- The string is empty or None
- The string uses characters that are not allowed in a URL
- The string breaks any of the HTTP syntactic rules
- The URL scheme specified (if one is specified) is not 'http' or 'https'
- The top-level domain (if a host name is specified) does not exist
requires = IS_URL()) |
(These rules are based on RFC 2396 )
- The string is empty or None
- The string uses characters that are not allowed in a URL
- The URL scheme specified (if one is specified) is not valid
requires = IS_URL(mode='generic')
requires = IS_URL(allowed_schemes=['https'])
requires = IS_URL(prepend_scheme='https')
" Web2py Book"