[Zope] RE: loginManager rackList is empty, but what about UserSource?

[Jean Lagarde]

Replying to my own question.

LoginManager redefines getItem to look into its userSourcesList rather
than into the rackList, as in the specialist class. So it seems to me
that loginManager is not following the Liskov substitution principle
(LSP) by not equivalently redefining newItem. So for now, I have fixed
my problem by also redefining newItem in loginManager, substituting
userSourcesList[0] for rackList[0]. Seems to me that would be a
desirable behavior of loginManager.

Another solution, which would also satisfy LSP without redefining
newItem, would be to have rackList return the contents of
userSourcesList rather than an empty list (I haven't looked into why
rackList is empty in the first place in loginManager). Again, I think
that would be a consistent interpretation based on the behavior of
getItem as implemented in loginManager.

Cheers,

Jean
 
> Hi folks,
> 
> I am slowly, very slowly, getting comfortable with 
> loginManager, but I've hit yet another snag, and I am too 
> tired today so I'll just ask and hope for a kind soul 
> to hep me out.
>     ^
>     |
>     -------- See, I am tired!

And I also forgot that the paragraph would auto wrap, so even my attempt
at making fun of my typo failed ;-)

> 
> I am in the process of adapting the example provided by 
> dlpierson (thanks by the way), so I am using a skinscript and 
> an external database (MySQL). In coming up with form based 
> addition of new users, I figured might as well use newItem 
> and the skinscript rather than calling SQL methods directly. 
> But newItem complains, and I found out that the problem is 
> that rackList is empty, but isn't UserSource a rack? Why 
> isn't it in rackList? (In case someone asks, yes I do have a 
> UserSource in the LoginManager, and it seems to work OK otherwise).
> 
> Cheers,
> 
> Jean
>