[ic] Cart programming question

[interchange-users@interchange.redhat.com (Mike Heins)]

Quoting Steffen Dettmer (steffen@dett.de):
> Hi,
> 
> ... and my loved customers have a requirement.
> There are multiple (shop-) users organized in groups. Now it's
> possible that a user A saves a cart or a recurring order. Now it
> should made possible that a customer B (which is in the same
> group as user A) can get the carts A saved.
> 
> Here I see two possibilities: I could make a page that loads the
> cart value from userdb from the other user (A), parse it in some
> way, and add the selected cart to the value in userdb for this
> user (B). The second possibility: I could add some new button
> which stores the contents of "uneval $Carts->{'main'}" into a
> database table (I would use my groups-table I think). 
> 
> 	$cart_string = uneval $Carts->{'main'};
> 	query "insert into group_carts ( content, group_id ) 
> 		VALUES ( $cart_string, $group_id )";
> 	#   (or some Data-Tag instead of query)
> 
> So far this shouldn't be a problem. For loading/getting, I think
> I just need somethink like 
> 
> 
> 	$db_field_content = query "select content from group_carts 
> 		where group_id = $group_id
> 		  and cart_id  = $cart_to_load";
> 	#   (or some Data-Tag instead of query)
> 	$Carts->{'main'} = eval $db_field_content;
> 
> Now my questions:
> 
> 	- Is there a better third way to do it?

No, not that I know of.

> 
> 	- Would method 2 work if I program a global user tag for
> 	  it (inside pages or catalog.cfg "eval" wouldn't work
> 	  beacuse of Safe, is this correct)?

Yes, it would work fine. I have done it. 

> 
> 	- Is there a better way to "reload" this cart than with
> 	  eval?

If you want to use embedded Perl with safe, it is OK to do

[try]
    [calc]
	$Carts->{main} = <<'EOF';
[data table=group_carts column=content key=cart_id]
EOF
    [/calc]
[/try]

[catch]
	Eval error in cart.
[/catch]

> 
> 	- I never wrote into a table from IC. Do I have to expect
> 	  problems here (catalog.cfg permissions or similar)?
> 

Not unless you have WRITE_CONTROL set, in which case you need
to [flag type=write table=foo].

> 	- Should I use another approach by editing UserDB.pm and 
> 	  modify get_cart (and others) in a way, that they handle
> 	  group-assigned carts on this level?

Probably not the best way for a one-off.
> 
> I don't have the right idea, since the cart functionality is part
> of the IC core and cannot be modified easily, so I would prefere
> method 2 (saving a uneval $Carts->{'main'}, and for reloading it
> doing a eval $field_content). 
> 

Au contraire. It is easy to add functionality to UserDB.pm. Consider:

UserTag  my-cart-stuff  Routine <<EOR

package UserDB;

sub group_get_cart {
	## Some code
}

sub group_set_cart {
	## Some code
}

package Vend::Interpolate;

sub {
	# Normal usertag stuff
}
EOR

Now [userdb function=group_get_cart ....] will do what you want....

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