自定义Web组件

一、Session

1、面向对象基础

面向对象中通过索引的方式访问对象，需要内部实现 __getitem__ 、__delitem__、__setitem__方法

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

class Foo(object):

    def __getitem__(self, key):

        print  '__getitem__',key

    def __setitem__(self, key, value):

        print '__setitem__',key,value

    def __delitem__(self, key):

        print '__delitem__',key

obj = Foo()

result = obj['k1']
#obj['k2'] = 'wupeiqi'
#del obj['k1']

2、Tornado扩展

Tornado框架中，默认执行Handler的get/post等方法之前默认会执行 initialize方法，所以可以通过自定义的方式使得所有请求在处理前执行操作...

class BaseHandler(tornado.web.RequestHandler):

    def initialize(self):

        self.xxoo = "wupeiqi"

class MainHandler(BaseHandler):

    def get(self):

        print(self.xxoo)

        self.write('index')
 
class IndexHandler(BaseHandler):

    def get(self):

        print(self.xxoo)

        self.write('index')

3、session

session其实就是定义在服务器端用于保存用户回话的容器，其必须依赖cookie才能实现。

#!/usr/bin/env python
# -*- coding:utf-8 -*-
import config
from hashlib import sha1
import os
import time

create_session_id = lambda: sha1(bytes('%s%s' % (os.urandom(16), time.time()), encoding='utf-8')).hexdigest()


class SessionFactory:

    @staticmethod
    def get_session_obj(handler):
        obj = None

        if config.SESSION_TYPE == "cache":
            obj = CacheSession(handler)
        elif config.SESSION_TYPE == "memcached":
            obj = MemcachedSession(handler)
        elif config.SESSION_TYPE == "redis":
            obj = RedisSession(handler)
        return obj


class CacheSession:
    session_container = {}
    session_id = "__sessionId__"

    def __init__(self, handler):
        self.handler = handler
        client_random_str = handler.get_cookie(CacheSession.session_id, None)
        if client_random_str and client_random_str in CacheSession.session_container:
            self.random_str = client_random_str
        else:
            self.random_str = create_session_id()
            CacheSession.session_container[self.random_str] = {}

        expires_time = time.time() + config.SESSION_EXPIRES
        handler.set_cookie(CacheSession.session_id, self.random_str, expires=expires_time)

    def __getitem__(self, key):
        ret = CacheSession.session_container[self.random_str].get(key, None)
        return ret

    def __setitem__(self, key, value):
        CacheSession.session_container[self.random_str][key] = value

    def __delitem__(self, key):
        if key in CacheSession.session_container[self.random_str]:
            del CacheSession.session_container[self.random_str][key]


class RedisSession:
    def __init__(self, handler):
        pass


class MemcachedSession:
    def __init__(self, handler):
        pass

自定义session