Regexp::Common::URI::gopher -- Returns a pattern for gopher URIs.


Regexp::Common::URI::gopher -- Returns a pattern for gopher URIs.


    use Regexp::Common qw /URI/;
    while (<>) {
        /$RE{URI}{gopher}/       and  print "Contains a gopher URI.\n";



Gopher URIs are poorly defined. Originally, RFC 1738 defined gopher URIs, but they were later redefined in an internet draft. One that was expired in June 1997.

The internet draft for gopher URIs defines them as follows:

    "gopher:"; "//" host [ ":" port ] "/" gopher-type selector
                        [ "%09" search [ "%09" gopherplus_string ]]

Unfortunally, a selector is defined in such a way that characters may be escaped using the URI escape mechanism. This includes tabs, which escaped are %09. Hence, the syntax cannot distinguish between a URI that has both a selector and a search part, and an URI where the selector includes an escaped tab. (The text of the draft forbids tabs to be present in the selector though).

$RE{URI}{gopher} follows the defined syntax. To disallow escaped tabs in the selector and search parts, use $RE{URI}{gopher}{-notab}.

There are other differences between the text and the given syntax. According to the text, selector strings cannot have tabs, linefeeds or carriage returns in them. The text also allows the entire gopher-path, (the part after the slash following the hostport) to be empty; if this is empty the slash may be omitted as well. However, this isn't reflected in the syntax.

Under {-keep}, the following are returned:

The entire URI.

The scheme.

The host (name or address).

The port (if any).

The ``gopher-path'', the part after the / following the host and port.

The gopher-type.

The selector. (When no {-notab} is used, this includes the search and gopherplus_string, including the separating escaped tabs).

The search, if given. (Only when {-notab} is given).

The gopherplus_string, if given. (Only when {-notab} is given).


[RFC 1738]
Berners-Lee, Tim, Masinter, L., McCahill, M.: Uniform Resource Locators (URL). December 1994.

[RFC 1808]
Fielding, R.: Relative Uniform Resource Locators (URL). June 1995.

Krishnan, Murali R., Casey, James: ``A Gopher URL Format''. Expired Internet draft draft-murali-url-gopher. December 1996.


 $Log:,v $
 Revision 2.100  2003/02/21 14:40:59  abigail
 Gopher URLs


the Regexp::Common::URI manpage for other supported URIs.


Damian Conway (


This package is maintained by Abigail (


Bound to be plenty.


     Copyright (c) 2001 - 2003, Damian Conway. All Rights Reserved.
       This module is free software. It may be used, redistributed
      and/or modified under the terms of the Perl Artistic License

 Regexp::Common::URI::gopher -- Returns a pattern for gopher URIs.