How to send group messages via dbus-send?

[hasdf]

Can somebody explain how to send group messages via dbus-send?

This works great for sending to a single recipient:

dbus-send --session --type=method_call --print-reply --dest="org.asamk.Signal" /org/asamk/Signal org.asamk.Signal.sendMessage string:MessageText array:string: string:RECIPIENT

I found void sendGroupMessage in Signal.java, but I'm not sure how to pass that group ID to dbus-send.

Thank you!

[exquo]

Sending to a group can be done with a similar command:

dbus-send --session --type=method_call  --print-reply --dest=org.asamk.Signal /org/asamk/Signal org.asamk.Signal.sendGroupMessage  string:'The message goes here'  array:string:'/path/to/attachmnt1','/path/to/attachmnt2'  array:byte:139,22,72,247,116,32,170,104,205,164,207,21,248,77,185

where the byte array at the end is the groupId in the bytes form. It can be obtained from the list of groupIds:

dbus-send --session --type=method_call  --print-reply --dest='org.asamk.Signal' /org/asamk/Signal org.asamk.Signal.getGroupIds

Note: when daemon was started without explicit -u USERNAME, all the dbus-send commands require adding the phone number in /org/asamk/Signal/_<phonenum>. See signal-cli-dbus man page.

To get the group name corresponding to a groupId, run

dbus-send --session --type=method_call  --print-reply --dest='org.asamk.Signal' /org/asamk/Signal org.asamk.Signal.getGroupName    array:byte:139,22,72,247,116,32,170,104,205,164,207,21,248,77,185     

Alternatively, the groupId byte array can be obtained from the base64-encoded groupId that looks like ixZI93QgqmjNpM8V+E25== and can be found in signal-cli's config file, by default in ~/.local/share/signal-cli/data/<PHONE_NUMBER>. To decode it to byte array, can use python:

python3 -c 'import base64; print(",".join(str(i) for i in base64.b64decode(b"ixZI93QgqmjNpM8V+E25==")))'

[exquo]

One dbus quirk here: it takes bytearrays as input (for sendGroupMessage and getGroupName) in the form 139,22,72,247,.., but returns bytearrays (by getGroupIds) as space-separated hex digits 8b 16 48 f7 74 20 aa 68 cd a4 cf 15 f8 4d b9. To convert one to the other:

python3 -c 'print(",".join(str(x) for x in bytes.fromhex("8b 16 48 f7 74 20 aa 68 cd a4 cf 15 f8 4d b9")))'

[hasdf]

Thank you for the detailed explanation!

Stay healthy :)

[patcon]

Note that /org/asamk/Signal is now /org/asamk/Signal/_15555555555 (where 15555555555 is your phone number on account)

If you don't do this, you will get error:

Error org.freedesktop.dbus.errors.UnknownObject: /org/asamk/Signal is not an object provided by this process.

[exquo]

Thanks for the comment! I've added a note to my post above.