使用Redis构建简单的社交网站

社交网站已经成为人类生活中不可或缺的部分。现有的两大社交网站——微博，推特都高度依赖 Redis 承载海量用户访问。

本实训项目从创建用户与状态，处理用户关系，状态与信息流三个方面介绍如何使用 Redis 构建简单的社交网站。

第1关：创建用户与动态

#!/usr/bin/env python
#-*- coding:utf-8 -*-

import re
import time
import redis

conn = redis.Redis()

# 创建新用户
def create_user(login_name, real_name):
    # 请在下面完成要求的功能
    #********* Begin *********#
    login_name = login_name.lower()
    if conn.hget("users", login_name):
        return None

    uid = conn.incr("user:id")
    pipe = conn.pipeline(True)
    pipe.hset("users", login_name, uid)
    pipe.hmset("user:%i"%(uid), {
    
    
        'login_name': login_name,
        'id': uid,
        'real_name': real_name,
        'followers': 0,
        'following': 0,
        'posts': 0,
        'last_signup': time.time(),
    })
    pipe.execute()

    return uid
    #********* End *********#

# 为用户创建新动态
def create_post(uid, content):
    # 请在下面完成要求的功能
    #********* Begin *********#
    pipe = conn.pipeline(True)
    pipe.hget("user:%i"%(uid), 'login_name')
    pipe.incr("post:id")
    login_name, pid = pipe.execute()

    if not login_name:
        return None

    pipe.hmset("post:%i"%(pid), {
    
    
        'id': pid,
        'uid': uid,
        'content': content,
        'posted': time.time(),
        'user_name': login_name,
    })
    pipe.hincrby("user:%i"%(uid), 'posts')
    pipe.execute()

    return pid
    #********* End *********#

第2关：处理用户关系

#!/usr/bin/env python
#-*- coding:utf-8 -*-

import re
import time
import redis

conn = redis.Redis()

# 关注用户
def follow(uid, other_uid):
    # 请在下面完成要求的功能
    #********* Begin *********#
    fkey1 = "following:%s"%(uid)
    fkey2 = "followers:%s"%(other_uid)

    if conn.zscore(fkey1, other_uid):
        return None

    now = time.time()
    pipe = conn.pipeline(True)
    pipe.zadd(fkey1, other_uid, now)
    pipe.zadd(fkey2, uid, now)
    following, followers = pipe.execute()

    pipe.hincrby("user:%s"%(uid), 'following', int(following))
    pipe.hincrby("user:%s"%(other_uid), 'followers', int(followers))
    pipe.execute()

    return True
    #********* End *********#

# 取消关注
def unfollow(uid, other_uid):
    # 请在下面完成要求的功能
    #********* Begin *********#
    fkey1 = "following:%s"%(uid)
    fkey2 = "followers:%s"%(other_uid)

    if not conn.zscore(fkey1, other_uid):
        return None

    pipe = conn.pipeline(True)
    pipe.zrem(fkey1, other_uid)
    pipe.zrem(fkey2, uid)
    following, followers = pipe.execute()

    pipe.hincrby("user:%s"%(uid), 'following', -int(following))
    pipe.hincrby("user:%s"%(other_uid), 'followers', -int(followers))
    pipe.execute()

    return True
    #********* End *********#

# 创建新用户
def create_user(login_name, real_name):
    login_name = login_name.lower()
    if conn.hget("users", login_name):
        return None

    uid = conn.incr("user:id")
    pipe = conn.pipeline(True)
    pipe.hset("users", login_name, uid)
    pipe.hmset("user:%i"%(uid), {
    
    
        'login_name': login_name,
        'id': uid,
        'real_name': real_name,
        'followers': 0,
        'following': 0,
        'posts': 0,
        'last_signup': time.time(),
    })
    pipe.execute()

    return uid

# 为用户创建新动态
def create_post(uid, content):
    pipe = conn.pipeline(True)
    pipe.hget("user:%i"%(uid), 'login_name')
    pipe.incr("post:id")
    login_name, pid = pipe.execute()

    if not login_name:
        return None

    pipe.hmset("post:%i"%(pid), {
    
    
        'id': pid,
        'uid': uid,
        'content': content,
        'posted': time.time(),
        'user_name': login_name,
    })
    pipe.hincrby("user:%i"%(uid), 'posts')
    pipe.execute()

    return pid

第3关：状态与信息流

#!/usr/bin/env python
#-*- coding:utf-8 -*-

import re
import time
import redis

conn = redis.Redis()

# 获得主页时间线
def get_home_timeline(uid, page=1, count=30):
    # 请在下面完成要求的功能
    #********* Begin *********#
    post_ids = conn.zrevrange("home:%s"%(uid), 0, -1)

    pipe = conn.pipeline(True)
    for pid in post_ids:
        pipe.hgetall("post:%s"%(pid))

    return pipe.execute()
    #********* End *********#

# 发布动态并将动态推送给粉丝
def post(uid, content):
    # 请在下面完成要求的功能
    #********* Begin *********#
    pid = create_post(uid, content)
    if not pid:
        return None

    posted = conn.hget("post:%s"%(pid), "posted")
    conn.zadd("profile:%s"%(uid), pid, float(posted))
    followers = conn.zrange("followers:%s"%(uid), 0, -1)

    pipe = conn.pipeline(False)
    for follower in followers:
        pipe.zadd("home:%s"%(follower), pid, float(posted))
    pipe.execute()

    return pid
    #********* End *********#

# 关注用户
def follow(uid, other_uid):
    fkey1 = "following:%s"%(uid)
    fkey2 = "followers:%s"%(other_uid)

    if conn.zscore(fkey1, other_uid):
        return None

    now = time.time()
    pipe = conn.pipeline(True)
    pipe.zadd(fkey1, other_uid, now)
    pipe.zadd(fkey2, uid, now)
    following, followers = pipe.execute()

    posts = conn.zrevrange("profile:%s"%(other_uid), 0, 100, withscores=True)
    if posts:
        pipe.zadd("home:%s"%(uid), **dict(posts))

    pipe.hincrby("user:%s"%(uid), 'following', int(following))
    pipe.hincrby("user:%s"%(other_uid), 'followers', int(followers))
    pipe.execute()

    return True

# 取消关注
def unfollow(uid, other_uid):
    fkey1 = "following:%s"%(uid)
    fkey2 = "followers:%s"%(other_uid)

    if not conn.zscore(fkey1, other_uid):
        return None

    pipe = conn.pipeline(True)
    pipe.zrem(fkey1, other_uid)
    pipe.zrem(fkey2, uid)
    following, followers = pipe.execute()

    posts = conn.zrevrange("profile:%s"%(other_uid), 0, -1)
    if posts:
        pipe.zrem("home:%s"%(uid), *posts)

    pipe.hincrby("user:%s"%(uid), 'following', -int(following))
    pipe.hincrby("user:%s"%(other_uid), 'followers', -int(followers))
    pipe.execute()

    return True

# 创建新用户
def create_user(login_name, real_name):
    login_name = login_name.lower()
    if conn.hget("users", login_name):
        return None

    uid = conn.incr("user:id")
    pipe = conn.pipeline(True)
    pipe.hset("users", login_name, uid)
    pipe.hmset("user:%i"%(uid), {
    
    
        'login_name': login_name,
        'id': uid,
        'real_name': real_name,
        'followers': 0,
        'following': 0,
        'posts': 0,
        'last_signup': time.time(),
    })
    pipe.execute()

    return uid

# 为用户创建新动态
def create_post(uid, content):
    pipe = conn.pipeline(True)
    pipe.hget("user:%i"%(uid), 'login_name')
    pipe.incr("post:id")
    login_name, pid = pipe.execute()

    if not login_name:
        return None

    pipe.hmset("post:%i"%(pid), {
    
    
        'id': pid,
        'uid': uid,
        'content': content,
        'posted': time.time(),
        'user_name': login_name,
    })
    pipe.hincrby("user:%i"%(uid), 'posts')
    pipe.execute()

    return pid