Added support to filepath_from_url for UNC paths and tests for UNC and posix paths

[douglascomet]

This PR is a follow up to #1664 to add support to filepath_from_url and tests for UNC paths.

[douglascomet]

Just occurred to me, should filepath_from_url raise or do nothing if a urlstr does not have the file:// prefix? Same question if a url with a different scheme is provided?

[codecov-commenter]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (d22935e) 79.84% compared to head (1ad7b70) 79.84%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1674   +/-   ##
=======================================
  Coverage   79.84%   79.84%           
=======================================
  Files         197      197           
  Lines       21796    21820   +24     
  Branches     4358     4363    +5     
=======================================
+ Hits        17403    17423   +20     
- Misses       2232     2234    +2     
- Partials     2161     2163    +2     

Flag	Coverage Δ
py-unittests	79.84% <87.09%> (+<0.01%)	⬆️

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Files	Coverage Δ
tests/test_url_conversions.py	95.34% <100.00%> (+2.49%)	⬆️
src/py-opentimelineio/opentimelineio/url_utils.py	85.18% <63.63%> (-14.82%)	⬇️

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[apetrynet]

Thanks @douglascomet for working on covering more windows URL cases.

Here is a suggestion for an alternative way of achieving this. It only manipulates the path if a windows drive is found or an URL only contains two leading slashes like so: "file://host/share/path/to/file.ext"

Please note that I've also done some minor adjustments to code untouched by your PR.

def filepath_from_url(urlstr):
    """
    Take an url and return a filepath.

    URLs can either be encoded according to the `RFC 3986`_ standard or not.
    Additionally, Windows mapped drive letter and UNC paths need to be accounted for
    when processing URL(s); however, there are `ongoing discussions`_ about how to best
    handle this within Python developer community. This function is meant to cover
    these scenarios in the interim.

    .. _RFC 3986: https://tools.ietf.org/html/rfc3986#section-2.1
    .. _ongoing discussions: https://discuss.python.org/t/file-uris-in-python/15600
    """

    # Parse provided URL
    parsed_result = urlparse.urlparse(urlstr)

    # De-encode the parsed path
    decoded_parsed_path = urlparse.unquote(parsed_result.path)

    # Convert the parsed URL to a path
    filepath = Path(request.url2pathname(decoded_parsed_path))

    # If the network location is a window drive, reassemble the path
    if PureWindowsPath(parsed_result.netloc).drive:
        filepath = Path(parsed_result.netloc + decoded_parsed_path)

    # Check if the specified index is a windows drive, then offset the path
    elif PureWindowsPath(filepath.parts[1]).drive:
        # Remove leading "/" if/when `request.url2pathname` yields "/S:/path/file.ext"
        filepath = filepath.relative_to(filepath.root)

    # Should catch UNC paths, as parsing "file:///some/path/to/file.ext" doesn't provide a netloc
    elif parsed_result.netloc and parsed_result.netloc != 'localhost':
        # Paths of type: "file://host/share/path/to/file.ext" provide "host" as netloc
        filepath = Path('//', parsed_result.netloc + decoded_parsed_path)

    # Convert "\" to "/" if needed
    return filepath.as_posix()

[meshula]

@douglascomet Does your latest commit resolve either of the conversations?

[douglascomet]

@douglascomet Does your latest commit resolve either of the conversations?

@meshula Yes, it will. Apologies for the delay with pushing this PR forward.

[meshula]

@douglascomet No need to apologize, I was just checking status, no urgency.

[reinecke]

@douglascomet in response to:

Just occurred to me, should filepath_from_url raise or do nothing if a urlstr does not have the file:// prefix? Same question if a url with a different scheme is provided?

I would say it should not raise - the implication is that that is a relative URL. That does, however, imply that filepath_from_url should maybe accepts something like a base_path with is the filepath that paths can be relative to (usually this would be the path of parent dir the loaded otio file is in).

But I think this is out of scope for this PR.

[apetrynet]

LGTM!