深入python的类和对象
1、为类或对象动态创建属性或方法
2、__slots__ = ('name','age')，【实例】只能创建指定的属性属性或方法 ---新式类
3、执行父类的构造函数的不同
Father.__init__(self) --经典类
super(Son,self).__init__() --新式类
4、Person.__bases__ 只会显示一层继承的所有父类
5、__call__
__call__ 一个已经实例化的对象p，在调用p()
6、python中一切都是对象，类本身也是对象，类是由type产生的。
class Foo
pass
Bar = type('Bar',(object,),{'name':123,'Func':Hello})
既然这样，那么对于定义的类来说，只要定义了一个类，就调用一次 type类的构造函数，如何验证？
7、__metaclass__ 可以指定类是由那个type来产生的
1 2 3 4 5 6 7 8 9 | class MetaClass(type):
def __init__(self,name,bases,dicts):
print name
class C1:
__metaclass__ = MetaClass
class C2:
__metaclass__ = MetaClass
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8、__init__ __new__ __call__
我们知道执行 f = Foo() 会默认执行构造函数 __init__
实际上执行了：type('Foo',bases,dicts).__call__('Foo')
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | class MetaClass(type):
def __init__(self,name,bases,dicts):
print name
def __call__(self, *args, **kwargs):
print self
result = self.__new__(self, *args, **kwargs)
print result
type(result).__init__(result,*args,**kwargs)
return result
class C1:
__metaclass__ = MetaClass
def __init__(self):
print 'c1.__init__'
self.name = 'alex'
def __new__(cls, *args, **kwargs):
print cls
print args
print kwargs
return object.__new__(cls, *args, **kwargs)
def Hello(self):
print 'hello'
class C2:
__metaclass__ = MetaClass
#c = C1()
c1 = object.__new__(C1)
c1.Hello()
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Session
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 | #!/usr/bin/env python
#coding:utf-8
from hashlib import sha1
import os, time
create_session_id = lambda: sha1('%s%s' % (os.urandom(16), time.time())).hexdigest()
class session(object):
'''自定义session框架'''
_sessionid = '__sessionid'
def __init__(self,request,timeout = 1800):
#根据request从cookie中获取 __sessionid 的值
self._request = request
self._timeout = 1800
self._redis = {}
self.__initialize()
def __initialize(self):
id = self._request.get_cookie(session._sessionid)
if not id:
id = create_session_id()
self._request.set_cookie(session._sessionid,id)
self._id = id
print id
def __getitem__(self,name):
#return self._redis.hget(self._id, name)
print name
return name
def __setitem__(self,name,value):
#self._redis.hset(self._id, name, value)
#self._redis.expire(self._id, self.session_lifetime)
print name,value
def __delitem__(self, name):
#return self._redis.hdel(self._id, name)
return 'del'
__all__ = ["session"]
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Tornado
View Code 1、根据请求不同定位到指定类的 get、post、put、delete方法上
https://chrome.google.com/webstore/detail/postman-rest-client/fdmmgilgnpjigdojojpjoooidkmcomcm
2、render
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