Utils¶

Utility Functions¶

chamber.utils.remove_accent(string_with_diacritics)¶

chamber.utils.get_class_method(cls_or_inst, method_name)¶

Returns a method of a given class or instance.

chamber.utils.forms.formset_has_file_field()¶

Returns True if passed formset contains FileField (or ImageField).

chamber.utils.http.query_string_from_dict()¶

Assembles query string from a Python dict.

>>> query_string_from_dict({'q': 'query1', 'user': 'test'})
u'q=query1&user=test'

Enums¶

class chamber.utils.datastructures.AbstractEnum¶

Base enumeration class with controlled __getattr__.

chamber.utils.datastructures.AbstractEnum.all¶

Returns all enum values in a tuple.

chamber.utils.datastructures.AbstractEnum.__iter__()¶

Returns iterator over enum values.

chamber.utils.datastructures.AbstractEnum.get_name()¶

Returns name of the choice accorting to its value.

chamber.utils.datastructures.AbstractEnum.get_name()

Implementation of in operator. Return True if value is part of the enum.

class chamber.utils.datastructures.Enum¶

Python’s set with AbstractEnum behaviour. Enum key can be only string type. Key and values can be different.

>>> enum = NumEnum('A', 'B') #  {'A': 'A', 'B': 'B'}
>>> enum.all
('A', 'B')
>>> 'A' in enum
True
>>> list(enum)
['A', 'B']
>>> enum.A
'A'

>>> enum = NumEnum(('A', 'a'), ('B', 'b')) #  {'A': 'a', 'B': 'b'}
>>> enum.all
('a', 'b')
>>> 'a' in enum
True
>>> list(enum)
['a', 'b']
>>> enum.A
'a'

class chamber.utils.datastructures.NumEnum¶

Python’s dict with AbstractEnum behaviour.

>>> enum = NumEnum('A', 'B') #  {'A': 1, 'B': 2}
>>> enum.all
(1, 2)
>>> 1 in enum
True
>>> list(enum)
[1, 2]
>>> enum.A
1

>>> enum = NumEnum(('A', 6), ('B', 5)) #  {'A': 6, 'B': 5}
>>> enum.all
(6, 5)
>>> 5 in enum
True
>>> list(enum)
[6, 5]
>>> enum.A
6

class chamber.utils.datastructures.AbstractChoicesEnum¶

Base choices class (can be used as a model field’s choices argument).

class chamber.utils.datastructures.ChoicesEnum¶

django.utils.datastructures.SortedDict with AbstractEnum and AbstractChoicesEnum behaviour. Useful for string based choices.

>>> enum = ChoicesEnum(('OK', 'label ok'), ('KO', 'label ko'))  # {'OK': ('OK', 'label ok), 'ko': ('KO', 'label ko)}
>>> enum.OK
'OK'
>>> enum.choices
[('OK', 'ok'), ('KO', 'ko')]
>>> enum.get_label(enum.OK)
'label ok'

>>> enum = ChoicesEnum(('OK', 'label ok', 'ok'), ('KO', 'label ko', 'ko'))  #  {'OK': ('ok', 'label ok), 'ko': ('ko', 'label ko)}
>>> enum.OK
'ok'
>>> enum.choices
[('ok', 'label ok'), ('ko', 'label ko')]
>>> enum.get_label(enum.OK)
'label ok'

class chamber.utils.datastructures.ChoicesNumEnum¶

django.utils.datastructures.SortedDict with AbstractEnum and AbstractChoicesEnum behaviour. Useful for integer-based choices.

>>> enum = ChoicesNumEnum(('OK', 'label ok', 1), ('KO', 'label ko', 2))
>>> enum.KO
2
>>> enum.choices
[(1, 'ok'), (2, 'ko')]
>>> enum.get_label(2)
'ko'

Decorators¶

@chamber.utils.decorators.classproperty¶

Decorator that turns a class method into a property of the class.

class RestResource(BaseResource):
    @classproperty
    def csrf_exempt(cls):
        return not cls.login_required

    @classmethod
    def as_view(cls, allowed_methods=None, **initkwargs):
        view.csrf_exempt = cls.csrf_exempt

@chamber.utils.decorators.singleton¶

Class decorator, which allows for only one instance of class to exist.

@chamber.utils.decorators.short_description¶

Sets short_description attribute that is used to render description of a Django form field.

@short_description('amount')
def absolute_amount(self):
    return abs(self.amount)

is equivalent to

def absolute_amount(self):
    return abs(self.amount)
absolute_amount.short_description = 'amount'

Tqdm¶

class chamber.utils.tqdm.tqdm¶

The class extends tqdm library (https://tqdm.github.io/). Now the tqdm context processor can be used with th django commands. Django command stdout writes newline after every write to the stdout which breaks the progress bar:

# a custom command
from django.core.management.base import BaseCommand
from chamber.utils.tqdm import tqdm

class Command(BaseCommand):

    def handle(self, *args, **options):
        for i in tqdm(range(10), file=self.stdout):
            custom_operation(i)

Logging¶

class chamber.logging.AppendExtraJSONHandler¶

Log handler which writes every extra argument in the log to the output message in a json format:

# logged message with handler
logger.log('message', extra={'extra': 'data'})

# logger output
message --- {"extra": "data"}

Storages¶

class chamber.storages.BaseS3Storage¶

Class fixes bugs in the boto3 library storage. For example you can write only bytes with the standard boto3 S3Boto3Storage. Strings will raise exception. The chamber BaseS3Storage adds possibility to saves strings to the storage.

class chamber.storages.BasePrivateS3Storage¶

Improves boto3 storage with url method. With this method you can generate temporary URL address to the private s3 storage. The URL will expire after CHAMBER_PRIVATE_S3_STORAGE_URL_EXPIRATION (default value is one day).

Commands¶

makemessages¶

Django makemessages commands is expanded with another keywords which represents transaction strings. This keyword you can use instead of long django functions:

_l - instead of gettext_lazy
_n - instead of ngettext
_nl - instead of ngettext_lazy
_p - instead of pgettext
_np - instead of npgettext
_pl - instead of pgettext_lazy
_npl - instead of npgettext_lazy

Second improvement is parameter no-creation-date which remove POT-Creation-Date from the result file.

initdata¶

Init data is command similar to django loaddata. The command automatically loads the file from the path defined in setting CHAMBER_INITAL_DATA_PATH.