1 """

     2 35. DB-API Shortcuts

     3 

     4 get_object_or_404 is a shortcut function to be used in view functions for

     5 performing a get() lookup and raising a Http404 exception if a DoesNotExist

     6 exception was rasied during the get() call.

     7 

     8 get_list_or_404 is a shortcut function to be used in view functions for

     9 performing a filter() lookup and raising a Http404 exception if a DoesNotExist

    10 exception was rasied during the filter() call.

    11 """

    12 

    13 from django.db import models

    14 from django.http import Http404

    15 from django.shortcuts import get_object_or_404, get_list_or_404

    16 

    17 class Author(models.Model):

    18     name = models.CharField(maxlength=50)

    19     

    20     def __str__(self):

    21         return self.name

    22 

    23 class ArticleManager(models.Manager):

    24     def get_query_set(self):

    25         return super(ArticleManager, self).get_query_set().filter(authors__name__icontains='sir')

    26 

    27 class Article(models.Model):

    28     authors = models.ManyToManyField(Author)

    29     title = models.CharField(maxlength=50)

    30     objects = models.Manager()

    31     by_a_sir = ArticleManager()

    32     

    33     def __str__(self):

    34         return self.title

    35 

    36 __test__ = {'API_TESTS':"""

    37 # Create some Authors.

    38 >>> a = Author.objects.create(name="Brave Sir Robin")

    39 >>> a.save()

    40 >>> a2 = Author.objects.create(name="Patsy")

    41 >>> a2.save()

    42 

    43 # No Articles yet, so we should get a Http404 error.

    44 >>> get_object_or_404(Article, title="Foo")

    45 Traceback (most recent call last):

    46 ...

    47 Http404: No Article matches the given query.

    48 

    49 # Create an Article.

    50 >>> article = Article.objects.create(title="Run away!")

    51 >>> article.authors = [a, a2]

    52 >>> article.save()

    53 

    54 # get_object_or_404 can be passed a Model to query.

    55 >>> get_object_or_404(Article, title__contains="Run")

    56 <Article: Run away!>

    57 

    58 # We can also use the the Article manager through an Author object.

    59 >>> get_object_or_404(a.article_set, title__contains="Run")

    60 <Article: Run away!>

    61 

    62 # No articles containing "Camelot".  This should raise a Http404 error.

    63 >>> get_object_or_404(a.article_set, title__contains="Camelot")

    64 Traceback (most recent call last):

    65 ...

    66 Http404: No Article matches the given query.

    67 

    68 # Custom managers can be used too.

    69 >>> get_object_or_404(Article.by_a_sir, title="Run away!")

    70 <Article: Run away!>

    71 

    72 # get_list_or_404 can be used to get lists of objects

    73 >>> get_list_or_404(a.article_set, title__icontains='Run')

    74 [<Article: Run away!>]

    75 

    76 # Http404 is returned if the list is empty

    77 >>> get_list_or_404(a.article_set, title__icontains='Shrubbery')

    78 Traceback (most recent call last):

    79 ...

    80 Http404: No Article matches the given query.

    81 

    82 # Custom managers can be used too.

    83 >>> get_list_or_404(Article.by_a_sir, title__icontains="Run")

    84 [<Article: Run away!>]

    85 

    86 """}