Merge 6938103 into 6192357

AUTHORS.rst

@@ -1,6 +1,7 @@
 Alejandro Varas <alej0varas@gmail.com>
 Alex Orange <crazycasta@gmail.com>
 Andy Freeland <andy@andyfreeland.net>
+Björn Andersson <ba@sanitarium.se>
 Carl Meyer <carl@dirtcircle.com>
 Curtis Maloney <curtis@tinbrain.net>
 Den Lesnov

CHANGES.rst

@@ -4,6 +4,8 @@ CHANGES
 master (unreleased)
 -------------------
 
+* Add ``random_function`` to models, a factory used with ``FileField``.
+
 
 2.0.3 (2014.03.19)
 -------------------
@@ -240,4 +242,3 @@ master (unreleased)
 -----
 
 * Added ``QueryManager``
-

docs/models.rst

@@ -47,3 +47,37 @@ returns objects with that status only:
 
     # this query will only return published articles:
     Article.published.all()
+
+
+random_filename
+---------------
+
+A factory for random filenames to be used with the ``FileField``'s
+``upload_to`` parameter.
+
+The extension from the uploaded file is taken and used for the newly
+generated filename.
+
+``random_filename`` can take two arguments:
+
+``directory``:
+    The directory the uploaded file should be placed in. Defaults is blank.
+``random_function``:
+    A function that takes one argument, filename, and returns a random/unique
+    representation of that filename.
+    Default is ``uuid.uuid4``.
+
+
+An example filename: `assets/270ef3e7-2105-4986-a8fb-6ef715273211.png`.
+
+
+.. code-block:: python
+
+   from django.db import models
+
+   from model_utils.models import random_filename
+
+
+   class Asset(models.Model):
+       name = models.CharField(max_length=50)
+       file = models.FileField(upload_to=random_filename('assets/'))

model_utils/models.py

@@ -1,4 +1,5 @@
 from __future__ import unicode_literals
+from os import path
 
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
@@ -92,3 +93,32 @@ def add_timeframed_query_manager(sender, **kwargs):
 
 models.signals.class_prepared.connect(add_status_query_managers)
 models.signals.class_prepared.connect(add_timeframed_query_manager)
+
+
+def random_filename(directory='', random_function=None):
+    """Returns a function that generates random filenames for file
+    uploads. The new filename keeps the extension from the original
+    upload.
+
+    The default ``random_function`` is uuid.uuid4 which also will
+    ensure that the filename is reasonably unique.
+
+    Args:
+      directory: The directory the file should be uploaded to. Default: ''
+      random_function: A function that takes a filename as an argument
+        to generate a unique filename. The file extension will be added
+        to the value returned from this function. Default: uuid.uuid4
+
+    Returns: a function that can be used with Django's ``FileField``.
+
+    """
+    if not random_function:
+        from uuid import uuid4
+        random_function = lambda _: uuid4()
+
+    def random_name(instance, filename):
+        return path.join(directory,
+                         '{0}{1}'.format(random_function(filename),
+                                         path.splitext(filename)[1]))
+
+    return random_name

model_utils/tests/tests.py

@@ -17,7 +17,8 @@
 from model_utils import Choices, FieldTracker
 from model_utils.fields import get_excerpt, MonitorField, StatusField
 from model_utils.managers import QueryManager
-from model_utils.models import StatusModel, TimeFramedModel
+from model_utils.models import (StatusModel, TimeFramedModel,
+                                random_filename)
 from model_utils.tests.models import (
     InheritanceManagerTestRelated, InheritanceManagerTestGrandChild1,
     InheritanceManagerTestGrandChild1_2,
@@ -1871,3 +1872,48 @@ def test_child_fields_not_tracked(self):
         self.name2 = 'test'
         self.assertEqual(self.tracker.previous('name2'), None)
         self.assertTrue(self.tracker.has_changed('name2'))
+
+
+class RandomFilenameFactoryTest(TestCase):
+    def setUp(self):
+        self.random = lambda _: 'HELLO-IR-UUID'
+        self.random_name = random_filename(
+            'test_dir',
+            self.random
+        )
+
+    def test_upload_directory_should_be_configurable(self):
+        random_name = random_filename('new-directory/', self.random)
+        self.assertEqual(random_name(None, 'hello.jpeg'),
+                         'new-directory/HELLO-IR-UUID.jpeg')
+
+    def test_should_return_a_random_name(self):
+        self.assertEqual(self.random_name(None, 'hello.jpeg'),
+                         'test_dir/HELLO-IR-UUID.jpeg')
+
+    def test_should_use_the_current_extension_from_passed_in_filename(self):
+        self.assertEqual(self.random_name(None, 'foo.bar'),
+                         'test_dir/HELLO-IR-UUID.bar')
+
+    def test_should_work_with_no_file_extension(self):
+        self.assertEqual(self.random_name(None, 'hello'),
+                         'test_dir/HELLO-IR-UUID')
+
+    def test_allow_the_random_function_to_be_replaced(self):
+        random_name = random_filename('test_dir', lambda _: 'UNIQUE')
+        self.assertEqual(random_name(None, 'hello.jpeg'),
+                         'test_dir/UNIQUE.jpeg')
+
+    def test_random_function_takes_the_filename_as_an_argument(self):
+        random_name = random_filename(
+            'test_dir',
+            lambda f: 'UNIQUE-{0}'.format(f)
+        )
+        self.assertEqual(random_name(None, 'hello.jpeg'),
+                         'test_dir/UNIQUE-hello.jpeg.jpeg')
+
+    def test_default_random_function_accepts_parameter(self):
+        random_name = random_filename('test_dir')
+        filename = random_name(None, 'hello.jpeg')
+        self.assertTrue(filename.startswith('test_dir/'))
+        self.assertTrue(filename.endswith('.jpeg'))