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Merge pull request #12559 from jkozera/svg-thumbnail-generation

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[TNL-3960] Fix for thumbnail generation code crashing with SVG files
This commit is contained in:
Christina Roberts
2016-06-03 16:36:39 -04:00
parent 4b25766aed d7ca5d94d9
commit efdb84ca83
2 changed files with 94 additions and 25 deletions
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63
common/lib/xmodule/xmodule/contentstore/content.py
View File

@@ -44,13 +44,17 @@ class StaticContent(object):
return self.location.category == 'thumbnail'
@staticmethod
def generate_thumbnail_name(original_name, dimensions=None):
def generate_thumbnail_name(original_name, dimensions=None, extension=None):
"""
- original_name: Name of the asset (typically its location.name)
- dimensions: `None` or a tuple of (width, height) in pixels
- extension: `None` or desired filename extension of the thumbnail
"""
if extension is None:
extension = XASSET_THUMBNAIL_TAIL_NAME
name_root, ext = os.path.splitext(original_name)
if not ext == XASSET_THUMBNAIL_TAIL_NAME:
if not ext == extension:
name_root = name_root + ext.replace(u'.', u'-')
if dimensions:
@@ -59,7 +63,7 @@ class StaticContent(object):
return u"{name_root}{extension}".format(
name_root=name_root,
extension=XASSET_THUMBNAIL_TAIL_NAME,
extension=extension,
)
@staticmethod
@@ -330,9 +334,10 @@ class ContentStore(object):
pixels. It defaults to None.
"""
thumbnail_content = None
is_svg = content.content_type == 'image/svg+xml'
# use a naming convention to associate originals with the thumbnail
thumbnail_name = StaticContent.generate_thumbnail_name(
content.location.name, dimensions=dimensions
content.location.name, dimensions=dimensions, extension='.svg' if is_svg else None
)
thumbnail_file_location = StaticContent.compute_location(
content.location.course_key, thumbnail_name, is_thumbnail=True
@@ -340,28 +345,42 @@ class ContentStore(object):
# if we're uploading an image, then let's generate a thumbnail so that we can
# serve it up when needed without having to rescale on the fly
if content.content_type is not None and content.content_type.split('/')[0] == 'image':
try:
try:
if is_svg:
# for svg simply store the provided svg file, since vector graphics should be good enough
# for downscaling client-side
if tempfile_path is None:
thumbnail_file = StringIO.StringIO(content.data)
else:
with open(tempfile_path) as f:
thumbnail_file = StringIO.StringIO(f.read())
thumbnail_content = StaticContent(thumbnail_file_location, thumbnail_name,
'image/svg+xml', thumbnail_file)
self.save(thumbnail_content)
elif content.content_type is not None and content.content_type.split('/')[0] == 'image':
# use PIL to do the thumbnail generation (http://www.pythonware.com/products/pil/)
# My understanding is that PIL will maintain aspect ratios while restricting
# the max-height/width to be whatever you pass in as 'size'
# @todo: move the thumbnail size to a configuration setting?!?
if tempfile_path is None:
im = Image.open(StringIO.StringIO(content.data))
source = StringIO.StringIO(content.data)
else:
im = Image.open(tempfile_path)
source = tempfile_path
# I've seen some exceptions from the PIL library when trying to save palletted
# PNG files to JPEG. Per the google-universe, they suggest converting to RGB first.
im = im.convert('RGB')
if not dimensions:
dimensions = (128, 128)
im.thumbnail(dimensions, Image.ANTIALIAS)
# We use the context manager here to avoid leaking the inner file descriptor
# of the Image object -- this way it gets closed after we're done with using it.
thumbnail_file = StringIO.StringIO()
im.save(thumbnail_file, 'JPEG')
thumbnail_file.seek(0)
with Image.open(source) as image:
# I've seen some exceptions from the PIL library when trying to save palletted
# PNG files to JPEG. Per the google-universe, they suggest converting to RGB first.
thumbnail_image = image.convert('RGB')
if not dimensions:
dimensions = (128, 128)
thumbnail_image.thumbnail(dimensions, Image.ANTIALIAS)
thumbnail_image.save(thumbnail_file, 'JPEG')
thumbnail_file.seek(0)
# store this thumbnail as any other piece of content
thumbnail_content = StaticContent(thumbnail_file_location, thumbnail_name,
@@ -369,9 +388,11 @@ class ContentStore(object):
self.save(thumbnail_content)
except Exception, e:
# log and continue as thumbnails are generally considered as optional
logging.exception(u"Failed to generate thumbnail for {0}. Exception: {1}".format(content.location, str(e)))
except Exception, exc: # pylint: disable=broad-except
# log and continue as thumbnails are generally considered as optional
logging.exception(
u"Failed to generate thumbnail for {0}. Exception: {1}".format(content.location, str(exc))
)
return thumbnail_content, thumbnail_file_location

56
common/lib/xmodule/xmodule/tests/test_content.py
View File

@@ -3,6 +3,7 @@
import os
import unittest
import ddt
from mock import Mock, patch
from path import Path as path
from xmodule.contentstore.content import StaticContent, StaticContentStream
@@ -58,6 +59,7 @@ class Content(object):
def __init__(self, location, content_type):
self.location = location
self.content_type = content_type
self.data = None
class FakeGridFsItem(object):
@@ -84,6 +86,17 @@ class FakeGridFsItem(object):
return chunk
class MockImage(Mock):
"""
This class pretends to be PIL.Image for purposes of thumbnails testing.
"""
def __enter__(self):
return self
def __exit__(self, *args):
self.close()
@ddt.ddt
class ContentTest(unittest.TestCase):
def test_thumbnail_none(self):
@@ -103,11 +116,43 @@ class ContentTest(unittest.TestCase):
)
@ddt.unpack
def test_generate_thumbnail_image(self, original_filename, thumbnail_filename):
contentStore = ContentStore()
content_store = ContentStore()
content = Content(AssetLocation(u'mitX', u'800', u'ignore_run', u'asset', original_filename), None)
(thumbnail_content, thumbnail_file_location) = contentStore.generate_thumbnail(content)
(thumbnail_content, thumbnail_file_location) = content_store.generate_thumbnail(content)
self.assertIsNone(thumbnail_content)
self.assertEqual(AssetLocation(u'mitX', u'800', u'ignore_run', u'thumbnail', thumbnail_filename), thumbnail_file_location)
self.assertEqual(
AssetLocation(u'mitX', u'800', u'ignore_run', u'thumbnail', thumbnail_filename),
thumbnail_file_location
)
@patch('xmodule.contentstore.content.Image')
def test_image_is_closed_when_generating_thumbnail(self, image_class_mock):
# We used to keep the Image's file descriptor open when generating a thumbnail.
# It should be closed after being used.
mock_image = MockImage()
image_class_mock.open.return_value = mock_image
content_store = ContentStore()
content = Content(AssetLocation(u'mitX', u'800', u'ignore_run', u'asset', "monsters.jpg"), "image/jpeg")
content.data = 'mock data'
content_store.generate_thumbnail(content)
self.assertTrue(image_class_mock.open.called, "Image.open not called")
self.assertTrue(mock_image.close.called, "mock_image.close not called")
def test_store_svg_as_thumbnail(self):
# We had a bug that caused generate_thumbnail to attempt to pass SVG to PIL to generate a thumbnail.
# SVG files should be stored in original form for thumbnail purposes.
content_store = ContentStore()
content_store.save = Mock()
thumbnail_filename = u'test.svg'
content = Content(AssetLocation(u'mitX', u'800', u'ignore_run', u'asset', u'test.svg'), 'image/svg+xml')
content.data = 'mock svg file'
(thumbnail_content, thumbnail_file_location) = content_store.generate_thumbnail(content)
self.assertEqual(thumbnail_content.data.read(), b'mock svg file')
self.assertEqual(
AssetLocation(u'mitX', u'800', u'ignore_run', u'thumbnail', thumbnail_filename),
thumbnail_file_location
)
def test_compute_location(self):
# We had a bug that __ got converted into a single _. Make sure that substitution of INVALID_CHARS (like space)
@@ -115,7 +160,10 @@ class ContentTest(unittest.TestCase):
asset_location = StaticContent.compute_location(
SlashSeparatedCourseKey('mitX', '400', 'ignore'), 'subs__1eo_jXvZnE .srt.sjson'
)
self.assertEqual(AssetLocation(u'mitX', u'400', u'ignore', u'asset', u'subs__1eo_jXvZnE_.srt.sjson', None), asset_location)
self.assertEqual(
AssetLocation(u'mitX', u'400', u'ignore', u'asset', u'subs__1eo_jXvZnE_.srt.sjson', None),
asset_location
)
def test_get_location_from_path(self):
asset_location = StaticContent.get_location_from_path(u'/c4x/a/b/asset/images_course_image.jpg')