Add support for sending realtime UDP frames

xled/__init__.py

@@ -26,6 +26,7 @@
 from xled.control import ControlInterface, HighControlInterface  # noqa: F401
 from xled.device import Device  # noqa: F401
 from xled.discover import DiscoveryInterface  # noqa: F401
+from xled.realtime import RealtimeChannel  # noqa: F401
 
 from .__version__ import __title__, __description__, __version__  # noqa: F401
 from .__version__ import __author__, __author_email__  # noqa: F401

xled/control.py

@@ -320,11 +320,11 @@ def set_mode(self, mode):
         """
         Sets new LED operation mode.
 
-        :param str mode: Mode to set. One of 'movie', 'demo', 'off'.
+        :param str mode: Mode to set. One of 'movie', 'rt', 'demo', 'off'.
         :raises ApplicationError: on application error
         :rtype: None
         """
-        assert mode in ("movie", "demo", "off")
+        assert mode in ("movie", "rt", "demo", "off")
         json_payload = {"mode": mode}
         url = urljoin(self.base_url, "led/mode")
         response = self.session.post(url, json=json_payload)

xled/realtime.py

@@ -0,0 +1,68 @@
+# -*- coding: utf-8 -*-
+
+"""
+xled.realtime
+~~~~~~~~~~~~~
+
+Functions to support the realtime mode of the device.
+"""
+
+from __future__ import absolute_import
+
+import base64
+import math
+import socket
+
+from xled.control import ControlInterface
+
+#: UDP port to send realtime frames to
+REALTIME_UDP_PORT_NUMBER = 7777
+
+
+class RealtimeChannel(object):
+    """
+    Main interface to send realtime frames to device.
+
+    :param control: An activated ControlInterface for the device to control
+    :param int leds_number: the number of leds in a frame
+    :param int bytes_per_led: the number of bytes per led (3 or 4)
+    """
+
+    def __init__(self, control, leds_number, bytes_per_led):
+        self.control = control
+        self.leds_number = leds_number
+        self.bytes_per_led = bytes_per_led
+
+    def start_realtime(self):
+        self.control.set_mode('rt')
+
+    def send_frame(self, data):
+        """
+        Sends a realtime frame. Before calling this, start_realtime() must have
+        been called.
+
+        :param bytearray data: byte array containing the raw frame data
+        :rtype: None
+        """
+        data_size = self.leds_number*self.bytes_per_led
+        assert len(data) == data_size
+        with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as sock:
+            if data_size < 900 and self.leds_number < 256:
+                # Send single frame
+                packet = bytearray(b'\x01')
+                packet.extend(base64.b64decode(self.control.session.access_token))
+                packet.extend(bytes([self.leds_number]))
+                packet.extend(data)
+                sock.sendto(packet, (self.control.host, REALTIME_UDP_PORT_NUMBER))
+            else:
+                # Send multi frame
+                packet_size = 900//self.bytes_per_led
+                for i in range(0, math.ceil(data_size/packet_size)):
+                    packet_data = data[:(900//self.bytes_per_led)]
+                    data = data[(900//self.bytes_per_led):]
+                    packet = [ b'\x03', base64.b64decode(self.control.session.access_token),
+                        b'\x00\x00', bytes([i])]
+                    packet.append(packet_data)
+                    sock.sendto(packet, (self.control.host, REALTIME_UDP_PORT_NUMBER))
+
+