Inline URL preview documentation near the implementation.
2.9 KiB
Media Repository
Synapse implementation-specific details for the media repository
The media repository
- stores avatars, attachments and their thumbnails for media uploaded by local users.
- caches avatars, attachments and their thumbnails for media uploaded by remote users.
- caches resources and thumbnails used for URL previews.
All media in Matrix can be identified by a unique MXC URI, consisting of a server name and media ID:
mxc://<server-name>/<media-id>
Local Media
Synapse generates 24 character media IDs for content uploaded by local users. These media IDs consist of upper and lowercase letters and are case-sensitive. Other homeserver implementations may generate media IDs differently.
Local media is recorded in the local_media_repository
table, which includes
metadata such as MIME types, upload times and file sizes.
Note that this table is shared by the URL cache, which has a different media ID
scheme.
Paths
A file with media ID aabbcccccccccccccccccccc
and its 128x96
image/jpeg
thumbnail, created by scaling, would be stored at:
local_content/aa/bb/cccccccccccccccccccc
local_thumbnails/aa/bb/cccccccccccccccccccc/128-96-image-jpeg-scale
Remote Media
When media from a remote homeserver is requested from Synapse, it is assigned
a local filesystem_id
, with the same format as locally-generated media IDs,
as described above.
A record of remote media is stored in the remote_media_cache
table, which
can be used to map remote MXC URIs (server names and media IDs) to local
filesystem_id
s.
Paths
A file from matrix.org
with filesystem_id
aabbcccccccccccccccccccc
and its
128x96
image/jpeg
thumbnail, created by scaling, would be stored at:
remote_content/matrix.org/aa/bb/cccccccccccccccccccc
remote_thumbnail/matrix.org/aa/bb/cccccccccccccccccccc/128-96-image-jpeg-scale
Older thumbnails may omit the thumbnailing method:
remote_thumbnail/matrix.org/aa/bb/cccccccccccccccccccc/128-96-image-jpeg
Note that remote_thumbnail/
does not have an s
.
URL Previews
When generating previews for URLs, Synapse may download and cache various
resources, including images. These resources are assigned temporary media IDs
of the form yyyy-mm-dd_aaaaaaaaaaaaaaaa
, where yyyy-mm-dd
is the current
date and aaaaaaaaaaaaaaaa
is a random sequence of 16 case-sensitive letters.
The metadata for these cached resources is stored in the
local_media_repository
and local_media_repository_url_cache
tables.
Resources for URL previews are deleted after a few days.
Paths
The file with media ID yyyy-mm-dd_aaaaaaaaaaaaaaaa
and its 128x96
image/jpeg
thumbnail, created by scaling, would be stored at:
url_cache/yyyy-mm-dd/aaaaaaaaaaaaaaaa
url_cache_thumbnails/yyyy-mm-dd/aaaaaaaaaaaaaaaa/128-96-image-jpeg-scale