308 lines
No EOL
11 KiB
Python
308 lines
No EOL
11 KiB
Python
import uuid
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import io
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import os
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import glob
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import datetime
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import copy
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import logging
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from PIL import Image
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import atexit
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pil_formats = ['JPG', 'JPEG', 'PNG', 'TIF', 'TIFF']
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thumbnail_size = (60, 60)
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BASE_CAPTURE_PATH = os.path.join(os.path.expanduser('~'), 'micrographs')
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TEMP_CAPTURE_PATH = os.path.join(BASE_CAPTURE_PATH, 'tmp')
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def clear_tmp():
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global TEMP_CAPTURE_PATH
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logging.info("Clearing {}...".format(TEMP_CAPTURE_PATH))
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files = glob.glob('{}/*'.format(TEMP_CAPTURE_PATH))
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for f in files:
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os.remove(f)
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logging.debug("Removed {}".format(f))
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class CaptureObject(object):
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"""
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StreamObject used to store and process capture data, and metadata.
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Note: Captures cannot be stored in a lower-level directory than BASE_CAPTURE_PATH.
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"""
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def __init__(
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self,
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write_to_file: bool=False,
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keep_on_disk: bool=True,
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filename: str='',
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folder: str='',
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fmt: str='') -> None:
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"""Create a new StreamObject, to manage capture data."""
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# Store a nice ID
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self.id = uuid.uuid4().hex
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logging.info("Created StreamObject {}".format(self.id))
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self.timestring = datetime.datetime.now().strftime("%Y-%m-%d_%H-%M-%S")
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# Store file format
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self.format = fmt
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# Keep on disk after close by default
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self.keep_on_disk = keep_on_disk
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# Explicitally state if capture should be written to a file, not a bytestream
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self.write_to_file = write_to_file
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# Create file name. Default to UUID
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if not filename:
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filename = self.id
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self.filename = "{}.{}".format(filename, fmt)
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self.folder = folder
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# Initialise the capture stream
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self.initialise_capture()
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# Log if created by context manager
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self.context_manager = False
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# Object lock
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self.locked = False
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# Thumbnail (populated only for PIL captures)
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self.thumb_bytes = None
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def __enter__(self):
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"""Create StreamObject in context, to auto-clean disk data."""
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logging.debug("Entering context for {}. Stored files will be cleaned up automatically regardless of location.".format(self.id))
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self.keep_on_disk = False # Flag file to be removed on close.
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self.context_manager = True # Used in metadata
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logging.info("Rebuilding as a temporary capture...")
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self.initialise_capture()
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return self
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def __exit__(self, *args):
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"""Exit StreamObject, and auto-clean disk data."""
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logging.info("Cleaning up {}".format(self.id))
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self.close()
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def initialise_capture(self):
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self.build_file_path(self.filename, self.folder)
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# Byte bytestream properties
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self.bytestream = io.BytesIO() # Byte bytestream that data will be written to
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# Set default write target
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if not self.write_to_file:
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logging.debug("Target for {} set to 'bytestream'".format(self.id))
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self.stream = self.bytestream
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else:
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logging.debug("Target for {} set to 'file'".format(self.id))
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self.stream = self.file
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def build_file_path(
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self,
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filename: str,
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folder: str):
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"""
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Construct a full file path, based on filename, folder, and file format.
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Defaults to UUID.
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"""
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global TEMP_CAPTURE_PATH
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self.file = os.path.join(folder, filename) # Full file name by joining given folder to given name
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self.split_file_path(self.file) # Split file path into folder, filename, and basename
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# Check directory is a subdirectory of BASE_CAPTURE_PATH
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if not os.path.commonprefix([self.file, BASE_CAPTURE_PATH]) == BASE_CAPTURE_PATH:
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raise Exception("Captures cannot be stored in a lower-level directory than {}.".format(BASE_CAPTURE_PATH))
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# Move to tmp directory if not being kept
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if not self.keep_on_disk:
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# TODO: Empty tmp folder on module load and atexit
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self.file_notmp = self.file # Store originally defined folder
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self.filefolder = TEMP_CAPTURE_PATH
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self.file = os.path.join(self.filefolder, self.filename)
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# Create folder and file
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if not os.path.exists(self.filefolder):
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os.makedirs(self.filefolder)
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logging.debug(self.file)
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logging.debug(self.filename)
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logging.debug(self.basename)
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logging.debug(self.filefolder)
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def split_file_path(self, filepath):
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"""Takes a full file path, and splits it into separated class properties."""
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self.filefolder, self.filename = os.path.split(filepath) # Split the full file path into a folder and a filename
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self.basename = os.path.splitext(self.filename)[0] # Split the filename out from it's file extension
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def lock(self):
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"""Set locked flag to True."""
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self.locked = True
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def unlock(self):
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"""Set locked flag to False."""
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self.locked = False
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@property
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def stream_exists(self, auto_rewind=True) -> bool:
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"""Check if BytesIO bytestream is empty."""
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if auto_rewind:
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self.bytestream.seek(0) # Rewind the data bytes for reading
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if self.bytestream.getvalue(): # If data bytestream contains data
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self.bytestream.seek(0) # Rewind the data bytes for reading
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return True
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else:
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self.bytestream.seek(0) # Rewind the data bytes for reading
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return False
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@property
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def file_exists(self) -> bool:
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"""Check if corresponding file exists."""
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if os.path.isfile(self.file):
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return True
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else:
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return False
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@property
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def metadata(self) -> dict:
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"""Return dictionary of StreamObject properties."""
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d = {
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'id': self.id,
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'locked': self.locked,
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'keep_on_disk': self.keep_on_disk,
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'filename': self.filename,
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'path': self.file,
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'time': self.timestring
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}
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# Check bytestream
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if self.stream_exists:
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d['bytestream'] = True
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else:
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d['bytestream'] = False
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# Combined availability of data
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if self.stream_exists or self.file_exists:
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d['available'] = True
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else:
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d['available'] = False
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# Check if file was manually deleted
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if self.keep_on_disk and not self.file_exists:
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d['path'] = "{} (Deleted)".format(d['path'])
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return d
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@property
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def data(self) -> io.BytesIO:
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"""Return a byte string of the capture data."""
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self.bytestream.seek(0) # Rewind the data bytes for reading
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if self.stream_exists: # If data bytestream contains data
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# Create a copy of the bytestream bytes
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data = io.BytesIO(self.bytestream.getbuffer())
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else: # If data bytestream is empty
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if self.file_exists: # If data file exists
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logging.info("Opening from file {}".format(self.file))
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with open(self.file, 'rb') as f:
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d = io.BytesIO(f.read()) # Load bytes from file
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d.seek(0) # Rewind loaded bytestream
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# Create a copy of the bytestream bytes
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data = io.BytesIO(d.getbuffer())
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else:
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data = None
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return data # Read and return bytes data
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@property
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def binary(self) -> bytes:
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"""Return a byte string of the capture data."""
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return self.data.getvalue()
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@property
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def thumbnail(self) -> io.BytesIO:
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# If no thumbnail exists, try and make one
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if not self.thumb_bytes:
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logging.info("Building thumbnail")
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if self.format.upper() in pil_formats:
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im = Image.open(self.data)
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im.thumbnail(thumbnail_size)
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self.thumb_bytes = io.BytesIO()
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im.save(self.thumb_bytes, self.format)
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self.thumb_bytes.seek(0)
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else:
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self.thumb_bytes.seek(0)
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# Copy the buffer, to avoid closing the file
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data = io.BytesIO(self.thumb_bytes.getbuffer())
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return data
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def load_file(self) -> bool:
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"""Load data stored on disk to the in-memory bytestream."""
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if self.file_exists: # If data file exists
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with open(self.file, 'rb') as f:
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self.bytestream = io.BytesIO(f.read()) # Load bytes from file
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self.bytestream.seek(0) # Rewind data bytes again
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return True
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else:
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return False
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def save_file(self) -> bool:
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"""Write the StreamObjects bytestream to a file."""
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if not self.keep_on_disk: # If capture is currently temporary
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self.load_file() # Load data from tmp file into bytestream, if tmp file exists
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self.keep_on_disk = True # Flag as kept on disk
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self.file = self.file_notmp # Reset file path to non-temporary path
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self.split_file_path(self.file) # Set split properties based on new path
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logging.info("Moved temporary file out to {}".format(self.file))
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if self.stream_exists: # If there's a bytestream to save
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with open(self.file, 'ab') as f: # Load file as bytes
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logging.debug("Writing bytestream to file {}".format(self.file))
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f.seek(0, 0) # Seek to the start of the file
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f.write(self.binary) # Write data bytes to file
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return True
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else:
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return False
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def delete_stream(self):
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"""Clear the BytesIO bytestream of the StreamObject."""
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self.bytestream = io.BytesIO()
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def delete_file(self) -> bool:
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"""If the StreamObject has been saved, delete the file."""
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if os.path.isfile(self.file):
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logging.info("Deleting file {}".format(self.file))
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os.remove(self.file)
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return True
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else:
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return False
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def delete(self):
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"""Entirely delete all capture data."""
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logging.info("Deleting {}".format(self.id))
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self.delete_stream()
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self.delete_file()
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def shunt(self):
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"""Demote the StreamObject from being stored in memory."""
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if not self.file_exists: # If file doesn't already exist
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self.save_file() # Save bytestream to disk, if it exists
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self.delete_stream() # Delete the bytestream from memory
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def close(self):
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"""Both clear the bytestream, and delete any associated on-disk data."""
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logging.info("Closing {}".format(self.id))
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self.delete_stream()
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if not self.keep_on_disk:
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self.delete_file()
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atexit.register(clear_tmp) |