This API gets a list of known media in a room.
The API is:
GET /_synapse/admin/v1/room/<room_id>/media
including an access_token
of a server admin.
It returns a JSON body like the following:
{
"local": [
"mxc://localhost/xwvutsrqponmlkjihgfedcba",
"mxc://localhost/abcdefghijklmnopqrstuvwx"
],
"remote": [
"mxc://matrix.org/xwvutsrqponmlkjihgfedcba",
"mxc://matrix.org/abcdefghijklmnopqrstuvwx"
]
}