Refactor media modules. (#15146)

* Removes the `v1` directory from `test.rest.media.v1`.
* Moves the non-REST code from `synapse.rest.media.v1` to `synapse.media`.
* Flatten the `v1` directory from `synapse.rest.media`,  but leave compatiblity
  with 3rd party media repositories and spam checkers.

synapse/rest/media/media_repository_resource.py

@@ -0,0 +1,93 @@
+# Copyright 2014-2016 OpenMarket Ltd
+# Copyright 2018-2021 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from typing import TYPE_CHECKING
+
+from synapse.config._base import ConfigError
+from synapse.http.server import UnrecognizedRequestResource
+
+from .config_resource import MediaConfigResource
+from .download_resource import DownloadResource
+from .preview_url_resource import PreviewUrlResource
+from .thumbnail_resource import ThumbnailResource
+from .upload_resource import UploadResource
+
+if TYPE_CHECKING:
+    from synapse.server import HomeServer
+
+
+class MediaRepositoryResource(UnrecognizedRequestResource):
+    """File uploading and downloading.
+
+    Uploads are POSTed to a resource which returns a token which is used to GET
+    the download::
+
+        => POST /_matrix/media/r0/upload HTTP/1.1
+           Content-Type: <media-type>
+           Content-Length: <content-length>
+
+           <media>
+
+        <= HTTP/1.1 200 OK
+           Content-Type: application/json
+
+           { "content_uri": "mxc://<server-name>/<media-id>" }
+
+        => GET /_matrix/media/r0/download/<server-name>/<media-id> HTTP/1.1
+
+        <= HTTP/1.1 200 OK
+           Content-Type: <media-type>
+           Content-Disposition: attachment;filename=<upload-filename>
+
+           <media>
+
+    Clients can get thumbnails by supplying a desired width and height and
+    thumbnailing method::
+
+        => GET /_matrix/media/r0/thumbnail/<server_name>
+                /<media-id>?width=<w>&height=<h>&method=<m> HTTP/1.1
+
+        <= HTTP/1.1 200 OK
+           Content-Type: image/jpeg or image/png
+
+           <thumbnail>
+
+    The thumbnail methods are "crop" and "scale". "scale" tries to return an
+    image where either the width or the height is smaller than the requested
+    size. The client should then scale and letterbox the image if it needs to
+    fit within a given rectangle. "crop" tries to return an image where the
+    width and height are close to the requested size and the aspect matches
+    the requested size. The client should scale the image if it needs to fit
+    within a given rectangle.
+    """
+
+    def __init__(self, hs: "HomeServer"):
+        # If we're not configured to use it, raise if we somehow got here.
+        if not hs.config.media.can_load_media_repo:
+            raise ConfigError("Synapse is not configured to use a media repo.")
+
+        super().__init__()
+        media_repo = hs.get_media_repository()
+
+        self.putChild(b"upload", UploadResource(hs, media_repo))
+        self.putChild(b"download", DownloadResource(hs, media_repo))
+        self.putChild(
+            b"thumbnail", ThumbnailResource(hs, media_repo, media_repo.media_storage)
+        )
+        if hs.config.media.url_preview_enabled:
+            self.putChild(
+                b"preview_url",
+                PreviewUrlResource(hs, media_repo, media_repo.media_storage),
+            )
+        self.putChild(b"config", MediaConfigResource(hs))