Do not error when thumbnailing invalid files (#8236)

If a file cannot be thumbnailed for some reason (e.g. the file is empty), then
catch the exception and convert it to a reasonable error message for the client.
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Patrick Cloke 2020-09-09 12:59:41 -04:00 committed by GitHub
parent 2ea1c68249
commit b312769c0e
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5 changed files with 107 additions and 23 deletions

1
changelog.d/8236.bugfix Normal file
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@ -0,0 +1 @@
Fix a longstanding bug where files that could not be thumbnailed would result in an Internal Server Error.

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@ -53,7 +53,7 @@ from .media_storage import MediaStorage
from .preview_url_resource import PreviewUrlResource
from .storage_provider import StorageProviderWrapper
from .thumbnail_resource import ThumbnailResource
from .thumbnailer import Thumbnailer
from .thumbnailer import Thumbnailer, ThumbnailError
from .upload_resource import UploadResource
logger = logging.getLogger(__name__)
@ -460,13 +460,30 @@ class MediaRepository:
return t_byte_source
async def generate_local_exact_thumbnail(
self, media_id, t_width, t_height, t_method, t_type, url_cache
):
self,
media_id: str,
t_width: int,
t_height: int,
t_method: str,
t_type: str,
url_cache: str,
) -> Optional[str]:
input_path = await self.media_storage.ensure_media_is_in_local_cache(
FileInfo(None, media_id, url_cache=url_cache)
)
thumbnailer = Thumbnailer(input_path)
try:
thumbnailer = Thumbnailer(input_path)
except ThumbnailError as e:
logger.warning(
"Unable to generate a thumbnail for local media %s using a method of %s and type of %s: %s",
media_id,
t_method,
t_type,
e,
)
return None
t_byte_source = await defer_to_thread(
self.hs.get_reactor(),
self._generate_thumbnail,
@ -506,14 +523,36 @@ class MediaRepository:
return output_path
# Could not generate thumbnail.
return None
async def generate_remote_exact_thumbnail(
self, server_name, file_id, media_id, t_width, t_height, t_method, t_type
):
self,
server_name: str,
file_id: str,
media_id: str,
t_width: int,
t_height: int,
t_method: str,
t_type: str,
) -> Optional[str]:
input_path = await self.media_storage.ensure_media_is_in_local_cache(
FileInfo(server_name, file_id, url_cache=False)
)
thumbnailer = Thumbnailer(input_path)
try:
thumbnailer = Thumbnailer(input_path)
except ThumbnailError as e:
logger.warning(
"Unable to generate a thumbnail for remote media %s from %s using a method of %s and type of %s: %s",
media_id,
server_name,
t_method,
t_type,
e,
)
return None
t_byte_source = await defer_to_thread(
self.hs.get_reactor(),
self._generate_thumbnail,
@ -559,6 +598,9 @@ class MediaRepository:
return output_path
# Could not generate thumbnail.
return None
async def _generate_thumbnails(
self,
server_name: Optional[str],
@ -590,7 +632,18 @@ class MediaRepository:
FileInfo(server_name, file_id, url_cache=url_cache)
)
thumbnailer = Thumbnailer(input_path)
try:
thumbnailer = Thumbnailer(input_path)
except ThumbnailError as e:
logger.warning(
"Unable to generate thumbnails for remote media %s from %s using a method of %s and type of %s: %s",
media_id,
server_name,
media_type,
e,
)
return None
m_width = thumbnailer.width
m_height = thumbnailer.height

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@ -16,6 +16,7 @@
import logging
from synapse.api.errors import SynapseError
from synapse.http.server import DirectServeJsonResource, set_cors_headers
from synapse.http.servlet import parse_integer, parse_string
@ -173,7 +174,7 @@ class ThumbnailResource(DirectServeJsonResource):
await respond_with_file(request, desired_type, file_path)
else:
logger.warning("Failed to generate thumbnail")
respond_404(request)
raise SynapseError(400, "Failed to generate thumbnail.")
async def _select_or_generate_remote_thumbnail(
self,
@ -235,7 +236,7 @@ class ThumbnailResource(DirectServeJsonResource):
await respond_with_file(request, desired_type, file_path)
else:
logger.warning("Failed to generate thumbnail")
respond_404(request)
raise SynapseError(400, "Failed to generate thumbnail.")
async def _respond_remote_thumbnail(
self, request, server_name, media_id, width, height, method, m_type

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@ -15,7 +15,7 @@
import logging
from io import BytesIO
from PIL import Image as Image
from PIL import Image
logger = logging.getLogger(__name__)
@ -31,12 +31,22 @@ EXIF_TRANSPOSE_MAPPINGS = {
}
class ThumbnailError(Exception):
"""An error occurred generating a thumbnail."""
class Thumbnailer:
FORMATS = {"image/jpeg": "JPEG", "image/png": "PNG"}
def __init__(self, input_path):
self.image = Image.open(input_path)
try:
self.image = Image.open(input_path)
except OSError as e:
# If an error occurs opening the image, a thumbnail won't be able to
# be generated.
raise ThumbnailError from e
self.width, self.height = self.image.size
self.transpose_method = None
try:

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@ -120,12 +120,13 @@ class _TestImage:
extension = attr.ib(type=bytes)
expected_cropped = attr.ib(type=Optional[bytes])
expected_scaled = attr.ib(type=Optional[bytes])
expected_found = attr.ib(default=True, type=bool)
@parameterized_class(
("test_image",),
[
# smol png
# smoll png
(
_TestImage(
unhexlify(
@ -161,6 +162,8 @@ class _TestImage:
None,
),
),
# an empty file
(_TestImage(b"", b"image/gif", b".gif", None, None, False,),),
],
)
class MediaRepoTests(unittest.HomeserverTestCase):
@ -303,12 +306,16 @@ class MediaRepoTests(unittest.HomeserverTestCase):
self.assertEqual(headers.getRawHeaders(b"Content-Disposition"), None)
def test_thumbnail_crop(self):
self._test_thumbnail("crop", self.test_image.expected_cropped)
self._test_thumbnail(
"crop", self.test_image.expected_cropped, self.test_image.expected_found
)
def test_thumbnail_scale(self):
self._test_thumbnail("scale", self.test_image.expected_scaled)
self._test_thumbnail(
"scale", self.test_image.expected_scaled, self.test_image.expected_found
)
def _test_thumbnail(self, method, expected_body):
def _test_thumbnail(self, method, expected_body, expected_found):
params = "?width=32&height=32&method=" + method
request, channel = self.make_request(
"GET", self.media_id + params, shorthand=False
@ -325,11 +332,23 @@ class MediaRepoTests(unittest.HomeserverTestCase):
)
self.pump()
self.assertEqual(channel.code, 200)
if expected_body is not None:
self.assertEqual(
channel.result["body"], expected_body, channel.result["body"]
)
if expected_found:
self.assertEqual(channel.code, 200)
if expected_body is not None:
self.assertEqual(
channel.result["body"], expected_body, channel.result["body"]
)
else:
# ensure that the result is at least some valid image
Image.open(BytesIO(channel.result["body"]))
else:
# ensure that the result is at least some valid image
Image.open(BytesIO(channel.result["body"]))
# A 404 with a JSON body.
self.assertEqual(channel.code, 404)
self.assertEqual(
channel.json_body,
{
"errcode": "M_NOT_FOUND",
"error": "Not found [b'example.com', b'12345?width=32&height=32&method=%s']"
% method,
},
)