06day15

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

    class MetaClass(type):
        def __init__(self,name,bases,dicts):
            print name
        
    class C1:
        __metaclass__ = MetaClass
        
    class C2:
        __metaclass__ = MetaClass

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')

    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()

Session 

#!/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"]

Tornado

#!/usr/bin/env python
#coding:utf-8
 
import socket
 
def handle_request(client): 
    buf = client.recv(1024) 
    print buf 
    client.send("HTTP/1.1 200 OK\r\n\r\n") 
    client.send("Hello, World") 
 
def main():
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
    sock.bind(('127.0.0.1',8080)) 
    sock.listen(5) 
    while True:
        connection, address = sock.accept()
        handle_request(connection)
        connection.close() 

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