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detail.py 6.4KB

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  1. from django.core.exceptions import ImproperlyConfigured
  2. from django.db import models
  3. from django.http import Http404
  4. from django.utils.translation import gettext as _
  5. from django.views.generic.base import ContextMixin, TemplateResponseMixin, View
  6. class SingleObjectMixin(ContextMixin):
  7. """
  8. Provide the ability to retrieve a single object for further manipulation.
  9. """
  10. model = None
  11. queryset = None
  12. slug_field = 'slug'
  13. context_object_name = None
  14. slug_url_kwarg = 'slug'
  15. pk_url_kwarg = 'pk'
  16. query_pk_and_slug = False
  17. def get_object(self, queryset=None):
  18. """
  19. Return the object the view is displaying.
  20. Require `self.queryset` and a `pk` or `slug` argument in the URLconf.
  21. Subclasses can override this to return any object.
  22. """
  23. # Use a custom queryset if provided; this is required for subclasses
  24. # like DateDetailView
  25. if queryset is None:
  26. queryset = self.get_queryset()
  27. # Next, try looking up by primary key.
  28. pk = self.kwargs.get(self.pk_url_kwarg)
  29. slug = self.kwargs.get(self.slug_url_kwarg)
  30. if pk is not None:
  31. queryset = queryset.filter(pk=pk)
  32. # Next, try looking up by slug.
  33. if slug is not None and (pk is None or self.query_pk_and_slug):
  34. slug_field = self.get_slug_field()
  35. queryset = queryset.filter(**{slug_field: slug})
  36. # If none of those are defined, it's an error.
  37. if pk is None and slug is None:
  38. raise AttributeError(
  39. "Generic detail view %s must be called with either an object "
  40. "pk or a slug in the URLconf." % self.__class__.__name__
  41. )
  42. try:
  43. # Get the single item from the filtered queryset
  44. obj = queryset.get()
  45. except queryset.model.DoesNotExist:
  46. raise Http404(_("No %(verbose_name)s found matching the query") %
  47. {'verbose_name': queryset.model._meta.verbose_name})
  48. return obj
  49. def get_queryset(self):
  50. """
  51. Return the `QuerySet` that will be used to look up the object.
  52. This method is called by the default implementation of get_object() and
  53. may not be called if get_object() is overridden.
  54. """
  55. if self.queryset is None:
  56. if self.model:
  57. return self.model._default_manager.all()
  58. else:
  59. raise ImproperlyConfigured(
  60. "%(cls)s is missing a QuerySet. Define "
  61. "%(cls)s.model, %(cls)s.queryset, or override "
  62. "%(cls)s.get_queryset()." % {
  63. 'cls': self.__class__.__name__
  64. }
  65. )
  66. return self.queryset.all()
  67. def get_slug_field(self):
  68. """Get the name of a slug field to be used to look up by slug."""
  69. return self.slug_field
  70. def get_context_object_name(self, obj):
  71. """Get the name to use for the object."""
  72. if self.context_object_name:
  73. return self.context_object_name
  74. elif isinstance(obj, models.Model):
  75. return obj._meta.model_name
  76. else:
  77. return None
  78. def get_context_data(self, **kwargs):
  79. """Insert the single object into the context dict."""
  80. context = {}
  81. if self.object:
  82. context['object'] = self.object
  83. context_object_name = self.get_context_object_name(self.object)
  84. if context_object_name:
  85. context[context_object_name] = self.object
  86. context.update(kwargs)
  87. return super().get_context_data(**context)
  88. class BaseDetailView(SingleObjectMixin, View):
  89. """A base view for displaying a single object."""
  90. def get(self, request, *args, **kwargs):
  91. self.object = self.get_object()
  92. context = self.get_context_data(object=self.object)
  93. return self.render_to_response(context)
  94. class SingleObjectTemplateResponseMixin(TemplateResponseMixin):
  95. template_name_field = None
  96. template_name_suffix = '_detail'
  97. def get_template_names(self):
  98. """
  99. Return a list of template names to be used for the request. May not be
  100. called if render_to_response() is overridden. Return the following list:
  101. * the value of ``template_name`` on the view (if provided)
  102. * the contents of the ``template_name_field`` field on the
  103. object instance that the view is operating upon (if available)
  104. * ``<app_label>/<model_name><template_name_suffix>.html``
  105. """
  106. try:
  107. names = super().get_template_names()
  108. except ImproperlyConfigured:
  109. # If template_name isn't specified, it's not a problem --
  110. # we just start with an empty list.
  111. names = []
  112. # If self.template_name_field is set, grab the value of the field
  113. # of that name from the object; this is the most specific template
  114. # name, if given.
  115. if self.object and self.template_name_field:
  116. name = getattr(self.object, self.template_name_field, None)
  117. if name:
  118. names.insert(0, name)
  119. # The least-specific option is the default <app>/<model>_detail.html;
  120. # only use this if the object in question is a model.
  121. if isinstance(self.object, models.Model):
  122. object_meta = self.object._meta
  123. names.append("%s/%s%s.html" % (
  124. object_meta.app_label,
  125. object_meta.model_name,
  126. self.template_name_suffix
  127. ))
  128. elif getattr(self, 'model', None) is not None and issubclass(self.model, models.Model):
  129. names.append("%s/%s%s.html" % (
  130. self.model._meta.app_label,
  131. self.model._meta.model_name,
  132. self.template_name_suffix
  133. ))
  134. # If we still haven't managed to find any template names, we should
  135. # re-raise the ImproperlyConfigured to alert the user.
  136. if not names:
  137. raise
  138. return names
  139. class DetailView(SingleObjectTemplateResponseMixin, BaseDetailView):
  140. """
  141. Render a "detail" view of an object.
  142. By default this is a model instance looked up from `self.queryset`, but the
  143. view will support display of *any* object by overriding `self.get_object()`.
  144. """