Flask 进阶

OOP 面向对象反射

# __call__方法
# class Foo(object):
#   def __call__(self, *args, **kwargs):
#       return "i am call"
#
#
# f = Foo()  # f 是Foo的对象
# print(f())  # f() 对象加括号执行当前对象下__call__ 函数


# __setattr__ , def __getattr__ 属性的创建  赋值  提取
# class Foo(object):
#   # 属性赋值
#   def __setattr__(self, key, value):
#       print(f'{key},{value}')
#
#   # def __getattr__(self, key, value):
#   #   print(key)
#   # 获取属性名
#   def __getattribute__(self, item):
#       print(item)

# f = Foo()
# 调用__setattr__ 方法;属性的创建及赋值
# f.name = "anwen"  # 对象.name  对象打点调属性
# 调用__getattribute__ 方法
# f.name


# __setitem__  __getitem__
class Foo(object):
    # 字典的键值
    def __setitem__(self, key, value):
        # name anwen
        print(key, value)

    # 字典的键
    def __getitem__(self, item):
        print(item)

f = Foo()
# 调用 __setitem__ 方法;
f["name"] = "anwen"
# 调用__getitem__ 方法;获取的是字典的键
print(f["name"])

偏函数

from functools import partial

# def abfunc(a, b):
#   print("a:", a)
#   print("b:", b)
#   return a + b
#
# # 将原函数和原函数接收的参数一并存放,返回新函数 在执行新函数时 将参数传入原函数中一并执行
# new_ab = partial(abfunc, a=2, b=3)
# print(new_ab)
# print(new_ab())


# 传入 x ,等待计算
def abfunc(a, b, x):
    print("a:", a)
    print("b:", b)
    return a + b + x


# 将原函数和原函数接收的参数一并存放,返回新函数, 在执行新函数时 将参数传入原函数中一并执行
new_ab = partial(abfunc, x=4)
print(new_ab)
print(new_ab(2, 3))

线程安全

import time
import copy
from copy import deepcopy
from threading import Thread, get_ident


class Foo(object):
    pass


f = Foo()
f.num = 0
local_dic = {}
# {
#   get_ident():{f.num:1},
#   get_ident():{f.num:2},
#   get_ident():{f.num:3},
# }

def add(i):
    # print(get_ident())
    # 极快解决阻塞问题,保证公共对象的安全性;但是浪费了很多内存,空间换时间
    local_dic[get_ident()] = deepcopy(f)
    local_dic[get_ident()].num = i
    f.num = i
    time.sleep(1)
    print(local_dic[get_ident()].num)


for i in range(20):
    # 多线程操作同一个对象, 出现线程不安全
    task = Thread(target=add, args=(i,))
    # add(i)
    task.start()

线程安全 local

import time
from threading import Thread, local

# 继承local 解决线程安全问题,还不浪费资源
class Foo(local):
    pass

f = Foo()
f.num = 0

def add(i):
    f.num = i
    time.sleep(1)
    print(f.num)

for i in range(20):
    # 多线程操作同一个对象, 出现线程不安全
    task = Thread(target=add, args=(i,))
    # add(i)
    task.start()

请求上下文 阅读源码

# 请求是如何到达Flask应用的
from werkzeug.wrappers import Request, Response
from werkzeug import run_simple

@Request.application
def app(env):
    print(env, type(env))
    return Response("200 ok")   # 函数+()运行

run_simple("127.0.0.1", 5000, app)

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