# -*- coding: utf-8 -*-
""" 值轉換輔助函式值 / Value convert functions """
import re
import datetime
from uuid import UUID
from collections import Sequence, Iterable, Mapping
import logging
_log = logging.getLogger(__name__)
[docs]def to_text(v, default_value=None):
# type: (Any, Optional[str]) -> Optional[str]
"""
將輸入值轉換為字串，當輸入值為 None 或空字串或是無法轉換的物件時傳回 None
Convert given variable into string. Return None or given default value when convert failed.
Args:
v: 要轉換的值或物件
default_value=None: 預設值
Returns:
非空字串，或是 None 當輸入是空字串或是無法轉換的物件
"""
if v is None:
return default_value
# {{{ convert to unicode string
r = None
if isinstance(v, unicode):
r = v
elif isinstance(v, str):
r = unicode(v, 'utf-8', 'ignore')
else:
try:
r = unicode(str(v), 'utf-8', 'ignore')
except Exception:
_log.info("cannot convert input (%r) to string @[convert.to_text]", v)
r = None
# }}} convert to unicode string
if r is not None:
r = r.strip()
if r:
return r
return default_value
[docs]def to_integer(v, default_value=None):
# type: (Any, Optional[int]) -> Optional[int]
"""
將輸入值轉換為整數，當輸入值為 None 或是無法轉換的物件時傳回 None
Convert given variable into integer. Return None or given default value when convert failed.
Args:
v: 要轉換的值或物件
default_value=None: 預設值
Returns:
整數，或是 None 當輸入是空字串或是無法轉換的物件
"""
if v is None:
return default_value
try:
r = int(v)
return r
except Exception:
_log.info("cannot convert input (%r) to integer @[convert.to_integer]", v)
return default_value
[docs]def to_float(v, default_value=None):
# type: (Any, Optional[float]) -> Optional[float]
"""
將輸入值轉換為浮點數，當輸入值為 None 或是無法轉換的物件時傳回 None
Convert given variable into float. Return None or given default value when convert failed.
Args:
v: 要轉換的值或物件
default_value=None: 預設值
Returns:
非空字串，或是 None 當輸入是空字串或是無法轉換的物件
"""
if v is None:
return default_value
try:
r = float(v)
return r
except Exception:
_log.info("cannot convert input (%r) to float @[convert.to_float]", v)
return default_value
[docs]def to_bool(v, default_value=None):
# type: (Any, Optional[bool]) -> Optional[bool]
"""
將輸入值轉換為布林值，當輸入值為 None 或是無法轉換的物件時傳回 None
Convert given variable into boolean. Return None or given default value when convert failed.
Args:
v: 要轉換的值或物件
default_value=None: 預設值
Returns:
布林值，或是 None 當輸入無法轉換
"""
if v is None:
return default_value
try:
if isinstance(v, bool):
return v
if isinstance(v, basestring):
if len(v) < 1:
return False
return True if (str(v[0]) in ('Y', 'y', 'T', 't', '1', '+')) else False
elif isinstance(v, (int, float)):
return True if (int(v) > 0) else False
else:
return bool(v)
except Exception:
_log.info("cannot convert input (%r) to boolean @[convert.to_bool]", v)
return default_value
_DATETIME_REGEX_yyyymmddhhmmss = re.compile('([0-9]{4})-?([0-9]{2})-?([0-9]{2})[_T\s\.]?([0-9]{2})?[\:\.\s_]?([0-9]{2})?[\:\.\s_]?([0-9]{2})?')
_DATETIME_REGEX_hhmmoffset = re.compile('([-+]?)([0-9]{2})([0-9]{2})?')
def _to_datetime_for_basestring(v):
v = v.strip()
if v in (
"utc-now",
"UTC-NOW",
"utcnow",
"UTCNOW",
"now",
"NOW",
):
return datetime.datetime.utcnow()
if v in (
"local-now",
"LOCAL-NOW",
"localnow",
"LOCALNOW",
):
return datetime.datetime.now()
m = _DATETIME_REGEX_yyyymmddhhmmss.match(v)
if m is not None:
year = to_integer(m.group(1), 1970)
month = to_integer(m.group(2), 1)
day = to_integer(m.group(3), 1)
hour = to_integer(m.group(4), 0)
minute = to_integer(m.group(5), 0)
second = to_integer(m.group(6), 0)
return datetime.datetime(year, month, day, hour, minute, second)
m = _DATETIME_REGEX_hhmmoffset.match(v)
if m is not None:
direction = m.group(1)
hour_offset = to_integer(m.group(2), 0)
minute_offset = to_integer(m.group(3), 0)
# when not +/- mode, replace given hour and minute into current time as result
current_tstamp = datetime.datetime.now()
if (direction is None) or (direction == ""):
return current_tstamp.replace(hour=hour_offset, minute=minute_offset, second=0)
# when not offset to any time point
if (hour_offset == 0) and (minute_offset == 0):
return current_tstamp
# when offset symbol (+/-) is given
d = datetime.timedelta(hours=hour_offset, minutes=minute_offset)
return (current_tstamp - d) if (direction == '-') else (current_tstamp + d)
return None
def _to_datetime_for_sequence(v):
year = None
month = 1
day = 1
hour = 0
minute = 0
second = 0
if len(v) >= 3:
year = to_integer(v[0], 1970)
month = to_integer(v[1], 1)
day = to_integer(v[2], 1)
if len(v) >= 4:
hour = to_integer(v[3], 0)
if len(v) >= 5:
minute = to_integer(v[4], 0)
if len(v) >= 6:
second = to_integer(v[5], 0)
# return result if valid
return None if (year is None) else datetime.datetime(year, month, day, hour, minute, second)
[docs]def to_datetime(v, default_value=None):
# type: (Any, Optional[datetime.datetime]) -> Optional[datetime.datetime]
"""
將輸入值轉換為時間格式，當輸入值為 None 或是無法轉換的物件時傳回 None
Convert given variable into datetime.datetime object. Return None or given default value when convert failed.
輸入範例 / Input Examples:
整數/浮點數 (視為 UNIX time-stamp) / Integer or Float (will treat as UNIT time-stamp):
1352454146.387523
字串 / String:
'2012-11-10 10:10:10', '+01' (加 1 小時), '+0123' (加 1 小時 23 分鐘)
串列或數對 / List or Tuple):
(2012, 11, 10, 10, 10, 10, 0, 0, 0,)
Args:
v: 要轉換的值或物件
default_value=None: 預設值
Returns:
時間格式，或是 None 當輸入無法轉換
"""
if v is None:
return default_value
if isinstance(v, datetime.datetime):
return v
elif isinstance(v, (int, float)):
return datetime.datetime.fromtimestamp(v)
elif isinstance(v, basestring):
r = _to_datetime_for_basestring(v)
elif isinstance(v, Sequence):
r = _to_datetime_for_sequence(v)
if r is not None:
return r
_log.info("cannot convert input (%r) to datetime @[convert.to_datetime]", v)
return default_value
[docs]def to_uuid(v, default_value=None):
# type: (Any, Optional[uuid.UUID]) -> Optional[uuid.UUID]
"""
將輸入值轉換為 UUID 物件
Convert given variable into UUID object. Return None or given default value when convert failed.
Args:
v: 要轉換的值或物件
default_value=None: 預設值
Returns:
uuid.UUID 物件實體，或是 None 當輸入無法轉換
"""
if v is None:
return default_value
if isinstance(v, UUID):
return v
try:
aux = UUID(v)
return aux
except Exception:
pass
return default_value
[docs]def to_list(v, element_converter, default_value=None):
# type: (Any, Callable[[Any], Any], Optional[Any]) -> Optional[List[Any]]
"""
將輸入值轉換為串列，各輸入值透過傳入的轉換函式進行轉換
Convert given variable into list object with given element convert function.
Return None or given default value when convert failed or result into empty list.
Args:
v: 要轉換的值或物件
element_converter (callable): 單一個元素的轉換函式，當轉換結果為 None 時此元素會被丟棄
default_value=None: 預設值
Returns:
串列，或是 None 當輸入無法轉換
"""
if v is None:
return default_value
result = []
if (not isinstance(v, basestring)) and (not isinstance(v, Mapping)) and isinstance(v, Iterable):
for e in v:
item = element_converter(e)
if item is not None:
result.append(item)
else:
item = element_converter(v)
if item is not None:
result.append(item)
return result if result else default_value
[docs]def to_dict(v, element_converter, key_converter=None, default_value=None):
# type: (Any, Callable[[Any], Any], Optional[Callable[[Any], Any]], Optional[Any]) -> Optional[Dict[Any, Any]]
"""
將輸入值轉換為字典，各輸入值透過傳入的轉換函式進行轉換
Convert given variable into dict object with given key and value convert function.
Return None or given default value when convert failed or result into empty dict.
Args:
v: 要轉換的值或物件
element_converter (callable): 單一個元素的轉換函式，當轉換結果為 None 時此元素會被丟棄
key_converter=None (callable): 單一元素對應之鍵值的轉換函式，當轉換結果為 None 時此元素會被丟棄
default_value=None: 預設值
Return:
字典，或是 None 當輸入無法轉換
"""
if v is None:
return default_value
if key_converter is None:
key_converter = to_text
result = {}
try:
for k, e in v.iteritems():
kidx = key_converter(k)
if kidx is None:
continue
item = element_converter(e)
if item is not None:
result[kidx] = item
except Exception as e:
_log.exception("failed on convert dictionary: %r", e)
return result if result else default_value
_HOSTPORT_ADDR_REGEX = re.compile("(.+)\\:([0-9]+)$")
[docs]def parse_hostport_location(loc, default_value=None):
# type: (str, Optional[Tuple[str, int]]) -> Tuple[str, int]
"""
解析 Host:Port 型式的字串為 (Host, Port,) 型式的 tuple 物件
Parse string in "Host:Port" form into tuple object in (Host, Port,) form.
Args:
loc (str): 要轉換的位址字串
default_value=None: 當無法轉換時的預設值
Returns:
轉換結果，或是當失敗時為預設值
"""
m = _HOSTPORT_ADDR_REGEX.match(str(loc))
if m is not None:
addr = m.group(1)
port = int(m.group(2))
return (addr, port)
return default_value
[docs]def parse_hostport_location_list(location_list):
# type: (List[str]) -> List[Tuple[str, int]]
"""
解析 Host:Port 型式的字串 list 為 (Host, Port,) 型式的 tuple 物件所構成的 list
Parse list of strings in "Host:Port" form into list of tuple objects in (Host, Port,) form.
Args:
location_list (list of str): 要轉換的位址字串串列
Returns:
轉換結果，或是當失敗時為空的 tuple 物件
"""
return to_list(location_list, parse_hostport_location, ())
# vim: ts=4 sw=4 ai nowrap