Function _check_bracketed_netloc

Lib/urllib/parse.py:527–542

(netloc)

                             "characters under NFKC normalization")

def _check_bracketed_netloc(netloc):
    # Note that this function must mirror the splitting
    # done in NetlocResultMixins._hostinfo().
    hostname_and_port = netloc.rpartition('@')[2]
    before_bracket, have_open_br, bracketed = hostname_and_port.partition('[')
    if have_open_br:
        # No data is allowed before a bracket.
        if before_bracket:
            raise ValueError("Invalid IPv6 URL")
        hostname, _, port = bracketed.partition(']')
        # No data is allowed after the bracket but before the port delimiter.
        if port and not port.startswith(":"):
            raise ValueError("Invalid IPv6 URL")
    else:
        hostname, _, port = hostname_and_port.partition(':')
    _check_bracketed_host(hostname)

# Valid bracketed hosts are defined in
# https://www.rfc-editor.org/rfc/rfc3986#page-49 and https://url.spec.whatwg.org/