Request & follow redirects for /media/v3/download (#16701)

Implement MSC3860 to follow redirects for federated media downloads.

Note that the Client-Server API doesn't support this (yet) since the media
repository in Synapse doesn't have a way of supporting redirects.
This commit is contained in:
Patrick Cloke 2023-11-29 14:03:42 -05:00 committed by GitHub
parent a14678492e
commit d6c3b7584f
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7 changed files with 211 additions and 37 deletions

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@ -0,0 +1 @@
Follow redirects when downloading media over federation (per [MSC3860](https://github.com/matrix-org/matrix-spec-proposals/pull/3860)).

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@ -21,6 +21,7 @@ from typing import (
TYPE_CHECKING,
AbstractSet,
Awaitable,
BinaryIO,
Callable,
Collection,
Container,
@ -1862,6 +1863,43 @@ class FederationClient(FederationBase):
return filtered_statuses, filtered_failures
async def download_media(
self,
destination: str,
media_id: str,
output_stream: BinaryIO,
max_size: int,
max_timeout_ms: int,
) -> Tuple[int, Dict[bytes, List[bytes]]]:
try:
return await self.transport_layer.download_media_v3(
destination,
media_id,
output_stream=output_stream,
max_size=max_size,
max_timeout_ms=max_timeout_ms,
)
except HttpResponseException as e:
# If an error is received that is due to an unrecognised endpoint,
# fallback to the r0 endpoint. Otherwise, consider it a legitimate error
# and raise.
if not is_unknown_endpoint(e):
raise
logger.debug(
"Couldn't download media %s/%s with the v3 API, falling back to the r0 API",
destination,
media_id,
)
return await self.transport_layer.download_media_r0(
destination,
media_id,
output_stream=output_stream,
max_size=max_size,
max_timeout_ms=max_timeout_ms,
)
@attr.s(frozen=True, slots=True, auto_attribs=True)
class TimestampToEventResponse:

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@ -18,6 +18,7 @@ import urllib
from typing import (
TYPE_CHECKING,
Any,
BinaryIO,
Callable,
Collection,
Dict,
@ -804,6 +805,58 @@ class TransportLayerClient:
destination=destination, path=path, data={"user_ids": user_ids}
)
async def download_media_r0(
self,
destination: str,
media_id: str,
output_stream: BinaryIO,
max_size: int,
max_timeout_ms: int,
) -> Tuple[int, Dict[bytes, List[bytes]]]:
path = f"/_matrix/media/r0/download/{destination}/{media_id}"
return await self.client.get_file(
destination,
path,
output_stream=output_stream,
max_size=max_size,
args={
# tell the remote server to 404 if it doesn't
# recognise the server_name, to make sure we don't
# end up with a routing loop.
"allow_remote": "false",
"timeout_ms": str(max_timeout_ms),
},
)
async def download_media_v3(
self,
destination: str,
media_id: str,
output_stream: BinaryIO,
max_size: int,
max_timeout_ms: int,
) -> Tuple[int, Dict[bytes, List[bytes]]]:
path = f"/_matrix/media/v3/download/{destination}/{media_id}"
return await self.client.get_file(
destination,
path,
output_stream=output_stream,
max_size=max_size,
args={
# tell the remote server to 404 if it doesn't
# recognise the server_name, to make sure we don't
# end up with a routing loop.
"allow_remote": "false",
"timeout_ms": str(max_timeout_ms),
# Matrix 1.7 allows for this to redirect to another URL, this should
# just be ignored for an old homeserver, so always provide it.
"allow_redirect": "true",
},
follow_redirects=True,
)
def _create_path(federation_prefix: str, path: str, *args: str) -> str:
"""

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@ -153,12 +153,18 @@ class MatrixFederationRequest:
"""Query arguments.
"""
txn_id: Optional[str] = None
"""Unique ID for this request (for logging)
txn_id: str = attr.ib(init=False)
"""Unique ID for this request (for logging), this is autogenerated.
"""
uri: bytes = attr.ib(init=False)
"""The URI of this request
uri: bytes = b""
"""The URI of this request, usually generated from the above information.
"""
_generate_uri: bool = True
"""True to automatically generate the uri field based on the above information.
Set to False if manually configuring the URI.
"""
def __attrs_post_init__(self) -> None:
@ -168,22 +174,23 @@ class MatrixFederationRequest:
object.__setattr__(self, "txn_id", txn_id)
destination_bytes = self.destination.encode("ascii")
path_bytes = self.path.encode("ascii")
query_bytes = encode_query_args(self.query)
if self._generate_uri:
destination_bytes = self.destination.encode("ascii")
path_bytes = self.path.encode("ascii")
query_bytes = encode_query_args(self.query)
# The object is frozen so we can pre-compute this.
uri = urllib.parse.urlunparse(
(
b"matrix-federation",
destination_bytes,
path_bytes,
None,
query_bytes,
b"",
# The object is frozen so we can pre-compute this.
uri = urllib.parse.urlunparse(
(
b"matrix-federation",
destination_bytes,
path_bytes,
None,
query_bytes,
b"",
)
)
)
object.__setattr__(self, "uri", uri)
object.__setattr__(self, "uri", uri)
def get_json(self) -> Optional[JsonDict]:
if self.json_callback:
@ -513,6 +520,7 @@ class MatrixFederationHttpClient:
ignore_backoff: bool = False,
backoff_on_404: bool = False,
backoff_on_all_error_codes: bool = False,
follow_redirects: bool = False,
) -> IResponse:
"""
Sends a request to the given server.
@ -555,6 +563,9 @@ class MatrixFederationHttpClient:
backoff_on_404: Back off if we get a 404
backoff_on_all_error_codes: Back off if we get any error response
follow_redirects: True to follow the Location header of 307/308 redirect
responses. This does not recurse.
Returns:
Resolves with the HTTP response object on success.
@ -714,6 +725,26 @@ class MatrixFederationHttpClient:
response.code,
response_phrase,
)
elif (
response.code in (307, 308)
and follow_redirects
and response.headers.hasHeader("Location")
):
# The Location header *might* be relative so resolve it.
location = response.headers.getRawHeaders(b"Location")[0]
new_uri = urllib.parse.urljoin(request.uri, location)
return await self._send_request(
attr.evolve(request, uri=new_uri, generate_uri=False),
retry_on_dns_fail,
timeout,
long_retries,
ignore_backoff,
backoff_on_404,
backoff_on_all_error_codes,
# Do not continue following redirects.
follow_redirects=False,
)
else:
logger.info(
"{%s} [%s] Got response headers: %d %s",
@ -1383,6 +1414,7 @@ class MatrixFederationHttpClient:
retry_on_dns_fail: bool = True,
max_size: Optional[int] = None,
ignore_backoff: bool = False,
follow_redirects: bool = False,
) -> Tuple[int, Dict[bytes, List[bytes]]]:
"""GETs a file from a given homeserver
Args:
@ -1392,6 +1424,8 @@ class MatrixFederationHttpClient:
args: Optional dictionary used to create the query string.
ignore_backoff: true to ignore the historical backoff data
and try the request anyway.
follow_redirects: True to follow the Location header of 307/308 redirect
responses. This does not recurse.
Returns:
Resolves with an (int,dict) tuple of
@ -1412,7 +1446,10 @@ class MatrixFederationHttpClient:
)
response = await self._send_request(
request, retry_on_dns_fail=retry_on_dns_fail, ignore_backoff=ignore_backoff
request,
retry_on_dns_fail=retry_on_dns_fail,
ignore_backoff=ignore_backoff,
follow_redirects=follow_redirects,
)
headers = dict(response.headers.getAllRawHeaders())

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@ -77,7 +77,7 @@ class MediaRepository:
def __init__(self, hs: "HomeServer"):
self.hs = hs
self.auth = hs.get_auth()
self.client = hs.get_federation_http_client()
self.client = hs.get_federation_client()
self.clock = hs.get_clock()
self.server_name = hs.hostname
self.store = hs.get_datastores().main
@ -644,22 +644,13 @@ class MediaRepository:
file_info = FileInfo(server_name=server_name, file_id=file_id)
with self.media_storage.store_into_file(file_info) as (f, fname, finish):
request_path = "/".join(
("/_matrix/media/r0/download", server_name, media_id)
)
try:
length, headers = await self.client.get_file(
length, headers = await self.client.download_media(
server_name,
request_path,
media_id,
output_stream=f,
max_size=self.max_upload_size,
args={
# tell the remote server to 404 if it doesn't
# recognise the server_name, to make sure we don't
# end up with a routing loop.
"allow_remote": "false",
"timeout_ms": str(max_timeout_ms),
},
max_timeout_ms=max_timeout_ms,
)
except RequestSendFailed as e:
logger.warning(

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@ -27,10 +27,11 @@ from typing_extensions import Literal
from twisted.internet import defer
from twisted.internet.defer import Deferred
from twisted.python.failure import Failure
from twisted.test.proto_helpers import MemoryReactor
from twisted.web.resource import Resource
from synapse.api.errors import Codes
from synapse.api.errors import Codes, HttpResponseException
from synapse.events import EventBase
from synapse.http.types import QueryParams
from synapse.logging.context import make_deferred_yieldable
@ -247,6 +248,7 @@ class MediaRepoTests(unittest.HomeserverTestCase):
retry_on_dns_fail: bool = True,
max_size: Optional[int] = None,
ignore_backoff: bool = False,
follow_redirects: bool = False,
) -> "Deferred[Tuple[int, Dict[bytes, List[bytes]]]]":
"""A mock for MatrixFederationHttpClient.get_file."""
@ -257,10 +259,15 @@ class MediaRepoTests(unittest.HomeserverTestCase):
output_stream.write(data)
return response
def write_err(f: Failure) -> Failure:
f.trap(HttpResponseException)
output_stream.write(f.value.response)
return f
d: Deferred[Tuple[bytes, Tuple[int, Dict[bytes, List[bytes]]]]] = Deferred()
self.fetches.append((d, destination, path, args))
# Note that this callback changes the value held by d.
d_after_callback = d.addCallback(write_to)
d_after_callback = d.addCallbacks(write_to, write_err)
return make_deferred_yieldable(d_after_callback)
# Mock out the homeserver's MatrixFederationHttpClient
@ -316,10 +323,11 @@ class MediaRepoTests(unittest.HomeserverTestCase):
self.assertEqual(len(self.fetches), 1)
self.assertEqual(self.fetches[0][1], "example.com")
self.assertEqual(
self.fetches[0][2], "/_matrix/media/r0/download/" + self.media_id
self.fetches[0][2], "/_matrix/media/v3/download/" + self.media_id
)
self.assertEqual(
self.fetches[0][3], {"allow_remote": "false", "timeout_ms": "20000"}
self.fetches[0][3],
{"allow_remote": "false", "timeout_ms": "20000", "allow_redirect": "true"},
)
headers = {
@ -671,6 +679,52 @@ class MediaRepoTests(unittest.HomeserverTestCase):
[b"cross-origin"],
)
def test_unknown_v3_endpoint(self) -> None:
"""
If the v3 endpoint fails, try the r0 one.
"""
channel = self.make_request(
"GET",
f"/_matrix/media/v3/download/{self.media_id}",
shorthand=False,
await_result=False,
)
self.pump()
# We've made one fetch, to example.com, using the media URL, and asking
# the other server not to do a remote fetch
self.assertEqual(len(self.fetches), 1)
self.assertEqual(self.fetches[0][1], "example.com")
self.assertEqual(
self.fetches[0][2], "/_matrix/media/v3/download/" + self.media_id
)
# The result which says the endpoint is unknown.
unknown_endpoint = b'{"errcode":"M_UNRECOGNIZED","error":"Unknown request"}'
self.fetches[0][0].errback(
HttpResponseException(404, "NOT FOUND", unknown_endpoint)
)
self.pump()
# There should now be another request to the r0 URL.
self.assertEqual(len(self.fetches), 2)
self.assertEqual(self.fetches[1][1], "example.com")
self.assertEqual(
self.fetches[1][2], f"/_matrix/media/r0/download/{self.media_id}"
)
headers = {
b"Content-Length": [b"%d" % (len(self.test_image.data))],
}
self.fetches[1][0].callback(
(self.test_image.data, (len(self.test_image.data), headers))
)
self.pump()
self.assertEqual(channel.code, 200)
class TestSpamCheckerLegacy:
"""A spam checker module that rejects all media that includes the bytes

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@ -133,7 +133,7 @@ class MediaRepoShardTestCase(BaseMultiWorkerStreamTestCase):
self.assertEqual(request.method, b"GET")
self.assertEqual(
request.path,
f"/_matrix/media/r0/download/{target}/{media_id}".encode(),
f"/_matrix/media/v3/download/{target}/{media_id}".encode(),
)
self.assertEqual(
request.requestHeaders.getRawHeaders(b"host"), [target.encode("utf-8")]