82 lines
2.9 KiB
Python
82 lines
2.9 KiB
Python
# Copyright 2016 OpenMarket Ltd
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# Copyright 2020-2021 The Matrix.org Foundation C.I.C.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from typing import TYPE_CHECKING
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from synapse.http.server import (
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DirectServeJsonResource,
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respond_with_json,
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respond_with_json_bytes,
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)
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from synapse.http.servlet import parse_integer, parse_string
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from synapse.http.site import SynapseRequest
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from synapse.media.media_storage import MediaStorage
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from synapse.media.url_previewer import UrlPreviewer
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if TYPE_CHECKING:
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from synapse.media.media_repository import MediaRepository
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from synapse.server import HomeServer
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class PreviewUrlResource(DirectServeJsonResource):
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"""
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The `GET /_matrix/media/r0/preview_url` endpoint provides a generic preview API
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for URLs which outputs Open Graph (https://ogp.me/) responses (with some Matrix
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specific additions).
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This does have trade-offs compared to other designs:
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* Pros:
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* Simple and flexible; can be used by any clients at any point
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* Cons:
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* If each homeserver provides one of these independently, all the homeservers in a
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room may needlessly DoS the target URI
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* The URL metadata must be stored somewhere, rather than just using Matrix
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itself to store the media.
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* Matrix cannot be used to distribute the metadata between homeservers.
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"""
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isLeaf = True
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def __init__(
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self,
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hs: "HomeServer",
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media_repo: "MediaRepository",
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media_storage: MediaStorage,
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):
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super().__init__()
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self.auth = hs.get_auth()
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self.clock = hs.get_clock()
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self.media_repo = media_repo
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self.media_storage = media_storage
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self._url_previewer = UrlPreviewer(hs, media_repo, media_storage)
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async def _async_render_OPTIONS(self, request: SynapseRequest) -> None:
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request.setHeader(b"Allow", b"OPTIONS, GET")
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respond_with_json(request, 200, {}, send_cors=True)
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async def _async_render_GET(self, request: SynapseRequest) -> None:
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# XXX: if get_user_by_req fails, what should we do in an async render?
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requester = await self.auth.get_user_by_req(request)
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url = parse_string(request, "url", required=True)
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ts = parse_integer(request, "ts")
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if ts is None:
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ts = self.clock.time_msec()
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og = await self._url_previewer.preview(url, requester.user, ts)
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respond_with_json_bytes(request, 200, og, send_cors=True)
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