TCP Communication

WORK IN PROGRESS - MIGHT BE SUBJECT TO CHANGE

Both the controller and the client GUI send their data as JSON Objects.
In JSON every Object is an unordered set of key/value pairs. The values of these pairs can be a JSON Object, a JSON Array or a primitive value (integer, string, boolean or null).
For more information or a complete grammar see http://www.json.org/.

Messages sent by Controller

Every message must provide the keys msgType and data.
Valid values for msgType are log, error or status.

Log messages

For log messages the data segment consists of a JSON Array, containing zero or more strings.

Error messages

For error messages the data segment consists of one single string, describing the error.

Status messages

In status messages the data segment is a JSON Object which must contain the following key/value pairs.

debug - true if the controller is set to verbose debug output, false otherwise
cleanup - true after cleanup mode has been engaged, false before that point
pause - true while the controller is paused, false otherwise
write - true if receiving client has write access, false otherwise
trainCount - an integer with the number of active trains on the railway

trains - a JSON Array with the data of all trains, each entry is a JSON Object with these values

trainNum - the individual controller number of the train
waiting - boolean value, true if the train is waiting in a station, false otherwise REMOVED
waitTime - (integer) remaining milliseconds until departure (0 if not waiting) CHANGED
spdSlow - the integer PWM value of this train while driving slow
spdCaution - the integer PWM value of this train while driving caution
spdNormal - the integer PWM value of this train while driving normally
currentIndex -an integer describing the current position in the schedule

schedule - a JSON Array of integer values, representing the station tracks, encoded in the following fashion

Number	Track	Number	Track	Number	Track	Number	Track
0	KH_ST_1	8	KH_ST_1 (reverse)	16	IC_ST_1	24	OC_ST_1
1	KH_ST_2	9	KH_ST_2 (reverse)	17	IC_ST_2	25	OC_ST_2
2	KH_ST_3	10	KH_ST_3 (reverse)	18	IC_ST_3	26	OC_ST_3
3	KH_ST_4	11	KH_ST_4 (reverse)
4	KH_ST_5	12	KH_ST_5 (reverse)

locks - a JSON Array containing the current value of the track permissions, ordered by the default encoding (Hoermann API)
tickTime - Time consumption of tick function. 3 element array [min,avg,max].
overallTime - Time consumption of overall controller loop. 3 element array [min,avg,max].

Sample status

<<OUTDATED>>

{"msgType":"status",
	"data":{
		"debug":false,
		"cleanup":false,
		"pause":false,
		"trainCount":8,
		"trains":[
			{"trainNum":0, "waiting":false, "waitTime":0, "spdSlow":40, "spdCaution":60, "spdNormal":100, "currentIndex":2, "schedule":[8, 10, 25, 29, 41, 43]},
			{"trainNum":1, "waiting":true, "waitTime":1234545667, "spdSlow":50, "spdCaution":70, "spdNormal":100, "currentIndex":0, "schedule":[8]},
			... ],
		"locks":[-1, -1, -1, 5, -1, -1, 2, 10, -1, -1, ..., -1]}}

[One line to test via netcat]
{"msgType":"status", "data":{"debug":false, "cleanup":false, "pause":false, "trainCount":8, "trains":[ {"trainNum":0, "waiting":false, "waitTime":0, "spdSlow":40, "spdCaution":60, "spdNormal":100, "currentIndex":2, "schedule":[1, 1, 11, 14, 6]}, {"trainNum":1, "waiting":true, "waitTime":9999999999, "spdSlow":51, "spdCaution":71, "spdNormal":101, "currentIndex":0, "schedule":[2, 1, 11, 14, 6]}, {"trainNum":2, "waiting":false, "waitTime":0, "spdSlow":52, "spdCaution":72, "spdNormal":102, "currentIndex":1, "schedule":[3, 1, 11, 14, 6]}, {"trainNum":3, "waiting":false, "waitTime":0, "spdSlow":53, "spdCaution":73, "spdNormal":103, "currentIndex":1, "schedule":[4, 1, 11, 14, 6]}, {"trainNum":4, "waiting":false, "waitTime":0, "spdSlow":54, "spdCaution":74, "spdNormal":104, "currentIndex":2, "schedule":[5, 1, 11, 14, 6]}, {"trainNum":5, "waiting":false, "waitTime":0, "spdSlow":55, "spdCaution":75, "spdNormal":105, "currentIndex":3, "schedule":[6, 1, 11, 14, 6]}, {"trainNum":6, "waiting":false, "waitTime":0, "spdSlow":56, "spdCaution":76, "spdNormal":106, "currentIndex":1, "schedule":[7, 1, 11, 14, 6]}, {"trainNum":7, "waiting":false, "waitTime":0, "spdSlow":57, "spdCaution":77, "spdNormal":107, "currentIndex":0, "schedule":[8, 1, 11, 14, 6]}], "locks":[-1, -1, -1, 5, -1, -1, 2, 3, -1, -1, -1, -1, 6, -1, -1, -1, -1, -1, -1, 4, -1, -1, -1, -1, 0, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, -1, -1, -1, -1, -1, -1, 7, -1, -1, -1, -1, -1, -1]}}

Messages received by controller

Every message must contain the key command.
Depending on the command, additional keys might be required.

Valid commands

STATUS - Poll for the current status, should trigger a status reply message
SHUTDOWN - Causing the controller to end the program and close all sockets
LOGOUT - Closing the connection, leaving the controller running
PAUSE - suspend or resume the controller, must supply additional payload
- state - boolean value, true if controller should be suspended
WRITE - Acquire write access mutex to the controller
CLEANUP (write) - Start the cleanup procedure, sending the trains back to their home tacks
DEBUG (write) - enable or disable verbose output, must supply additional payload
- state - boolean value, true if verbose output should be activated
LIGHT (write) - activate or deactivate the lights on the railway, must supply additional payload
- state - boolean value, true if lights should be lit
WAIT (write) - Force a train to wait in the next station, must supply additional payload
- train - integer train identification
START (write) - Force a waiting train to immediately abort the waiting timer, must supply additional payload
- train - integer train identification
SCHEDULE (write) - Set the new schedule for a train, needs additional payload
- train - integer train identification
- currentIndex - current integer position in the schedule array
- tracks - a JSON Array of integer values, representing the station tracks in encoding above
SPEED (write) - Change the speed settings of a train, needs additional payload
- train - integer train identification
- speeds - JSON Array with three integer values spdSlow, spdCaution, spdNormal
TIME (write) - Change the waiting times for a train
- train - integer train identification
- times - DEFINE A FORMAT FOR THIS

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