IO

New in version 8.1.3.

Various functions to do io

• File
• Dir

New in version 8.1.5.

• Serial
• SPI

File

Allows interaction with files

API

userdata pilight.io.file(string file)

Creates a new file object

boolean exists()

Returns true if the file exists and false if not

iterator open(string mode)

Opens the file with a specific mode

Mode	Description
r	Opens a file for reading. The file must exist.
w	Creates an empty file for writing. If a file with the same name already exists, its content is erased and the file is considered as a new empty file.
a	Appends to a file. Writing operations, append data at the end of the file. The file is created if it does not exist.
r+	Opens a file to update both reading and writing. The file must exist.
w+	Creates an empty file for both reading and writing.
a+	Opens a file for reading and appending.

iterator read(number bytes)

Reads maximum number of bytes from the opened file at a time

iterator readline()

Returns an iterator to read the lines of the file

for line in file.readline() do
   print(line);
end

iterator write(string data)

Writes date to the opened file

iterator seek(number location [, string whence])

Sets the position of the file to the given offset, relative to the optional whence

Whence	Description
set	Beginning of file (default)
cur	Current position of the file pointer
end	End of file

boolean close()

Closes the file object

Example

function M.run()
   local file = pilight.io.file("/var/log/syslog");
   file.open("r");
   local content = '';
   for line in file.readline() do
      content = content .. line;
   end
   file.close();

  return 1;
end

return M;

Dir

Allows interaction with directories

API

userdata pilight.io.dir(string directory)

Creates a new directory object

boolean exists()

Returns true if the directory exists and false if not

boolean close()

Closes the directory object

Example

function M.run()
   local dir = pilight.io.dir("/tmp");
   if dir.exists() == false then
      dir.close();
      error("/tmp does not exists")

   dir.close();

  return 1;
end

return M;

Serial

Allows interaction with serial devices

API

userdata pilight.io.serial(string port)

Creates a new serial object or return a previously created object for the same port

boolean setBaudrate()

Sets or changes the baudrate of the serial connection Supported baudrates are:

Supported baudrates

50, 75, 110, 134, 150, 200, 600, 1200, 1800, 2400, 4800 9600, 19200, 38400, 57600, 115200, 230400

boolean setParity()

Sets or changes the parity of the serial connection

Letter	Function
n, s	No parity
o	Disable parity checking
e	Enable parity checking

boolean open()

Open the serial device

boolean close()

Close the serial device

boolean write(string line)

Write the line to the serial device

boolean read()

Tell the serial device we are (still) reading

boolean setCallback(string callback)

The name of the callback being triggered when io occured. This callback will be called when data was read, written or when an error occured.

userdata getUserdata()

Returns a persistent userdata table for the lifetime of the serial object.

boolean setUserdata(userdata table)

Set a new persistent userdata table for the lifetime of the serial object. The userdata table cannot be of another type as returned from the getUserdata functions.

Example

function M.callback(rw, serial, line)
  if rw == 'write' then
    print(line); -- success or fail
  elseif rw == 'read' then
    print(line);
    serial.read();
  elseif rw == 'disconnect' then
    serial.close();
  end
end

function M.run()
  local serial = pilight.io.serial("/dev/ttyUSB0");
  serial.setBaudrate(57600);
  serial.setParity('n');
  serial.setCallback("callback");
  if serial.open() == false then
    error("could not connect to device /dev/ttyUSB0");
  end
  serial.write("foo");
  serial.read();
end

return M;

SPI

Allows interaction with Serial Peripheral Interfaces

API

userdata pilight.io.spi(number channel[, number frequency])

Creates a new SPI object or return a previously created object for the same channel.

number rw(table value)

Sets or gets the value of a certain register. The table required should have the following format:

{ adr = adr, val = val }

• read

  The adr key should contain the register addres to be read, the val key is ignored. A number is returned when valid data was read.

• write

  The adr key should contain the register addres to be written, the val should contain the value to be set. No data is returned.

Example

function M.run()
  local spi = pilight.io.spi(0, 2500000);
  spi.rw({ adr = 0x01, val = 0x02 });

  print(spi.rw({ adr = 0xAB, val = 0x00 }));
end

return M;