If your Apache Config file invokes CGI processing with the directive
ScriptAlias, you can construct links in your HTML
that have extra data passed with them as if they were directory names
passed in the Environment variable PATH_INFO. For
instance:
... <A HREF="/cgi-bin/script2_html/whole_database">Click here to see whole database</A> ...
When the user clicks on this link she invokes
script2_html and makes available to it the
Environment variable PATH_INFO, containing the
string /whole_database. We can test this in our
Perl script with this:
if($ENV{'PATH_INFO'} eq '/whole_database')
{
#do something
}Our script can then make a decision about what to do next on the
basis of this information. The same mechanism is available with the
HTML FORM
ACTION attribute. We
might set up a form in our HTML with the command:
<FORM METHOD='POST' ACTION="/cgi-bin/script2_html/receipts">
As previously, /receipts will turn up in
PATH_INFO, and your script knows which form sent
the data and can go to the appropriate subroutine to deal with it.
What happens inside Apache is that the
URI — /cgi-bin/script2_html/receipts — is
parsed from right to left, looking for a filename, which does not
have to be a CGI script. The material to the right of the filename is
passed in PATH_INFO.