Redis accepts both a structured protocol, and a simple space-separated tokens protocol (called the inline protocol) that helps sysadmins to avoid a disaster just because they lack a proper redis-cli but are in need to run a Redis command ASAP. Perhaps this proxy is also supporting both forms.

You can do that with any modern enough Redis server:

    Escape character is '^]'.
    ping
    +PONG
    set foo bar
    +OK
    get foo
    $3
    bar