Trafaret
Ultimate transformation library that supports validation, contexts and aiohttp.
Trafaret is rigid and powerful lib to work with foreign data, configs etc. It provides simple way to check anything, and convert it accordingly to your needs.
It has shortcut syntax and ability to express anything that you can code:
>>> from trafaret.constructor import construct >>> validator = construct({'a': int, 'b': [str]}) >>> validator({'a': 5, 'b': ['lorem', 'ipsum']}) {'a': 5, 'b': ['lorem', 'ipsum']} >>> validator({'a': 5, 'b': ['gorky', 9]}) Traceback (most recent call last): File "" , line 1, in <module> File "/Users/mkrivushin/w/trafaret/trafaret/__init__.py", line 204, in __call__ return self.check(val) File "/Users/mkrivushin/w/trafaret/trafaret/__init__.py", line 144, in check return self._convert(self.check_and_return(value)) File "/Users/mkrivushin/w/trafaret/trafaret/__init__.py", line 1105, in check_and_return raise DataError(error=errors, trafaret=self) trafaret.DataError: {'b': DataError({1: DataError(value is not a string)})}
Read The Docs hosted documentation http://trafaret.readthedocs.org/en/latest/ or look to the docs/intro.rst for start.
Trafaret can even generate Trafarets instances to build transformators from json, like in json schema implementation Trafaret Schema
New
2.0.2
- construct for int and float will use ToInt and ToFloat
2.0.0
WithRepr– use it to return custom representation, like- Strip a lot from dict, like
keys() - Trafarets are not mutable
- DataError has new
codeattribute, self.failure hascodeargument - OnError has
codeargument too - New
DataError.to_structmethod that returns errors in more consistent way String,AnyString,Bytes,FromBytes(encoding=utf-8)Int,ToInt,Float,ToFloatToDecimalIterablethat acts like aList, but works with any iterable- New
Date,ToDateandDateTime,ToDateTimetrafarets StrBooltrafaret renamed toToBoolVisitortrafaret was deleted- Test coverage
1.x.x
- converters and
convert=Falseare deleted in favor ofAndand& Stringparameterregexdeleted in favor ofRegexpandRegexpRawusage- new
OnErrorto customize error message context=somethingargument for__call__andcheckTrafaret methods. Supported byOr,And,Forwardetc.- new customizable method
transformlikechange_and_returnbut takescontext=arg - new
trafaret_instance.async_checkmethod that works withawait
Doc
For simple example what can be done:
import datetime
import trafaret as t
date = t.Dict(year=t.Int, month=t.Int, day=t.Int) >> (lambda d: datetime.datetime(**d))
assert date.check({'year': 2012, 'month': 1, 'day': 12}) == datetime.datetime(2012, 1, 12)
Work with regex:
>>> c = t.RegexpRaw(r'^name=(\w+)$') >> (lambda m: m.group(1))
>>> c.check('name=Jeff')
'Jeff'
Rename dict keys:
>>> c = t.Dict({(t.Key('uNJ') >> 'user_name'): t.String})
>>> c.check({'uNJ': 'Adam'})
{'user_name': 'Adam'}
Arrow date checking:
import arrow
def check_datetime(str):
try:
return arrow.get(str).naive
except arrow.parser.ParserError:
return t.DataError('value is not in proper date/time format')
Yes, you can write trafarets that simple.
45 Nov 17, 2022
120 Nov 20, 2022
0 Jun 11, 2022
216 Dec 30, 2022
97 Dec 03, 2022
1 Oct 30, 2021
123 Nov 09, 2022
1 May 13, 2022
0 Jun 11, 2022
0 Dec 12, 2021
2 Feb 21, 2022
394 Dec 17, 2022
31 Dec 27, 2022
2 Jan 06, 2022
574 Dec 30, 2022
1 Jan 26, 2022
30 Dec 16, 2022
58 Dec 23, 2022
9 Jun 10, 2022