python非标准时间的转换

可匹配结构:

今天~前天, 几天前, 分钟秒前等 | 2017-1-4 12:10 | 2017/1/4 12:10 | 2018年4月2日 12:12 | 2018年4月2日 | 2017-1-4 | 2017/1/4 | 1/4 |

# -*- coding:utf-8 -*-
from datetime import datetime, timedelta
import re
import time


def tz_offset(tz):
    res = (re.search(r\'(?P<F>[-+])(?P<H>\\d{2}):?(?P<M>\\d{2})\', tz) or re.search(\'\', \'\')).groupdict()
    offset = (1 if res.get(\'F\', \'+\')==\'+\' else -1) * timedelta(
                        hours   = int(res.get(\'H\', 0)),
                        minutes = int(res.get(\'M\', 0)))
    return offset


def parse_date(data, fmt, tz):
    \"\"\"
        时间匹配模块，可转化为固定格式
        返回时间字符串 0000-00-00 00:00:00
        可匹配结构 |今天~前天， 几天前，分钟秒前等 | 2017-1-4 12:10 | 2017/1/4 12:10 | 2018年4月2日 12:12
                        | 2018年4月2日 | 2017-1-4 | 2017/1/4 | 1/4 |
    \"\"\"
    offset = tz_offset(tz)
    if fmt == \'auto\':
        now = (datetime.utcnow() + timedelta(hours=8)).replace(microsecond=0) + offset
        now_1 = now - timedelta(days=1)
        now_2 = now - timedelta(days=2)

        # 几/刚/今天/昨天/前天
        x = data.strip()
        x = x.replace(u\'几\', \' 0 \')
        x = x.replace(u\'刚[刚才]\', now.strftime(\' %Y-%m-%d %H:%M:%S \'))
        x = x.replace(u\'今天\', now.strftime(\' %Y-%m-%d \'))
        x = x.replace(u\'昨天\', now_1.strftime(\' %Y-%m-%d \'))
        x = x.replace(u\'前天\', now_2.strftime(\' %Y-%m-%d \'))
        x = re.sub(r\'[年月]\', \'/\', x)
        x = re.sub(r\'[日]\', \' \', x)
        x = re.sub(r\'\\s{2,}\', r\' \', x)

        # XX前
        res = (re.search(r\'(?P<S>\\d+)\\s*秒钟?前\', x) \\
               or re.search(r\'(?P<M>\\d+)\\s*分钟前\', x) \\
               or re.search(r\'(?P<H>\\d+)\\s*小时前\', x) \\
               or re.search(r\'(?P<d>\\d+)\\s*天前\', x) \\
               or re.search(\'\', \'\')).groupdict()
        if res:
            dt = now - timedelta(
                days=int(res.get(\'d\', 0)),
                hours=int(res.get(\'H\', 0)),
                minutes=int(res.get(\'M\', 0)),
                seconds=int(res.get(\'S\', 0))
            )
        # 不是几天前分钟前的形式
        else:
            # XX-XX-XX XX:XX:XX
            res = (re.search(r\'(?P<Y>\\d+)[/-](?P<m>\\d+)[/-](?P<d>\\d+)(\\s+(?P<H>\\d{1,2}):(?P<M>\\d{2})(:(?P<S>\\d{2}))?)?\',
                             x) or re.search(\'\', \'\')).groupdict()
            if res == dict():
                # 匹配没有年份的时候，格式 XX-XX XX:XX:XX  月-日 时：分：秒 或 17年10月10日 时：分：秒
                res = (re.search(
                    r\'(?P<m>\\d{1,2})[/-](?P<d>\\d+)(\\s+(?P<H>\\d{2}):(?P<M>\\d{2})(:(?P<S>\\d{2}))?)?\',
                    x) or re.search(\'\', \'\')).groupdict()
            if res:
                Y = res.get(\'Y\', now.year)
                Y = \"20\" + Y if len(str(Y)) == 2 else Y
                m = res.get(\'m\', now.month)
                d = res.get(\'d\', now.day)
                H = res.get(\'H\', now.hour)
                M = res.get(\'M\', now.minute)
                S = res.get(\'S\', 0)
                dt = datetime(
                    year=int(Y) if Y != None and 1987 <= int(Y) <= now.year else now.year,
                    month=int(m) if m != None else now.month,
                    day=int(d) if d != None else now.day,
                    # 如果没有时分秒，则被认定为00:00:00
                    hour=int(H) if H != None else 0,
                    minute=int(M) if M != None else 0,
                    second=int(S) if S != None else 0
                )
            else:
                # 1970-01-01 00:00:00
                # dt = datetime.utcfromtimestamp(0)+offset
                return \"\"
        # 时间可能超过当前时间，若超过则减去一年
        if int(time.mktime((dt - offset).timetuple())) > int(time.time()):
            # 时间超过当前时间，减去一年
            delta = timedelta(days=-365)
            real_time = (dt - offset) + delta
            real_time = real_time.strftime(\"%Y-%m-%d %H:%M:%S\")
        else:
            real_time = (dt - offset).strftime(\"%Y-%m-%d %H:%M:%S\")
        return real_time


if __name__ == \'__main__\':
    print(parse_date(\'2秒前\', \'auto\', \'\'))
    print(parse_date(\'2分钟前\', \'auto\', \'\'))
    print(parse_date(\'2小时前\', \'auto\', \'\'))
    print(parse_date(\'昨天 00:30\', \'auto\', \'\'))
    print(parse_date(\'07-20\', \'auto\', \'\'))