George Jempty wrote:
>
> >From the time I first started tinkering with CGI, just
> 3 years ago, I always thought that submit buttons were
> greatly under-utilized in maintaining state. Between
> this, and the recent discussion on this group about
> 'finite state machines', I thought I could use submit
> buttons to that end, within the framework of
> CGI::Application.
> >
> > <form>
> > <input type="hidden" name="rm" value="create">
> > <input type="button" value="Create a new Whatever">
> > </form>
>
> Unfortunately this could never work for the system I
> am envisioning, because, even if you are in the middle
> of a 'create' of a new record, the back button is a
> 'read' of the previous page's data.
>
George,
If you search the archives of this list, you'll find some more
discussion of using submit buttons with run modes. As you noticed they
often don't work directly. Jesse had a simple solution for this, which I
have adopted. If the submit buttons can't set the run mode directly, and
a direct hidden field doesn't work, some simple JavaScript can be used
to fill the gap. Because the JavaScript is very basic, it's easy to
implement and widely compatible. Here's a real-world example:
function item_edit () {
document.item_form.rm.value="item_edit";
}
function item_suggest_add () {
document.item_form.rm.value="item_suggest_add";
}
function item_delete () {
if (confirm('Really Delete?')) {
document.item_form.rm.value="item_delete";
return true;
} else {
return false;
}
}
This can help for a few reasons
* The form can submit to multiple run modes from a single form
* The run modes aren't tied to the language on the button, allowing the "design"
of the run mode name to changed without affecting the code. This would
be a
significant feature if someone wanted to translate your app into another
language.
To make the above work, the remaining details are:
* Have the form named "item_form", or otherwise match your JavaScript
* include an empty "rm" hidden field:
<input type="hidden" name="rm" value="">
* Call the function through a method such as "onClick":
<INPUT TYPE="submit" NAME="action" VALUE="delete" onClick="item_delete()">
Sometimes I skip using the functions and just include the JavaScript
directly in the button, like this:
<input type="submit" name="submit" value="Add"
onClick="document.item_form.rm.value='item_suggest_add';">
I use this scheme and really like it. Just for fun, below is my setup
routine from Cascade.
It's fairly basic except that I use the start_mode in a slightly unusual
way as mechanism to direct people to register if they need to. I also
make use of a few (gasp!) global variables and my &err rotuine isn't a
CGI::App method when maybe it should be.
-mark
#############
sub setup {
my $self = shift;
$DBH ||= connect_db() or die "Could not connect to database. Check
connection parameters";
# Put param variables into a global hash
$q = $self->query;
%FORM = (%FORM, $q->Vars);
# set $FORM{rm} (run mode)
$FORM{rm} ||= 'front_page';
$self->get_mode_param;
%SES = validate_session();
my $start_mode = $SES{valid_idle} ? $FORM{rm} : 'login';
$self->start_mode($start_mode);
$self->run_modes(
'front_page' => 'front_page',
# other run modes here
AUTOLOAD =>
sub { return err(title=>'Page not found',msg=>"(the run mode tried
was: $FORM{rm})") }
);
}
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
