Add Azure File/URL helpers

[andrewbolster]

def az_file_url_to_query_components(url:str):
    p = urlparse(url)
    assert not p.params, f"Invalid Params: {p.params}"
    assert not p.fragment, f"Invalid Fragment: {p.fragment}"
    assert not p.query, f"Invalid Params: {p.query}"
    
    netlocs =  p.netloc.split('.')
    assert len(netlocs) == 5, f"Invalid netlocs: {p.netloc}: Not long enough"
    assert netlocs[2:] == ['core','windows','net'], f"Invalid netlocs: {p.netloc} should end in core.windows.net"
    assert netlocs[1] in ['blob','dfs'], f"Invalid netlocs: {p.netloc} should be one of blob/dfs"
    
    storage_account = netlocs[0]
    _, container, *paths = p.path.split('/') #path starts with a / so p.path.split('/')[0] == ''
    file_path = '/'.join(paths)

    return  dict(
        storage_account = storage_account, 
        container = container,
        file_path = file_path
    )

And then query like

d = az_file_url_to_query_components("https://storageaccount.blob.core.windows.net/container/file_path.parquet")
df = pd.read_parquet(
  f"az://{d['container']}/{d['file_path']}", 
  storage_options = dict(
    account_name=d['storage_account'], 
    anon=False)
)