Flask的线程，携程与并发 (2)

目录

• pipreqs：
• 函数和方法
• threading.local
  • 不用threading.local
  • threading.local使用
  • 通过字典自定义threading.local（函数）
  • 面向对象版
  • 通过setattr和getattr实现
  • 每个对象有自己的存储空间（字典）
  • 兼容线程和协程
• partial偏函数
• session源码分析

 

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Flask的线程，携程与并发 (2)

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pipreqs：

- 项目依赖 pip3 install pipreqs
- 生成依赖文件：pipreqs ./ 
- 安装依赖文件：pip3 install -r requirements.txt 

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函数和方法

from types import MethodType,FunctionType
 
class Foo(object):
	def fetch(self):
		pass
 
print(isinstance(Foo.fetch,MethodType))
print(isinstance(Foo.fetch,FunctionType)) # True
 
obj = Foo()
print(isinstance(obj.fetch,MethodType)) # True
print(isinstance(obj.fetch,FunctionType))

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threading.local

多个线程修改同一个数据，复制多份变量给每个线程用,为每个线程开辟一块空间进行数据存储

不用threading.local

# 不用local
from threading import Thread
import time
lqz = -1
def task(arg):
    global lqz
    lqz = arg
    # time.sleep(2)
    print(lqz)
 
for i in range(10):
    t = Thread(target=task,args=(i,))
    t.start()

threading.local使用

from threading import Thread
from threading import local
import time
from threading import get_ident
# 特殊的对象
lqz = local()
def task(arg):
    # 对象.val = 1/2/3/4/5
    lqz.value = arg
    time.sleep(2)
    print(lqz.value)
for i in range(10):
    t = Thread(target=task,args=(i,))
    t.start()

通过字典自定义threading.local（函数）

from threading import get_ident,Thread
import time
storage = {}
def set(k,v):
    ident = get_ident()
    if ident in storage:
        storage[ident][k] = v
    else:
        storage[ident] = {k:v}
def get(k):
    ident = get_ident()
    return storage[ident][k]
def task(arg):
    set('val',arg)
    v = get('val')
    print(v)
 
for i in range(10):
    t = Thread(target=task,args=(i,))
    t.start()

面向对象版

from threading import get_ident,Thread
import time
class Local(object):
    storage = {}
    def set(self, k, v):
        ident = get_ident()
        if ident in Local.storage:
            Local.storage[ident][k] = v
        else:
            Local.storage[ident] = {k: v}
    def get(self, k):
        ident = get_ident()
        return Local.storage[ident][k]
obj = Local()
def task(arg):
    obj.set('val',arg) 
    v = obj.get('val')
    print(v)
for i in range(10):
    t = Thread(target=task,args=(i,))
    t.start()

通过setattr和getattr实现

from threading import get_ident,Thread
import time
class Local(object):
    storage = {}
    def __setattr__(self, k, v):
        ident = get_ident()
        if ident in Local.storage:
            Local.storage[ident][k] = v
        else:
            Local.storage[ident] = {k: v}
    def __getattr__(self, k):
        ident = get_ident()
        return Local.storage[ident][k]
obj = Local()
def task(arg):
    obj.val = arg
    print(obj.val)
for i in range(10):
    t = Thread(target=task,args=(i,))
    t.start()

每个对象有自己的存储空间（字典）

from threading import get_ident,Thread
import time
class Local(object):
    def __init__(self):
        object.__setattr__(self,'storage',{})
    def __setattr__(self, k, v):
        ident = get_ident()
        if ident in self.storage:
            self.storage[ident][k] = v
        else:
            self.storage[ident] = {k: v}
    def __getattr__(self, k):
        ident = get_ident()
        return self.storage[ident][k]
obj = Local()
def task(arg):
    obj.val = arg
    obj.xxx = arg
    print(obj.val)
for i in range(10):
    t = Thread(target=task,args=(i,))
    t.start()

兼容线程和协程

try:
    from greenlet import getcurrent as get_ident
except Exception as e:
    from threading import get_ident
from threading import Thread
import time
class Local(object):
    def __init__(self):
        object.__setattr__(self,'storage',{})
    def __setattr__(self, k, v):
        ident = get_ident()
        if ident in self.storage:
            self.storage[ident][k] = v
        else:
            self.storage[ident] = {k: v}
    def __getattr__(self, k):
        ident = get_ident()
        return self.storage[ident][k]
obj = Local()
def task(arg):
    obj.val = arg
    obj.xxx = arg
    print(obj.val)
for i in range(10):
    t = Thread(target=task,args=(i,))
    t.start()

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partial偏函数

#偏函数的第二个部分(可变参数)，按原有函数的参数顺序进行补充，参数将作用在原函数上，最后偏函数返回一个新函数
from functools import partial
def test(a,b,c,d):
    return a+b+c+d
 
tes=partial(test,1,2)
print(tes(3,4))

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session源码分析

SecureCookieSessionInterface
	-open_session
	-save_session