Support rendering some media downloads as inline (#15988)

Use an `inline` Content-Disposition header when the media is
"safe" to display inline (some known text, image, video, audio
formats).
This commit is contained in:
Will Hunt 2023-09-29 12:19:38 +01:00 committed by GitHub
parent fb664cf159
commit 79eb6c0cdc
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4 changed files with 106 additions and 6 deletions

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@ -0,0 +1 @@
Render plain, CSS, CSV, JSON and common image formats media content in the browser (inline) when requested through the /download endpoint.

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@ -50,6 +50,39 @@ TEXT_CONTENT_TYPES = [
"text/xml",
]
# A list of all content types that are "safe" to be rendered inline in a browser.
INLINE_CONTENT_TYPES = [
"text/css",
"text/plain",
"text/csv",
"application/json",
"application/ld+json",
# We allow some media files deemed as safe, which comes from the matrix-react-sdk.
# https://github.com/matrix-org/matrix-react-sdk/blob/a70fcfd0bcf7f8c85986da18001ea11597989a7c/src/utils/blobs.ts#L51
# SVGs are *intentionally* omitted.
"image/jpeg",
"image/gif",
"image/png",
"image/apng",
"image/webp",
"image/avif",
"video/mp4",
"video/webm",
"video/ogg",
"video/quicktime",
"audio/mp4",
"audio/webm",
"audio/aac",
"audio/mpeg",
"audio/ogg",
"audio/wave",
"audio/wav",
"audio/x-wav",
"audio/x-pn-wav",
"audio/flac",
"audio/x-flac",
]
def parse_media_id(request: Request) -> Tuple[str, str, Optional[str]]:
"""Parses the server name, media ID and optional file name from the request URI
@ -153,8 +186,13 @@ def add_file_headers(
request.setHeader(b"Content-Type", content_type.encode("UTF-8"))
# Use a Content-Disposition of attachment to force download of media.
disposition = "attachment"
# A strict subset of content types is allowed to be inlined so that they may
# be viewed directly in a browser. Other file types are forced to be downloads.
if media_type.lower() in INLINE_CONTENT_TYPES:
disposition = "inline"
else:
disposition = "attachment"
if upload_name:
# RFC6266 section 4.1 [1] defines both `filename` and `filename*`.
#

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@ -12,7 +12,9 @@
# See the License for the specific language governing permissions and
# limitations under the License.
from synapse.media._base import get_filename_from_headers
from unittest.mock import Mock
from synapse.media._base import add_file_headers, get_filename_from_headers
from tests import unittest
@ -36,3 +38,28 @@ class GetFileNameFromHeadersTests(unittest.TestCase):
expected,
f"expected output for {hdr!r} to be {expected} but was {res}",
)
class AddFileHeadersTests(unittest.TestCase):
TEST_CASES = {
"text/plain": b"inline; filename=file.name",
"text/csv": b"inline; filename=file.name",
"image/png": b"inline; filename=file.name",
"text/html": b"attachment; filename=file.name",
"any/thing": b"attachment; filename=file.name",
}
def test_content_disposition(self) -> None:
for media_type, expected in self.TEST_CASES.items():
request = Mock()
add_file_headers(request, media_type, 0, "file.name")
request.setHeader.assert_any_call(b"Content-Disposition", expected)
def test_no_filename(self) -> None:
request = Mock()
add_file_headers(request, "text/plain", 0, None)
request.setHeader.assert_any_call(b"Content-Disposition", b"inline")
request.reset_mock()
add_file_headers(request, "text/html", 0, None)
request.setHeader.assert_any_call(b"Content-Disposition", b"attachment")

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@ -129,6 +129,8 @@ class _TestImage:
a 404/400 is expected.
unable_to_thumbnail: True if we expect the thumbnailing to fail (400), or
False if the thumbnailing should succeed or a normal 404 is expected.
is_inline: True if we expect the file to be served using an inline
Content-Disposition or False if we expect an attachment.
"""
data: bytes
@ -138,6 +140,7 @@ class _TestImage:
expected_scaled: Optional[bytes] = None
expected_found: bool = True
unable_to_thumbnail: bool = False
is_inline: bool = True
@parameterized_class(
@ -198,6 +201,25 @@ class _TestImage:
unable_to_thumbnail=True,
),
),
# An SVG.
(
_TestImage(
b"""<?xml version="1.0"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"
"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg xmlns="http://www.w3.org/2000/svg"
width="400" height="400">
<circle cx="100" cy="100" r="50" stroke="black"
stroke-width="5" fill="red" />
</svg>""",
b"image/svg",
b".svg",
expected_found=False,
unable_to_thumbnail=True,
is_inline=False,
),
),
],
)
class MediaRepoTests(unittest.HomeserverTestCase):
@ -339,7 +361,11 @@ class MediaRepoTests(unittest.HomeserverTestCase):
)
self.assertEqual(
headers.getRawHeaders(b"Content-Disposition"),
[b"attachment; filename=out" + self.test_image.extension],
[
(b"inline" if self.test_image.is_inline else b"attachment")
+ b"; filename=out"
+ self.test_image.extension
],
)
def test_disposition_filenamestar_utf8escaped(self) -> None:
@ -359,7 +385,12 @@ class MediaRepoTests(unittest.HomeserverTestCase):
)
self.assertEqual(
headers.getRawHeaders(b"Content-Disposition"),
[b"attachment; filename*=utf-8''" + filename + self.test_image.extension],
[
(b"inline" if self.test_image.is_inline else b"attachment")
+ b"; filename*=utf-8''"
+ filename
+ self.test_image.extension
],
)
def test_disposition_none(self) -> None:
@ -373,7 +404,10 @@ class MediaRepoTests(unittest.HomeserverTestCase):
self.assertEqual(
headers.getRawHeaders(b"Content-Type"), [self.test_image.content_type]
)
self.assertEqual(headers.getRawHeaders(b"Content-Disposition"), [b"attachment"])
self.assertEqual(
headers.getRawHeaders(b"Content-Disposition"),
[b"inline" if self.test_image.is_inline else b"attachment"],
)
def test_thumbnail_crop(self) -> None:
"""Test that a cropped remote thumbnail is available."""