datalad.api.extract_metadata

datalad.api.extract_metadata(types, files=None, dataset=None)

Run one or more of DataLad’s metadata extractors on a dataset or file.

The result(s) are structured like the metadata DataLad would extract during metadata aggregation. There is one result per dataset/file.

Examples

Extract metadata with two extractors from a dataset in the current directory and also from all its files:

$ datalad extract-metadata -d . --type frictionless_datapackage --type datalad_core

Extract XMP metadata from a single PDF that is not part of any dataset:

$ datalad extract-metadata --type xmp Downloads/freshfromtheweb.pdf

Examples

Parameters:
  • types – Name of a metadata extractor to be executed.
  • files (sequence of str or None, optional) – Path of a file to extract metadata from. [Default: None]
  • dataset (Dataset or None, optional) – “Dataset to extract metadata from. If no file is given, metadata is extracted from all files of the dataset. [Default: None]
  • on_failure ({'ignore', 'continue', 'stop'}, optional) – behavior to perform on failure: ‘ignore’ any failure is reported, but does not cause an exception; ‘continue’ if any failure occurs an exception will be raised at the end, but processing other actions will continue for as long as possible; ‘stop’: processing will stop on first failure and an exception is raised. A failure is any result with status ‘impossible’ or ‘error’. Raised exception is an IncompleteResultsError that carries the result dictionaries of the failures in its failed attribute. [Default: ‘continue’]
  • result_filter (callable or None, optional) – if given, each to-be-returned status dictionary is passed to this callable, and is only returned if the callable’s return value does not evaluate to False or a ValueError exception is raised. If the given callable supports **kwargs it will additionally be passed the keyword arguments of the original API call. [Default: None]
  • result_renderer ({'default', 'json', 'json_pp', 'tailored'} or None, optional) – format of return value rendering on stdout. [Default: None]
  • result_xfm ({'datasets', 'successdatasets-or-none', 'paths', 'relpaths', 'metadata'} or callable or None, optional) – if given, each to-be-returned result status dictionary is passed to this callable, and its return value becomes the result instead. This is different from result_filter, as it can perform arbitrary transformation of the result value. This is mostly useful for top- level command invocations that need to provide the results in a particular format. Instead of a callable, a label for a pre-crafted result transformation can be given. [Default: None]
  • return_type ({'generator', 'list', 'item-or-list'}, optional) – return value behavior switch. If ‘item-or-list’ a single value is returned instead of a one-item return value list, or a list in case of multiple return values. None is return in case of an empty list. [Default: ‘list’]