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Explicit output stream must be specified when capturing

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This commit is contained in:
Joel Collins 2019-01-08 15:46:57 +00:00
parent 3f69332240
commit 78ce3a9a11
4 changed files with 187 additions and 153 deletions
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111
openflexure_microscope/camera/capture.py
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@ -12,7 +12,7 @@ thumbnail_size = (60, 60)
BASE_CAPTURE_PATH = os.path.join(os.path.expanduser('~'), 'micrographs')
TEMP_CAPTURE_PATH = os.path.join(BASE_CAPTURE_PATH, 'tmp')
class StreamObject(object):
class CaptureObject(object):
"""
StreamObject used to store and process capture data, and metadata.
@ -26,6 +26,7 @@ class StreamObject(object):
folder: str='',
fmt: str='') -> None:
"""Create a new StreamObject, to manage capture data."""
# Store a nice ID
self.id = uuid.uuid4().hex
logging.info("Created StreamObject {}".format(self.id))
@ -37,24 +38,18 @@ class StreamObject(object):
# Keep on disk after close by default
self.keep_on_disk = keep_on_disk
# Explicitally state if capture should be written to a file, not a bytestream
self.write_to_file = write_to_file
# Create file name. Default to UUID
if not filename:
filename = self.id
self.filename = filename
self.filename = "{}.{}".format(filename, fmt)
self.folder = folder
self.build_file_path(self.filename, self.folder, self.format)
# 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 not self.write_to_file:
logging.debug("Target for {} set to 'stream'".format(self.id))
self.target = self.stream
else:
logging.debug("Target for {} set to 'file'".format(self.id))
self.target = self.file
# Initialise the capture stream
self.initialise_capture()
# Log if created by context manager
self.context_manager = False
@ -67,14 +62,12 @@ class StreamObject(object):
def __enter__(self):
"""Create StreamObject in context, to auto-clean disk data."""
logging.debug("Entering context for {}.\
Stored files will be cleaned up automatically.".format(self.id))
logging.debug("Entering context for {}. Stored files will be cleaned up automatically regardless of location.".format(self.id))
self.keep_on_disk = False # Flag file to be removed on close.
self.context_manager = True # Used in metadata
# Re-generate file name for temp file
logging.info("Re-generating file name for temp file")
self.build_file_path(self.filename, self.folder, self.format)
logging.info("Rebuilding as a temporary capture...")
self.initialise_capture()
return self
@ -83,11 +76,24 @@ class StreamObject(object):
logging.info("Cleaning up {}".format(self.id))
self.close()
def initialise_capture(self):
self.build_file_path(self.filename, self.folder)
# Byte bytestream properties
self.bytestream = io.BytesIO() # Byte bytestream that data will be written to
# Set default write target
if not self.write_to_file:
logging.debug("Target for {} set to 'bytestream'".format(self.id))
self.stream = self.bytestream
else:
logging.debug("Target for {} set to 'file'".format(self.id))
self.stream = self.file
def build_file_path(
self,
filename: str,
folder: str,
fmt: str):
folder: str):
"""
Construct a full file path, based on filename, folder, and file format.
@ -95,9 +101,7 @@ class StreamObject(object):
"""
global TEMP_CAPTURE_PATH
file_given_name = "{}.{}".format(filename, fmt) # Given file name. May include a relative path
self.file = os.path.join(folder, file_given_name) # Full file name by joining given folder to given name
self.file = os.path.join(folder, filename) # Full file name by joining given folder to given name
self.split_file_path(self.file) # Split file path into folder, filename, and basename
@ -116,6 +120,11 @@ class StreamObject(object):
if not os.path.exists(self.filefolder):
os.makedirs(self.filefolder)
logging.debug(self.file)
logging.debug(self.filename)
logging.debug(self.basename)
logging.debug(self.filefolder)
def split_file_path(self, filepath):
"""Takes a full file path, and splits it into separated class properties."""
self.filefolder, self.filename = os.path.split(filepath) # Split the full file path into a folder and a filename
@ -131,14 +140,14 @@ class StreamObject(object):
@property
def stream_exists(self, auto_rewind=True) -> bool:
"""Check if BytesIO stream is empty."""
"""Check if BytesIO bytestream is empty."""
if auto_rewind:
self.stream.seek(0) # Rewind the data bytes for reading
if self.stream.getvalue(): # If data stream contains data
self.stream.seek(0) # Rewind the data bytes for reading
self.bytestream.seek(0) # Rewind the data bytes for reading
if self.bytestream.getvalue(): # If data bytestream contains data
self.bytestream.seek(0) # Rewind the data bytes for reading
return True
else:
self.stream.seek(0) # Rewind the data bytes for reading
self.bytestream.seek(0) # Rewind the data bytes for reading
return False
@property
@ -161,11 +170,11 @@ class StreamObject(object):
'time': self.timestring
}
# Check stream
# Check bytestream
if self.stream_exists:
d['stream'] = True
d['bytestream'] = True
else:
d['stream'] = False
d['bytestream'] = False
# Combined availability of data
if self.stream_exists or self.file_exists:
@ -182,19 +191,19 @@ class StreamObject(object):
@property
def data(self) -> io.BytesIO:
"""Return a byte string of the capture data."""
self.stream.seek(0) # Rewind the data bytes for reading
self.bytestream.seek(0) # Rewind the data bytes for reading
if self.stream_exists: # If data stream contains data
# Create a copy of the stream bytes
data = io.BytesIO(self.stream.getbuffer())
if self.stream_exists: # If data bytestream contains data
# Create a copy of the bytestream bytes
data = io.BytesIO(self.bytestream.getbuffer())
else: # If data stream is empty
else: # If data bytestream is empty
if self.file_exists: # If data file exists
logging.info("Opening from file {}".format(self.file))
with open(self.file, 'rb') as f:
d = io.BytesIO(f.read()) # Load bytes from file
d.seek(0) # Rewind loaded stream
# Create a copy of the stream bytes
d.seek(0) # Rewind loaded bytestream
# Create a copy of the bytestream bytes
data = io.BytesIO(d.getbuffer())
else:
data = None
@ -226,27 +235,27 @@ class StreamObject(object):
return data
def load_file(self) -> bool:
"""Load data stored on disk to the in-memory stream."""
"""Load data stored on disk to the in-memory bytestream."""
if self.file_exists: # If data file exists
with open(self.file, 'rb') as f:
self.stream = io.BytesIO(f.read()) # Load bytes from file
self.stream.seek(0) # Rewind data bytes again
self.bytestream = io.BytesIO(f.read()) # Load bytes from file
self.bytestream.seek(0) # Rewind data bytes again
return True
else:
return False
def save_file(self) -> bool:
"""Write the StreamObjects stream to a file."""
"""Write the StreamObjects bytestream to a file."""
if not self.keep_on_disk: # If capture is currently temporary
self.load_file() # Load data from tmp file into stream, if tmp file exists
self.load_file() # Load data from tmp file into bytestream, if tmp file exists
self.keep_on_disk = True # Flag as kept on disk
self.file = self.file_notmp # Reset file path to non-temporary path
self.split_file_path(self.file) # Set split properties based on new path
logging.info("Moved temporary file out to {}".format(self.file))
if self.stream_exists: # If there's a stream to save
if self.stream_exists: # If there's a bytestream to save
with open(self.file, 'ab') as f: # Load file as bytes
logging.debug("Writing stream to file {}".format(self.file))
logging.debug("Writing bytestream 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
return True
@ -254,8 +263,8 @@ class StreamObject(object):
return False
def delete_stream(self):
"""Clear the BytesIO stream of the StreamObject."""
self.stream = io.BytesIO()
"""Clear the BytesIO bytestream of the StreamObject."""
self.bytestream = io.BytesIO()
def delete_file(self) -> bool:
"""If the StreamObject has been saved, delete the file."""
@ -275,11 +284,11 @@ class StreamObject(object):
def shunt(self):
"""Demote the StreamObject from being stored in memory."""
if not self.file_exists: # If file doesn't already exist
self.save_file() # Save stream to disk, if it exists
self.delete_stream() # Delete the stream from memory
self.save_file() # Save bytestream to disk, if it exists
self.delete_stream() # Delete the bytestream from memory
def close(self):
"""Both clear the stream, and delete any associated on-disk data."""
"""Both clear the bytestream, and delete any associated on-disk data."""
logging.info("Closing {}".format(self.id))
self.delete_stream()
if not self.keep_on_disk: