1. u:<uid> hash, 存放用户信息，例如name/avatar等
2. s:<uid> stream, 这个队列用于接收/发送用户消息
3. c:<uid> sorted set, 用于存放用户联系人（包括群组）
4. gm:<gid> set, 用于存放群用户id
5. gs:<gid> stream, 用于接收/发送群消息
6. gi:<gid> hash, 存放群信息，例如name，还有一些配置信息（例如加群是否需要验证？）

redis module实现IM

IM.RECIVE [uid] BLOCK [ms] COUNT [count] START [start]
获取历史消息，以及监听新的消息

IM.RECIVE [GROUP | USER] [uid | gid] [mid]
获取单条消息

IM.SEND [uid] [tuid] [field value] [field value ... ]
发送单聊消息

IM.GSEND [uid] [gid] [field value] [field value ... ]
发送群聊消息

IM.USER [uid]
(get user info) 获取用户信息
IM.USER [uid] [field value] [field value ... ]
(create user or update user info)

IM.GROUP [gid]
(get group info)
IM.GROUP [gid] [uid] [field value] [field value ... ]
(create group or update group info)

IM.LINK [uid] [tuid]
(add to user contact list)

IM.UNLINK [uid] [tuid]
(remove from user contact list)

IM.LINK [uid] [gid]
(add to user group)

IM.QUIT [uid] [gid]
(remove from user group)

1. using tornado WebSocketHandler to create websocket.
2. using svelte create simple ui to send message (using localStorage to save message)

docker run --rm --name=redisim -p 8888:8888 lloydzhou/redisim

pip install redisim

import asyncio
import redis.asyncio as redis
import redisim

async def main():
    client = redis.Redis(decode_responses=True)
    res = await client.im().recive(user_id, **kwargs)
    print(res)

asyncio.run(main())

im = client.im(module=False)

using lua script version with apache/kvrocks