datalad.api.download_url(urls, *, dataset=None, path=None, overwrite=False, archive=False, save=True, message=None)

Download content

It allows for a uniform download interface to various supported URL schemes (see command help for details), re-using or asking for authentication details maintained by datalad.


Download files from an http and S3 URL:

> download_url(urls=['', 's3://bucket/file2.dat'])

Download a file to a path and provide a commit message:

> download_url(urls='s3://bucket/file2.dat', message='added a file', path='myfile.dat')

Append a trailing slash to the target path to download into a specified directory:

> download_url([''], path='data/')

Leave off the trailing slash to download into a regular file:

> download_url([''], path='data')
  • urls (non-empty sequence of str) – URL(s) to be downloaded. Supported protocols: ‘ftp’, ‘http’, ‘https’, ‘s3’, ‘shub’.

  • dataset (Dataset or None, optional) – specify the dataset to add files to. If no dataset is given, an attempt is made to identify the dataset based on the current working directory. Use save=False to prevent adding files to the dataset. [Default: None]

  • path (str or None, optional) – target for download. If the path has a trailing separator, it is treated as a directory, and each specified URL is downloaded under that directory to a base name taken from the URL. Without a trailing separator, the value specifies the name of the downloaded file (file name extensions inferred from the URL may be added to it, if they are not yet present) and only a single URL should be given. In both cases, leading directories will be created if needed. This argument defaults to the current directory. [Default: None]

  • overwrite (bool, optional) – flag to overwrite it if target file exists. [Default: False]

  • archive (bool, optional) – pass the downloaded files to add_archive_content(…, delete=True). [Default: False]

  • save (bool, optional) – by default all modifications to a dataset are immediately saved. Giving this option will disable this behavior. [Default: True]

  • message (str or None, optional) – a description of the state or the changes made to a 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 – select rendering mode command results. ‘tailored’ enables a command- specific rendering style that is typically tailored to human consumption, if there is one for a specific command, or otherwise falls back on the the ‘generic’ result renderer; ‘generic’ renders each result in one line with key info like action, status, path, and an optional message); ‘json’ a complete JSON line serialization of the full result record; ‘json_pp’ like ‘json’, but pretty-printed spanning multiple lines; ‘disabled’ turns off result rendering entirely; ‘<template>’ reports any value(s) of any result properties in any format indicated by the template (e.g. ‘{path}’, compare with JSON output for all key-value choices). The template syntax follows the Python “format() language”. It is possible to report individual dictionary values, e.g. ‘{metadata[name]}’. If a 2nd-level key contains a colon, e.g. ‘music:Genre’, ‘:’ must be substituted by ‘#’ in the template, like so: ‘{metadata[music#Genre]}’. [Default: ‘tailored’]

  • 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’]