Added ImageField.rerender()

CHANGELOG.rst

@@ -9,6 +9,7 @@ Current
   Resized images are now compressed.
   Default image can also be optimized on upload with ``FS_IMAGES_OPTIMIZE = True``
   or by specifying `optimize=True` as field parameter.
+- ``ImageField`` has now the ability to rerender images with the ``rerender()`` method.
 
 0.2.1 (2017-01-17)
 ------------------

docs/mongoengine.rst

@@ -54,6 +54,7 @@ On instance:
  - the `best_url(size)` method match a thumbnail URL given a size
  - the `thumbnail(size)` method get a thumbnail filename given a registered size
  - the `save` method accept an optionnal `bbox` kwarg for to crop the thumbnails
+ - the `rerender` method allows to force a new image rendering (taking in account new parameters)
  - the instance is callable as shortcut for `best_url()`
 
 .. code-block:: python

flask_fs/mongo.py

@@ -96,7 +96,7 @@ def to_mongo(self):
             data['bbox'] = self.bbox
         return data
 
-    def save(self, file_or_wfs, filename=None, bbox=None):
+    def save(self, file_or_wfs, filename=None, bbox=None, overwrite=None):
         '''Save a Werkzeug FileStorage object'''
         self._mark_as_changed()
         override = filename is not None
@@ -111,6 +111,7 @@ def save(self, file_or_wfs, filename=None, bbox=None):
 
         ext = extension(filename)
         prefix = self.upload_to(self._instance) if callable(self.upload_to) else self.upload_to
+        kwargs = {'prefix': prefix, 'overwrite': overwrite}
 
         if self.optimize is not None:
             should_optimize = self.optimize
@@ -127,17 +128,17 @@ def name(size=None, new_ext=None):
             resized = resize(file_or_wfs, self.max_size)
             file_or_wfs.seek(0)
             if resized:
-                self.original = self.fs.save(file_or_wfs, name('original'), prefix=prefix)
-                self.filename = self.fs.save(resized, name(new_ext='png'), prefix=prefix)
+                self.original = self.fs.save(file_or_wfs, name('original'), **kwargs)
+                self.filename = self.fs.save(resized, name(new_ext='png'), **kwargs)
             else:
-                self.filename = self.fs.save(file_or_wfs, name(), prefix=prefix)
+                self.filename = self.fs.save(file_or_wfs, name(), **kwargs)
         elif should_optimize:
             optimized = optimize(file_or_wfs)
             file_or_wfs.seek(0)
-            self.original = self.fs.save(file_or_wfs, name('original'), prefix=prefix)
-            self.filename = self.fs.save(optimized, name(new_ext='png'), prefix=prefix)
+            self.original = self.fs.save(file_or_wfs, name('original'), **kwargs)
+            self.filename = self.fs.save(optimized, name(new_ext='png'), **kwargs)
         else:
-            self.filename = self.fs.save(file_or_wfs, name(), prefix=prefix)
+            self.filename = self.fs.save(file_or_wfs, name(), **kwargs)
 
         if self.thumbnail_sizes:
             self.bbox = bbox
@@ -146,7 +147,7 @@ def name(size=None, new_ext=None):
                 thumbnail = make_thumbnail(file_or_wfs, size, self.bbox)
                 self.thumbnails[str(size)] = self.fs.save(FileStorage(thumbnail),
                                                           name(size, 'png'),
-                                                          prefix=prefix)
+                                                          **kwargs)
         return self.filename
 
     @property
@@ -186,6 +187,15 @@ def best_url(self, size=None, external=False):
         filename = self.thumbnail(best_size)
         return self.fs.url(filename, external=external) if filename else None
 
+    def rerender(self):
+        '''
+        Rerender all derived images from the original.
+        If optmization settings or expected sizes changed,
+        they will be used for the new rendering.
+        '''
+        with self.fs.open(self.original, 'rb') as img:
+            self.save(img, filename=self.filename, bbox=self.bbox, overwrite=True)
+
     __call__ = best_url
 
 

tests/test_mongoengine.py

@@ -750,3 +750,48 @@ class Tester(db.Document):
         tester.save()
         tester = Tester.objects.get(id=tester.id)
         assert tester.image.filename == expected_filename
+
+    def test_rerender(self, app, storage, resource, image):
+        class Tester(db.Document):
+            image = ImageField(fs=storage, optimize=True)
+
+        filename = 'flask.png'
+        filename_original = 'flask-original.png'
+
+        storage.write(filename, image)
+
+        tester = Tester()
+        tester.image.filename = filename
+        assert tester.to_mongo() == {
+            'image': {
+                'filename': filename,
+            }
+        }
+
+        tester.image.rerender()
+        tester.save().reload()
+
+        assert tester.image
+        assert str(tester.image) == tester.image.url
+        assert tester.image.filename == filename
+        assert tester.image.original == filename_original
+        assert filename in storage
+        assert tester.to_mongo() == {
+            '_id': tester.pk,
+            'image': {
+                'filename': filename,
+                'original': filename_original,
+            }
+        }
+
+        path_original = storage.path(filename_original)
+        path_optimized = storage.path(filename)
+
+        with open(path_original, 'rb') as f_orig:
+            with open(path_optimized, 'rb') as f_optimized:
+                source = Image.open(image)
+                original = Image.open(f_orig)
+                optimized = Image.open(f_optimized)
+                assert original.size == source.size
+                assert optimized.size == source.size
+        assert os.stat(path_optimized).st_size < os.stat(path_original).st_size