目录
Redis是一个高效的key-value数据存储系统，支持多种数据结构。Redis是基于内存的操作，支持的数据类型有字符串、哈希表、列表、集合以及有序集合，主要用于缓存、高速队列以及消息的订阅与发布等。
Redis本身涉及到的内容很丰富，本文只概述学习Redis在Python中的应用。Redis的详细内容再另文概述。
Redis在Python中的应用包括Redis的连接以及各种数据结构的操作。
1.Redis连接
redis-py提供了Redis与StrictRedis两个类用于实现Redis的命令。StrictRedis用于实现官方大部分的命令，Redis是StrictRedis的子类，用于向后兼容。首先预览一下Redis类的构造函数。Redis连接方式有两种，直接创建连接或者通过连接池的方式。
def __init__(self,
host='localhost', #Redis服务器地址
port=6379, #Redis连接端口
db=0, #db
password=None, #Redis连接秘钥(服务器需要打开认证)
socket_timeout=None, #客户端空闲断开连接
socket_connect_timeout=None,
socket_keepalive=None,
socket_keepalive_options=None,
connection_pool=None, #使用连接池方式连接Redis
unix_socket_path=None, #unix socket 实现Redis本地连接
encoding='utf-8',
encoding_errors='strict',
charset=None,
errors=None,
decode_responses=False,
retry_on_timeout=False,
ssl=False,
ssl_keyfile=None,
ssl_certfile=None,
ssl_cert_reqs='required',
ssl_ca_certs=None,
max_connections=None): #最大连接数1.1新建连接
redis-py每次请求时都会创建redis连接。即使使用的是直接创建连接方式，redis-py也会首先创建一个redis连接池，然后再向连接池申请一个连接。这种方式下，redis连接池没有复用。
# !/usr/bin/env python3
# Filename:redis_helper.py
conf = {'HOST':'192.168.9.130',
'PORT':6379
}
import redis
class RedisHelper(object):
def getValue(self,
host = '127.0.0.1',
port = 6379,
db = 0,
*args):
try:
connection = redis.Redis(host = host,
port = port,
db = db,
decode_responses = True)
if len(args) == 0:
keys = connection.keys()
for key in keys:
print(key)
else:
for key in args:
print("{0:<10}:{1}".format(key,str(connection.get(key))))
except Exception as e:
print("redis connect error!",e)
if __name__ == "__main__":
helper = RedisHelper()
helper.getValue(conf['HOST'], conf['PORT'], 0,'user.age')1.2连接池
redis-py通过ConnectionPool管理所有的redis连接，避免了每次创建redis连接的系统开销。
# !/usr/bin/env python3
# Filename:redis_helper.py
conf = {'HOST':'192.168.9.130',
'PORT':6379
}
import redis
class RedisHelper(object):
#redis连接池
pool = ''
def __init__(self,
host = '127.0.0.1',
port = 6379,
db = 0,):
try:
self.pool = redis.ConnectionPool(host = host,
port = port,
db = db,
decode_responses = True)
except Exception as e:
print("redis connect error!",e)
def getValue(self,*args):
try:
connection = redis.Redis(connection_pool = self.pool)
if len(args) == 0:
keys = connection.keys()
for key in keys:
print(key)
else:
for key in args:
print("{0:<10}:{1}".format(key,str(connection.get(key))))
except Exception as e:
print("redis connect error!",e)
if __name__ == "__main__":
helper = RedisHelper(conf['HOST'], conf['PORT'], 0)
helper.getValue('user.age')
2.Redis操作
redis-py支持Redis的所有操作，api接口命名方式也基本相同。详细命令可以参阅Redis官网《The full list of commands》或者参阅《Redis命令参考》
2.1Key
Key（键）相关操作移步《Key》
#!/usr/bin/env python3
#Filename:redis_helper.py
conf = {'HOST':'192.168.9.130',
'PORT':6379
}
import redis,time
class RedisHelper(object):
#redis连接池
pool = ''
def __init__(self,
host = '127.0.0.1',
port = 6379,
db = 0,):
try:
self.pool = redis.ConnectionPool(host = host,
port = port,
db = db,
decode_responses = True)
except Exception as e:
print("redis connect error!",e)
def op_keys(self):
try:
connection = redis.StrictRedis(connection_pool = self.pool)
key = "user.name"
#redis所有的键值
rt = connection.keys("user.*");
self.__print__(rt,"所有键值")
#检测key是否存在
rt = connection.exists(key)
self.__print__(rt,"键值是否存在")
#删除给定的一个或者多个key
rt = connection.delete("key")
self.__print__(rt,"删除给定键值")
#给key赋值
rt = connection.set(key, "lreis", ex=1000)
self.__print__(rt,"给key赋值")
#查询key的过期时间
time.sleep(10)
rt = connection.ttl(key)
self.__print__(rt,"查询key值生存时间")
#修改key过期时间
rt = connection.expire(key, 100)
self.__print__(rt,"修正key生存时间")
rt = connection.ttl(key)
self.__print__(rt,"查询key值生存时间")
#键值对应的数据类型
rt = connection.type(key)
self.__print__(rt,"键值对应的数据类型")
#键值重命名
rt = connection.rename(key, "user.nickname")
self.__print__(rt,"键值重命名")
rt = connection.exists(key)
self.__print__(rt,"键值是否存在")
except Exception as e:
print("redis connect error!",e)
def __print__(self,rt,*args):
if len(args)>0:
print("[命令测试]%s==>"%args[0])
if isinstance(rt, int):
print("Redis操作结果:%d"%rt)
elif isinstance(rt, str):
print("Redis操作结果：%s"%rt)
elif isinstance(rt, list):
print("Redis操作结果：%s"%(",".join(rt)))
else:
print("Redis操作结果类型：%s"%type(rt))
pass
if __name__ == "__main__":
helper = RedisHelper(conf['HOST'], conf['PORT'], 0)
helper.op_keys()
2.2String
字符串类型
def op_string(self):
try:
connection = redis.StrictRedis(connection_pool = self.pool)
#给key赋值 set key val (ex 有效期秒)(px 有效期毫秒)(nx 不存在添加)(xx 存在才添加)
key = "user.name"
#删除key
rt = connection.delete(key)
self.__print__(rt,"删除给定键")
rt = connection.set(key,"lreis2010",ex = 1000)
self.__print__(rt,"键值赋值")
#给key值附加新的属性append key value
rt = connection.append(key, " is a nickname!")
self.__print__(rt,"字符追加")
#赋值数值型数据
age = "user.age"
rt = connection.set(age, 19)
#数值型数据自增
rt = connection.incr(age, 1)
self.__print__(rt,"数值型数据自增")
#数值型数据自减
rt = connection.decr(age, 1)
self.__print__(rt,"数值型数据自减")
#获取字符串片段
rt = connection.getrange(key, 0, 4)
self.__print__(rt,"获取字符串片段")
#位图操作
rt = connection.setbit("bit1",0, 1)
rt = connection.setbit("bit1",3, 1)
except Exception as e:
print("redis connect error!",e)