275 lines
No EOL
8.8 KiB
Python
275 lines
No EOL
8.8 KiB
Python
import time
|
|
import os
|
|
import io
|
|
import threading
|
|
import copy
|
|
import datetime
|
|
from PIL import Image
|
|
|
|
try:
|
|
from greenlet import getcurrent as get_ident
|
|
except ImportError:
|
|
try:
|
|
from thread import get_ident
|
|
except ImportError:
|
|
from _thread import get_ident
|
|
|
|
# Slightly crappy debugger logging
|
|
DEBUG = True
|
|
|
|
def log(s):
|
|
if DEBUG:
|
|
print('DEBUG: {}'.format(s))
|
|
|
|
|
|
class StreamObject(object):
|
|
def __init__(self, write_to_file: bool=None, filename: str=None, folder: str=None, fmt: str='file') -> None:
|
|
# Store a nice ID
|
|
self.id = filename
|
|
log("Created {}".format(self.id))
|
|
|
|
# Create file name
|
|
self.file = self.build_file_path(filename, folder, fmt)
|
|
|
|
# Byte stream properties
|
|
self.stream = io.BytesIO() # Byte stream that data will be written to
|
|
|
|
# Set default write target
|
|
self.write_to_file = write_to_file
|
|
if self.write_to_file == False:
|
|
log("Default target for {} set to 'stream'".format(self.id))
|
|
self.target = self.stream
|
|
else:
|
|
log("Default target for {} set to 'file'".format(self.id))
|
|
self.target = self.file
|
|
|
|
# Object lock
|
|
self.locked = False # Is the StreamObject locked for writing? (Handled by StreamingCamera)
|
|
|
|
def __enter__(self):
|
|
log("Entering context for {}. Stored files will be cleaned up automatically.".format(self.id))
|
|
return self
|
|
|
|
def __exit__(self, *args):
|
|
log("Cleaning up {}".format(self.id))
|
|
self.delete()
|
|
|
|
def build_file_path(self, filename: str, folder: str, fmt: str) -> str:
|
|
"""
|
|
Construct a full file path, based on filename, folder, and file format. Defaults to datestamp
|
|
"""
|
|
if filename:
|
|
file_name = "{}.{}".format(filename, fmt)
|
|
else:
|
|
file_name = "{}.{}".format(datetime.datetime.now().strftime("%Y-%m-%d_%H-%M-%S"), fmt)
|
|
|
|
# Create folder and file
|
|
if folder:
|
|
if not os.path.exists(folder):
|
|
os.mkdir(folder)
|
|
|
|
file_path = os.path.join(folder, file_name)
|
|
else:
|
|
file_path = file_name
|
|
|
|
return file_path
|
|
|
|
def lock(self):
|
|
"""Set locked flag to True"""
|
|
self.locked = True
|
|
|
|
def unlock(self):
|
|
"""Set locked flag to False"""
|
|
self.locked = False
|
|
|
|
@property
|
|
def data(self) -> io.BytesIO:
|
|
"""Return a byte string of the capture data"""
|
|
self.stream.seek(0) # Rewind the data bytes for reading
|
|
|
|
if not self.stream.getvalue() and os.path.isfile(self.file): # If stream is empty but file is not
|
|
log("No stream data. Opening from file {}".format(self.file))
|
|
with open(self.file, 'rb') as f:
|
|
self.stream = io.BytesIO(f.read()) # Load bytes from file in disk
|
|
self.stream.seek(0) # Rewind data bytes again
|
|
|
|
data = self.stream.getbuffer() # Create a copy of the stream bytes
|
|
|
|
return io.BytesIO(data) # Read and return bytes data
|
|
|
|
@property
|
|
def binary(self) -> bytes:
|
|
"""Return a byte string of the capture data"""
|
|
return self.data.getvalue()
|
|
|
|
def save(self):
|
|
"""
|
|
Creates/opens a file, and writes this StreamObjects bytestring to the file.
|
|
"""
|
|
with open(self.file, 'ab') as f: # Load file as bytes
|
|
log("Writing stream to file {}".format(self.file))
|
|
f.seek(0, 0) # Seek to the start of the file
|
|
f.write(self.binary) # Write data bytes to file
|
|
|
|
def delete(self) -> bool:
|
|
"""
|
|
If the StreamObject has been saved to disk, deletes the file and returns True.
|
|
"""
|
|
if os.path.isfile(self.file):
|
|
log("Deleting file {}".format(self.file))
|
|
os.remove(self.file)
|
|
return True
|
|
else:
|
|
log("File not found {}".format(self.file))
|
|
return False
|
|
|
|
|
|
class CameraEvent(object):
|
|
"""An Event-like class that signals all active clients when a new frame is
|
|
available.
|
|
"""
|
|
def __init__(self):
|
|
self.events = {}
|
|
|
|
def wait(self, timeout: int=5):
|
|
"""Invoked from each client's thread to wait for the next frame."""
|
|
ident = get_ident()
|
|
if ident not in self.events:
|
|
# this is a new client
|
|
# add an entry for it in the self.events dict
|
|
# each entry has two elements, a threading.Event() and a timestamp
|
|
self.events[ident] = [threading.Event(), time.time()]
|
|
return self.events[ident][0].wait(timeout)
|
|
|
|
def set(self):
|
|
"""Invoked by the camera thread when a new frame is available."""
|
|
now = time.time()
|
|
remove = None
|
|
for ident, event in self.events.items():
|
|
if not event[0].isSet():
|
|
# if this client's event is not set, then set it
|
|
# also update the last set timestamp to now
|
|
event[0].set()
|
|
event[1] = now
|
|
else:
|
|
# if the client's event is already set, it means the client
|
|
# did not process a previous frame
|
|
# if the event stays set for more than 5 seconds, then assume
|
|
# the client is gone and remove it
|
|
if now - event[1] > 5:
|
|
remove = ident
|
|
if remove:
|
|
del self.events[remove]
|
|
|
|
def clear(self):
|
|
"""Invoked from each client's thread after a frame was processed."""
|
|
self.events[get_ident()][0].clear()
|
|
|
|
|
|
class BaseCamera(object):
|
|
thread = None # Background thread that reads frames from camera
|
|
camera = None # Camera object, for direct access to camera
|
|
|
|
frame = None # Current frame is stored here by background thread
|
|
last_access = 0 # Time of last client access to the camera
|
|
event = CameraEvent()
|
|
|
|
def __init__(self):
|
|
self.start_worker()
|
|
|
|
# Stores state of StreamingCamera
|
|
self.state = {
|
|
}
|
|
|
|
def start_worker(self, timeout: int=5) -> bool:
|
|
"""Start the background camera thread if it isn't running yet."""
|
|
timeout_time = time.time() + timeout
|
|
|
|
self.last_access = time.time()
|
|
self.stop = False
|
|
|
|
if self.thread is None:
|
|
# start background frame thread
|
|
self.thread = threading.Thread(target=self._thread)
|
|
self.thread.start()
|
|
|
|
# wait until frames are available
|
|
log("Waiting for frames")
|
|
while self.get_frame() is None:
|
|
if time.time() > timeout_time:
|
|
raise TimeoutError("Timeout waiting for frames.")
|
|
break
|
|
else:
|
|
time.sleep(0)
|
|
return True
|
|
|
|
def stop_worker(self, timeout: int=5) -> bool:
|
|
"""Flags worker thread for stop. Waits for thread to close, or times out."""
|
|
timeout_time = time.time() + timeout
|
|
|
|
self.stop = True
|
|
while self.thread:
|
|
if time.time() > timeout_time:
|
|
raise TimeoutError("Timeout waiting for worker thread to close.")
|
|
break
|
|
else:
|
|
time.sleep(0)
|
|
return True
|
|
|
|
def get_frame(self):
|
|
"""Return the current camera frame."""
|
|
self.last_access = time.time()
|
|
|
|
# wait for a signal from the camera thread
|
|
self.event.wait()
|
|
self.event.clear()
|
|
|
|
return self.frame
|
|
|
|
def frames(self):
|
|
"""Generator that returns frames from the camera."""
|
|
raise RuntimeError('Must be implemented by subclasses.')
|
|
|
|
def close(self):
|
|
"""Handles closing the StreamingCamera"""
|
|
self.stop_worker()
|
|
|
|
def __enter__(self):
|
|
return self
|
|
|
|
def __exit__(self, exc_type, exc_value, traceback):
|
|
"""Close camera stream on context exit."""
|
|
self.close()
|
|
|
|
def _thread(self):
|
|
"""Camera background thread."""
|
|
self.frames_iterator = self.frames()
|
|
|
|
# Update state
|
|
self.state['stream_active'] = True
|
|
|
|
for frame in self.frames_iterator:
|
|
self.frame = frame
|
|
self.event.set() # send signal to clients
|
|
time.sleep(0)
|
|
|
|
# if there hasn't been any clients asking for frames in
|
|
# the last 10 seconds then stop the thread
|
|
if time.time() - self.last_access > 20:
|
|
self.frames_iterator.close()
|
|
break
|
|
|
|
try:
|
|
if self.stop is True:
|
|
self.frames_iterator.close()
|
|
break
|
|
|
|
except AttributeError:
|
|
pass
|
|
|
|
# Reset thread
|
|
self.thread = None
|
|
# Destroy any stored camera object (used especially for handling Pi cameras)
|
|
self.camera = None
|
|
# Update state
|
|
self.state['stream_active'] = False |