Add basic implementation

dream_cheeky/__init__.py

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+"""Simple interface for the Dream Cheeky Big Red Button."""
+
+
+import os
+import time
+
+
+def _run_callbacks(callbacks):
+    """Runs all the callbacks.
+
+    :param callbacks: List of callable functions.
+    """
+    for callback in callbacks:
+        callback()
+
+
+class BigRedButton(object):
+    """Encapsulates the big red button."""
+
+    POLL_SIGNAL = b"\x08\x00\x00\x00\x00\x00\x00\x02"
+    LID_CLOSED = b"\x15\x00\x00\x00\x00\x00\x00\x00"
+    BUTTON_DOWN = b"\x16\x00\x00\x00\x00\x00\x00\x00"
+    LID_OPEN = b"\x17\x00\x00\x00\x00\x00\x00\x00"
+
+    def __init__(self, device_fd):
+        """Initializes the BigRedButton.
+
+        :param device_fd: File descriptor for the device
+        """
+        self.device_fd = device_fd
+        self._prior = self.LID_CLOSED
+        self._button_press_callbacks = []
+        self._lid_open_callbacks = []
+        self._lid_close_callbacks = []
+
+    def on_button_press(self, callback):
+        """Registers callback for button press event.
+
+        :param callback: Callback function to run on button press
+        """
+        self._button_press_callbacks.append(callback)
+
+    def on_lid_open(self, callback):
+        """Registers callback for lid open event.
+
+        :param callback: Callback function to run on lid open
+        """
+        self._lid_open_callbacks.append(callback)
+
+    def on_lid_close(self, callback):
+        """Registers callback for lid close event.
+
+        :param callback: Callback function to run on lid close
+        """
+        self._lid_close_callbacks.append(callback)
+
+    def _step(self):
+        """Executes one step of the event loop."""
+        bytes_written = os.write(self.device_fd, self.POLL_SIGNAL)
+        if not bytes_written:
+            raise RuntimeError("Could not write to device file.")
+        bytes_read = os.read(self.device_fd, 8)
+        if not bytes_read:
+            raise RuntimeError("Could not read from device file.")
+        if bytes_read == self.LID_CLOSED and self._prior != self.LID_CLOSED:
+            _run_callbacks(self._lid_close_callbacks)
+        if bytes_read == self.BUTTON_DOWN and self._prior != self.BUTTON_DOWN:
+            _run_callbacks(self._button_press_callbacks)
+        if bytes_read == self.LID_OPEN and self._prior == self.LID_CLOSED:
+            _run_callbacks(self._lid_open_callbacks)
+        if bytes_read != self.POLL_SIGNAL:
+            self._prior = bytes_read
+
+    def run(self):
+        """Executes the main event loop for the big red button."""
+        while True:
+            self._step()
+            time.sleep(0.01)

examples/print_on_button_press.py

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+#!/usr/bin/env python
+"""Sample script for python-dream-cheeky."""
+
+import os
+
+from dream_cheeky import BigRedButton
+
+
+def handle_button_press():
+    """Handles a button press."""
+    print("Button pressed!")
+
+
+def main():
+    """Main function for the sync button."""
+    device_file = os.open("/dev/big_red_button", os.O_RDWR)
+    button = BigRedButton(device_file)
+    button.on_button_press(handle_button_press)
+    button.run()
+
+
+if __name__ == '__main__':
+    main()

setup.py

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+from distutils.core import setup
+
+description = "Event-driven Python library for interacting with the Dream Cheeky big red button."
+
+setup(
+        name='python-dream-cheeky',
+        version='0.1.0',
+        author='Ian Adam Naval',
+        author_email='ianonavy@gmail.com',
+        packages=['dream_cheeky'],
+        scripts=[],
+        url='https://git.ianonavy.com/ianonavy/python-dream-cheeky/',
+        license='MIT',
+        description=description,
+        long_description=description,
+        install_requires=[],
+
+)