Python常用模块集锦

Python常用模块集锦

常用模块主要分为以下几类(缺失的后续再补充):

  • 时间转换
  • 时间计算
  • 序列化和反序列化:jsonpickle
  • 编解码:unicodebase64
  • 加解密:md5sha1hmac_sha1aes
  • 常见装饰器:
    • 计算执行时间装饰器
    • 缓存装饰器
    • 错误重试装饰器
    • 延迟装饰器
    • 尾递归优化装饰器
  • ini配置文件读取

代码整合如下:

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#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Created on 9/21/17 1:46 PM
@author: Chen Liang
@function: python常用模块集锦,util.py
"""
import time
import datetime
import ConfigParser
import ast
import sys
import json
import pickle
import base64
import hashlib
from Crypto.Cipher import AES
from binascii import b2a_hex, a2b_hex
from functools import wraps
BEFORE = 1
LATER = 2
class CommonUtil(object):
"""Python通用单元:不好归类但常用的方法此处添加"""
pass
class TimeTransferUtil(object):
"""时间相关的常见转换方法"""
class TimeUtil(object):
"""时间相关的常见计算方法"""
@staticmethod
def str_to_date():
pass
class SerializeUtil(object):
"""序列化和反序列化:json, pickle"""
@staticmethod
def json_loads(json_str, encoding=None):
try:
obj = json.loads(s=json_str, encoding=encoding)
return True, obj
except ValueError as e:
return False, str(e)
except Exception as e:
return False, str(e)
@staticmethod
def json_dumps(obj):
try:
json_str = json.dumps(obj=obj)
return True, json_str
except TypeError as e:
return False, str(e)
except Exception as e:
return False, str(e)
@staticmethod
def pickle_loads(pickle_str):
try:
obj = pickle.loads(pickle_str)
return True, obj
except IndexError as e:
return False, str(e)
except Exception as e:
return False, str(e)
@staticmethod
def pickle_dumps(obj):
try:
pickle_str = pickle.dumps(obj)
return True, pickle_str
except Exception as e:
return False, str(e)
class CodecUtil(object):
"""编解码相关常见方法:base64 unicode"""
@staticmethod
def base64_encode(data):
try:
return True, base64.b64encode(data)
except TypeError as e:
return False, str(e)
except Exception as e:
return False, str(e)
@staticmethod
def base64_decode(encoded_data):
try:
return True, base64.b64decode(encoded_data)
except TypeError as e:
return False, str(e)
except Exception as e:
return False, str(e)
@staticmethod
def to_unicode(s, encoding='utf-8'):
return s if isinstance(s, unicode) else unicode(s, encoding)
@staticmethod
def unicode_to(unicode_s, encoding='utf-8'):
return unicode_s.encode(encoding)
class CryptoUtil(object):
"""加解密相关常见方法: md5 aes"""
@staticmethod
def md5(str_object):
"""md5"""
m = hashlib.md5()
m.update(str_object)
return m.hexdigest()
@staticmethod
def aes_encrypt(s, key, salt, mode=AES.MODE_CBC):
"""
aes加密
:param s: 待加密字符串
:param key: 密钥
:param salt: 盐, 16bit eg. b'0000000101000000'
:param mode: AES模式
:return: 加密后的字符串
"""
cipher = AES.new(hashlib.md5(key).hexdigest(), mode, salt)
n_text = s + ('\0' * (16 - (len(s) % 16)))
return b2a_hex(cipher.encrypt(n_text))
@staticmethod
def aes_decrypt(s, key, salt, mode=AES.MODE_CBC):
"""
aes解密
:param s: 待解密字符串
:param key: 密钥
:param salt: 盐, 16bit eg. b'0000000101000000'
:param mode: AES模式
:return: 解密后的字符串
"""
cipher = AES.new(hashlib.md5(key).hexdigest(), mode, salt)
return cipher.decrypt(a2b_hex(s)).rstrip('\0')
class TailRecurseException:
"""尾递归异常"""
def __init__(self, args, kwargs):
self.args = args
self.kwargs = kwargs
class DecoratorUtil(object):
"""常见装饰器: 执行时间timeit,缓存cache,错误重试retry"""
__cache_dict = {}
@staticmethod
def timeit(fn):
"""计算执行时间"""
@wraps(fn)
def wrap(*args, **kwargs):
start = time.time()
ret = fn(*args, **kwargs)
end = time.time()
print "@timeit: {0} tasks, {1} secs".format(fn.__name__, str(end - start))
return ret
return wrap
@staticmethod
def __is_expired(entry, duration):
"""是否过期"""
if duration == -1:
return False
return time.time() - entry['time'] > duration
@staticmethod
def __compute_key(fn, args, kw):
"""序列化并求其哈希值"""
key = pickle.dumps((fn.__name__, args, kw))
return hashlib.sha1(key).hexdigest()
@classmethod
def cache(cls, expired_time=-1):
"""
缓存
:param expired_time: 过期时间,-1 表示不过期
:return: 返回缓存的结果或者计算的结果
"""
def _cache(fn):
@wraps(fn)
def wrap(*args, **kwargs):
key = cls.__compute_key(fn, args, kwargs)
if key in cls.__cache_dict:
if cls.__is_expired(cls.__cache_dict[key], expired_time) is False:
return cls.__cache_dict[key]['value']
ret = fn(*args, **kwargs)
cls.__cache_dict[key] = {
'value': ret,
'time': time.time()
}
return ret
return wrap
return _cache
@staticmethod
def retry(exceptions, retry_times=3, time_pause=3, time_offset=1):
"""
错误重试
:param exceptions: 单个异常比如ValueError, 或者tuple,元组元素是异常,比如(ValueError, TypeError)
:param retry_times: 重试次数
:param time_pause: 初始暂停时间
:param time_offset: 暂停时间的偏移倍数,默认不偏移
:return: 返回成功的值,或者重拾次数结束时抛出异常
"""
def _retry(fn):
@wraps(fn)
def wrap(*args, **kwargs):
retry_times_tmp, time_pause_tmp = retry_times, time_pause
while retry_times_tmp > 1:
try:
return fn(*args, **kwargs)
except exceptions:
time.sleep(time_pause_tmp)
retry_times_tmp -= 1
time_pause_tmp *= time_offset
return fn(*args, **kwargs)
return wrap
return _retry
@staticmethod
def delay(delay_time=3, mode=BEFORE):
"""
延迟装饰器,支持在函数执行之前和之后加延时,如果想在前后同时加,可以使用两次装饰。
time.sleep只会阻塞当前线程不会阻塞整个进程,其它线程不受影响
:param delay_time: 延迟时间,是float类型
:param mode: 模式,指定是在函数执行之前加延时还是在执行之后加,值为BEFORE(1)或者LATER(2)
:return:
"""
def _delay(fn):
@wraps(fn)
def wrap(*args, **kwargs):
if mode == BEFORE:
time.sleep(delay_time)
ret = fn(*args, **kwargs)
if mode == LATER:
time.sleep(delay_time)
return ret
return wrap
return _delay
@staticmethod
def tail_call_optimized(fn):
"""尾递归优化装饰器,如果被装饰函数不是尾递归函数则会报错"""
@wraps(fn)
def wrap(*args, **kwargs):
f = sys._getframe()
if f.f_back and f.f_back.f_back and f.f_back.f_back.f_code == f.f_code:
raise TailRecurseException(args, kwargs)
else:
while True:
try:
return fn(*args, **kwargs)
except TailRecurseException as e:
args = e.args
kwargs = e.kwargs
return wrap
class IniConfigParserUtil(object):
"""ini配置文件读取"""
def __init__(self, *file_names):
"""
init
:param file_names: 包含多个元素的可迭代对象
"""
self.config = ConfigParser.ConfigParser()
for file_name in file_names:
try:
self.config.readfp(open(file_name, 'rb'))
break
except IOError:
continue
else:
sys.exit('All files have failed to read')
def get_string(self, section, option):
return self.config.get(section, option)
def get_int(self, section, option):
return self.config.getint(section, option)
def get_float(self, section, option):
return self.config.getfloat(section, option)
def get_boolean(self, section, option):
return self.config.getboolean(section, option)
def get_list(self, section, option):
return ast.literal_eval(self.config.get(section, option))
def get_dict(self, section, option):
return ast.literal_eval(self.config.get(section, option))

缺失部分后续待添加,记得填坑。

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