Resolve path to original file pointed to by macOS alias

resolve_macos_alias_path.py

"""Resolve path to original file pointed to by macOS alias

To use: 
pip install pyobjc-core

python3 resolve_macos_alias_path.py /path/to/alias
"""

from Foundation import (
    NSURL,
    NSData,
    NSError,
    NSURLBookmarkResolutionWithoutMounting,
    NSURLBookmarkResolutionWithoutUI,
)


def resolve_alias_path(alias_path: str) -> str:
    """Given a path to a macOS alias file, return the resolved path to the original file"""
    options = NSURLBookmarkResolutionWithoutUI | NSURLBookmarkResolutionWithoutMounting
    alias_url = NSURL.fileURLWithPath_(alias_path)
    bookmark, error = NSURL.bookmarkDataWithContentsOfURL_error_(alias_url, None)
    if error:
        raise ValueError(f"Error creating bookmark data: {error}")

    resolved_url, is_stale, error = (
        NSURL.URLByResolvingBookmarkData_options_relativeToURL_bookmarkDataIsStale_error_(
            bookmark, options, None, None, None
        )
    )
    if error:
        raise ValueError(f"Error resolving bookmark data: {error}")

    return str(resolved_url.path())


if __name__ == "__main__":
    import sys

    if len(sys.argv) < 2:
        print("Usage: python alias.py <alias_path>")
        sys.exit(1)

    alias_path = sys.argv[1]
    resolved_path = resolve_alias_path(alias_path)
    print(f"alias: {alias_path}\noriginal: {resolved_path}")