Fixed #15961 -- Modified ModelAdmin to allow for custom search methods.

This adds a get_search_results method that users can override to
provide custom search strategies.

Thanks to Daniele Procida for help with the docs.

AUTHORS

@@ -99,6 +99,7 @@ answer newbie questions, and generally made Django that much better:
     Brian Beck <http://blog.brianbeck.com/>
     Shannon -jj Behrens <http://jjinux.blogspot.com/>
     Esdras Beleza <linux@esdrasbeleza.com>
+    Božidar Benko <bbenko@gmail.com>
     Chris Bennett <chrisrbennett@yahoo.com>
     Danilo Bargen
     Shai Berger <shai@platonix.com>

django/contrib/admin/options.py

 import copy
+import operator
 from functools import update_wrapper, partial
 
 from django import forms
@@ -9,7 +10,7 @@ from django.forms.models import (modelform_factory, modelformset_factory,
 from django.contrib.contenttypes.models import ContentType
 from django.contrib.admin import widgets, helpers
 from django.contrib.admin.util import (unquote, flatten_fieldsets, get_deleted_objects,
-    model_format_dict, NestedObjects)
+    model_format_dict, NestedObjects, lookup_needs_distinct)
 from django.contrib.admin import validation
 from django.contrib.admin.templatetags.admin_static import static
 from django.contrib import messages
@@ -255,6 +256,34 @@ class BaseModelAdmin(six.with_metaclass(RenameBaseModelAdminMethods)):
         """
         return self.prepopulated_fields
 
+    def get_search_results(self, request, queryset, search_term):
+        # Apply keyword searches.
+        def construct_search(field_name):
+            if field_name.startswith('^'):
+                return "%s__istartswith" % field_name[1:]
+            elif field_name.startswith('='):
+                return "%s__iexact" % field_name[1:]
+            elif field_name.startswith('@'):
+                return "%s__search" % field_name[1:]
+            else:
+                return "%s__icontains" % field_name
+
+        use_distinct = False
+        if self.search_fields and search_term:
+            orm_lookups = [construct_search(str(search_field))
+                           for search_field in self.search_fields]
+            for bit in search_term.split():
+                or_queries = [models.Q(**{orm_lookup: bit})
+                              for orm_lookup in orm_lookups]
+                queryset = queryset.filter(reduce(operator.or_, or_queries))
+            if not use_distinct:
+                for search_spec in orm_lookups:
+                    if lookup_needs_distinct(self.opts, search_spec):
+                        use_distinct = True
+                        break
+
+        return queryset, use_distinct
+
     def get_queryset(self, request):
         """
         Returns a QuerySet of all model instances that can be edited by the

django/contrib/admin/views/main.py

-import operator
 import sys
 import warnings
-from functools import reduce
 
 from django.core.exceptions import SuspiciousOperation, ImproperlyConfigured
 from django.core.paginator import InvalidPage
@@ -331,7 +329,7 @@ class ChangeList(six.with_metaclass(RenameChangeListMethods)):
     def get_queryset(self, request):
         # First, we collect all the declared list filters.
         (self.filter_specs, self.has_filters, remaining_lookup_params,
-         use_distinct) = self.get_filters(request)
+         filters_use_distinct) = self.get_filters(request)
 
         # Then, we let every list filter modify the queryset to its liking.
         qs = self.root_queryset
@@ -378,31 +376,11 @@ class ChangeList(six.with_metaclass(RenameChangeListMethods)):
         ordering = self.get_ordering(request, qs)
         qs = qs.order_by(*ordering)
 
-        # Apply keyword searches.
-        def construct_search(field_name):
-            if field_name.startswith('^'):
-                return "%s__istartswith" % field_name[1:]
-            elif field_name.startswith('='):
-                return "%s__iexact" % field_name[1:]
-            elif field_name.startswith('@'):
-                return "%s__search" % field_name[1:]
-            else:
-                return "%s__icontains" % field_name
-
-        if self.search_fields and self.query:
-            orm_lookups = [construct_search(str(search_field))
-                           for search_field in self.search_fields]
-            for bit in self.query.split():
-                or_queries = [models.Q(**{orm_lookup: bit})
-                              for orm_lookup in orm_lookups]
-                qs = qs.filter(reduce(operator.or_, or_queries))
-            if not use_distinct:
-                for search_spec in orm_lookups:
-                    if lookup_needs_distinct(self.lookup_opts, search_spec):
-                        use_distinct = True
-                        break
+        # Apply search results
+        qs, search_use_distinct = self.model_admin.get_search_results(request, qs, self.query)
 
-        if use_distinct:
+        # Remove duplicates from results, if neccesary
+        if filters_use_distinct | search_use_distinct:
             return qs.distinct()
         else:
             return qs

docs/ref/contrib/admin/index.txt

@@ -1005,6 +1005,9 @@ subclass::
         Performs a full-text match. This is like the default search method but
         uses an index. Currently this is only available for MySQL.
 
+    If you need to customize search you can use :meth:`ModelAdmin.get_search_results` to provide additional or alternate
+    search behaviour.
+
 Custom template options
 ~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -1102,6 +1105,39 @@ templates used by the :class:`ModelAdmin` views:
                 else:
                     return ['name']
 
+.. method:: ModelAdmin.get_search_results(self, request, queryset, search_term)
+
+    .. versionadded:: 1.6
+
+    The ``get_search_results`` method modifies the list of objects displayed in
+    to those that match the provided search term. It accepts the request, a
+    queryset that applies the current filters, and the user-provided search term.
+    It returns a tuple containing a queryset modified to implement the search, and
+    a boolean indicating if the results may contain duplicates.
+
+    The default implementation searches the fields named in :attr:`ModelAdmin.search_fields`.
+
+    This method may be overridden with your own custom search method. For
+    example, you might wish to search by an integer field, or use an external
+    tool such as Solr or Haystack. You must establish if the queryset changes
+    implemented by your search method may introduce duplicates into the results,
+    and return ``True`` in the second element of the return value.
+
+    For example, to enable search by integer field, you could use::
+
+        class PersonAdmin(admin.ModelAdmin):
+            list_display = ('name', 'age')
+            search_fields = ('name',)
+
+            def get_search_results(self, request, queryset, search_term):
+                queryset, use_distinct = super(PersonAdmin, self).get_search_results(request, queryset, search_term)
+                try:
+                    search_term_as_int = int(search_term)
+                    queryset |= self.model.objects.filter(age=search_term_as_int)
+                except:
+                    pass
+                return queryset, use_distinct
+
 .. method:: ModelAdmin.save_related(self, request, form, formsets, change)
 
     The ``save_related`` method is given the ``HttpRequest``, the parent

tests/admin_views/admin.py

@@ -24,7 +24,7 @@ from .models import (Article, Chapter, Account, Media, Child, Parent, Picture,
     Gadget, Villain, SuperVillain, Plot, PlotDetails, CyclicOne, CyclicTwo,
     WorkHour, Reservation, FoodDelivery, RowLevelChangePermissionModel, Paper,
     CoverLetter, Story, OtherStory, Book, Promo, ChapterXtra1, Pizza, Topping,
-    Album, Question, Answer, ComplexSortedPerson, PrePopulatedPostLargeSlug,
+    Album, Question, Answer, ComplexSortedPerson, PluggableSearchPerson, PrePopulatedPostLargeSlug,
     AdminOrderedField, AdminOrderedModelMethod, AdminOrderedAdminMethod,
     AdminOrderedCallable, Report, Color2, UnorderedObject, MainPrepopulated,
     RelatedPrepopulated, UndeletableObject, UserMessenger, Simple, Choice,
@@ -530,6 +530,20 @@ class ComplexSortedPersonAdmin(admin.ModelAdmin):
     colored_name.admin_order_field = 'name'
 
 
+class PluggableSearchPersonAdmin(admin.ModelAdmin):
+    list_display = ('name', 'age')
+    search_fields = ('name',)
+
+    def get_search_results(self, request, queryset, search_term):
+        queryset, use_distinct = super(PluggableSearchPersonAdmin, self).get_search_results(request, queryset, search_term)
+        try:
+            search_term_as_int = int(search_term)
+            queryset |= self.model.objects.filter(age=search_term_as_int)
+        except:
+            pass
+        return queryset, use_distinct
+
+
 class AlbumAdmin(admin.ModelAdmin):
     list_filter = ['title']
 
@@ -733,6 +747,7 @@ site.register(Question)
 site.register(Answer)
 site.register(PrePopulatedPost, PrePopulatedPostAdmin)
 site.register(ComplexSortedPerson, ComplexSortedPersonAdmin)
+site.register(PluggableSearchPerson, PluggableSearchPersonAdmin)
 site.register(PrePopulatedPostLargeSlug, PrePopulatedPostLargeSlugAdmin)
 site.register(AdminOrderedField, AdminOrderedFieldAdmin)
 site.register(AdminOrderedModelMethod, AdminOrderedModelMethodAdmin)

tests/admin_views/models.py

@@ -591,6 +591,12 @@ class ComplexSortedPerson(models.Model):
     age = models.PositiveIntegerField()
     is_employee = models.NullBooleanField()
 
+
+class PluggableSearchPerson(models.Model):
+    name = models.CharField(max_length=100)
+    age = models.PositiveIntegerField()
+
+
 class PrePopulatedPostLargeSlug(models.Model):
     """
     Regression test for #15938: a large max_length for the slugfield must not

tests/admin_views/tests.py

@@ -46,7 +46,7 @@ from .models import (Article, BarAccount, CustomArticle, EmptyModel, FooAccount,
     DooHickey, FancyDoodad, Whatsit, Category, Post, Plot, FunkyTag, Chapter,
     Book, Promo, WorkHour, Employee, Question, Answer, Inquisition, Actor,
     FoodDelivery, RowLevelChangePermissionModel, Paper, CoverLetter, Story,
-    OtherStory, ComplexSortedPerson, Parent, Child, AdminOrderedField,
+    OtherStory, ComplexSortedPerson, PluggableSearchPerson, Parent, Child, AdminOrderedField,
     AdminOrderedModelMethod, AdminOrderedAdminMethod, AdminOrderedCallable,
     Report, MainPrepopulated, RelatedPrepopulated, UnorderedObject,
     Simple, UndeletableObject, Choice, ShortMessage, Telegram)
@@ -2202,6 +2202,20 @@ class AdminSearchTest(TestCase):
         self.assertContains(response, "\n0 persons\n")
         self.assertNotContains(response, "Guido")
 
+    def test_pluggable_search(self):
+        p1 = PluggableSearchPerson.objects.create(name="Bob", age=10)
+        p2 = PluggableSearchPerson.objects.create(name="Amy", age=20)
+
+        response = self.client.get('/test_admin/admin/admin_views/pluggablesearchperson/?q=Bob')
+        # confirm the search returned one object
+        self.assertContains(response, "\n1 pluggable search person\n")
+        self.assertContains(response, "Bob")
+
+        response = self.client.get('/test_admin/admin/admin_views/pluggablesearchperson/?q=20')
+        # confirm the search returned one object
+        self.assertContains(response, "\n1 pluggable search person\n")
+        self.assertContains(response, "Amy")
+
 
 @override_settings(PASSWORD_HASHERS=('django.contrib.auth.hashers.SHA1PasswordHasher',))
 class AdminInheritedInlinesTest(TestCase):