Add support for a Redis-specific alternative to "unix://" as a URL schema

[stevecj]

Currently, the schema that is recognized for a Unix socket connection is "unix" but that is a terrible name for a schema. It is only useful in a context that is constrained to only refer to Redis. One would never want to use that, for instance, as a URL for Celery/Kombu where the URL can be used to specify any of several kinds of backend of which Redis is only one.

Is it possible that "unix" is also too specific. Might it also possibly refer to a Windows named pipe at some time in the future?

…so I suggest maybe "redis+socket://" where "socket" is more general than "unix", and the schema name is also distinct from Lettuce's "redis-socket://" (with a dash, not a plus) which has a different structure.

[petyaslavova]

Hi @stevecj, thanks for the suggestion!
I believe this schema pattern relates to one of the AbstractConnection subclasses—specifically UnixDomainSocketConnection, which works with Redis instances configured to listen on a socket file. Since Unix Domain Sockets are specific to Unix-like systems, they’re generally not exposed on Windows.

If you have an idea for how something other than Unix could be supported, I’d be happy to review a PR with a POC and a brief explanation of the use case it would cover.