__init__.py 文件源码

def _hostname_to_x509(hostname):
    # Because we are a DWIM library for lazy slackers, we cheerfully pervert
    # the cryptography library's carefully type-safe API, and silently DTRT
    # for any of the following hostname types:
    #
    # - "example.org"
    # - "example.org"
    # - "éxamplë.org"
    # - "xn--xampl-9rat.org"
    # - "xn--xampl-9rat.org"
    # - "127.0.0.1"
    # - "::1"
    # - "10.0.0.0/8"
    # - "2001::/16"
    #
    # and wildcard variants of the hostnames.
    if not isinstance(hostname, unicode):
        raise TypeError("hostnames must be text (unicode on py2, str on py3)")

    # Have to try ip_address first, because ip_network("127.0.0.1") is
    # interpreted as being the network 127.0.0.1/32. Which I guess would be
    # fine, actually, but why risk it.
    for ip_converter in [ipaddress.ip_address, ipaddress.ip_network]:
        try:
            ip_hostname = ip_converter(hostname)
        except ValueError:
            continue
        else:
            return x509.IPAddress(ip_hostname)

    # Encode to an A-label, like cryptography wants
    if hostname.startswith("*."):
        alabel_bytes = b"*." + idna.encode(hostname[2:], uts46=True)
    else:
        alabel_bytes = idna.encode(hostname, uts46=True)
    # Then back to text, which is mandatory on cryptography 2.0 and earlier,
    # and may or may not be deprecated in cryptography 2.1.
    alabel = alabel_bytes.decode("ascii")
    return x509.DNSName(alabel)