涉及到的key:
1. article_time, 记录文章的发布时间，zset结构
2. article_score, 记录文章的得分， zset结构
得分 = 发布时间 + 投票用户数 X 432
3. voted_article_id, 记录文章的投票用户集合，文章的发布者默认为文章的投票用户，set结构
4. article_article_id, 用来描述文章，hash结构
5. group_groupname, 群组groupname下的文章集合，set结构
6. score_groupname, 群组groupname下的文章得分集合，zset结构
# python3
# -*- coding: utf-8 -*- import redis
import time ONE_WEEK_IN_SECONDS = 7 * 86400
# 如果一篇文章获得200个赞，那么这篇文章就是有趣的
VOTE_SCORE = 86400 / 200
ARTICLES_PER_PAGE = 25 def redis_init(redis):
# article_time记录文章发布时间
redis.zadd('article_time', article_100408=1496762197, article_100635=1496769721, article_100716=1496760089)
# article_score记录文章得分
redis.zadd('article_score', article_100408=1496766517, article_100635=1496770153, article_100716=1496765705)
# voted_article_id记录编号为article_id的文章的点赞用户集合
redis.sadd('voted_100408', 'user_234487', 'user_253378', 'user_364680',
'user_132097', 'user_350917')
# 用hash描述每篇文章
article_desc = {'title':'kunlun', 'link':'www.kunlun.com', 'poster':'user_234487',
'time':1441728000, 'votes':523}
redis.hmset('article_100408', article_desc)
article_desc = {'title': 'zhuxian', 'link': 'www.zhuxian.com', 'poster': 'user_234488',
'time': 1081440000, 'votes': 677}
redis.hmset('article_100635', article_desc)
article_desc = {'title': 'soushenji', 'link': 'www.soushenji.com', 'poster': 'user_234489',
'time': 1187280000, 'votes': 421}
redis.hmset('article_100635', article_desc)
# 记录文章总数
redis.set('article_index', 200000) # 用户给文章投票
def article_vote(conn, user, article):
cutoff = time.time() - ONE_WEEK_IN_SECONDS
if conn.zscore('article_time', article) < cutoff:
return article_id = article.partition('_')[-1]
if conn.sadd('voted_' + article_id, user):
conn.zincrby('article_score', article, VOTE_SCORE)
conn.hincrby(article, 'votes', 1) # 发布新文章
def post_article(conn, user, title, link):
article_id = str(conn.incr('article_index')) voted = 'voted_' + article_id
# poster默认为文章的投票用户
conn.sadd(voted, user)
# 设置key过期时间
conn.expire(voted, ONE_WEEK_IN_SECONDS) now = time.time()
article = 'article_' + article_id
conn.hmset(article, {
'title': title,
'link': link,
'poster': user,
'time': now,
'votes': 1,
}) conn.zadd('article_score', article, now + VOTE_SCORE)
conn.zadd('article_time', article, now) return article_id # 取出评分最高的文章
# 取最新发布的文章，order='article_time'
# page, 按页取
def get_articles(conn, page, order='article_score'):
start = (page-1) * ARTICLES_PER_PAGE
end = start + ARTICLES_PER_PAGE - 1 ids = conn.zrevrange(order, start, end)
articles = []
for id in ids:
article_data = conn.hgetall(id)
article_data['id'] = id
articles.append(article_data) return articles # 添加文章到群组，或者从群组里删除文章
def add_remove_groups(conn, article_id, to_add=[], to_remove=[]):
article = 'article_' + article_id
for group in to_add:
conn.sadd('group_' + group, article)
for group in to_remove:
conn.srem('group_' + group, article) # 获取群组中的文章
def get_group_articles(conn, group, page, order='article_score'):
key = order + group
if not conn.exists(key):
conn.zinterstore(key,
['group_' + group, order],
aggregate='max'
)
# 缓存60s
conn.expire(key, 60)
return get_articles(conn, page, key) r = redis.Redis(host='redis_serverip', port=6379, password='redis_passwd', db=0) # redis_init(r) # article_vote(r,'use_115423', 'article_100408')
#
# new_article_id = post_article(r, 'user_5424', 'yingxiongzhi', 'www.yingxiongzhi.com')
# print('new_article_id:', new_article_id)
#
# add_remove_groups(r, 'article_100408')
#
# get_group_articles(r, 'programming', 1)
PS:
redis-py模块中有两个类:Redis和StrictRedis，两者部分API稍有不同，本文使用Redis这个类。
反对票的实现:
def article_against(conn, user, article):
cutoff = time.time() - ONE_WEEK_IN_SECONDS
if conn.zscore('article_time', article) < cutoff:
return article_id = article.partition('_')[-1]
if conn.sadd('against_' + article_id, user):
conn.incrby('article_score', article, -VOTE_SCORE)
conn.hincrby(article, 'votes', -1)
移除投票的竞争条件:
def article_against(conn, user, article):
cutoff = time.time() - ONE_WEEK_IN_SECONDS
if conn.zscore('article_time', article) < cutoff:
return article_id = article.partition('_')[-1]
if conn.sadd('against_' + article_id, user):
pipeline = conn.pipeline() conn.incrby('article_score', article, -VOTE_SCORE)
conn.hincrby(article, 'votes', -1) pipeline.execute()
参考资料:
《Redis实战》