LuckyServer

The server is listening on LuckyLoop at port 1219. During boot-up of the app, it will print the host IP address to the TFT. Read it from there. Start the Python Client on your measurement PC, i.e. luckyloop.client.Client(host, port) using these values to connect it with the LuckyServer.

The server accepts specific ascii-encoded commands following the format 

[command: arg1, arg2, ...]

Example command 

[set_condition: threshold, target_phase, target_frequency, trigger]

Defines

PORT

port at which clients should expect the server. Defaults to 1219

MAX_LISTENERS

how many listeners can be enqueued at max defaults to 1

Functions

static void error_exit(char *errorMessage)

shuts the server down with an error message

Parameters

  • errorMessage – the errormessage to stderr

int send_condition(int client, condition *cond)

send the current status to the connected client The status message will be encoded as defined by sri::create_condition_JSON

Parameters

  • client – to whom to send the message

  • cond – the status information to be sent

Returns

0 if successful

int send_status(int client, condition *cond, char *session_ID)

send the current status to the connected client The status message will be encoded as defined by sri:: create_status_JSON

Parameters

  • client – to whom to send the message

  • cond – the condition information to be sent

  • session_ID – the session_ID as read from the config file

Returns

0 if successful

void removeSpaces(char *str)

removes all spaces from a string

int accept_client()

accept a TCP/IP client blocks until a client connects

Returns

the client file descriptor

int start_server()

start and bind a TCP/IP server

Returns

the server file descriptor

int get_lsl_config_filename(char *filename)

This function determines the filename of the LSL config file.

Parameters

  • filename – is a string that will contain the filname

Returns

EXIT_SUCCESS or error code

int change_session_id(char *argument)

This function reads a message from the client and changes the LSL config file accordingly.

The message format is a string formatted with one arguments

Format: [set_lsl_session_ID: <session_ID>]

It will create the config file in ~/lsl_api/lsl_api.cfg If the directory/file does not exist, it will be created.

Parameters

  • argument – is a string that contains the session_ID

Returns

EXIT_SUCCESS or error code

int get_session_id(char *session_ID, int buffersize)

This function reads the session ID from the LSL config.

The function reads the config file in ~/lsl_api/lsl_api.cfg and extracts the session ID

Parameters

  • session_ID – The destination where to write the session_ID

  • buffersize – The size of session_ID

Returns

int indicates success

int set_condition_from_arguments(char *arguments, condition *condition)

Overwrite an already existing condition based on arguments from a command message

Parameters

  • arguments – the arguments part of the message received from a client the positional order of the arguments is <threshold>, <frequency>, <phase>, <trigger>. Each argument is either an integer to overwrite the current setting or an equality symbol to keep the current setting. For example if the message [set_condition: =, =, 12, 0] would be received, the arguments part would be =, =, 12, 0 which would keep threshold and target phase untouched while the target_frequency is changed to 12 and the trigger is disarmed by setting it to zero.

condition recv_message(int client, condition *new_status)

This function reads a message from the client and executes the given command.

The message format is a string formatted with positional arguments

Format: [<command>: <arg1>, <arg2>, …, <argN>]

Implemented are:

  • [set_condition: <threshold>, <frequency>, <phase>, <trigger>] where each argument can be either an integer or the equality symbol =.

  • [shutdown:] shuts the server down gracefully.

  • [send_status:] just return the current conditions without changing anything

  • [set_lsl_session_ID: <session_ID>] sets lsl config file to a new session ID. Change will be applyed after restart.

Parameters

  • client – is the socket from whom the server will read. This is the client returned by :func:~.accept_client()

  • condition – *new_status the status object which will be filled based on the message received from the client

Returns

EXIT_SUCCESS or error code

int loop()

The main loop accepting clients, parsing messages and executing commands

Will be started when the executable is started

Note

shut the loop down by sending the shutdown command with a client