as Postfix or Sendmail - much in the same way as you host a WSGI application behind Apache or Nginx.
It is a combination of developers wanting to have cross platform end users, while also working around restrictions in place on corporate networks. It's been downhill since hotmail.
Node.js / Python both have very good support for http. Soap etc, run a web server for quick file serving from command line if you want. Dgraoh and other tools can easily be interfaced via http.
Why not leverage all that?