测试1
deco运行，但myfunc并没有运行
复制代码 代码如下:
def deco(func):
print \’before func\’
return func
def myfunc():
print \’myfunc() called\’
myfunc = deco(myfunc)
测试2
需要的deco中调用myfunc，这样才可以执行
复制代码 代码如下:
def deco(func):
print \’before func\’
func()
print \’after func\’
return func
def myfunc():
print \’myfunc() called\’
myfunc = deco(myfunc)
测试3
@函数名 但是它执行了两次
复制代码 代码如下:
def deco(func):
print \’before func\’
func()
print \’after func\’
return func
@deco
def myfunc():
print \’myfunc() called\’
myfunc()
测试4
这样装饰才行
复制代码 代码如下:
def deco(func):
def _deco():
print \’before func\’
func()
print \’after func\’
return _deco
@deco
def myfunc():
print \’myfunc() called\’
myfunc()
测试5
@带参数，使用嵌套的方法
复制代码 代码如下:
def deco(arg):
def _deco(func):
print arg
def __deco():
print \’before func\’
func()
print \’after func\’
return __deco
return _deco
@deco(\’deco\’)
def myfunc():
print \’myfunc() called\’
myfunc()
测试6
函数参数传递
复制代码 代码如下:
def deco(arg):
def _deco(func):
print arg
def __deco(str):
print \’before func\’
func(str)
print \’after func\’
return __deco
return _deco
@deco(\’deco\’)
def myfunc(str):
print \’myfunc() called \’, str
myfunc(\’hello\’)
测试7
未知参数个数
复制代码 代码如下:
def deco(arg):
def _deco(func):
print arg
def __deco(*args, **kwargs):
print \’before func\’
func(*args, **kwargs)
print \’after func\’
return __deco
return _deco
@deco(\’deco1\’)
def myfunc1(str):
print \’myfunc1() called \’, str
@deco(\’deco2\’)
def myfunc2(str1,str2):
print \’myfunc2() called \’, str1, str2
myfunc1(\’hello\’)
myfunc2(\’hello\’, \’world\’)
测试8
class作为修饰器
复制代码 代码如下:
class myDecorator(object):
def __init__(self, fn):
print \”inside myDecorator.__init__()\”
self.fn = fn
def __call__(self):
self.fn()
print \”inside myDecorator.__call__()\”
@myDecorator
def aFunction():
print \”inside aFunction()\”
print \”Finished decorating aFunction()\”
aFunction()
测试9
复制代码 代码如下:
class myDecorator(object):
def __init__(self, str):
print \”inside myDecorator.__init__()\”
self.str = str
print self.str
def __call__(self, fn):
def wrapped(*args, **kwargs):
fn()
print \”inside myDecorator.__call__()\”
return wrapped
@myDecorator(\’this is str\’)
def aFunction():
print \”inside aFunction()\”
print \”Finished decorating aFunction()\”
aFunction()
实例
给函数做缓存 — 斐波拉契数列
复制代码 代码如下:
from functools import wraps
def memo(fn):
cache = {}
miss = object()
@wraps(fn)
def wrapper(*args):
result = cache.get(args, miss)
if result is miss:
result = fn(*args)
cache[args] = result
return result
return wrapper
@memo
def fib(n):
if n < 2:
return n
return fib(n – 1) + fib(n – 2)
print fib(10)
注册回调函数 — web请求回调
复制代码 代码如下:
class MyApp():
def __init__(self):
self.func_map = {}
def register(self, name):
def func_wrapper(func):
self.func_map[name] = func
return func
return func_wrapper
def call_method(self, name=None):
func = self.func_map.get(name, None)
if func is None:
raise Exception(\”No function registered against – \” + str(name))
return func()
app = MyApp()
@app.register(\’/\’)
def main_page_func():
return \”This is the main page.\”
@app.register(\’/next_page\’)
def next_page_func():
return \”This is the next page.\”
print app.call_method(\’/\’)
print app.call_method(\’/next_page\’)
mysql封装 — 很好用
复制代码 代码如下:
import umysql
from functools import wraps
class Configuraion:
def __init__(self, env):
if env == \”Prod\”:
self.host = \”coolshell.cn\”
self.port = 3306
self.db = \”coolshell\”
self.user = \”coolshell\”
self.passwd = \”fuckgfw\”
elif env == \”Test\”:
self.host = \’localhost\’
self.port = 3300
self.user = \’coolshell\’
self.db = \’coolshell\’
self.passwd = \’fuckgfw\’
def mysql(sql):
_conf = Configuraion(env=\”Prod\”)
def on_sql_error(err):
print err
sys.exit(-1)
def handle_sql_result(rs):
if rs.rows > 0:
fieldnames = [f[0] for f in rs.fields]
return [dict(zip(fieldnames, r)) for r in rs.rows]
else:
return []
def decorator(fn):
@wraps(fn)
def wrapper(*args, **kwargs):
mysqlconn = umysql.Connection()
mysqlconn.settimeout(5)
mysqlconn.connect(_conf.host, _conf.port, _conf.user, \\
_conf.passwd, _conf.db, True, \’utf8\’)
try:
rs = mysqlconn.query(sql, {})
except umysql.Error as e:
on_sql_error(e)
data = handle_sql_result(rs)
kwargs[\”data\”] = data
result = fn(*args, **kwargs)
mysqlconn.close()
return result
return wrapper
return decorator
@mysql(sql = \”select * from coolshell\” )
def get_coolshell(data):
… …
… ..
线程异步
复制代码 代码如下:
from threading import Thread
from functools import wraps
def async(func):
@wraps(func)
def async_func(*args, **kwargs):
func_hl = Thread(target = func, args = args, kwargs = kwargs)
func_hl.start()
return func_hl
return async_func
if __name__ == \’__main__\’:
from time import sleep
@async
def print_somedata():
print \’starting print_somedata\’
sleep(2)
print \’print_somedata: 2 sec passed\’
sleep(2)
print \’print_somedata: 2 sec passed\’
sleep(2)
print \’finished print_somedata\’
def main():
print_somedata()
print \’back in main\’
print_somedata()
print \’back in main\’
main()