How to do a "login required" type of filter

I need to get login credentials for some pages that might be deep
linked.  I have a LoginForm component that gets called, returning the
user if its found:

authenticate
        (AccountRepository find: domain verify: password) ifNotNil: [ self
answer: account. ].

authenticate is called when the login form is submitted.

So how do I get to render the login form?  Well I started off with a
LoginDecoration.  It looks like
renderContentOn: html
        self session account ifNotNil: [
                self renderOwnerOn: html.
        ] ifNil: [ self session account: (self call: ANLoginForm new) ].

WADecorations don't have call: though.  So I tried doing the call
directly from my component requiring an authenticated user:

renderContentOn: html
        self requireLogin.
        "the stuff that I render after I have a logged in user"

requireLogin
        self session account ifNil: [self session account: (self call:
ANLoginForm new)].

When I tried this, I got the following error:
MessageNotUnderstood: UndefinedObject>>updateStates:
WARenderContinuation(WASessionContinuation)>>updateStates:
[] in WARenderContinuation(WASessionContinuation)>>respond: {[:value |
self updateStates: states]}
[] in ANSession(WASession)>>onRespond: {[:response | aBlock value:
response. previous value: response]}
ANSession(WASession)>>returnResponse:
ANSession(WASession)>>pageIntentionallyLeftBlank
[] in ANSession(WASession)>>withEscapeContinuation: {[:cc |
escapeContinuation := cc. aBlock value. self
pageIntentionallyLeft...]}
EscapeContinuation class(Continuation class)>>currentDo:
ANSession(WASession)>>withEscapeContinuation:
ANSession(WASession)>>responseForRequest:
[] in ANSession(WASession)>>incomingRequest: {[self
responseForRequest: aRequest]}
BlockContext>>on:do:
[] in WAProcessMonitor>>critical:ifError: {[value := aBlock on: Error
do: anErrorBlock]}
BlockContext>>ensure:
[] in WAProcessMonitor>>critical:ifError: {[[value := aBlock on: Error
do: anErrorBlock] ensure: [semaphore signal]]}
[] in BlockContext>>newProcess {[self value. Processor terminateActive]}

No clue what that means, couldn't find anything on google, and this
errors without all the nice seaside links so I'm not able to fire up
the debugger.

I read in http://www.shaffer-consulting.com/david/Seaside/CallAnswer/index.html
that you shouldn't use call from within renderContentOn.  I don't know
if that means that call *doesn't work* from within renderContentOn, or
it's just a style thing.

Anyway...all I want to do is, when I begin to render a page, check for
an account in the session and if it doesn't exist prompt a login.  I'm
sure this is simple and I'm just doing something stupid at this point.
 Can anyone help out?

Pat
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I changed the LoginForm component to set the account in the session
instead of using answer.  Now my LoginDecoration renders the LoginForm
when there's no user in the session.

Now I'm running into a problem with children.  The LoginForm isn't in
my main component's children list...which, there's really no way it
could be - the main component doesn't know anything about the
LoginForm, it only gets created as a result of my Decoration.  I
verified that this is the problem by moving all the code from my
LoginForm into my LoginDecoration, and it works fine.

So again I think I'm doing something stupid here.  I'm somewhat close
in that I can get the decoration to render my LoginForm component, but
now that component has to go into the decorated component's children
(apparently).  That feels ugly so I would think there's a better way
to do this.

Pat
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you might try overriding the states method to return your decoration
John




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http://jmck.seasidehosting.st

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What does your LoginForm do? Does it have persistent state? If not,
why not have the LoginDecoration do the rendering itself? Or if you
just want it factored out but don't need state or call/answer just
implement a class that has a #renderOn: method and pass that to "html
render:" (any object can render itself and only Components need to be
listed in #children). This stuff is all a bit clearer, I think, in 2.9
(not that I'm suggesting you should start using it - just saying
you're right to find it problematic).

Otherwise... hm Seaside 2.8 doesn't have #children on WADecoration
does it? That's fixed in 2.9 too. :) I guess if you really needed
component features on LoginForm you would implement #nextPresentersDo:
on your Decoration to make sure it evaluates the block for the child
component.

And to answer your earlier question, calling or answering while
rendering just doesn't make sense. I can't remember what the failure
mode is in 2.8 (in 2.9 it will definitely fail completely) but the
continuations don't work right if you try to do that. Rendering
shouldn't really change state - it should just render the current
state so that it can be done over and over again.

(this doesn't feel like my most articulate post ever but I'm on my way
to bed - I'm sure the European contingent can clarify anything that
doesn't make sense :) )

Julian

On Wed, May 27, 2009 at 7:21 PM, Pat Maddox <[hidden email]> wrote: _______________________________________________
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