====/itg/checkinplayer====
To check in or un-checkin a player within a tee time reservation / flight.

parameters:
|auth	|the authorisation code you received from Intogolf BV (mandatory)|
|action |1=check in, 2=check in (same as 1), 3=un-checkin, 4=check in as qualifying round|
|fltnr	|internal id of the flight (mandatory)|
|flpnr	|internal id of the flightplayer|
|relnr	|internal id of a golfer within the domain of ikgagolfen (if flpnr is not provided)|
|relnrlocal	|local id of a golfer within the domain of the golfcourse (if flpnr is not provided)|
|pmtnr	|internal id of the paymethod to use for the financial transaction (see/itg/paymethods for a list of available paymethods |
|empnr	|internal id of the employee/user account to use for this transaction (mandatory). (see /itg/employees for a list of available accounts) it is best to create a special user account for any external systems that connect through this interface |
|hosnr	|internal id of the host/computer account to use for this transaction (mandatory). (see /itg/computers for a list of available accounts) it is best to create a special computer account for any external systems that connect through this interface |
|wahnr	|internal id of the warehouse to be used for any items sold through this transaction. (see /itg/employees for a list of available accounts). If you do not use the stock functions you can omti this parameter |

Apart from the mandatory parameters, at least one of the parameters flpnr, relnr, relnrlocal needs to be provided, otherwise the return code 449 - Retry with valid parameters is returned.

If the combination of parameters fltnr and flpnr do not match, the return code 449 - Retry with valid parameters is returned.

If the start date of the flight with fltnr is not today, the return code 449 - Retry with valid parameters is returned.

An attempt will be made to lock the Flight for any changes by other computers. If this lock fails because the Flight is already locked by another computer, "Unable to lock Flight" is returned.

If a wrong authorisation code is provided, the backend will return 401,“Unauthorized”

example: https://backend.intogolf.com/itg/checkinplayer?auth=<your authorisation code>&fltnr=3438035&flpnr=11168698&action=1&pmtnr=75&empnr=10&hosnr=7&wahnr=2

result:
<code>{

    "checkinplayer": [
        {
            "flpnr": 11168698,
            "scorecardnr": 208,
            "qcardnr": 0,
            "vouchernr": 0,
            "errorcode": 0
        }
    ]

}</code>

Flight info:
|flpnr          |internal id of the player in this flight|
|scorecardnr    |id of the assigned scorecard (if check in succeeded, 0 otherwise)|
|qcardnr|id of the assigned qualifying card (if check in succeeded and action=4, 0 otherwise)|
|vouchernr |id of voucher to be printed (if the greenfee was connected to an item that has the voucher option enabled)|
|errorcode      |0- all went ok, 1=player already checkin (with action 1,2,4), 2=player should be registered for q-card (you cant hand out Q-cards for golfers that do not have a local relnr), 3=player not yet checked in (with action=3) 4=player has qualifying card (you cant undo a qualifying card check in), 5=flight in future, cancelled or not found (should already be handled by return code 449), 6=could not issue new scorecard nr, 7=could not issue new q-card nr, 8=could not register sales, 9=pos transaction pending (you should use a hosnr that has no POS system attached), 10=external pos transaction pending (you should use a hosnr that has no POS system attached), 11=insufficient client balance (if a pmtnr was used that holds a pre-paid balance for the client)|