"""

 Network Utilities

 (from web.py)

 """

 __all__ = [

   "validipaddr", "validipport", "validip", "validaddr", 

   "urlquote",

   "httpdate", "parsehttpdate", 

   "htmlquote", "htmlunquote", "websafe",

 ]

 import urllib, time

 try: import datetime

 except ImportError: pass

 def validipaddr(address):

     """

     Returns True if `address` is a valid IPv4 address.

         >>> validipaddr('192.168.1.1')

         True

         >>> validipaddr('192.168.1.800')

         False

         >>> validipaddr('192.168.1')

         False

     """

     try:

         octets = address.split('.')

         if len(octets) != 4:

             return False

         for x in octets:

             if not (0 <= int(x) <= 255):

                 return False

     except ValueError:

         return False

     return True

 def validipport(port):

     """

     Returns True if `port` is a valid IPv4 port.

         >>> validipport('9000')

         True

         >>> validipport('foo')

         False

         >>> validipport('1000000')

         False

     """

     try:

         if not (0 <= int(port) <= 65535):

             return False

     except ValueError:

         return False

     return True

 def validip(ip, defaultaddr="0.0.0.0", defaultport=8080):

     """Returns `(ip_address, port)` from string `ip_addr_port`"""

     addr = defaultaddr

     port = defaultport

     ip = ip.split(":", 1)

     if len(ip) == 1:

         if not ip[0]:

             pass

         elif validipaddr(ip[0]):

             addr = ip[0]

         elif validipport(ip[0]):

             port = int(ip[0])

         else:

             raise ValueError, ':'.join(ip) + ' is not a valid IP address/port'

     elif len(ip) == 2:

         addr, port = ip

         if not validipaddr(addr) and validipport(port):

             raise ValueError, ':'.join(ip) + ' is not a valid IP address/port'

         port = int(port)

     else:

         raise ValueError, ':'.join(ip) + ' is not a valid IP address/port'

     return (addr, port)

 def validaddr(string_):

     """

     Returns either (ip_address, port) or "/path/to/socket" from string_

         >>> validaddr('/path/to/socket')

         '/path/to/socket'

         >>> validaddr('8000')

         ('0.0.0.0', 8000)

         >>> validaddr('127.0.0.1')

         ('127.0.0.1', 8080)

         >>> validaddr('127.0.0.1:8000')

         ('127.0.0.1', 8000)

         >>> validaddr('fff')

         Traceback (most recent call last):

             ...

         ValueError: fff is not a valid IP address/port

     """

     if '/' in string_:

         return string_

     else:

         return validip(string_)

 def urlquote(val):

     """

     Quotes a string for use in a URL.

         >>> urlquote('://?f=1&j=1')

         '%3A//%3Ff%3D1%26j%3D1'

         >>> urlquote(None)

         ''

         >>> urlquote(u'\u203d')

         '%E2%80%BD'

     """

     if val is None: return ''

     if not isinstance(val, unicode): val = str(val)

     else: val = val.encode('utf-8')

     return urllib.quote(val)

 def httpdate(date_obj):

     """

     Formats a datetime object for use in HTTP headers.

         >>> import datetime

         >>> httpdate(datetime.datetime(1970, 1, 1, 1, 1, 1))

         'Thu, 01 Jan 1970 01:01:01 GMT'

     """

     return date_obj.strftime("%a, %d %b %Y %H:%M:%S GMT")

 def parsehttpdate(string_):

     """

     Parses an HTTP date into a datetime object.

         >>> parsehttpdate('Thu, 01 Jan 1970 01:01:01 GMT')

         datetime.datetime(1970, 1, 1, 1, 1, 1)

     """

     try:

         t = time.strptime(string_, "%a, %d %b %Y %H:%M:%S %Z")

     except ValueError:

         return None

     return datetime.datetime(*t[:6])

 def htmlquote(text):

     r"""

     Encodes `text` for raw use in HTML.

         >>> htmlquote(u"<'&\">")

         u'<'&">'

     """

     text = text.replace(u"&", u"&") # Must be done first!

     text = text.replace(u"<", u"&lt;")

     text = text.replace(u">", u">")

     text = text.replace(u"'", u"'")

     text = text.replace(u'"', u""")

     return text

 def htmlunquote(text):

     r"""

     Decodes `text` that's HTML quoted.

         >>> htmlunquote(u'<'&">')

         u'<\'&">'

     """

     text = text.replace(u""", u'"')

     text = text.replace(u"'", u"'")

     text = text.replace(u">", u">")

     text = text.replace(u"&lt;", u"<")

     text = text.replace(u"&", u"&") # Must be done last!

     return text

 def websafe(val):

     r"""Converts `val` so that it is safe for use in Unicode HTML.

         >>> websafe("<'&\">")

         u'<'&">'

         >>> websafe(None)

         u''

         >>> websafe(u'\u203d')

         u'\u203d'

         >>> websafe('\xe2\x80\xbd')

         u'\u203d'

     """

     if val is None:

         return u''

     elif isinstance(val, str):

         val = val.decode('utf-8')

     elif not isinstance(val, unicode):

         val = unicode(val)

     return htmlquote(val)

 if __name__ == "__main__":

     import doctest

     doctest.testmod()