[Engine-devel] ok to sort login domains on backend?

Mon Sep 2 13:18:22 UTC 2013

Hi Alon,

GetDomainListQuery already sorts domains by name before returning domain list to client (GetDomainListQuery:23), so what's the big deal with adding internal admin domain (ConfigValues.AdminDomain) as the last entry anyway?

If I understand correctly, GetDomainListQuery already sorts domains not due to presentation purposes, but to make resulting domain list more consistent for clients to process (and humans to inspect).

Vojtech

----- Original Message -----
> From: "Alon Bar-Lev" <alonbl at redhat.com>
> To: "Einav Cohen" <ecohen at redhat.com>
> Cc: engine-devel at ovirt.org
> Sent: Friday, August 30, 2013 7:14:13 PM
> Subject: Re: [Engine-devel] ok to sort login domains on backend?
> 
> 
> 
> ----- Original Message -----
> > From: "Einav Cohen" <ecohen at redhat.com>
> > To: "Alon Bar-Lev" <alonbl at redhat.com>
> > Cc: engine-devel at ovirt.org
> > Sent: Friday, August 30, 2013 7:56:13 PM
> > Subject: Re: [Engine-devel] ok to sort login domains on backend?
> > 
> > > ----- Original Message -----
> > > From: "Alon Bar-Lev" <alonbl at redhat.com>
> > > Sent: Friday, August 30, 2013 12:35:24 PM
> > > 
> > > 
> > > 
> > > ----- Original Message -----
> > > > From: "Einav Cohen" <ecohen at redhat.com>
> > > > To: "Alon Bar-Lev" <alonbl at redhat.com>
> > > > Cc: "Greg Sheremeta" <gshereme at redhat.com>, engine-devel at ovirt.org
> > > > Sent: Friday, August 30, 2013 5:12:37 PM
> > > > Subject: Re: [Engine-devel] ok to sort login domains on backend?
> > > > 
> > > > > ----- Original Message -----
> > > > > From: "Alon Bar-Lev" <alonbl at redhat.com>
> > > > > Sent: Friday, August 30, 2013 9:32:46 AM
> > > > > 
> > > > > 
> > > > > 
> > > > > ----- Original Message -----
> > > > > > From: "Greg Sheremeta" <gshereme at redhat.com>
> > > > > > To: engine-devel at ovirt.org
> > > > > > Sent: Friday, August 30, 2013 3:26:48 PM
> > > > > > Subject: [Engine-devel] ok to sort login domains on backend?
> > > > > > 
> > > > > > Hi,
> > > > > > 
> > > > > > I'm working on https://bugzilla.redhat.com/785555 -- "domain
> > > > > > selection
> > > > > > list
> > > > > > in login screen should be sorted alphabetically"
> > > > > > 
> > > > > > I was going to put the sort logic in the web apps, but it makes
> > > > > > sense
> > > > > > to
> > > > > > just
> > > > > > put it in the backend, specifically in GetDomainListQuery. (There
> > > > > > is
> > > > > > already
> > > > > > a sort there, but it needs to be tweaked to put "internal" always
> > > > > > last.)
> > > > > > This would affect non-webapp clients (REST API), so I want to make
> > > > > > sure
> > > > > > there are no objections. Unit tests pass and it seems to work fine
> > > > > > (screen
> > > > > > attached).
> > > > > > 
> > > > > > Any objections?
> > > > > 
> > > > > I think that sorting of visualization is presentation layer role.
> > > > 
> > > > true in general, but I think that there is no harm in returning items
> > > > from the backend in some default order, especially if this is a list
> > > > of simple items that have only one possible order that makes sense.
> > > 
> > > Even if that so, there is no reason to relay on it.
> > 
> > if this method will return a sorted list *by definition*, there would be
> > no reason to NOT relay on it.
> > for this particular case, I think that it would be a bit of waste if the
> > exact same sorting logic will be duplicated across the different clients'
> > code (including 3rd-party clients). If we can make it a little bit easier
> > on the clients, I don't see why not to do it.
> > 
> > > If sort is required at presentation, presentation layer should apply
> > > sort.
> > 
> > define "presentation"; looking at the xml response of a rest-api GET
> > request
> > in a browser is also "presentation", but I can't really apply sort there;
> > yes,
> > I can change the rest-api code to sort the results, but why not simply make
> > it
> > a bit easier for *all* clients, and return the results from the backend
> > already
> > sorted in the way which is probably the most comfortable for everyone?
> > 
> > [again - you are generally correct, but in this particular case, of simple
> > business entities which have pretty much only one way of sorting that makes
> > sense, I don't see why not make an exception and apply the sort on the
> > backend]
> 
> Well, we can agree to disagree.
> 
> RestAPI is not presentation, the fact that browser has presentation layer to
> interact with RestAPI does not mean that the server side is responsible on
> ordering etc. The RestAPI presentation layer may allow sorting.
> 
> I do not think that API should have any sense of presentation ordering it
> only makes it more complex without a reason.
> 
> Let's assume the API sort is based on plain text, and you have a bug to sort
> using case insensitive, so API definition should be fixed? so you pass a
> parameter to request specific casing?
> 
> Let's assume that each domain has value and description, you agree that sort
> should be based on description, right? Now, let's say that description can
> be localized, which sort can the server apply?
> 
> These are the reason why presentation layer was split out, ever since IBM
> Mainframe 3270 the layer is running on the client side.
> 
> Regards,
> Alon Bar-Lev
> 
> > 
> > > 
> > > > 
> > > > > 
> > > > > > 
> > > > > > Thanks,
> > > > > > Greg
> > > > > > 
> > > > > > 
> > > > > > Greg Sheremeta
> > > > > > Red Hat, Inc.
> > > > > > Sr. Software Engineer, RHEV
> > > > > > Cell: 919-807-1086
> > > > > > gshereme at redhat.com
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> > > > > > Engine-devel at ovirt.org
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> > > > > > 
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> > > > > 
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> > 
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