Update keyboard_remote.py (#5112)

* Update keyboard_remote.py

I changed os.path.isFile() to os.path.exists: as far as I know isFile doesn't work with device files. At least on my Ubuntu it wasn't working.

Then I added some error control in case the keyboard disconnects: with bluetooth keyboards this happen often due to battery saving. Now it reconnects automatically when the keyboard wakes up.

We could fire an event to hass when the keyboard connects-disconnects, maybe I'll do this later.

We should also manage errors due to permissions problems on the device file, or at least give some info in the docs about how to allow HA to grab control over an system input file.

I'm sorry if my coding isn't up to some standard practice I'm not aware of: I'm new to HA and to python itself, I'm just trying to be of help.
Gianluca

* Update keyboard_remote.py

I changed some other few things.

Not the component gets loaded even if the keyboard is disconnected. When it connects, it starts to fire events when keys are pressed.

I also added a sleep(0.1) that reduces a lot the load on the CPU, but without many consequences on key pressed detection.

homeassistant/components/keyboard_remote.py

@@ -1,5 +1,5 @@
 """
-Recieve signals from a keyboard and use it as a remote control.
+Receive signals from a keyboard and use it as a remote control.
 
 This component allows to use a keyboard as remote control. It will
 fire ´keyboard_remote_command_received´ events witch can then be used
@@ -12,7 +12,7 @@ because `evdev` will block it.
 Example:
   keyboard_remote:
     device_descriptor: '/dev/input/by-id/foo'
-    key_value: 'key_up' # optional alternaive 'key_down' and 'key_hold'
+    type: 'key_up' # optional alternaive 'key_down' and 'key_hold'
     # be carefull, 'key_hold' fires a lot of events
 
   and an automation rule to bring breath live into it.
@@ -33,6 +33,7 @@ Example:
 import threading
 import logging
 import os
+import time
 
 import voluptuous as vol
 
@@ -65,8 +66,8 @@ def setup(hass, config):
     """Setup keyboard_remote."""
     config = config.get(DOMAIN)
     device_descriptor = config.get(DEVICE_DESCRIPTOR)
-    if not device_descriptor or not os.path.isfile(device_descriptor):
-        id_folder = '/dev/input/by-id/'
+    if not device_descriptor:
+        id_folder = '/dev/input/'
         _LOGGER.error(
             'A device_descriptor must be defined. '
             'Possible descriptors are %s:\n%s',
@@ -107,7 +108,20 @@ class KeyboardRemote(threading.Thread):
         """Construct a KeyboardRemote interface object."""
         from evdev import InputDevice
 
-        self.dev = InputDevice(device_descriptor)
+        self.device_descriptor = device_descriptor
+        try:
+            self.dev = InputDevice(device_descriptor)
+        except OSError:  # Keyboard not present
+            _LOGGER.debug(
+                'KeyboardRemote: keyboard not connected, %s',
+                self.device_descriptor)
+            self.keyboard_connected = False
+        else:
+            self.keyboard_connected = True
+            _LOGGER.debug(
+                'KeyboardRemote: keyboard connected, %s',
+                self.dev)
+
         threading.Thread.__init__(self)
         self.stopped = threading.Event()
         self.hass = hass
@@ -115,13 +129,36 @@ class KeyboardRemote(threading.Thread):
 
     def run(self):
         """Main loop of the KeyboardRemote."""
-        from evdev import categorize, ecodes
-        _LOGGER.debug('KeyboardRemote interface started for %s', self.dev)
+        from evdev import categorize, ecodes, InputDevice
 
-        self.dev.grab()
+        if self.keyboard_connected:
+            self.dev.grab()
+            _LOGGER.debug(
+                'KeyboardRemote interface started for %s',
+                self.dev)
 
         while not self.stopped.isSet():
-            event = self.dev.read_one()
+            # Sleeps to ease load on processor
+            time.sleep(.1)
+
+            if not self.keyboard_connected:
+                try:
+                    self.dev = InputDevice(self.device_descriptor)
+                except OSError:  # still disconnected
+                    continue
+                else:
+                    self.dev.grab()
+                    self.keyboard_connected = True
+                    _LOGGER.debug('KeyboardRemote: keyboard re-connected, %s',
+                                  self.device_descriptor)
+
+            try:
+                event = self.dev.read_one()
+            except IOError:  # Keyboard Disconnected
+                self.keyboard_connected = False
+                _LOGGER.debug('KeyboardRemote: keyard disconnected, %s',
+                              self.device_descriptor)
+                continue
 
             if not event:
                 continue