Creation of a new platform for the existing switch component.

.coveragerc

@@ -156,6 +156,7 @@ omit =
     homeassistant/components/switch/hikvisioncam.py
     homeassistant/components/switch/mystrom.py
     homeassistant/components/switch/orvibo.py
+    homeassistant/components/switch/pulseaudio_loopback.py
     homeassistant/components/switch/rest.py
     homeassistant/components/switch/transmission.py
     homeassistant/components/switch/wake_on_lan.py

homeassistant/components/switch/pulseaudio_loopback.py

@@ -0,0 +1,131 @@
+"""
+Switch logic for loading/unloading pulseaudio loopback modules.
+
+For more details about this platform, please refer to the documentation at
+https://home-assistant.io/components/switch.pulseaudio_loopback/
+"""
+import logging
+import re
+import socket
+
+from homeassistant.components.switch import SwitchDevice
+from homeassistant.util import convert
+
+_LOGGER = logging.getLogger(__name__)
+
+DEFAULT_NAME = "paloopback"
+DEFAULT_HOST = "localhost"
+DEFAULT_PORT = 4712
+DEFAULT_BUFFER_SIZE = 1024
+DEFAULT_TCP_TIMEOUT = 3
+LOAD_CMD = "load-module module-loopback sink={0} source={1}"
+UNLOAD_CMD = "unload-module {0}"
+MOD_REGEX = r"index: ([0-9]+)\s+name: <module-loopback>" \
+            r"\s+argument: <sink={0} source={1}>"
+
+
+# pylint: disable=unused-argument
+def setup_platform(hass, config, add_devices_callback, discovery_info=None):
+    """Read in all of our configuration, and initialize the loopback switch."""
+    if config.get('sink_name') is None:
+        _LOGGER.error("Missing required variable: sink_name")
+        return False
+
+    if config.get('source_name') is None:
+        _LOGGER.error("Missing required variable: source_name")
+        return False
+
+    add_devices_callback([PALoopbackSwitch(
+        hass,
+        convert(config.get('name'), str, DEFAULT_NAME),
+        convert(config.get('host'), str, DEFAULT_HOST),
+        convert(config.get('port'), int, DEFAULT_PORT),
+        convert(config.get('buffer_size'), int, DEFAULT_BUFFER_SIZE),
+        convert(config.get('tcp_timeout'), int, DEFAULT_TCP_TIMEOUT),
+        config.get('sink_name'),
+        config.get('source_name')
+        )])
+
+
+# pylint: disable=too-many-arguments, too-many-instance-attributes
+class PALoopbackSwitch(SwitchDevice):
+    """Represents the presence or absence of a pa loopback module."""
+
+    def __init__(self, hass, name, pa_host, pa_port, buff_sz,
+                 tcp_timeout, sink_name, source_name):
+        """Initialize the switch."""
+        self._module_idx = -1
+        self._hass = hass
+        self._name = name
+        self._pa_host = pa_host
+        self._pa_port = int(pa_port)
+        self._sink_name = sink_name
+        self._source_name = source_name
+        self._buffer_size = int(buff_sz)
+        self._tcp_timeout = int(tcp_timeout)
+
+    @property
+    def name(self):
+        """Return the name of the switch."""
+        return self._name
+
+    @property
+    def is_on(self):
+        """Tell the core logic if device is on."""
+        return self._module_idx > 0
+
+    def _send_command(self, cmd, response_expected):
+        """Send a command to the pa server using a socket."""
+        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        sock.settimeout(self._tcp_timeout)
+        try:
+            sock.connect((self._pa_host, self._pa_port))
+            _LOGGER.info("Calling pulseaudio:" + cmd)
+            sock.send((cmd + "\n").encode("utf-8"))
+            if response_expected:
+                return_data = self._get_full_response(sock)
+                _LOGGER.debug("Data received from pulseaudio: " + return_data)
+            else:
+                return_data = ""
+        finally:
+            sock.close()
+        return return_data
+
+    def _get_full_response(self, sock):
+        """Helper method to get the full response back from pulseaudio."""
+        result = ""
+        rcv_buffer = sock.recv(self._buffer_size)
+        result += rcv_buffer.decode("utf-8")
+
+        while len(rcv_buffer) == self._buffer_size:
+            rcv_buffer = sock.recv(self._buffer_size)
+            result += rcv_buffer.decode("utf-8")
+
+        return result
+
+    def turn_on(self, **kwargs):
+        """Turn the device on."""
+        self._send_command(str.format(LOAD_CMD,
+                                      self._sink_name,
+                                      self._source_name),
+                           False)
+        self.update()
+        self.update_ha_state()
+
+    def turn_off(self, **kwargs):
+        """Turn the device off."""
+        self._send_command(str.format(UNLOAD_CMD, self._module_idx), False)
+        self.update()
+        self.update_ha_state()
+
+    def update(self):
+        """Refresh state in case an alternate process modified this data."""
+        return_data = self._send_command("list-modules", True)
+        result = re.search(str.format(MOD_REGEX,
+                                      re.escape(self._sink_name),
+                                      re.escape(self._source_name)),
+                           return_data)
+        if result and result.group(1).isdigit():
+            self._module_idx = int(result.group(1))
+        else:
+            self._module_idx = -1