Title: Capture HTML form data into a usable hash... (CGI)
Submitter: Greg Patnude (other recipes)
Last Updated: 2002/12/06
Version no: 1.0
Category: Miscellaneous

Description:

I developed this technique as an alternative to having to specifically cast name-value pairs into discrete Perl variables within your program.

This a technique where you capture all of an HTML form's data into a usable hash at one point in the program. Since the hash is a public variable, the form data is then available throughout your Perl script. Call this subroutine early in your script and the name-value pairs are magically available throughout the script without having to manually declare a Perl variable and get each and every value from the form's query string.

Not using a database but want to save the form ? Pipe the hash into an open DBM file...

Need to set the values of form fields ? You can assign to the $PARAMS hash $PARAMS{NEWVALUE} = "Cool trick.";

Need to do a database INSERT ? Embed the hash elements directly into your SQL construct and let $SQL->prepare($SQLSTMT) take care of it..

BTW: The $MSG variable is a little trick you can use to display what the form actually submitted to your Perl script... At any point / time in your program, AFTER getFormData() has been called, you can simply issue a

print "$MSG"; # FORM TRACE...

to see all of the form fields and the name value pairs that were submitted.

Usage: Text Source

Some simple examples:

if ($result = getFormData()) {

	print "$MSG";

        $COMPANY_NAME = $PARAMS{COMPANY_NAME};
	$SQLSTMT = "INSERT INTO tblName (COMPANY_NAME) VALUES ('$PARAMS{COMPANY_NAME}')";

	$SQL = $DBH->prepare("$SQLSTMT");
	$result = $SQL->execute();

	if($PARAMS{LOGIN_ID} eq "") {doLoginAgain();} else {doSomethingElse();}

} else {

        die "Unable to retrieve form contents...";

}

# RETRIEVES THE DATA FROM THE FORM...

sub getFormData() {

	use CGI:
	$capture = new CGI();	
	@FORMDATA = $capture->param();
	%PARAMS = {};

	# POPULATE THE HASH WITH THE FORM DATA...

	foreach $line (@FORMDATA) {

		chomp ($line);
		$V = $capture->param($line);
		chomp($V);
		# CAST THE PARAM PART OF {NAME=Value} pair to UPPERCASE...

		$line =~ uc($line);
		$PARAMS{$line} = $V;

	}

		while (($key, $value) = each (%PARAMS)) {

			$MSG .= "$key --> $value<BR>";

		}

	return TRUE;

}

The license for this recipe is available here.

Discussion:

If you are processing a LOT of forms in a web system (my systems generally consist of 130-140 discrete forms) you may want to use this technique to reduce the amount of code you actually need to write to retrieve the form contents (name-value pairs.).

I realized that processing form after form after form manually was extremely time consuming and prone to typographical errors, and that many times, I didn't even know which name-value pair was causing the error.