Support for scanning QR-codes and barcodes through a camera plugin

platypush/message/event/qrcode.py

@@ -0,0 +1,19 @@
+from typing import List
+
+from platypush.message.event import Event
+from platypush.message.response.qrcode import ResultModel
+
+
+class QrcodeEvent(Event):
+    pass
+
+
+class QrcodeScannedEvent(Event):
+    """
+    Event triggered when a QR-code or bar code is scanned.
+    """
+    def __init__(self, results: List[ResultModel], *args, **kwargs):
+        super().__init__(*args, results=results, **kwargs)
+
+
+# vim:sw=4:ts=4:et:

platypush/plugins/camera/__init__.py

@@ -19,27 +19,39 @@ from platypush.plugins import Plugin, action
 
 
 class StreamingOutput:
-    def __init__(self):
+    def __init__(self, raw=False):
         self.frame = None
+        self.raw_frame = None
+        self.raw = raw
         self.buffer = io.BytesIO()
         self.ready = threading.Condition()
 
-    @staticmethod
-    def is_new_frame(buf):
+    def is_new_frame(self, buf):
+        if self.raw:
+            return True
+
         # JPEG header begin
         return buf.startswith(b'\xff\xd8')
 
     def write(self, buf):
         if self.is_new_frame(buf):
-            # New frame, copy the existing buffer's content and notify all clients that it's available
-            self.buffer.truncate()
-            with self.ready:
-                self.frame = self.buffer.getvalue()
-                self.ready.notify_all()
-            self.buffer.seek(0)
+            if self.raw:
+                with self.ready:
+                    self.raw_frame = buf
+                    self.ready.notify_all()
+            else:
+                # New frame, copy the existing buffer's content and notify all clients that it's available
+                self.buffer.truncate()
+                with self.ready:
+                    self.frame = self.buffer.getvalue()
+                    self.ready.notify_all()
+                self.buffer.seek(0)
 
         return self.buffer.write(buf)
 
+    def close(self):
+        self.buffer.close()
+
 
 class CameraPlugin(Plugin):
     """
@@ -75,7 +87,7 @@ class CameraPlugin(Plugin):
                  sleep_between_frames=_default_sleep_between_frames,
                  max_stored_frames=_max_stored_frames,
                  color_transform=_default_color_transform,
-                 scale_x=None, scale_y=None, rotate=None, flip=None, **kwargs):
+                 scale_x=None, scale_y=None, rotate=None, flip=None, stream_raw_frames=False, **kwargs):
         """
         :param device_id: Index of the default video device to be used for
             capturing (default: 0)
@@ -145,6 +157,7 @@ class CameraPlugin(Plugin):
         self.frames_dir = os.path.abspath(os.path.expanduser(frames_dir or self._default_frames_dir))
         self.warmup_frames = warmup_frames
         self.video_type = video_type
+        self.stream_raw_frames = stream_raw_frames
 
         if isinstance(video_type, str):
             import cv2
@@ -321,12 +334,15 @@ class CameraPlugin(Plugin):
                                        interpolation=cv2.INTER_CUBIC)
 
                 if self._output:
-                    result, frame = cv2.imencode('.jpg', frame)
-                    if not result:
-                        self.logger.warning('Unable to convert frame to JPEG')
-                        continue
+                    if not self.stream_raw_frames:
+                        result, frame = cv2.imencode('.jpg', frame)
+                        if not result:
+                            self.logger.warning('Unable to convert frame to JPEG')
+                            continue
 
-                    self._output.write(frame.tobytes())
+                        self._output.write(frame.tobytes())
+                    else:
+                        self._output.write(frame)
                 elif frames_dir:
                     self._store_frame_to_file(frame=frame, frames_dir=frames_dir, image_file=image_file)
 
@@ -584,12 +600,14 @@ class CameraPlugin(Plugin):
 
     def __enter__(self):
         device_id = self.default_device_id
-        self._output = StreamingOutput()
+        self._output = StreamingOutput(raw=self.stream_raw_frames)
         self._init_device(device_id=device_id)
         self.start_recording(device_id=device_id)
 
     def __exit__(self, exc_type, exc_val, exc_tb):
         self.stop_recording(self.default_device_id)
+        if self._output:
+            self._output.close()
         self._output = None
 
 

platypush/plugins/qrcode.py

@@ -1,10 +1,20 @@
 import base64
 import io
 import os
-from typing import Optional
+import threading
+import time
+from typing import Optional, List
 
-from platypush.message.response.qrcode import QrcodeGeneratedResponse, QrcodeDecodedResponse
+import numpy as np
+from PIL import Image
+
+from platypush import Config
+from platypush.context import get_bus
+from platypush.message.event.qrcode import QrcodeScannedEvent
+from platypush.message.response.qrcode import QrcodeGeneratedResponse, QrcodeDecodedResponse, ResultModel
 from platypush.plugins import Plugin, action
+from platypush.plugins.camera import CameraPlugin
+from platypush.utils import get_plugin_class_by_name
 
 
 class QrcodePlugin(Plugin):
@@ -19,13 +29,29 @@ class QrcodePlugin(Plugin):
 
     """
 
-    def __init__(self, **kwargs):
+    def __init__(self, camera_plugin: Optional[str] = None, **kwargs):
+        """
+        :param camera_plugin: Name of the plugin that will be used as a camera to capture images (e.g.
+            ``camera`` or ``camera.pi``).
+        """
         super().__init__(**kwargs)
+        self.camera_plugin = camera_plugin
+        self._capturing = threading.Event()
+
+    def _get_camera(self, camera_plugin: Optional[str] = None, **config) -> CameraPlugin:
+        camera_plugin = camera_plugin or self.camera_plugin
+        if not config:
+            config = Config.get(camera_plugin) or {}
+        config['stream_raw_frames'] = True
+
+        cls = get_plugin_class_by_name(camera_plugin)
+        assert cls and issubclass(cls, CameraPlugin), '{} is not a valid camera plugin'.format(camera_plugin)
+        return cls(**config)
 
     # noinspection PyShadowingBuiltins
     @action
     def generate(self, content: str, output_file: Optional[str] = None, show: bool = False,
-                 format: str = 'png') -> QrcodeGeneratedResponse:
+                 format: str = 'png', camera_plugin: Optional[str] = None) -> QrcodeGeneratedResponse:
         """
         Generate a QR code.
         If you configured the :class`:platypush.backend.http.HttpBackend` then you can also generate
@@ -38,6 +64,8 @@ class QrcodePlugin(Plugin):
         :param show: If True, and if the device where the application runs has an active display,
             then the generated QR code will be shown on display.
         :param format: Output image format (default: ``png``).
+        :param camera_plugin: If set then this plugin (e.g. ``camera`` or ``camera.pi``) will be used to capture
+            live images from the camera and search for bar codes or QR-codes.
         :return: :class:`platypush.message.response.qrcode.QrcodeGeneratedResponse`.
         """
         import qrcode
@@ -76,5 +104,72 @@ class QrcodePlugin(Plugin):
         results = pyzbar.decode(img)
         return QrcodeDecodedResponse(results)
 
+    def _convert_frame(self, frame) -> Image:
+        assert isinstance(frame, np.ndarray), 'Image conversion only works with numpy arrays for now'
+        mode = 'RGB'
+        if len(frame.shape) > 2 and frame.shape[2] == 4:
+            mode = 'RGBA'
+
+        return Image.frombuffer(mode, (frame.shape[1], frame.shape[0]), frame, 'raw', mode, 0, 1)
+
+    @action
+    def start_scanning(self, camera_plugin: Optional[str] = None, duration: Optional[float] = None,
+                       n_codes: Optional[int] = None) -> Optional[List[ResultModel]]:
+        """
+        Decode QR-codes and bar codes using a camera.
+
+        Triggers:
+
+            - :class:`platypush.message.event.qrcode.QrcodeScannedEvent` when a code is successfully scanned.
+
+        :param camera_plugin: Camera plugin (overrides default ``camera_plugin``).
+        :param duration: How long the capturing phase should run (default: until ``stop_scanning`` or app termination).
+        :param n_codes: Stop after decoding this number of codes (default: None).
+        :return: When ``duration`` or ``n_codes`` are specified or ``stop_scanning`` is called, it will return a list of
+            :class:`platypush.message.response.qrcode.ResultModel` instances with the scanned results,
+        """
+        from pyzbar import pyzbar
+        assert not self._capturing.is_set(), 'A capturing process is already running'
+
+        camera = self._get_camera(camera_plugin)
+        codes = []
+        last_results = {}
+        last_results_timeout = 10.0
+        last_results_time = 0
+        self._capturing.set()
+
+        try:
+            with camera:
+                start_time = time.time()
+
+                while self._capturing.is_set() \
+                        and (not duration or time.time() < start_time + duration) \
+                        and (not n_codes or len(codes) < n_codes):
+                    output = camera.get_stream()
+                    with output.ready:
+                        output.ready.wait()
+                        img = self._convert_frame(output.raw_frame)
+                        results = pyzbar.decode(img)
+                        if results:
+                            results = [
+                                result for result in QrcodeDecodedResponse(results).output['results']
+                                if result['data'] not in last_results
+                                   or time.time() >= last_results_time + last_results_timeout
+                            ]
+
+                        if results:
+                            codes.extend(results)
+                            get_bus().post(QrcodeScannedEvent(results=results))
+                            last_results = {result['data']: result for result in results}
+                            last_results_time = time.time()
+        finally:
+            self._capturing.clear()
+
+        return codes
+
+    @action
+    def stop_scanning(self):
+        self._capturing.clear()
+
 
 # vim:sw=4:ts=4:et: