Simple redirection CGI program
Three steps to set up a redirection:
- Make sure your web server is set up to allow CGI
- Make a symbolic link from the file or directory you want
to redirect, pointing at this program in the CGI bin directory.
- Add an entry to the file ".redirects" in the
directory where your http server runs CGI programs. For most servers, this
is the directory where the given CGI program lives.
The format of the .redirects file is a bunch of lines with a filename,
whitespace, and the new URL. For example:
The easiest way to figure out precisely what filename to put into .redirects is
to set up the symlink and then click on it. You'll get back a "404 Not
Found" page which includes the filename as received by the redirect
program, and that's what you want to use.
You can also add a wildcard specification to redirect whole groups of files. For
will cause an access to the /wildtest/somefile.html to be redirected to
http://www.acme.com/test-somefile.html. (Note that the asterisk need not be
preceded by a slash.)
designed for use with
the latter has its own built-in redirect support today which is probably what
you want. Using redirect
with other web servers
may require some hacking. A possible gotcha is with the symbolic link from the
old file pointing at this script - servers other than thttpd may not allow
that link to be run as a CGI program, because they don't check the link to see
that it points into the allowed CGI directory.
It would be really cool to have this program look for the .redirects file in the
same directory as the file being redirected, instead of in the binaries
directory. Unfortunately, this appears to be impossible with the information
CGI gives, plus the non-standardized but widespread practice of running CGI
programs in the directory where the binary lives. Perhaps CGI 1.2 will address
The wildcard mechanism is very primitive. In particular, any characters that
follow the asterisk are blithely ignored.