ppsService.read()

Read PPS data from a PPS object file

Signature

ppsService.read(fd, datalistener, errorlistener);

Arguments

Argument	Type	Description
`fd`	Integer	A file descriptor returned by ppsService.open(). Required.
`datalistener`	Function	The callback function that gets called to supply the user with PPS data in JSON object format. Required. See dataListener() for details.
`errorlistener`	Function	The callback function that gets called if an error occurs. Required. See errorListener() for details.

Description

The ppsService.read() method reads data from the PPS object through the callback function specified in datalistener. See dataListener() for information on the data format.

Returns

True on success, false otherwise.

Examples

var PATH = '/pps/person';

var errorHandler = function(fd, errorID, errorMessage) {
   // handle the error
   console.log('FD: %d, Error ID: %d, Message: %s.', fd, errorID, errorMessage);
}

// open for write, create the file if it does not exist.
var fd_wrt = ppsService.open(PATH, ppsService.FLAG_WRONLY | ppsService.FLAG_CREAT | 
                                   ppsService.FLAG_TRUNC, ppsService.MODE_IRWXU | 
                                   ppsService.MODE_IRWXG | ppsService.MODE_IRWXO, 
                                   errorHandler);
if (fd_wrt < 1) {
   console.log('Open for write failed.');
}

// write PPS data
var PPS_DATA = { "name":"John", "age":31, "city":"New York" };
if (fd_wrt > 1 && !ppsService.write(fd_wrt, PPS_DATA, errorHandler)) {
   console.log('Write PPS data failed, FD: %d.', fd_wrt);
}

// open for read
var fd_r = ppsService.open(PATH, ppsService.FLAG_RDONLY, 0, errorHandler);
if (fd_r < 1) {
   console.log('Open for read failed.');
}

var dataHandler = function(fd, data) {
   console.log('FD: PPSData: %s.', fd, JSON.stringify(data));
}

// Read PPS data
if (fd_r > 1 && !ppsService.read(fd_r, dataHandler, errorHandler)) {
   console.log('Read PPS data failed, FD: %d.', fd_r);
}