Monks,

I've been trying to "upgrade" one of my scripts from the now-outdated (so I am told) CGI.pm to a more modern implementation that I had hoped would be mostly a "drop-in" replacement for it: CGI::Tiny. However, my script needs to function on several sets of pages, not all of them having the same form parameters. CGI.pm did not have any trouble with something like:

my $bookparam = $cgi->param('book') || '';

But CGI::Tiny is throwing a hissy fit over this if the form on that particular page does not happen to include the 'book' field, i.e. code execution is totally halted. Surely there is a way to avoid this, but I cannot find it. I tried this:

defined(my $bookparam = $cgi->param("book")) or my $bookparam = "";

...and I tried this:

my $bookparam;
if (defined $cgi->param("book")) {$bookparam = $cgi->param("book")};

[download]


...but both of these generate show-stopper errors, like this one (in the logfile):

[Sun Dec 11 22:03:35 2022] [error] [client ::1] Can't call method "param" on an undefined value at /Users/me/PERL/ScriptDir/dev.pl line 1026.

...and to the browser:

Status: 500 Internal Server Error Date: Sun, 11 Dec 2022 15:03:35 GMT Content-Type: text/plain Content-Length: 25 500 Internal Server Error

Obviously, that's not going to work. Must I return to CGI.pm? If a total code rewrite is required in order to switch, it's too big of an ask. I have tens of thousands of lines of code in this project, and hundreds of form fields.

Aside from a defined(%hash) is deprecated error in the log, no other errors are produced--and that "defined(%hash)" issue is part of debugging code that only runs in debug mode anyhow. And yes, "strict" is in use.

How can I detect an undefined field before crashing with CGI::Tiny on it?

NOTE: Before suggesting them, please understand I am not interested in Dancer, Dancer2, Mojolicious, Catalyst, Moose, etc. or other heavy-duty frameworks. I am not using PSGI nor FastCGI, and am not looking for something with large overhead. This is why I have tried CGI::Tiny.

Note 2: Online searches have not helped--results are mostly focused on folk with faulty package installations.

Blessings,

~Polyglot~

In reply to CGI::Tiny versus undefined parameter/form field by Polyglot

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