diff --git a/synapse/http/client.py b/synapse/http/client.py
index b21bf17378..f42a36ffa6 100644
--- a/synapse/http/client.py
+++ b/synapse/http/client.py
@@ -251,8 +251,8 @@ class SimpleHttpClient(object):
url (str): The URL to GET
output_stream (file): File to write the response body to.
Returns:
- A (int,dict) tuple of the file length and a dict of the response
- headers.
+ A (int,dict,string,int) tuple of the file length, dict of the response
+ headers, absolute URI of the response and HTTP response code.
"""
response = yield self.request(
@@ -287,7 +287,7 @@ class SimpleHttpClient(object):
logger.exception("Failed to download body")
raise
- defer.returnValue((length, headers, response.request.absoluteURI))
+ defer.returnValue((length, headers, response.request.absoluteURI, response.code))
# XXX: FIXME: This is horribly copy-pasted from matrixfederationclient.
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index 162e09ba71..86341cc4cc 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -37,6 +37,8 @@ class PreviewUrlResource(BaseMediaResource):
def __init__(self, hs, filepaths):
BaseMediaResource.__init__(self, hs, filepaths)
self.client = SpiderHttpClient(hs)
+
+ # simple memory cache mapping urls to OG metadata
self.cache = ExpiringCache(
cache_name = "url_previews",
clock = self.clock,
@@ -56,17 +58,41 @@ class PreviewUrlResource(BaseMediaResource):
# XXX: if get_user_by_req fails, what should we do in an async render?
requester = yield self.auth.get_user_by_req(request)
url = request.args.get("url")[0]
-
- if self.cache:
- og = self.cache.get(url)
- respond_with_json_bytes(request, 200, json.dumps(og), send_cors=True)
- return
+ ts = request.args.get("ts")[0] if "ts" in request.args else self.clock.time_msec()
# TODO: keep track of whether there's an ongoing request for this preview
# and block and return their details if there is one.
+ # first check the memory cache - good to handle all the clients on this
+ # HS thundering away to preview the same URL at the same time.
+ try:
+ og = self.cache[url]
+ respond_with_json_bytes(request, 200, json.dumps(og), send_cors=True)
+ return
+ except:
+ pass
+
+ # then check the URL cache in the DB (which will also provide us with
+ # historical previews, if we have any)
+ cache_result = yield self.store.get_url_cache(url, ts)
+ if (
+ cache_result and
+ cache_result["download_ts"] + cache_result["expires"] > ts and
+ cache_result["response_code"] / 100 == 2
+ ):
+ respond_with_json_bytes(
+ request, 200, cache_result["og"].encode('utf-8'),
+ send_cors=True
+ )
+ return
+
media_info = yield self._download_url(url, requester.user)
+ # FIXME: we should probably update our cache now anyway, so that
+ # even if the OG calculation raises, we don't keep hammering on the
+ # remote server. For now, leave it uncached to aid debugging OG
+ # calculation problems
+
logger.debug("got media_info of '%s'" % media_info)
if self._is_media(media_info['media_type']):
@@ -105,10 +131,21 @@ class PreviewUrlResource(BaseMediaResource):
logger.warn("Failed to find any OG data in %s", url)
og = {}
- if self.cache:
- self.cache[url] = og
+ logger.debug("Calculated OG for %s as %s" % (url, og));
+
+ # store OG in ephemeral in-memory cache
+ self.cache[url] = og
- logger.warn(og);
+ # store OG in history-aware DB cache
+ yield self.store.store_url_cache(
+ url,
+ media_info["response_code"],
+ media_info["etag"],
+ media_info["expires"],
+ json.dumps(og),
+ media_info["filesystem_id"],
+ media_info["created_ts"],
+ )
respond_with_json_bytes(request, 200, json.dumps(og), send_cors=True)
except:
@@ -187,6 +224,9 @@ class PreviewUrlResource(BaseMediaResource):
og['og:image'] = self._rebase_url(images[0].attrib['src'], media_info['uri'])
# pre-cache the image for posterity
+ # FIXME: it might be cleaner to use the same flow as the main /preview_url request itself
+ # and benefit from the same caching etc. But for now we just rely on the caching
+ # of the master request to speed things up.
if 'og:image' in og and og['og:image']:
image_info = yield self._download_url(og['og:image'], requester.user)
@@ -226,7 +266,6 @@ class PreviewUrlResource(BaseMediaResource):
text = text.strip()[:500]
og['og:description'] = text if text else None
- # TODO: persist a cache mapping { url, etag } -> { og, mxc of url (if we bother keeping it around), age }
# TODO: delete the url downloads to stop diskfilling, as we only ever cared about its OG
defer.returnValue(og);
@@ -256,7 +295,7 @@ class PreviewUrlResource(BaseMediaResource):
try:
with open(fname, "wb") as f:
logger.debug("Trying to get url '%s'" % url)
- length, headers, uri = yield self.client.get_file(
+ length, headers, uri, code = yield self.client.get_file(
url, output_stream=f, max_size=self.max_spider_size,
)
# FIXME: pass through 404s and other error messages nicely
@@ -311,6 +350,11 @@ class PreviewUrlResource(BaseMediaResource):
"filesystem_id": file_id,
"filename": fname,
"uri": uri,
+ "response_code": code,
+ # FIXME: we should calculate a proper expiration based on the
+ # Cache-Control and Expire headers. But for now, assume 1 hour.
+ "expires": 60 * 60 * 1000,
+ "etag": headers["ETag"] if "ETag" in headers else None,
})
def _is_media(self, content_type):
diff --git a/synapse/storage/media_repository.py b/synapse/storage/media_repository.py
index 9d3ba32478..bb002081ae 100644
--- a/synapse/storage/media_repository.py
+++ b/synapse/storage/media_repository.py
@@ -25,7 +25,7 @@ class MediaRepositoryStore(SQLBaseStore):
def get_local_media(self, media_id):
"""Get the metadata for a local piece of media
Returns:
- None if the meia_id doesn't exist.
+ None if the media_id doesn't exist.
"""
return self._simple_select_one(
"local_media_repository",
@@ -50,6 +50,58 @@ class MediaRepositoryStore(SQLBaseStore):
desc="store_local_media",
)
+ def get_url_cache(self, url, ts):
+ """Get the media_id and ts for a cached URL as of the given timestamp
+ Returns:
+ None if the URL isn't cached.
+ """
+ def get_url_cache_txn(txn):
+ # get the most recently cached result (relative to the given ts)
+ sql = (
+ "SELECT response_code, etag, expires, og, media_id, max(download_ts)"
+ " FROM local_media_repository_url_cache"
+ " WHERE url = ? AND download_ts <= ?"
+ )
+ txn.execute(sql, (url, ts))
+ row = txn.fetchone()
+
+ if not row[3]:
+ # ...or if we've requested a timestamp older than the oldest
+ # copy in the cache, return the oldest copy (if any)
+ sql = (
+ "SELECT response_code, etag, expires, og, media_id, min(download_ts)"
+ " FROM local_media_repository_url_cache"
+ " WHERE url = ? AND download_ts > ?"
+ )
+ txn.execute(sql, (url, ts))
+ row = txn.fetchone()
+
+ if not row[3]:
+ return None
+
+ return dict(zip((
+ 'response_code', 'etag', 'expires', 'og', 'media_id', 'download_ts'
+ ), row))
+
+ return self.runInteraction(
+ "get_url_cache", get_url_cache_txn
+ )
+
+ def store_url_cache(self, url, response_code, etag, expires, og, media_id, download_ts):
+ return self._simple_insert(
+ "local_media_repository_url_cache",
+ {
+ "url": url,
+ "response_code": response_code,
+ "etag": etag,
+ "expires": expires,
+ "og": og,
+ "media_id": media_id,
+ "download_ts": download_ts,
+ },
+ desc="store_url_cache",
+ )
+
def get_local_media_thumbnails(self, media_id):
return self._simple_select_list(
"local_media_repository_thumbnails",
diff --git a/synapse/storage/schema/delta/30/local_media_repository_url_cache.sql b/synapse/storage/schema/delta/30/local_media_repository_url_cache.sql
new file mode 100644
index 0000000000..9efb4280eb
--- /dev/null
+++ b/synapse/storage/schema/delta/30/local_media_repository_url_cache.sql
@@ -0,0 +1,27 @@
+/* Copyright 2016 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.
+ */
+
+CREATE TABLE local_media_repository_url_cache(
+ url TEXT, -- the URL being cached
+ response_code INTEGER, -- the HTTP response code of this download attempt
+ etag TEXT, -- the etag header of this response
+ expires INTEGER, -- the number of ms this response was valid for
+ og TEXT, -- cache of the OG metadata of this URL as JSON
+ media_id TEXT, -- the media_id, if any, of the URL's content in the repo
+ download_ts BIGINT -- the timestamp of this download attempt
+);
+
+CREATE INDEX local_media_repository_url_cache_by_url_download_ts
+ ON local_media_repository_url_cache(url, download_ts);
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