Ensure only one download for a given URL is active at a time

This commit is contained in:
Matthew Hodgson 2016-04-03 00:47:40 +01:00
parent 7426c86eb8
commit b09e29a03c

View File

@ -23,6 +23,7 @@ from synapse.util.stringutils import random_string
from synapse.util.caches.expiringcache import ExpiringCache
from synapse.http.client import SpiderHttpClient
from synapse.http.server import request_handler, respond_with_json, respond_with_json_bytes
from synapse.util.async import ObservableDeferred
import os
import re
@ -46,6 +47,8 @@ class PreviewUrlResource(BaseMediaResource):
)
self.cache.start()
self.downloads = {}
def render_GET(self, request):
self._async_render_GET(request)
return NOT_DONE_YET
@ -86,7 +89,21 @@ class PreviewUrlResource(BaseMediaResource):
)
return
media_info = yield self._download_url(url, requester.user)
# Ensure only one download for a given URL is active at a time
download = self.downloads.get(url)
if download is None:
download = self._download_url(url, requester.user)
download = ObservableDeferred(
download,
consumeErrors=True
)
self.downloads[url] = download
@download.addBoth
def callback(media_info):
del self.downloads[key]
return media_info
media_info = yield download.observe()
# FIXME: we should probably update our cache now anyway, so that
# even if the OG calculation raises, we don't keep hammering on the