Media not part of the outbound webhook body

[jficz]

When a message with an image attached is sent to a room, hookshot's webhook doesn't contain the media file, just mxs:// reference in the event json.

hookshot version: 5.4.2
matrix-synapse version: 1.124.0
(both from NixOS 24.11)

According to my research, this is probably because Synapse enforces Authenticated Media by default and I would prefer not to disable it.

What I found:

Hookshot debug log contains
[OutboundHookConnection] Failed to get media for $<random> in !<room-id>:<example.com> <ref *2> IncomingMessage {...
and
_header: 'GET /_matrix/media/v3/download/<example.com>/<media-id>?allow_remote=true HTTP/1.1\r\n'

which is the "old" media API URL. Authenticated Media API should instead use

GET /_matrix/client/v1/media/download/{serverName}/{mediaId}

The request is ultimately generated by matrix-bot-sdk method downloadContent which has the "old" API path hardcoded. The bot sdk last release apparently predates MSC3916.

[jficz]

There is a workaround if anyone needs it - if your home server is behind a reverse proxy, you can do something like

location ~ ^/_matrix/media/v3/download/(.*)$ {
        proxy_pass http://[::1]:8008/_matrix/client/v1/media/download/$1$is_args$args;
}

This will work so long as your clients which use the "old" endpoint also send authorization token with the requests which, fortunately, Hooshot does.