Emit error when websocket message is an error

[rmm5t]

What does it do?

Before, if an error message is sent from the server, that error is emitted as regular message data. Now, if a message of type=error arrives, it is emitted as an error instead.

What else?

Also removes auto-incrementing port for testing websocket server connections. We got to a point where we ran into port conflicts on the CI server.

Related Issues

• FIxes message errors not passed to the error handler #219

/cc @fb55

[fb55]

How do you feel about emitting an event with the type as the name as well? So instead of creating a special case for error just also create matches, open, l2update etc. events.

[rmm5t]

How do you feel about emitting an event with the type as the name as well? So instead of creating a special case for error just also create matches, open, l2update etc. events.

🤔 My initial gut reaction was to say no, but after considering how simple the implementation would be (simpler than this PR's changes), and as long as the generic message event is also emitted at the same time, I don’t really have any strong arguments that I can articulate at the moment.

Long story short, as long as message events remain for backwards compatibility and generic behavior, I think specific event types could be a nicety.

I'll modify this PR to be more generic like that.

[rmm5t]

@fb55 Oh. Here's an argument against the specfic event types. What about the websocket's open events (for Orders)? This would conflict with the socket's open events.

[fb55]

Whee, good point. Merging as is, thanks a lot :)