Replace Mochiweb/Webmachine with Cowboy/Cowmachine.

[mworrell]

Fixes #533

See also: https://github.com/zotonic/cowmachine 🐮

• Remove mochiweb/webmachine http server initialization
• Add cowboy http server initialization
• Remove webmachine from deps
• Replace #wm_reqdata{} with type mochiweb_req:req()
• Replace calls to wrq with calls to cowmachine_req
• Update controllers to simpler version with one Context argument
• Change service API to only use a Context argument
• Binaryfication of arguments
• Add web socket upgrade
• Cookie setting (new code in cowboy2)
• Get it compiling
• Test, test, test, and test.

Proposal is to move the re-addittion of the access log (z_access_log, z_stats, z_access_syslog and request watchers) to another separate issue.

[ddeboer]

Yeah, great start! 🐮

[arjan]

Why no hex.pm dependencies?

(oh wait, different branch, probably)

[mworrell]

Indeed, we are using the master (2.0 development) version of cowboy.

[mworrell]

I propose to add the access logs and stats via a different issue.

/cc @mmzeeman @arjan

[ddeboer]

And it’s green! 👏

@mworrell As you’ve just converted Zotonic’s internal controllers, would you mind adding a section to upgrading.rst on how users can convert any custom controllers they have? Something like:

1. remove the ReqDate argument
2. different way of getting request and setting response headers
3. remove init and ping functions
4. ...?

[mworrell]

@ddeboer Added docs, also updates some out of date information.
There is also a "Just enough webmachine" chapter, shall we update or remove that?

[mworrell]

We should also check chapters like directory structure that are not updated with the rebar3 changes.

[ddeboer]

Added docs, also updates some out of date information.

Great!

There is also a "Just enough webmachine" chapter, shall we update or remove that?

Let’s remove it.

We should also check chapters like directory structure that are not updated with the rebar3 changes.

As that doesn’t have to do with this change (Cowboy) per se, I created a separate issue for that: #1399.

[mworrell]

Let's warn the mailing list before we merge, as this is an incompatibel and quite drastic change.

[ddeboer]

Thanks, this is a great start. I’ll probably slightly rewrite this later for better developer experience. 😉 I noted that in #1399.

[mworrell]

We might want to add an example controller in the documentation, showing all possible callbacks.

[mworrell]

We have warned the mailing list and on twitter, so I think we can merge.

/cc @ArthurClemens @arjan @mmzeeman

[ddeboer]

Let’s give everyone one more day to look at this; if we hear no objections, I’ll squash and merge this tomorrow.

[ddeboer]

BOOM! 💣 🔥 🎆 🚒