On 6/5/07, Morgan Cheng <morgan.chengmo / gmail.com> wrote:
> On Jun 5, 5:24 pm, "Jano Svitok" <jan.svi... / gmail.com> wrote:
> > On 6/5/07, Morgan Cheng <morgan.chen... / gmail.com> wrote:
> >
> >
> >
> > > On Jun 5, 3:00 pm, "Jano Svitok" <jan.svi... / gmail.com> wrote:
> > > > On 6/5/07, Morgan Cheng <morgan.chen... / gmail.com> wrote:
> >
> > > > > I am using Ruby 1.8.6. I found URI cannot parse URI with "_" is host.
> >
> > > > > uri = "http://dr_gabriele.podomatic.com/enclosure/
> > > > > 2006-08-03T15_09_59-07_00.m4v"
> > > > > URI.parse(uri)
> >
> > > > > Is there any way to work around that?
> > > > > thanks
> >
> > > > It seems underscores are not allowed in host part of an URI. So it's
> > > > not a bug. See RFC 2396 (URI),  and 1035 (DNS). If you really want it,
> > > > you can open the class and redefine some of the methods and/or
> > > > manually edit URI sources.
> >
> > > In RFC 2396, "_" is taken as "Unreserved Characters".
> > >    Unreserved characters can be escaped without changing the semantics
> > >    of the URI, but this should not be done unless the URI is being
> > > used
> > >    in a context that does not allow the unescaped character to appear.
> >
> > > However, URI.escape doesn't escape "_".
> >
> > > require 'URI'
> > > original_uri = "http://dr_gabriele.podomatic.com/enclosure/"
> > > uri = URI.escape(original_uri)
> > > puts uri == original_uri
> >
> > I'm no expert on DNS, this is what I have found in appendix A:
> >
> > host          = hostname | IPv4address
> > hostname      = *( domainlabel "." ) toplabel [ "." ]
> > domainlabel   = alphanum | alphanum *( alphanum | "-" ) alphanum
> > toplabel      = alpha | alpha *( alphanum | "-" ) alphanum
> > IPv4address   = 1*digit "." 1*digit "." 1*digit "." 1*digit
> >
> > alphanum      = alpha | digit
> > alpha         = lowalpha | upalpha
> >
> > lowalpha = "a" | "b" | "c" | "d" | "e" | "f" | "g" | "h" | "i" |
> >              "j" | "k" | "l" | "m" | "n" | "o" | "p" | "q" | "r" |
> >              "s" | "t" | "u" | "v" | "w" | "x" | "y" | "z"
> > upalpha  = "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" | "I" |
> >              "J" | "K" | "L" | "M" | "N" | "O" | "P" | "Q" | "R" |
> >              "S" | "T" | "U" | "V" | "W" | "X" | "Y" | "Z"
> > digit    = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" |
> >              "8" | "9"
> >
> > There's no "_" there. YMMV ;-)
>
> Thanks a lot for your help.
>
> I am just wandering, internet is a wild world. Wierd non-standard
> stuff is all around. The non-standard host name is a example. Popular
> browser can handle these URLs well.
> Perhaps ruby should be more strong to survive better in such wild
> world :-)

If you want to really use underscores, modify lib/1.8/uri/common.rb:
add the following after line HOSTNAME=... and comment out (prefix with
#) the original HOSTNAME line.

      ALPHA_ = "a-zA-Z_"
      ALNUM_ = "#{ALPHA_}\\d"
      DOMLABEL_ = "(?:[#{ALNUM_}](?:[-#{ALNUM_}]*[#{ALNUM_}])?)"
      TOPLABEL_ = "(?:[#{ALPHA_}](?:[-#{ALNUM_}]*[#{ALNUM_}])?)"
      HOSTNAME = "(?:#{DOMLABEL_}\\.)*#{TOPLABEL_}\\.?"

J.