# Managing Jack Connections

When JackTrip clients connect corresponding jack clients are created on the server side that may have a name defined by the connecting client. In the SPRAWL system every client connects with a remote name that starts with AP_ followed by the user's name. Those jack clients must be connected to the right inputs and outputs of the sprawl system. There are several solution to do this automatically. With aj-snapshot you can create a snapshot of all current jack connections and reconnect that state later. You can even running aj-snapshot as a daemon to constantly watch that all connections of a snapshot are set.

In the sprawl system we don't know the full name of connecting jacktrip clients. With jack-matchmaker we are able to write pattern files that use regular expressions to connect jack clients:

#
# Direct Input

SPRAWL_Server:in_1
SPRAWL_Server:in_2
SPRAWL_Server:in_3
SPRAWL_Server:in_4


Those regexes in slashes are conforming python's regex syntax <https://docs.python.org/3/library/re.html>'_. Jack-Matchmaker can show you all current connections:

System Message: WARNING/2 (<string>, line 30); backlink

Inline interpreted text or phrase reference start-string without end-string.

\$ jack-matchmaker -c
SPRAWL_Server:in_1

SPRAWL_Server:out_1
AP_Nils_1:send_1

SPRAWL_Server:out_2
AP_Nils_1:send_2

SPRAWL_Server:out_33
AP_Nils_1:send_1

SPRAWL_Server:out_34
AP_Nils_1:send_2
`

As you see I'm sending one audio channel to the server that connects to the first input of the SPRAWL_Server SuperCollider application. The next two connections are the direct outputs to my receiving channels. The last two connections are the binaural rendered spatialised mix.

## Jack-Matchmaker user service

Right now the jack-matchmaker user service loads the pattern file located in /home/student/SPRAWL/matchmaker/sprawl_server_stereo.pattern. This might be changed in the future with a template instantiated service.