FileFormatter

class lsst.daf.butler.formatters.fileFormatter.FileFormatter

Bases: lsst.daf.butler.Formatter

Interface for reading and writing files on a POSIX file system.

Attributes Summary

extension	Default file extension to use for writing files.
unsupportedParameters

Methods Summary

name()	Returns the fully qualified name of the formatter.
predictPath(location)	Return the path that would be returned by write, without actually writing.
read(fileDescriptor[, component])	Read data from a file.
segregateParameters(parameters)	Segregate the supplied parameters into those understood by the formatter and those not understood by the formatter.
write(inMemoryDataset, fileDescriptor)	Write a Python object to a file.

Attributes Documentation

extension = None

Default file extension to use for writing files. None means that no modifications will be made to the supplied file extension.

unsupportedParameters = frozenset()

Methods Documentation

classmethod name()

Returns the fully qualified name of the formatter.

predictPath(location)

Return the path that would be returned by write, without actually writing.

location : Location

The location to simulate writing to.

read(fileDescriptor, component=None)

Read data from a file.

Parameters:

fileDescriptor : FileDescriptor

Identifies the file to read, type to read it into and parameters to be used for reading.

component : str, optional

Component to read from the file. Only used if the StorageClass for reading differed from the StorageClass used to write the file.

Returns:

inMemoryDataset : object

The requested data as a Python object. The type of object is controlled by the specific formatter.

Raises:

ValueError

Component requested but this file does not seem to be a concrete composite.

segregateParameters(parameters)

Segregate the supplied parameters into those understood by the formatter and those not understood by the formatter.

Any unsupported parameters are assumed to be usable by associated assemblers.

Parameters:

parameters : dict

Parameters with values that have been supplied by the caller and which might be relevant for the formatter.

Returns:

supported : dict

Those parameters supported by this formatter.

unsupported : dict

Those parameters not supported by this formatter.

write(inMemoryDataset, fileDescriptor)

Write a Python object to a file.

Parameters:

inMemoryDataset : object

The Python object to store.

fileDescriptor : FileDescriptor

Identifies the file to read, type to read it into and parameters to be used for reading.

Returns:

path : str

The URI where the primary file is stored.