Re: [cgiapp] Creating SuperClass for my application
Ed,
I keep a small example which takes each component thru
to tested modules with documentation in pod so you see
the development cycle for a base class:
http://www.geocities.com/leapingfrog/perl/perl.html
I hope that helps, I should create on for the newer
style of plugins unless someone has already done that
for the Perl presentations ...
David Scott
--- Ed Pigg [EMAIL PROTECTED] wrote:
On Apr 24, 2006, at 12:56 PM, Michael Peters wrote:
Cees Hek wrote:
On 4/24/06, Ed Pigg [EMAIL PROTECTED]
wrote:
So how I put things like session initialization,
database
connection,
etc.. in the SUPER::cgiapp_init sub. So my SUB
CLASS would be
something like
sub cgiapp_init {
my $self = shift;
$self-SUPER::cgiapp_init(@_);
$self-start_mode();
$self-run_modes( ... );
}
Yes, that would work. But if you are doing stuff
like session init
and database connections, and you are sure you
want to do this on all
requests, for every runmode, then I would suggest
using Michael's
suggestion and set up a callback (which will
always run regardless of
what you do in the subclass). That is safer,
since you don't have to
remember to add that SUPER call in the subclass
everytime.
__PACKAGE__-add_callback(init = \_my_init);
If you're just doing the standard stuff (session
initialization, db
connection, etc) there are plugins that will take
care of that for
you.
One of the biggest benefits of those plugins is
that most of them do
lazy loading, so no db connection is created until
you use it.
It is probably a combination of too much caffine,
not enough sleep,
eye's bleary from looking through docs and code, but
I think I made a
fundamental error in my example that, when I correct
it, will make
things much clearer.
I will keep cgiapp_init in the base class and this
will handle the
cgiapp_init for the sub classes. My example used
cgiapp_init sub in
the subclass, there by overriding the base class
cgiapp_init. What I
really want to do is override setup. Duh!!
Thanks for all of your help and insight Michael,
Cees, and Jaclyn.
Ed Pigg
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Re: [cgiapp] Creating SuperClass for my application
On 4/24/06, Ed Pigg [EMAIL PROTECTED] wrote:
Hi list,
I'm trying to get the concept of creating a super class for my
application and understand what elements need to be included in the
base application module.
Let's say I want to create a web app called MyApp. My Directory
structure looks like this ...
/MyApp
Base.pm
User.pm
Inventory.pm
Other.pm
My Base class would be
package MyApp::Base.pm
use base 'CGI::Application';
sub cgiapp_init {...};
sub cgiapp_prerun {...};
sub _some_common_code {...};
1;
Then all of my other packages will contain the run modes for that
module and can call methods from the base class as long as they are
setup as follows
package MyApp::User.pm;
use base 'MyApp::Base';
sub cgiapp_init {
my $self = shift;
$self-start_mode( 'display_users' );
$self-tmpl_path( set_template_path_here );
$self-run_modes( qw/ display_users display_user_form edit_user /);
... module specific init items here
}
sub display_users {...}
sub display_user_form {...}
sub edit_user {...}
1;
Am I understanding the layout correctly?
Yes, except that in your subclass example, the fact that you create a
new 'cgiapp_init' method will override the 'cgiapp_init' method in
your base class. That means the 'cgiapp_init' method in your base
class will not get executed. That may be desired, but if it is not,
then you can call the 'cgiapp_init' method in the base class directly
by adding the following line to your 'cgiapp_init' method in your
subclass:
$self-SUPER::cgiapp_init(@_);
Cheers,
Cees
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Re: [cgiapp] Creating SuperClass for my application
Cees Hek wrote: Yes, except that in your subclass example, the fact that you create a new 'cgiapp_init' method will override the 'cgiapp_init' method in your base class. That means the 'cgiapp_init' method in your base class will not get executed. That may be desired, but if it is not, then you can call the 'cgiapp_init' method in the base class directly by adding the following line to your 'cgiapp_init' method in your subclass: $self-SUPER::cgiapp_init(@_); Or you can do what I've been doing lately and just have your base class use the callback system to register it's init code. This makes it easier for your subclasses since they even have to know that the base class want's to do anything at init time. $self-add_callback(init = \_my_init); This won't work well however if you want to override your base's init in the child class. Just another way to do it :) -- Michael Peters Developer Plus Three, LP - Web Archive: http://www.mail-archive.com/cgiapp@lists.erlbaum.net/ http://marc.theaimsgroup.com/?l=cgiappr=1w=2 To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: [cgiapp] Creating SuperClass for my application
Michael wrote: Cees Heek wrote: Yes, except that in your subclass example, the fact that you create a new 'cgiapp_init' method will override the 'cgiapp_init' method in your base class. That means the 'cgiapp_init' method in your base class will not get executed. That may be desired, but if it is not, then you can call the 'cgiapp_init' method in the base class directly by adding the following line to your 'cgiapp_init' method in your subclass: $self-SUPER::cgiapp_init(@_); Or you can do what I've been doing lately and just have your base class use the callback system to register it's init code. This makes it easier for your subclasses since they even have to know that the base class want's to do anything at init time. $self-add_callback(init = \_my_init); This won't work well however if you want to override your base's init in the child class. Just another way to do it :) And for yet another way :-) It's probably not best practices, but what I do is implement the cgiapp_init, setup, etc. in the base class. Each of them makes a call to a my_init, my_setup, etc. I stub those out in the base class. Then my subclasses can implement those without overriding the base methods. If they still really need to override, that is available too. Depending on what I intend the subclasses to actually do in the my methods, I put the call at the beginning, in the middle, or at the end of the base method. Jaclyn - Web Archive: http://www.mail-archive.com/cgiapp@lists.erlbaum.net/ http://marc.theaimsgroup.com/?l=cgiappr=1w=2 To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: [cgiapp] Creating SuperClass for my application
On 4/24/06, Ed Pigg [EMAIL PROTECTED] wrote:
So how I put things like session initialization, database connection,
etc.. in the SUPER::cgiapp_init sub. So my SUB CLASS would be
something like
sub cgiapp_init {
my $self = shift;
$self-SUPER::cgiapp_init(@_);
$self-start_mode();
$self-run_modes( ... );
}
Yes, that would work. But if you are doing stuff like session init
and database connections, and you are sure you want to do this on all
requests, for every runmode, then I would suggest using Michael's
suggestion and set up a callback (which will always run regardless of
what you do in the subclass). That is safer, since you don't have to
remember to add that SUPER call in the subclass everytime.
__PACKAGE__-add_callback(init = \_my_init);
Just put that at the top of your base class somewhere (not inside a
subroutine), and make sure you are using at least CGI::Application
4.0, which is when the callback code was added. That will execute the
_my_init method for every runmode request during the 'init' stage.
The only problem you may run into, is that the init callbacks are
called immediately after the cgiapp_init method is called. So your
subclass can not do anything in cgiapp_init that depends on something
that happens in your init callback, since it will not have been
executed yet.
Cheers,
Cees
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Re: [cgiapp] Creating SuperClass for my application
Cees Hek wrote:
On 4/24/06, Ed Pigg [EMAIL PROTECTED] wrote:
So how I put things like session initialization, database connection,
etc.. in the SUPER::cgiapp_init sub. So my SUB CLASS would be
something like
sub cgiapp_init {
my $self = shift;
$self-SUPER::cgiapp_init(@_);
$self-start_mode();
$self-run_modes( ... );
}
Yes, that would work. But if you are doing stuff like session init
and database connections, and you are sure you want to do this on all
requests, for every runmode, then I would suggest using Michael's
suggestion and set up a callback (which will always run regardless of
what you do in the subclass). That is safer, since you don't have to
remember to add that SUPER call in the subclass everytime.
__PACKAGE__-add_callback(init = \_my_init);
If you're just doing the standard stuff (session initialization, db
connection, etc) there are plugins that will take care of that for you.
One of the biggest benefits of those plugins is that most of them do
lazy loading, so no db connection is created until you use it.
--
Michael Peters
Developer
Plus Three, LP
-
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Re: [cgiapp] Creating SuperClass for my application
On Apr 24, 2006, at 12:56 PM, Michael Peters wrote:
Cees Hek wrote:
On 4/24/06, Ed Pigg [EMAIL PROTECTED] wrote:
So how I put things like session initialization, database
connection,
etc.. in the SUPER::cgiapp_init sub. So my SUB CLASS would be
something like
sub cgiapp_init {
my $self = shift;
$self-SUPER::cgiapp_init(@_);
$self-start_mode();
$self-run_modes( ... );
}
Yes, that would work. But if you are doing stuff like session init
and database connections, and you are sure you want to do this on all
requests, for every runmode, then I would suggest using Michael's
suggestion and set up a callback (which will always run regardless of
what you do in the subclass). That is safer, since you don't have to
remember to add that SUPER call in the subclass everytime.
__PACKAGE__-add_callback(init = \_my_init);
If you're just doing the standard stuff (session initialization, db
connection, etc) there are plugins that will take care of that for
you.
One of the biggest benefits of those plugins is that most of them do
lazy loading, so no db connection is created until you use it.
It is probably a combination of too much caffine, not enough sleep,
eye's bleary from looking through docs and code, but I think I made a
fundamental error in my example that, when I correct it, will make
things much clearer.
I will keep cgiapp_init in the base class and this will handle the
cgiapp_init for the sub classes. My example used cgiapp_init sub in
the subclass, there by overriding the base class cgiapp_init. What I
really want to do is override setup. Duh!!
Thanks for all of your help and insight Michael, Cees, and Jaclyn.
Ed Pigg
-
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