让socket.io客户端版本落后于服务器版本

Question

Situation

We're using socket.io for mobile-server communications. Since we can't force-upgrade users' devices, if we want to upgrade to version 1 (non-back-compatible), we have to handle both versions on the server for a while.

Question

What are the options?

My current favourite is to wrap both the old version and the new version in a multiplexer. It detects the version of the incoming request based on headers and query parameters and thereby knows which functions to invoke.

Another (shittier) option is to wrap the new version in a module that can translate the old version of the protocol into the new version (and back again) when necessary. This suffers from a serious drawback. It would be time-consuming and uncertain work to ensure I've properly determined and handled all the tiny differences. Some differences might take some serious massaging.

(In case you're curious or it's helpful to know, we're doing this in Go.)

Answer 1

We're going to go the route of keeping both the 0.9.x version and the current version as separate libraries on the server. Eventually, when the pool of clients has more-or-less all updated, we'll just pull the plug on the 0.9.x version.

The way we'll manage the two versions is by wrapping the socket.io services in a package that will determine which wrapped socket.io version to pass the request off to. This determination will depend on features of the request, such as custom headers (that can be added to the newer clients) as well as query parameters and other headers utilized exclusively by one version or the other.

Since we're using Go, there's so far no universally agreed upon way to manage dependencies, let alone a way that can respect version differences. Assuming the back-compat branch of the repo wasn't broken (which it is), we'd have two options. The first would be to fork the repo and make the back-compat version the master. We'd then import it as if it had nothing to do with the other one. The second option would be to use gopkg.in to pretend the separate branches were separate repos.

In either event, we could import the two branches/repos like so

import (
    socketioV0 "github.com/path/to/older/version"
    socketioV1 "github.com/path/to/current/version"
)

And then refer to them in the code using their import names socketioV0 and socketioV1.