I'm still confused why we need a path_info for the additional info to
CGI/modperl scripts?
Generally under CGI we say x.cgi?key=value to pass arguments, under
modperl handler we say /myHandler/?key=value to do it, or using POST
method.
Under what case we use path_info?

//joy

On Sat, Mar 1, 2008 at 3:22 AM, Torsten Foertsch
wrote:
> On Fri 29 Feb 2008, Frank Maas wrote:
> > I am using a mechanism where I use the path_info to carry information
> > about the content to be served. However, as far as I know the only way to
> > do this is to create a handler that is defined for the correct location.
> > In the described situation, something like,
> >
> >
> > PerlHandler MyNews->handler()
> >

> >
> > I do not see how MapToStorage handler will help here. There probably is no
> > /var/www/archive/news file (or directory), and even if there is, it is of
> > no use to Apache. Or am I completely and utterly mistaken here?

>
> Your confusion comes from the fact that you look at it through mod_perl
> spectacles where you don't necessarily have a corresponding disk file. But
> Apache is made chiefly to ship files.
>
> So in the m2s phase apache splits the filename it gets from trans into the
> name of a filesystem entry and the trailing "path_info".
>
> If you have a CGI script say /bin/x.cgi that is located in /www/cgi-bin/x.cgi
> and you call it as /bin/x.cgi/path/info then after trans filename points
> to /www/cgi-bin/x.cgi/path/info. m2s then finds that /www/cgi-bin/x.cgi is a
> regular file. So it sets filename to /www/cgi-bin/x.cgi and path_info
> to /path/info. So in CGI context you can be certain that PATH_INFO is the
> remainder of the URI after the current script is stripped off.
>
> BTW, the default response handler the one that ships files returns 404 if
> path_info is not empty.
>
> Now in mod_perl you normally don't have a disk file. You have a compiled
> handler. So m2s will determine the start of path_info somewhere in the URI
> where it finds the last existing directory.
>
> Hence when using a modperl handler don't rely on path_info. By creating an
> additional directory or deleting one you can spoil your logic! That is called
> action at a distance.
>
> Use $r->uri and $r->location instead. Don't use in this case.
> Then the first part of $r->uri equals to $r->location. So you can compute a
> mod_perl version of path_info as "substr($r->uri, length($r->location))".
> This one doesn't depend on existing or non-existing filesystem entries.
>
> Torsten
>