481 lines
17 KiB
Python
481 lines
17 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 yaml
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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 = (200, 150)
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BASE_CAPTURE_PATH = os.path.join(os.path.expanduser('~'), 'micrographs') #: str: Base path to store all captures
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TEMP_CAPTURE_PATH = os.path.join(BASE_CAPTURE_PATH, 'tmp') #: str: Base path to store all temporary captures (automatically emptied)
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def clear_tmp():
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"""
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Removes all files in the ``TEMP_CAPTURE_PATH`` directory
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"""
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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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logging.debug("Cleared {}.".format(TEMP_CAPTURE_PATH))
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def capture_from_dict(capture_dict):
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"""
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Creates an instance of CaptureObject from a dictionary of capture information.
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This is used when reloading the API server, to restore captures created in the
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previous session.
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Args:
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capture_dict (dict): Dictionary containing capture information
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"""
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capture = CaptureObject(create_metadata_file=False) # Create a placeholder capture
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# Populate capture parameters
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capture.temporary = capture_dict['temporary']
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capture.id = capture_dict['metadata']['id']
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capture.timestring = capture_dict['metadata']['time']
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capture.format = capture_dict['metadata']['format']
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if 'custom' in capture_dict['metadata']:
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capture._metadata = capture_dict['metadata']['custom']
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if 'tags' in capture_dict['metadata']:
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capture.tags = capture_dict['metadata']['tags']
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capture.file = capture_dict['metadata']['path']
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capture.split_file_path(capture.file)
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return capture
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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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temporary: bool = False,
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filename: str = '',
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folder: str = '',
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fmt: str = '',
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create_metadata_file: bool = True) -> 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 #: str: Unique capture ID
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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") #: str: Timestring of capture creation time
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# Store file format
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self.format = fmt #: str: Capture data format (e.g. jpeg, h264)
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# Keep on disk after close by default
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self.temporary = temporary #: bool: Mark the capture as temporary, to be deleted as the server closes, or as resources are required
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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 #: bool: Write capture data to disk immediately, rather than to memory initially (useful for video recordings)
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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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# Create folder path. Default to BASE_CAPTURE_PATH
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if not folder:
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folder = BASE_CAPTURE_PATH
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self.folder = folder
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# Dictionary for storing custom metadata
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self._metadata = {} #: dict: Dictionary of custom metadata to be included in metadata file
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# List for storing tags
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self.tags = [] #: list: List of tags. Essentially just as extra custom metadata field, but useful for quick organisation
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# Initialise the capture stream
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self.initialise_capture(create_metadata_file=create_metadata_file)
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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(
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"Entering context for {}. Stored files will be cleaned up automatically regardless of location.".format(
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self.id))
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self.temporary = True # 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, create_metadata_file=True):
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"""
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Initialise the capture object. Creates a file name and builds a file path,
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creates an in-memory byte stream for capture data, and creates a metadata
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file on disk.
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Args:
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create_metadata_file (bool): Skips creating a metadata file if False (useful for captures being processed but not stored)
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"""
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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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# Save initial metadata file
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if create_metadata_file:
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self.save_metadata()
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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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Args:
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filename (str): Filename of capture
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folder (str): Directory on disk to store capture file
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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 self.temporary:
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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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"""
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Take a full file path, and split it into separated class properties.
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Args:
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filepath (str): String of the full file path, including file format extension
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"""
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self.filefolder, self.filename = os.path.split(
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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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self.metadataname = "{}.yaml".format(self.basename)
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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 capture data BytesIO bytestream exists in memory."""
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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 capture data file exists on disk."""
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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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# HANDLE TAGS
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def put_tag(self, tag: str):
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"""
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Add a new tag to the ``tags`` list attribute.
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Args:
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tag (str): Tag to be added
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"""
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if not tag in self.tags:
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self.tags.append(tag)
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self.save_metadata()
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def delete_tag(self, tag: str):
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"""
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Remove a tag from the ``tags`` list attribute, if it exists.
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Args:
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tag (str): Tag to be removed
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"""
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if tag in self.tags:
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self.tags = [new_tag for new_tag in self.tags if new_tag != tag]
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# HANDLE METADATA
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@property
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def metadata_file(self) -> str:
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"""
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Path to the associated on-disk metadata YAML file.
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"""
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return "{}.yaml".format(os.path.splitext(self.file)[0])
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def put_metadata(self, data: dict) -> None:
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"""
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Merge metadata from a passed dictionary into the capture metadata, and saves.
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Args:
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data (dict): Dictionary of metadata to be added
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"""
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self._metadata.update(data)
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self.save_metadata()
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def save_metadata(self) -> None:
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"""
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Save metadata to on-disk metadata YAML file
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"""
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logging.debug("Writing metadata to file {}".format(self.metadata_file))
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with open(self.metadata_file, 'w') as outfile:
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yaml.dump(self.metadata, outfile, default_flow_style=False)
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def delete_metadata(self) -> None:
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"""
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Delete on-disk metadata YAML file, if it exists
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"""
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if os.path.isfile(self.metadata_file):
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logging.info("Deleting file {}".format(self.metadata_file))
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os.remove(self.metadata_file)
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@property
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def metadata(self) -> dict:
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"""
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Create basic metadata dictionary from basic capture data,
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and any added custom metadata and tags.
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"""
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d = {'id': self.id, 'filename': self.filename, 'path': self.file, 'time': self.timestring,
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'format': self.format, 'tags': self.tags, 'custom': self._metadata}
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# Add custom metadata to dictionary
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return d
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@property
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def yaml(self) -> str:
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"""
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Return a string containing a YAML-formatted representation of the capture matadata
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"""
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return yaml.dump(self.metadata, default_flow_style=False)
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@property
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def exists(self) -> bool:
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"""
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Check if either an in-memory byte stream or on-disk file of capture data exists.
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If False, the capture data cannot be obtained.
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"""
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return self.stream_exists or self.file_exists
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@property
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def state(self) -> dict:
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"""
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Return a dictionary of objects full state, including metadata.
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"""
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# Create basic state dictionary
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d = {'locked': self.locked, 'temporary': self.temporary, 'metadata': self.metadata,
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'metadata_path': self.metadata_file}
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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.exists:
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d['available'] = True
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else:
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d['available'] = False
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return d
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@property
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def data(self) -> io.BytesIO:
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"""
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Return a byte string of the capture data.
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If the capture data exists in-memory, this will be loaded. If the data only exists
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on disk, this will automatically fall back to loading from disk.
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"""
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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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"""
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Returns a thumbnail of the capture data, for supported image formats.
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"""
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global thumbnail_size
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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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self.thumb_bytes = io.BytesIO()
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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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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 self.temporary: # 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.temporary = False # 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 save(self) -> None:
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"""Write stream to file, and save/update metadata file"""
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# Try to save the file (only succeeds if an unsaved stream exists)
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self.save_file()
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# If a stream OR file exists, save the metadata file
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if self.exists:
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self.save_metadata()
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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.metadata_file):
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logging.info("Deleting file {}".format(self.metadata_file))
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os.remove(self.metadata_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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self.delete_metadata()
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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() # 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 self.temporary:
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self.delete()
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atexit.register(clear_tmp)
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