While I find coding HTML with CGI.pm cumbersome, I can think of a couple reasons why you might want to use it.
Most scripts just gather input, validate and process one form.
By utilizing CGI.pm, you can bring error handling and presentation up a notch.
I recently wrote a simple module that inherets from CGI that allows me to register informational error messages for any missing/bad parameters with "error bullets" that are automatically displayed next to any form element registered with CGI.pm.
(Also keeps track of colspans from the previous row so I don't hard code it. Makes maintainence easier.)
All screens functions can do "double duty" (form/error respones) so usually you can have a one to one match between screens and functions.
This would be a big pain to do without CGI or something else to handle HTML generation.
I think an approach like this works very well as interfaces get bigger.
I wrote a 10,000 line product/order management CGI interface for a fairly big (now defunct) dot com mixing and matching perl and html because CGI.pm's syntax was too cumbersome for me (I was too lazy).
While I hacked it out in a couple days, enhancements where a huge headache.
Below is a pretty trivial example but it doesn't take much longer to code it this way than to do it the down and dirty way and I think it is much cleaner. Everything is in one nice spot.
The following example is at http://smb.yso.net/cgi-bin/silly.pl
#!/usr/bin/perl
# silly.pl
# http://smb.yso.net/cgi-bin/silly.pl
use CGI::ParamError qw(:standard :html3);
my $q = new CGI::ParamError;
# REQUIRED FIELDS
# first_name last_name email
print header();
unless (param()){
display_form();
}else{
unless (param('first_name')=~/\w/){
param_error('first_name',"Sorry, I need to know your first nam
+e");
}
unless (param('last_name')=~/\w/){
param_error('last_name',"Sorry, I need to know your last name"
+);
}
unless (param('email')=~/^\w+\@\w+\.\w/){
param_error('email',"Sorry, param('email') doesn't seem like a
+ valid email");
}
if ($q->has_errors){
display_form();
}else{
# DO SOMETHING HERE
confirmation();
}
}
#########################################
sub display_form{
# show_error_messages() is part of my module, this is where the ve
+rbose messages are displayed
# Should be called AFTER fields are validated.
print start_html(-title=>'Silly Script'),
show_error_message(),
start_form,
"First Name",textfield(-name=>'first_name'),br,
"Last Name",textfield(-name=>'last_name'),br,
"Your Email",textfield(-name=>'email'),br,
submit,br,
end_form,
end_html;
}
#########################################
sub confirmation{
print start_html(-title=>'Silly Script'),
"Thanks for stopping by ",param('first_name')," ",param('last_
+name'),"!";
end_html;
}
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[d/l] |
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Good point. This was as the name implied a silly demonstration I threw together for the sake of this post.
Probably unwise of me to post such an "iffy" example with newbies around.
-Not that I don't have a ton to learn still ;)
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