def field_file_to_local_path(
field_file: FieldFile) -> Generator[Path, None, None]:
"""
Provide a filesystem path to the content of a FieldFile.
Normally, a FieldFile is usable as a Python file-like object, as:
`with model.field.open() as file_stream:`
However, in some use cases, particularly when invoking third-party libraries,
an actual filesystem path to the content is required. This context manager
provides this as:
`with field_file_to_local_path(model.field) as file_path:`
When this context manager exists, the filesystem content and path will be
garbage collected.
"""
with field_file.open('rb'):
file_obj: File = field_file.file
if type(file_obj) is File:
# When file_obj is an actual File, (typically backed by FileSystemStorage),
# it is already at a stable path on disk.
yield Path(file_obj.name)
else:
# When file_obj is actually a subclass of File, it only provides a Python
# file-like object API. So, it must be copied to a stable path.
field_file_basename = PurePath(field_file.name).name
with tempfile.NamedTemporaryFile(
'wb', suffix=field_file_basename) as dest_stream:
shutil.copyfileobj(file_obj, dest_stream)
dest_stream.flush()
yield Path(dest_stream.name)
def get_exif(file_: FieldFile) -> str:
"""
Use exiftool to extract exif data from the given file field.
"""
exiftool_path = shutil.which('exiftool')
if not exiftool_path:
raise ExifError('Could not find `exiftool`')
if not file_._committed:
# pipe file content to exiftool
fo = file_._file
fo.seek(0)
else:
fo = file_.open()
process = subprocess.run(
[exiftool_path, '-j', '-l', '-'],
check=True,
input=fo.read(),
stdout=subprocess.PIPE,
)
return process.stdout
def compute_checksum_file(field_file: FieldFile, chunk_num_blocks=128):
with field_file.open() as f:
return _compute_hash(f, chunk_num_blocks)
