# documentação Django 2.0.8

# Date-based mixins

Nota

Todos os atributos de formatação de dados nesses “mixins” usam caracteres de formato `strftime()`. Não tente usar caracteres de formato a partir da tag de template `now`, porque eles não são compatíveis.

## `YearMixin`

class `YearMixin`

  Um mixin que pode ser usado para obter e fornecer informações de análise do componente ano de uma data.

  Métodos e Atributos

  `year_format`

    The `strftime()` format to use when parsing the year. By default, this is `'%Y'`.

  `year`

    Optional The value for the year, as a string. By default, set to `None`, which means the year will be determined using other means.

  `get_year_format`()

    Returns the `strftime()` format to use when parsing the year. Returns `year_format` by default.

  `get_year`()

    Retorna o ano para o qual essa view mostrará dado como uma string. Tenta as seguintes fontes, na ordem:

    - O valor do atributo `YearMixin.year`.
    - O valor do parâmetro `year` capturado pelo padrão da URL.
    - The value of the `year` `GET` query argument.

    Raises a 404 if no valid year specification can be found.

  `get_next_year`(date)

    Returns a date object containing the first day of the year after the date provided. This function can also return `None` or raise an `Http404` exception, depending on the values of `allow_empty` and `allow_future`.

  `get_previous_year`(date)

    Returns a date object containing the first day of the year before the date provided. This function can also return `None` or raise an `Http404` exception, depending on the values of `allow_empty` and `allow_future`.

## `MonthMixin`

class `MonthMixin`

  A “mixin” que pode ser usada para recuperar e fornecer informações de análise por um componente mês de uma data.

  Métodos e Atributos

  `month_format`

    The `strftime()` format to use when parsing the month. By default, this is `'%b'`.

  `month`

    Optional The value for the month, as a string. By default, set to `None`, which means the month will be determined using other means.

  `get_month_format`()

    Returns the `strftime()` format to use when parsing the month. Returns `month_format` by default.

  `get_month`()

    Returns the month for which this view will display data, as a string. Tries the following sources, in order:

    - O valor do atributo `MonthMixin.month`.
    - O valor do argumento “mês” capturado na URL, com base em um padrão.
    - The value of the `month` `GET` query argument.

    Retornará um erro 404 se nenhuma especificação de mês for localizada.

  `get_next_month`(date)

    Retorna um objeto do tipo data que contém o primeiro dia do mês após a data informada. Esta função pode também retornar “None” ou provocar uma excessão do tipo: class:~django.http.Http404, dependendo dos valores de `allow_empty` e `allow_future`.

  `get_previous_month`(date)

    Returns a date object containing the first day of the month before the date provided. This function can also return `None` or raise an `Http404` exception, depending on the values of `allow_empty` and `allow_future`.

## `DayMixin`

class `DayMixin`

  A mixin that can be used to retrieve and provide parsing information for a day component of a date.

  Métodos e Atributos

  `day_format`

    The `strftime()` format to use when parsing the day. By default, this is `'%d'`.

  `day`

    Optional The value for the day, as a string. By default, set to `None`, which means the day will be determined using other means.

  `get_day_format`()

    Returns the `strftime()` format to use when parsing the day. Returns `day_format` by default.

  `get_day`()

    Retorna o dia pra o qual essa view mostrará o dado como uma string. Tenta as seguintes fontes, na ordem:

    - O valor do atributo `DayMixin.day`.
    - O valor do argumento `day` capturado no padrão de URL
    - O valor do parâmetro `day` via `GET` query.

    Retorna um erro 404 se nenhuma especificação de dia válido for localizado.

  `get_next_day`(date)

    Returns a date object containing the next valid day after the date provided. This function can also return `None` or raise an `Http404` exception, depending on the values of `allow_empty` and `allow_future`.

  `get_previous_day`(date)

    Returns a date object containing the previous valid day. This function can also return `None` or raise an `Http404` exception, depending on the values of `allow_empty` and `allow_future`.

## `WeekMixin`

class `WeekMixin`

  Um “mixin” que pode ser utilizado para recuperar e forneceder informações de análise para um componente de semana de uma data.

  Métodos e Atributos

  `week_format`

    The `strftime()` format to use when parsing the week. By default, this is `'%U'`, which means the week starts on Sunday. Set it to `'%W'` if your week starts on Monday.

  `week`

    Optional The value for the week, as a string. By default, set to `None`, which means the week will be determined using other means.

  `get_week_format`()

    Returns the `strftime()` format to use when parsing the week. Returns `week_format` by default.

  `get_week`()

    Returns the week for which this view will display data, as a string. Tries the following sources, in order:

    - O valor do atributo `WeekMixin.week`.
    - O valor do parâmetro `week` capturado pelo padrão da URL
    - O valor do parâmetro `week` via `GET` query.

    Retorna um erro 404 se nenhuma especificação de semana válida for localizada.

  `get_next_week`(date)

    Returns a date object containing the first day of the week after the date provided. This function can also return `None` or raise an `Http404` exception, depending on the values of `allow_empty` and `allow_future`.

  `get_prev_week`(date)

    Returns a date object containing the first day of the week before the date provided. This function can also return `None` or raise an `Http404` exception, depending on the values of `allow_empty` and `allow_future`.

## `DateMixin`

class `DateMixin`

  A mixin class providing common behavior for all date-based views.

  Métodos e Atributos

  `date_field`

    The name of the `DateField` or `DateTimeField` in the `QuerySet`’s model that the date-based archive should use to determine the list of objects to display on the page.

    When time zone support is enabled and `date_field` is a `DateTimeField`, dates are assumed to be in the current time zone. Otherwise, the queryset could include objects from the previous or the next day in the end user’s time zone.

    Aviso

    In this situation, if you have implemented per-user time zone selection, the same URL may show a different set of objects, depending on the end user’s time zone. To avoid this, you should use a `DateField` as the `date_field` attribute.

  `allow_future`

    A boolean specifying whether to include “future” objects on this page, where “future” means objects in which the field specified in `date_field` is greater than the current date/time. By default, this is `False`.

  `get_date_field`()

    Returns the name of the field that contains the date data that this view will operate on. Returns `date_field` by default.

  `get_allow_future`()

    Determine whether to include “future” objects on this page, where “future” means objects in which the field specified in `date_field` is greater than the current date/time. Returns `allow_future` by default.

## `BaseDateListView`

class `BaseDateListView`

  A base class that provides common behavior for all date-based views. There won’t normally be a reason to instantiate `BaseDateListView`; instantiate one of the subclasses instead.

  While this view (and its subclasses) are executing, `self.object_list` will contain the list of objects that the view is operating upon, and `self.date_list` will contain the list of dates for which data is available.

  Mixins

  - `DateMixin`
  - `MultipleObjectMixin`

  Métodos e Atributos

  `allow_empty`

    A boolean specifying whether to display the page if no objects are available. If this is `True` and no objects are available, the view will display an empty page instead of raising a 404.

    This is identical to `django.views.generic.list.MultipleObjectMixin.allow_empty`, except for the default value, which is `False`.

  `date_list_period`

    Optional A string defining the aggregation period for `date_list`. It must be one of `'year'` (default), `'month'`, or `'day'`.

  `get_dated_items`()

    Returns a 3-tuple containing (`date_list`, `object_list`, `extra_context`).

    `date_list` is the list of dates for which data is available. `object_list` is the list of objects. `extra_context` is a dictionary of context data that will be added to any context data provided by the `MultipleObjectMixin`.

  `get_dated_queryset`(**lookup)

    Returns a queryset, filtered using the query arguments defined by `lookup`. Enforces any restrictions on the queryset, such as `allow_empty` and `allow_future`.

  `get_date_list_period`()

    Returns the aggregation period for `date_list`. Returns `date_list_period` by default.

  `get_date_list`(queryset, date_type=None, ordering='ASC')

    Returns the list of dates of type `date_type` for which `queryset` contains entries. For example, `get_date_list(qs, 'year')` will return the list of years for which `qs` has entries. If `date_type` isn’t provided, the result of `get_date_list_period()` is used. `date_type` and `ordering` are simply passed to `QuerySet.dates()`.