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Appendix C: Generic View Reference

Chapter 11 introduced generic views but leaves out some of the gory details. This appendix describes each generic view along with all the options each view can take. Be sure to read Chapter 11 before trying to understand the reference material that follows. You might want to refer back to the Book, Publisher, and Author objects defined in that chapter; the examples that follow use these models.

Common Arguments to Generic Views

Most of these views take a large number of arguments that can change the generic view's behavior. Many of these arguments work the same across a large number of views. Table C-1 describes each of these common arguments; anytime you see one of these arguments in a generic view's argument list, it will work as described in the table.

Table C-1. Common Arguments to Generic Views
Argument Description
allow_empty A Boolean specifying whether to display the page if no objects are available. If this is False and no objects are available, the view will raise a 404 error instead of displaying an empty page. By default, this is True.
context_processors A list of additional template-context processors (besides the defaults) to apply to the view's template. See Chapter 9 for information on template context processors.
extra_context A dictionary of values to add to the template context. By default, this is an empty dictionary. If a value in the dictionary is callable, the generic view will call it just before rendering the template.
mimetype The MIME type to use for the resulting document. It defaults to the value of the DEFAULT_MIME_TYPE setting, which is text/html if you haven't changed it.
queryset A QuerySet (i.e., something like Author.objects.all()) to read objects from. See Appendix B for more information about QuerySet objects. Most generic views require this argument.
template_loader The template loader to use when loading the template. By default, it's django.template.loader. See Chapter 9 for information on template loaders.
template_name The full name of a template to use in rendering the page. This lets you override the default template name derived from the QuerySet.
template_object_name The name of the template variable to use in the template context. By default, this is 'object'. Views that list more than one object (i.e., object_list views and various objects-for-date views) will append '_list' to the value of this parameter.

"Simple" Generic Views

The module``django.views.generic.simple`` contains simple views that handle a couple of common cases: rendering a template when no view logic is needed and issuing a redirect.

Rendering a Template

View function: django.views.generic.simple.direct_to_template

This view renders a given template, passing it a {{ params }} template variable, which is a dictionary of the parameters captured in the URL.

Example

Given the following URLconf:

from django.conf.urls.defaults import *
from django.views.generic.simple import direct_to_template

urlpatterns = patterns('',
    (r'^foo/$',             direct_to_template, {'template': 'foo_index.html'}),
    (r'^foo/(?P<id>\d+)/$', direct_to_template, {'template': 'foo_detail.html'}),
)

a request to /foo/ would render the template foo_index.html, and a request to /foo/15/ would render foo_detail.html with a context variable {{ params.id }} that is set to 15.

Required Arguments

  • template: The full name of a template to use.

Redirecting to Another URL

View function: django.views.generic.simple.redirect_to

This view redirects to another URL. The given URL may contain dictionary-style string formatting, which will be interpolated against the parameters captured in the URL.

If the given URL is None, Django will return an HTTP 410 ("Gone") message.

Example

This URLconf redirects from /foo/<id>/ to /bar/<id>/:

from django.conf.urls.defaults import *
from django.views.generic.simple import redirect_to

urlpatterns = patterns('django.views.generic.simple',
    ('^foo/(?p<id>\d+)/$', redirect_to, {'url': '/bar/%(id)s/'}),
)

This example returns a "Gone" response for requests to /bar/:

from django.views.generic.simple import redirect_to

urlpatterns = patterns('django.views.generic.simple',
    ('^bar/$', redirect_to, {'url': None}),
)

Required Arguments

  • url: The URL to redirect to, as a string. Or None to return a 410 ("Gone") HTTP response.

List/Detail Generic Views

The list/detail generic views (in the module django.views.generic.list_detail) handle the common case of displaying a list of items at one view and individual "detail" views of those items at another.

Lists of Objects

View function: django.views.generic.list_detail.object_list

Use this view to display a page representing a list of objects.

Example

Given the Author object from Chapter 5, we can use the object_list view to show a simple list of all authors given the following URLconf snippet:

from mysite.books.models import Author
from django.conf.urls.defaults import *
from django.views.generic import list_detail

author_list_info = {
    'queryset':   Author.objects.all(),
}

urlpatterns = patterns('',
    (r'authors/$', list_detail.object_list, author_list_info)
)

Required Arguments

  • queryset: A QuerySet of objects to list (see Table C-1).

Optional Arguments

  • paginate_by: An integer specifying how many objects should be displayed per page. If this is given, the view will paginate objects with paginate_by objects per page. The view will expect either a page query string parameter (via GET) containing a zero-indexed page number, or a page variable specified in the URLconf. See the following "Notes on Pagination" section.

Additionally, this view may take any of these common arguments described in Table C-1:

  • allow_empty
  • context_processors
  • extra_context
  • mimetype
  • template_loader
  • template_name
  • template_object_name

Template Name

If template_name isn't specified, this view will use the template <app_label>/<model_name>_list.html by default. Both the application label and the model name are derived from the queryset parameter. The application label is the name of the application that the model is defined in, and the model name is the lowercased version of the name of the model class.

In the previous example using Author.objects.all() as the queryset, the application label would be books and the model name would be author. This means the default template would be books/author_list.html.

Template Context

In addition to extra_context, the template's context will contain the following:

  • object_list: The list of objects. This variable's name depends on the template_object_name parameter, which is 'object' by default. If template_object_name is 'foo', this variable's name will be foo_list.
  • is_paginated: A Boolean representing whether the results are paginated. Specifically, this is set to False if the number of available objects is less than or equal to paginate_by.

If the results are paginated, the context will contain these extra variables:

  • results_per_page: The number of objects per page. (This is the same as the paginate_by parameter.)
  • has_next: A Boolean representing whether there's a next page.
  • has_previous: A Boolean representing whether there's a previous page.
  • page: The current page number, as an integer. This is 1-based.
  • next: The next page number, as an integer. If there's no next page, this will still be an integer representing the theoretical next-page number. This is 1-based.
  • previous: The previous page number, as an integer. This is 1-based.
  • pages: The total number of pages, as an integer.
  • hits: The total number of objects across all pages, not just this page.

A Note on Pagination

If paginate_by is specified, Django will paginate the results. You can specify the page number in the URL in one of two ways:

  • Use the page parameter in the URLconf. For example, this is what your URLconf might look like:

    (r'^objects/page(?P<page>[0-9]+)/$', 'object_list', dict(info_dict))
    
  • Pass the page number via the page query-string parameter. For example, a URL would look like this:

    /objects/?page=3
    

In both cases, page is 1-based, not 0-based, so the first page would be represented as page 1.

Detail Views

View function: django.views.generic.list_detail.object_detail

This view provides a "detail" view of a single object.

Example

Continuing the previous object_list example, we could add a detail view for a given author by modifying the URLconf:

from mysite.books.models import Author
from django.conf.urls.defaults import *
from django.views.generic import list_detail

author_list_info = {
    'queryset' :   Author.objects.all(),
}
author_detail_info = {
    "queryset" : Author.objects.all(),
    "template_object_name" : "author",
}

urlpatterns = patterns('',
    (r'authors/$', list_detail.object_list, author_list_info),
    (r'^authors/(?P<object_id>d+)/$', list_detail.object_detail, author_detail_info),
)

Required Arguments

  • queryset: A QuerySet that will be searched for the object (see Table C-1).

and either

  • object_id: The value of the primary-key field for the object.

or

  • slug: The slug of the given object. If you pass this field, then the slug_field argument (see the following section) is also required.

Optional Arguments

  • slug_field: The name of the field on the object containing the slug. This is required if you are using the slug argument, but it must be absent if you're using the object_id argument.

  • template_name_field: The name of a field on the object whose value is the template name to use. This lets you store template names in your data.

    In other words, if your object has a field 'the_template' that contains a string 'foo.html', and you set template_name_field to 'the_template', then the generic view for this object will use the template 'foo.html'.

    If the template named by template_name_field doesn't exist, the one named by template_name is used instead. It's a bit of a brain-bender, but it's useful in some cases.

This view may also take these common arguments (see Table C-1):

  • context_processors
  • extra_context
  • mimetype
  • template_loader
  • template_name
  • template_object_name

Template Name

If template_name and template_name_field aren't specified, this view will use the template <app_label>/<model_name>_detail.html by default.

Template Context

In addition to extra_context, the template's context will be as follows:

  • object: The object. This variable's name depends on the template_object_name parameter, which is 'object' by default. If template_object_name is 'foo', this variable's name will be foo.

Date-Based Generic Views

Date-based generic views are generally used to provide a set of "archive" pages for dated material. Think year/month/day archives for a newspaper, or a typical blog archive.

Tip:

By default, these views ignore objects with dates in the future.

This means that if you try to visit an archive page in the future, Django will automatically show a 404 ("Page not found") error, even if there are objects published that day.

Thus, you can publish postdated objects that don't appear publicly until their desired publication date.

However, for different types of date-based objects, this isn't appropriate (e.g., a calendar of upcoming events). For these views, setting the allow_future option to True will make the future objects appear (and allow users to visit "future" archive pages).

Archive Index

View function: django.views.generic.date_based.archive_index

This view provides a top-level index page showing the "latest" (i.e., most recent) objects by date.

Example

Say a typical book publisher wants a page of recently published books. Given some Book object with a publication_date field, we can use the archive_index view for this common task:

from mysite.books.models import Book
from django.conf.urls.defaults import *
from django.views.generic import date_based

book_info = {
    "queryset"   : Book.objects.all(),
    "date_field" : "publication_date"
}

urlpatterns = patterns('',
    (r'^books/$', date_based.archive_index, book_info),
)

Required Arguments

  • date_field: The name of the DateField or DateTimeField in the QuerySet's model that the date-based archive should use to determine the objects on the page.
  • queryset: A QuerySet of objects for which the archive serves.

Optional Arguments

  • allow_future: A Boolean specifying whether to include "future" objects on this page, as described in the previous note.
  • num_latest: The number of latest objects to send to the template context. By default, it's 15.

This view may also take these common arguments (see Table C-1):

  • allow_empty
  • context_processors
  • extra_context
  • mimetype
  • template_loader
  • template_name

Template Name

If template_name isn't specified, this view will use the template <app_label>/<model_name>_archive.html by default.

Template Context

In addition to extra_context, the template's context will be as follows:

  • date_list: A list of datetime.date objects representing all years that have objects available according to queryset. These are ordered in reverse.

    For example, if you have blog entries from 2003 through 2006, this list will contain four datetime.date objects: one for each of those years.

  • latest: The num_latest objects in the system, in descending order by date_field. For example, if num_latest is 10, then latest will be a list of the latest ten objects in queryset.

Year Archives

View function: django.views.generic.date_based.archive_year

Use this view for yearly archive pages. These pages have a list of months in which objects exists, and they can optionally display all the objects published in a given year.

Example

Extending the archive_index example from earlier, we'll add a way to view all the books published in a given year:

from mysite.books.models import Book
from django.conf.urls.defaults import *
from django.views.generic import date_based

book_info = {
    "queryset"   : Book.objects.all(),
    "date_field" : "publication_date"
}

urlpatterns = patterns('',
    (r'^books/$', date_based.archive_index, book_info),
    (r'^books/(?P<year>d{4})/?$', date_based.archive_year, book_info),
)

Required Arguments

  • date_field: As for archive_index (see the previous section).
  • queryset: A QuerySet of objects for which the archive serves.
  • year: The four-digit year for which the archive serves (as in our example, this is usually taken from a URL parameter).

Optional Arguments

  • make_object_list: A Boolean specifying whether to retrieve the full list of objects for this year and pass those to the template. If True, this list of objects will be made available to the template as object_list. (The name object_list may be different; see the information about object_list in the following "Template Context" section.) By default, this is False.
  • allow_future: A Boolean specifying whether to include "future" objects on this page.

This view may also take these common arguments (see Table C-1):

  • allow_empty
  • context_processors
  • extra_context
  • mimetype
  • template_loader
  • template_name
  • template_object_name

Template Name

If template_name isn't specified, this view will use the template <app_label>/<model_name>_archive_year.html by default.

Template Context

In addition to extra_context, the template's context will be as follows:

  • date_list: A list of datetime.date objects representing all months that have objects available in the given year, according to queryset, in ascending order.

  • year: The given year, as a four-character string.

  • object_list: If the make_object_list parameter is True, this will be set to a list of objects available for the given year, ordered by the date field. This variable's name depends on the template_object_name parameter, which is 'object' by default. If template_object_name is 'foo', this variable's name will be foo_list.

    If make_object_list is False, object_list will be passed to the template as an empty list.

Month Archives

View function: django.views.generic.date_based.archive_month

This view provides monthly archive pages showing all objects for a given month.

Example

Continuing with our example, adding month views should look familiar:

urlpatterns = patterns('',
    (r'^books/$', date_based.archive_index, book_info),
    (r'^books/(?P<year>d{4})/?$', date_based.archive_year, book_info),
    (
        r'^(?P<year>d{4})/(?P<month>[a-z]{3})/$',
        date_based.archive_month,
        book_info
    ),
)

Required Arguments

  • year: The four-digit year for which the archive serves (a string).
  • month: The month for which the archive serves, formatted according to the month_format argument.
  • queryset: A QuerySet of objects for which the archive serves.
  • date_field: The name of the DateField or DateTimeField in the QuerySet's model that the date-based archive should use to determine the objects on the page.

Optional Arguments

  • month_format: A format string that regulates what format the month parameter uses. This should be in the syntax accepted by Python's time.strftime. (See Python's strftime documentation at http://docs.python.org/library/time.html#time.strftime.) It's set to "%b" by default, which is a three-letter month abbreviation (i.e., "jan", "feb", etc.). To change it to use numbers, use "%m".
  • allow_future: A Boolean specifying whether to include "future" objects on this page, as described in the previous note.

This view may also take these common arguments (see Table C-1):

  • allow_empty
  • context_processors
  • extra_context
  • mimetype
  • template_loader
  • template_name
  • template_object_name

Template Name

If template_name isn't specified, this view will use the template <app_label>/<model_name>_archive_month.html by default.

Template Context

In addition to extra_context, the template's context will be as follows:

  • month: A datetime.date object representing the given month.
  • next_month: A datetime.date object representing the first day of the next month. If the next month is in the future, this will be None.
  • previous_month: A datetime.date object representing the first day of the previous month. Unlike next_month, this will never be None.
  • object_list: A list of objects available for the given month. This variable's name depends on the template_object_name parameter, which is 'object' by default. If template_object_name is 'foo', this variable's name will be foo_list.

Week Archives

View function: django.views.generic.date_based.archive_week

This view shows all objects in a given week.

Note

For the sake of consistency with Python's built-in date/time handling, Django assumes that the first day of the week is Sunday.

Example

urlpatterns = patterns('',
    # ...
    (
        r'^(?P<year>d{4})/(?P<week>d{2})/$',
        date_based.archive_week,
        book_info
    ),
)

Required Arguments

  • year: The four-digit year for which the archive serves (a string).
  • week: The week of the year for which the archive serves (a string).
  • queryset: A QuerySet of objects for which the archive serves.
  • date_field: The name of the DateField or DateTimeField in the QuerySet's model that the date-based archive should use to determine the objects on the page.

Optional Arguments

  • allow_future: A Boolean specifying whether to include "future" objects on this page, as described in the previous note.

This view may also take these common arguments (see Table C-1):

  • allow_empty
  • context_processors
  • extra_context
  • mimetype
  • template_loader
  • template_name
  • template_object_name

Template Name

If template_name isn't specified, this view will use the template <app_label>/<model_name>_archive_week.html by default.

Template Context

In addition to extra_context, the template's context will be as follows:

  • week: A datetime.date object representing the first day of the given week.
  • object_list: A list of objects available for the given week. This variable's name depends on the template_object_name parameter, which is 'object' by default. If template_object_name is 'foo', this variable's name will be foo_list.

Day Archives

View function: django.views.generic.date_based.archive_day

This view generates all objects in a given day.

Example

urlpatterns = patterns('',
    # ...
    (
        r'^(?P<year>d{4})/(?P<month>[a-z]{3})/(?P<day>d{2})/$',
        date_based.archive_day,
        book_info
    ),
)

Required Arguments

  • year: The four-digit year for which the archive serves (a string).
  • month: The month for which the archive serves, formatted according to the month_format argument.
  • day: The day for which the archive serves, formatted according to the day_format argument.
  • queryset: A QuerySet of objects for which the archive serves.
  • date_field: The name of the DateField or DateTimeField in the QuerySet's model that the date-based archive should use to determine the objects on the page.

Optional Arguments

  • month_format: A format string that regulates what format the month parameter uses. See the detailed explanation in the "Month Archives" section, above.
  • day_format: Like month_format, but for the day parameter. It defaults to "%d" (the day of the month as a decimal number, 01-31).
  • allow_future: A Boolean specifying whether to include "future" objects on this page, as described in the previous note.

This view may also take these common arguments (see Table C-1):

  • allow_empty
  • context_processors
  • extra_context
  • mimetype
  • template_loader
  • template_name
  • template_object_name

Template Name

If template_name isn't specified, this view will use the template <app_label>/<model_name>_archive_day.html by default.

Template Context

In addition to extra_context, the template's context will be as follows:

  • day: A datetime.date object representing the given day.
  • next_day: A datetime.date object representing the next day. If the next day is in the future, this will be None.
  • previous_day: A datetime.date object representing the previous day. Unlike next_day, this will never be None.
  • object_list: A list of objects available for the given day. This variable's name depends on the template_object_name parameter, which is 'object' by default. If template_object_name is 'foo', this variable's name will be foo_list.

Archive for Today

The django.views.generic.date_based.archive_today view shows all objects for today. This is exactly the same as archive_day, except the year/month/day arguments are not used, and today's date is used instead.

Example

urlpatterns = patterns('',
    # ...
    (r'^books/today/$', date_based.archive_today, book_info),
)

Date-Based Detail Pages

View function: django.views.generic.date_based.object_detail

Use this view for a page representing an individual object.

This has a different URL from the object_detail view; the object_detail view uses URLs like /entries/<slug>/, while this one uses URLs like /entries/2006/aug/27/<slug>/.

Note

If you're using date-based detail pages with slugs in the URLs, you probably also want to use the unique_for_date option on the slug field to validate that slugs aren't duplicated in a single day. See Appendix A for details on unique_for_date.

Example

This one differs (slightly) from all the other date-based examples in that we need to provide either an object ID or a slug so that Django can look up the object in question.

Since the object we're using doesn't have a slug field, we'll use ID-based URLs. It's considered a best practice to use a slug field, but in the interest of simplicity we'll let it go.

urlpatterns = patterns('',
    # ...
    (
        r'^(?P<year>d{4})/(?P<month>[a-z]{3})/(?P<day>d{2})/(?P<object_id>[w-]+)/$',
        date_based.object_detail,
        book_info
    ),
)

Required Arguments

  • year: The object's four-digit year (a string).
  • month: The object's month, formatted according to the month_format argument.
  • day: The object's day, formatted according to the day_format argument.
  • queryset: A QuerySet that contains the object.
  • date_field: The name of the DateField or DateTimeField in the QuerySet's model that the generic view should use to look up the object according to year, month, and day.

You'll also need either:

  • object_id: The value of the primary-key field for the object.

or:

  • slug: The slug of the given object. If you pass this field, then the slug_field argument (described in the following section) is also required.

Optional Arguments

  • allow_future: A Boolean specifying whether to include "future" objects on this page, as described in the previous note.
  • day_format: Like month_format, but for the day parameter. It defaults to "%d" (the day of the month as a decimal number, 01-31).
  • month_format: A format string that regulates what format the month parameter uses. See the detailed explanation in the "Month Archives" section, above.
  • slug_field: The name of the field on the object containing the slug. This is required if you are using the slug argument, but it must be absent if you're using the object_id argument.
  • template_name_field: The name of a field on the object whose value is the template name to use. This lets you store template names in the data. In other words, if your object has a field 'the_template' that contains a string 'foo.html', and you set template_name_field to 'the_template', then the generic view for this object will use the template 'foo.html'.

This view may also take these common arguments (see Table C-1):

  • context_processors
  • extra_context
  • mimetype
  • template_loader
  • template_name
  • template_object_name

Template Name

If template_name and template_name_field aren't specified, this view will use the template <app_label>/<model_name>_detail.html by default.

Template Context

In addition to extra_context, the template's context will be as follows:

  • object: The object. This variable's name depends on the template_object_name parameter, which is 'object' by default. If template_object_name is 'foo', this variable's name will be foo.
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