RFC 3986 URI BNF translated to a regular expression. (Uses Ruby/Oniguruma/Onigmo named capture syntax)

gistfile1.txt

(?xi)
\A
  # unreserved: [a-z0-9\-._~]
  # sub-delims: [!$&'()*+,;=]
  # pct-encoded: %[0-9a-f]{2}
  # dec-octet: (?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])
  # pchar: (?:[a-z0-9\-._~!$&'()*+,;=:@]|%[0-9a-f]{2})
  # h16: [0-9a-f]{1,4}
  # ls32: (?:[0-9a-f]{1,4}:[0-9a-f]{4}|
  #         (?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])
  #         \.
  #         (?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])
  #         \.
  #         (?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])
  #         \.
  #         (?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]))
  # segment:    (?:[a-z0-9\-._~!$&'()*+,;=:@]|%[0-9a-f]{2})*
  # segment-nz: (?:[a-z0-9\-._~!$&'()*+,;=:@]|%[0-9a-f]{2})+
  (?<scheme>[a-z][a-z0-9+\-.]*):
  (?<hier-part>
    (?:
      //(?<authority>
        (?:(?:(?<userinfo>(?:[a-z0-9\-._~!$&'()*+,;=:]|%[0-9a-f]{2})*)@)?)
        (?<host>
          (?<IP-literal>\[(?:
            (?<IPv6address>
              # OHSHI-
              (?:[0-9a-f]{1,4}){6}(?:[0-9a-f]{1,4}:[0-9a-f]{4}|(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]))
              |
              ::(?:[0-9a-f]{1,4}){5}(?:[0-9a-f]{1,4}:[0-9a-f]{4}|(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]))
              |
              (?:[0-9a-f]{1,4})?::(?:[0-9a-f]{1,4}){4}(?:[0-9a-f]{1,4}:[0-9a-f]{4}|(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]))
              |
              (?:(?:[0-9a-f]{1,4}:){0,1}[0-9a-f]{1,4})?::(?:[0-9a-f]{1,4}){3}(?:[0-9a-f]{1,4}:[0-9a-f]{4}|(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]))
              |
              (?:(?:[0-9a-f]{1,4}:){0,2}[0-9a-f]{1,4})?::(?:[0-9a-f]{1,4}){2}(?:[0-9a-f]{1,4}:[0-9a-f]{4}|(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]))
              |
              (?:(?:[0-9a-f]{1,4}:){0,3}[0-9a-f]{1,4})?::(?:[0-9a-f]{1,4})(?:[0-9a-f]{1,4}:[0-9a-f]{4}|(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]))
              |
              (?:(?:[0-9a-f]{1,4}:){0,4}[0-9a-f]{1,4})?::(?:[0-9a-f]{1,4}:[0-9a-f]{4}|(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]))
              |
              (?:(?:[0-9a-f]{1,4}:){0,5}[0-9a-f]{1,4})?::[0-9a-f]{1,4}
              |
              (?:(?:[0-9a-f]{1,4}:){0,6}[0-9a-f]{1,4})::
            )
            |
            (?<IPvFuture>v[0-9a-f]\.[a-z0-9\-._~!$&'()*+,;=:]+)
          )\])
          |
          (?<IPv4address>
            (?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])
            \.
            (?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])
            \.
            (?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])
            \.
            (?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])
          )
          |
          (?<reg-name>(?:[a-z0-9\-._~!$&'()*+,;=]|%[0-9a-f]{2})*)
        )
        (?::(?<port>[0-9]+))?
      )
      (?<path-abempty> (?:/(?:[a-z0-9\-._~!$&'()*+,;=:@]|%[0-9a-f]{2})*)*)
      |
      (?<path-absolute>
        /(?:
          (?:[a-z0-9\-._~!$&'()*+,;=:@]|%[0-9a-f]{2})+
          (?:/(?:[a-z0-9\-._~!$&'()*+,;=:@]|%[0-9a-f]{2})*)*
        )?
      )
      |
      (?<path-rootless>
        (?:[a-z0-9\-._~!$&'()*+,;=:@]|%[0-9a-f]{2})+
        (?:/(?:[a-z0-9\-._~!$&'()*+,;=:@]|%[0-9a-f]{2})*)*
      )
      |
      (?<path-empty>)
    )
  )
  (?:\?(?<query>    (?:[a-z0-9\-._~!$&'()*+,;=:@/?]|%[0-9a-f]{2})*))?
  (?:\#(?<fragment> (?:[a-z0-9\-._~!$&'()*+,;=:@/?]|%[0-9a-f]{2})*))?
\Z