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diff --git a/docs/media_repository.md b/docs/media_repository.md index ba17f8a856..99ee8f1ef7 100644 --- a/docs/media_repository.md +++ b/docs/media_repository.md @@ -2,80 +2,29 @@ *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](development/url_previews.md). +The media repository is where attachments and avatar photos are stored. +It stores attachment content and thumbnails for media uploaded by local users. +It caches attachment content and thumbnails for media uploaded by remote users. -All media in Matrix can be identified by a unique -[MXC URI](https://spec.matrix.org/latest/client-server-api/#matrix-content-mxc-uris), -consisting of a server name and media ID: -``` -mxc://<server-name>/<media-id> -``` +## Storage -## 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. +Each item of media is assigned a `media_id` when it is uploaded. +The `media_id` is a randomly chosen, URL safe 24 character string. -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. +Metadata such as the MIME type, upload time and length are stored in the +sqlite3 database indexed by `media_id`. -### 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 -``` +Content is stored on the filesystem under a `"local_content"` directory. -## 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. +Thumbnails are stored under a `"local_thumbnails"` directory. -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. +The item with `media_id` `"aabbccccccccdddddddddddd"` is stored under +`"local_content/aa/bb/ccccccccdddddddddddd"`. Its thumbnail with width +`128` and height `96` and type `"image/jpeg"` is stored under +`"local_thumbnails/aa/bb/ccccccccdddddddddddd/128-96-image-jpeg"` -### 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 -See [URL Previews](development/url_previews.md) for documentation on the URL preview -process. - -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 -``` +Remote content is cached under `"remote_content"` directory. Each item of +remote content is assigned a local `"filesystem_id"` to ensure that the +directory structure `"remote_content/server_name/aa/bb/ccccccccdddddddddddd"` +is appropriate. Thumbnails for remote content are stored under +`"remote_thumbnail/server_name/..."` |