Implement download support for media_repository

1 files changed, 194 insertions, 0 deletions

diff --git a/synapse/media/v1/download_resource.py b/synapse/media/v1/download_resource.py
new file mode 100644
index 0000000000..c243f16a74
--- /dev/null
+++ b/synapse/media/v1/download_resource.py
@@ -0,0 +1,194 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 OpenMarket Ltd
+#
+# 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 synapse.http.server import respond_with_json
+from synapse.util.stringutils import random_string
+from synapse.api.errors import (
+    cs_exception, CodeMessageException, cs_error, Codes
+)
+
+from twisted.protocols.basic import FileSender
+from twisted.web.resource import Resource
+from twisted.web.server import NOT_DONE_YET
+from twisted.internet import defer
+
+import os
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class DownloadResource(Resource):
+    isLeaf = True
+
+    def __init__(self, hs, filepaths):
+        Resource.__init__(self)
+        self.client = hs.get_http_client()
+        self.clock = hs.get_clock()
+        self.server_name = hs.hostname
+        self.store = hs.get_datastore()
+        self.filepaths = filepaths
+
+    def render_GET(self, request):
+        self._async_render_GET(request)
+        return NOT_DONE_YET
+
+    def _respond_404(self, request):
+        respond_with_json(
+            request, 404,
+            cs_error(
+                "Not found %r" % (request.postpath,),
+                code=Codes.NOT_FOUND,
+            ),
+            send_cors=True
+        )
+
+    @defer.inlineCallbacks
+    def _async_render_GET(self, request):
+
+        try:
+            server_name, media_id = request.postpath
+        except:
+            self._respond_404(request)
+            return
+
+        try:
+            if server_name == self.server_name:
+                yield self._respond_local_file(request, media_id)
+            else:
+                yield self._respond_remote_file(request, server_name, media_id)
+        except CodeMessageException as e:
+            logger.exception(e)
+            respond_with_json(request, e.code, cs_exception(e), send_cors=True)
+        except:
+            logger.exception("Failed to serve file")
+            respond_with_json(
+                request,
+                500,
+                {"error": "Internal server error"},
+                send_cors=True
+            )
+
+    @defer.inlineCallbacks
+    def _download_remote_file(self, server_name, media_id):
+        filesystem_id = random_string(24)
+
+        fname = self.filepaths.remote_media_filepath(
+            server_name, filesystem_id
+        )
+        os.makedirs(os.path.dirname(fname))
+
+        try:
+            with open(fname, "wb") as f:
+                length, headers = yield self.client.get_file(
+                    server_name,
+                    "/".join((
+                        "/_matrix/media/v1/download", server_name, media_id,
+                    )),
+                    output_stream=f,
+                )
+        except:
+            os.remove(fname)
+            raise
+
+        media_type = headers["Content-Type"][0]
+        time_now_ms = self.clock.time_msec()
+
+        yield self.store.store_cached_remote_media(
+            origin=server_name,
+            media_id=media_id,
+            media_type=media_type,
+            time_now_ms=self.clock.time_msec(),
+            upload_name=None,
+            media_length=length,
+            filesystem_id=filesystem_id,
+        )
+
+        defer.returnValue({
+            "media_type": media_type,
+            "media_length": length,
+            "upload_name": None,
+            "created_ts": time_now_ms,
+            "filesystem_id": filesystem_id,
+        })
+
+    @defer.inlineCallbacks
+    def _respond_remote_file(self, request, server_name, media_id):
+        media_info = yield self.store.get_cached_remote_media(
+            server_name, media_id
+        )
+
+        if not media_info:
+            media_info = yield self._download_remote_file(
+                server_name, media_id
+            )
+
+        filesystem_id = media_info["filesystem_id"]
+
+        file_path = self.filepaths.remote_media_filepath(
+            server_name, filesystem_id
+        )
+
+        if os.path.isfile(file_path):
+            media_type = media_info["media_type"]
+            request.setHeader(b"Content-Type", media_type.encode("UTF-8"))
+
+            # cache for at least a day.
+            # XXX: we might want to turn this off for data we don't want to
+            # recommend caching as it's sensitive or private - or at least
+            # select private. don't bother setting Expires as all our
+            # clients are smart enough to be happy with Cache-Control
+            request.setHeader(
+                b"Cache-Control", b"public,max-age=86400,s-maxage=86400"
+            )
+
+            with open(file_path, "rb") as f:
+                yield FileSender().beginFileTransfer(f, request)
+
+            request.finish()
+        else:
+            self._respond_404()
+
+    @defer.inlineCallbacks
+    def _respond_local_file(self, request, media_id):
+        media_info = yield self.store.get_local_media(media_id)
+        if not media_info:
+            self._respond_404()
+            return
+
+        file_path = self.filepaths.local_media_filepath(media_id)
+
+        logger.debug("Searching for %s", file_path)
+
+        if os.path.isfile(file_path):
+            media_type = media_info["media_type"]
+            request.setHeader(b"Content-Type", media_type.encode("UTF-8"))
+
+            # cache for at least a day.
+            # XXX: we might want to turn this off for data we don't want to
+            # recommend caching as it's sensitive or private - or at least
+            # select private. don't bother setting Expires as all our
+            # clients are smart enough to be happy with Cache-Control
+            request.setHeader(
+                b"Cache-Control", b"public,max-age=86400,s-maxage=86400"
+            )
+
+            with open(file_path, "rb") as f:
+                yield FileSender().beginFileTransfer(f, request)
+
+            request.finish()
+        else:
+            self._respond_404()