Ticket #15648: namedtuples.patch

django/db/models/manager.py

@@ -176 +176 @@
     def values_list(self, *args, **kwargs):
         return self.get_query_set().values_list(*args, **kwargs)
 
+    def namedtuples(self, *args, **kwargs):
+        return self.get_query_set().namedtuples(*args, **kwargs)
+
     def update(self, *args, **kwargs):
         return self.get_query_set().update(*args, **kwargs)
 

django/db/models/query.py

@@ -12 +12 @@
     deferred_class_factory, InvalidQuery)
 from django.db.models.deletion import Collector
 from django.db.models import signals, sql
+from django.utils.datastructures import namedtuple
 
 # Used to control how many objects are worked with at once in some cases (e.g.
 # when deleting objects).
@@ -513 +514 @@
         return self._clone(klass=ValuesListQuerySet, setup=True, flat=flat,
                 _fields=fields)
 
+    def namedtuples(self, *fields, **kwargs):
+        return self._clone(klass=NamedTuplesQuerySet, setup=True, _fields=fields)
+
     def dates(self, field_name, kind, order='ASC'):
         """
         Returns a list of datetime objects representing all available dates for
@@ -999 +1003 @@
         return clone
 
 
+class NamedTuplesQuerySet(ValuesQuerySet):
+    def iterator(self):
+        # get field names 
+        extra_names = self.query.extra_select.keys()
+        field_names = self.field_names
+        aggregate_names = self.query.aggregate_select.keys()
+        names = extra_names + field_names + aggregate_names
+       
+        # create named tuple class
+        tuple_cls = namedtuple('%sTuple' % self.model.__name__, names)
+
+        # wrap every string with our named tuple
+        for row in self.query.get_compiler(self.db).results_iter():
+            yield tuple_cls._make(row)
+
+
 class DateQuerySet(QuerySet):
     def iterator(self):
         return self.query.get_compiler(self.db).results_iter()

django/utils/datastructures.py

@@ -1 +1 @@
 import copy
 from types import GeneratorType
+try:
+    from collections import namedtuple
+except ImportError:
+    namedtuple = None
 
 class MergeDict(object):
     """
@@ -503 +507 @@
         if use_func:
             return self.func(value)
         return value
+
+if namedtuple is None:
+    ## {{{ http://code.activestate.com/recipes/500261/ (r15)
+    from operator import itemgetter as _itemgetter
+    from keyword import iskeyword as _iskeyword
+    import sys as _sys
+
+    def namedtuple(typename, field_names, verbose=False, rename=False):
+        """Returns a new subclass of tuple with named fields.
+
+        >>> Point = namedtuple('Point', 'x y')
+        >>> Point.__doc__                   # docstring for the new class
+        'Point(x, y)'
+        >>> p = Point(11, y=22)             # instantiate with positional args or keywords
+        >>> p[0] + p[1]                     # indexable like a plain tuple
+        33
+        >>> x, y = p                        # unpack like a regular tuple
+        >>> x, y
+        (11, 22)
+        >>> p.x + p.y                       # fields also accessable by name
+        33
+        >>> d = p._asdict()                 # convert to a dictionary
+        >>> d['x']
+        11
+        >>> Point(**d)                      # convert from a dictionary
+        Point(x=11, y=22)
+        >>> p._replace(x=100)               # _replace() is like str.replace() but targets named fields
+        Point(x=100, y=22)
+
+        """
+
+        # Parse and validate the field names.  Validation serves two purposes,
+        # generating informative error messages and preventing template injection attacks.
+        if isinstance(field_names, basestring):
+            field_names = field_names.replace(',', ' ').split() # names separated by whitespace and/or commas
+        field_names = tuple(map(str, field_names))
+        if rename:
+            names = list(field_names)
+            seen = set()
+            for i, name in enumerate(names):
+                if (not min(c.isalnum() or c=='_' for c in name) or _iskeyword(name)
+                    or not name or name[0].isdigit() or name.startswith('_')
+                    or name in seen):
+                        names[i] = '_%d' % i
+                seen.add(name)
+            field_names = tuple(names)
+        for name in (typename,) + field_names:
+            if not min(c.isalnum() or c=='_' for c in name):
+                raise ValueError('Type names and field names can only contain alphanumeric characters and underscores: %r' % name)
+            if _iskeyword(name):
+                raise ValueError('Type names and field names cannot be a keyword: %r' % name)
+            if name[0].isdigit():
+                raise ValueError('Type names and field names cannot start with a number: %r' % name)
+        seen_names = set()
+        for name in field_names:
+            if name.startswith('_') and not rename:
+                raise ValueError('Field names cannot start with an underscore: %r' % name)
+            if name in seen_names:
+                raise ValueError('Encountered duplicate field name: %r' % name)
+            seen_names.add(name)
+
+        # Create and fill-in the class template
+        numfields = len(field_names)
+        argtxt = repr(field_names).replace("'", "")[1:-1]   # tuple repr without parens or quotes
+        reprtxt = ', '.join('%s=%%r' % name for name in field_names)
+        template = '''class %(typename)s(tuple):
+            '%(typename)s(%(argtxt)s)' \n
+            __slots__ = () \n
+            _fields = %(field_names)r \n
+            def __new__(_cls, %(argtxt)s):
+                return _tuple.__new__(_cls, (%(argtxt)s)) \n
+            @classmethod
+            def _make(cls, iterable, new=tuple.__new__, len=len):
+                'Make a new %(typename)s object from a sequence or iterable'
+                result = new(cls, iterable)
+                if len(result) != %(numfields)d:
+                    raise TypeError('Expected %(numfields)d arguments, got %%d' %% len(result))
+                return result \n
+            def __repr__(self):
+                return '%(typename)s(%(reprtxt)s)' %% self \n
+            def _asdict(self):
+                'Return a new dict which maps field names to their values'
+                return dict(zip(self._fields, self)) \n
+            def _replace(_self, **kwds):
+                'Return a new %(typename)s object replacing specified fields with new values'
+                result = _self._make(map(kwds.pop, %(field_names)r, _self))
+                if kwds:
+                    raise ValueError('Got unexpected field names: %%r' %% kwds.keys())
+                return result \n
+            def __getnewargs__(self):
+                return tuple(self) \n\n''' % locals()
+        for i, name in enumerate(field_names):
+            template += '        %s = _property(_itemgetter(%d))\n' % (name, i)
+        if verbose:
+            print template
+
+        # Execute the template string in a temporary namespace
+        namespace = dict(_itemgetter=_itemgetter, __name__='namedtuple_%s' % typename,
+                         _property=property, _tuple=tuple)
+        try:
+            exec template in namespace
+        except SyntaxError, e:
+            raise SyntaxError(e.message + ':\n' + template)
+        result = namespace[typename]
+
+        # For pickling to work, the __module__ variable needs to be set to the frame
+        # where the named tuple is created.  Bypass this step in enviroments where
+        # sys._getframe is not defined (Jython for example) or sys._getframe is not
+        # defined for arguments greater than 0 (IronPython).
+        try:
+            result.__module__ = _sys._getframe(1).f_globals.get('__name__', '__main__')
+        except (AttributeError, ValueError):
+            pass
+
+        return result
+    ## end of http://code.activestate.com/recipes/500261/ }}}

tests/modeltests/lookup/tests.py

@@ -2 +2 @@
 from operator import attrgetter
 from django.core.exceptions import FieldError
 from django.db import connection
+from django.utils.datastructures import namedtuple
 from django.test import TestCase, skipUnlessDBFeature
 from models import Author, Article, Tag
 
@@ -318 +319 @@
             ], transform=identity)
         self.assertRaises(TypeError, Article.objects.values_list, 'id', 'headline', flat=True)
 
+    def test_namedtuples(self):
+        """
+           namedtuples() is similar to values() and values_list(), except that
+           the results are returned as a Named Tuple, that allows queryset to
+           behave both like list and dictionary.
+        """
+        identity = lambda x: x
+
+        def assert_namedtuple_equals(queryset, fields, values):
+            cls_name = queryset.model.__name__
+            tuple_cls = namedtuple(cls_name + 'Tuple', fields)
+            queryset = queryset.namedtuples(*fields)
+            values = [tuple_cls(*value) for value in values]
+            self.assertQuerysetEqual(queryset, values, transform=identity)
+
+        assert_namedtuple_equals(
+            Article.objects.all(),
+            ['headline'],
+            [
+                (u'Article 5',),
+                (u'Article 6',),
+                (u'Article 4',),
+                (u'Article 2',),
+                (u'Article 3',),
+                (u'Article 7',),
+                (u'Article 1',),
+            ]
+        )
+
+        assert_namedtuple_equals(
+            Author.objects.order_by('name', 'article__headline', 'article__tag__name'),
+            ['name', 'article__headline', 'article__tag__name'],
+            [
+                (self.au1.name, self.a1.headline, self.t1.name),
+                (self.au1.name, self.a2.headline, self.t1.name),
+                (self.au1.name, self.a3.headline, self.t1.name),
+                (self.au1.name, self.a3.headline, self.t2.name),
+                (self.au1.name, self.a4.headline, self.t2.name),
+                (self.au2.name, self.a5.headline, self.t2.name),
+                (self.au2.name, self.a5.headline, self.t3.name),
+                (self.au2.name, self.a6.headline, self.t3.name),
+                (self.au2.name, self.a7.headline, self.t3.name),
+            ]
+        )
+
+        article = Article.objects.namedtuples('headline')[0]
+        self.assertEqual(article[0], article.headline)
+
     def test_get_next_previous_by(self):
         # Every DateField and DateTimeField creates get_next_by_FOO() and
         # get_previous_by_FOO() methods. In the case of identical date values,