[Seaside] Asynchronous message sending and Comet

Rob Withers reefedjib at gmail.com
Wed Sep 29 11:44:56 UTC 2010 

I worried about that.  Thanks.

--------------------------------------------------
From: "Lukas Renggli" <renggli at gmail.com>
Sent: Wednesday, September 29, 2010 6:14 AM
To: "Seaside - general discussion" <seaside at lists.squeakfoundation.org>
Subject: Re: [Seaside] Asynchronous message sending and Comet

> You mail is too long ...
>
>> "GRError: You can only #call: and #answer: from within a callback or a 
>> Task"
>
> Try with the non-blocking #show:, see
> http://book.seaside.st/book/components/calling/show-answer.
>
> Lukas
>
> On 29 September 2010 11:48, Rob Withers <reefedjib at gmail.com> wrote:
>> bump.  Can someone help me with this question, please?
>>
>> --------------------------------------------------
>> From: "Rob Withers" <reefedjib at gmail.com>
>> Sent: Saturday, September 25, 2010 3:31 PM
>> To: "Seaside - general discussion" <seaside at lists.squeakfoundation.org>
>> Subject: Re: [Seaside] Asynchronous message sending and Comet
>>
>>> I am working my way to building the Login/Register/ChangePassword/Home
>>> components of my app and navigating between them.   There are 
>>> asynchronous
>>> messages being used.  I have an AccountManager instance, held by my 
>>> session,
>>> which asynchronously talks to a SecureAccountManager in another image. 
>>> This
>>> results in the following seaside callbacks not having an immediate 
>>> answer
>>> from async api invocation.
>>>
>>> LoginComponent>>login calls #login: on the acctMgr.  On success it 
>>> expects
>>> to go to the HomeComponent.  On failure it shows its page with an error
>>> message.
>>>
>>> RegisterComponent>>registerUser calls registerAccount: on the acctMgr. 
>>> On
>>> success it expects to go to the HomeComponent.  On failure it shows its 
>>> page
>>> with an error message.
>>>
>>> ChangePasswordComponent>>changePassword calls changePassword: on the
>>> acctMgr.  On success it expects to go to the HomeComponent.  On failure 
>>> it
>>> shows its page with an error message.
>>>
>>> My code looks like the following such that the callbacks I am 
>>> registering
>>> for dealing with the asynchronous messaging get called after control 
>>> leaves
>>> the Seaside callback.
>>>
>>> (self session login: self credentials)
>>> whenResolved: [:acct | self answer: acct];
>>> whenBroken: [:msg | self loginFailed].
>>>
>>>
>>> When I run the Register and then Login callbacks, I get the following
>>> error:
>>>
>>>   "GRError: You can only #call: and #answer: from within a callback or a
>>> Task"
>>>
>>> Sorry for the long lead up...I am definitely outside of a callback flow 
>>> of
>>> control, or a Task flow of control.  In otherwords I am outside of the 
>>> HTTP
>>> request/response cycle.
>>>
>>> So I need to use Comet.  It seems easy enough, but I am confused.
>>>
>>> Let's continue with my LoginComponent (presumably the same would be done
>>> to other Components).
>>>
>>> In its renderContentOn: html, I need to add the following:
>>>
>>> LoginComponent>>renderContentOn: html
>>>
>>>   html div
>>>       id: 'login';
>>>       class: 'generic';
>>>       with: [...];
>>>   html script: (html comet
>>>       pusher: self class pusher;
>>>       connect)
>>>
>>> I gave the div an id and I installed and connected a comet script.
>>>
>>> Later, when my async reply comes in, I call a method update
>>>
>>> LoginComponent>>update
>>>
>>>   self class pusher javascript: [:script |
>>>       script element
>>>           id: 'login';
>>>           update: ????].
>>>
>>> My question concerns what I should update with (where the ???? is).  To
>>> complicate matters, I want to do two different things depending on 
>>> success
>>> or failure of my code.  On success, I want to switch to a different
>>> component.  Without asynchrony I would send "answer: acct".   Is this
>>> possible in a comet script?  I want the other component to have 
>>> control/be
>>> the active component (I am not sure how to describe this.  When a 
>>> component
>>> sends #call: with another component, he is switching control to that
>>> component, right?).  On failure, I want to refresh the error message (it 
>>> may
>>> not be displayed...) showing login failed, but leaving the 
>>> LoginComponent as
>>> the active component.
>>>
>>> How can I go about doing these things?
>>>
>>> Many thanks!
>>> Rob
>>>
>>> --------------------------------------------------
>>> From: "Rob Withers" <reefedjib at gmail.com>
>>> Sent: Monday, September 20, 2010 7:21 PM
>>> To: "Seaside - general discussion" <seaside at lists.squeakfoundation.org>
>>> Subject: Re: [Seaside] Asynchronous message sending
>>> andSeaside/Script.aculo.us/JavaScript/AJAX
>>>
>>>> Thanks for pointing this out, Lukas.  I have a lot to learn with 
>>>> Seaside,
>>>> and am now just reading the book.  I noticed there is a section on 
>>>> Comet,
>>>> which I read.  It is good to know that async events can update the 
>>>> page.
>>>>
>>>> Cheers,
>>>> Rob
>>>>
>>>> --------------------------------------------------
>>>> From: "Lukas Renggli" <renggli at gmail.com>
>>>> Sent: Monday, September 20, 2010 11:47 AM
>>>> To: "Seaside - general discussion" <seaside at lists.squeakfoundation.org>
>>>> Subject: Re: [Seaside] Asynchronous message sending
>>>> andSeaside/Script.aculo.us/JavaScript/AJAX
>>>>
>>>>>> I am trying to figure out how I can integrate my asynchronous message
>>>>>> sending framework with Seaside.  From my reading, it seems that 
>>>>>> Seaside
>>>>>> works on a request/response model.  Furthermore, with
>>>>>> JavaScript/AJAX/Script.aculo.us it still works on a request/response
>>>>>> model.
>>>>>
>>>>> Yes, this is how HTTP is designed.
>>>>>
>>>>>> There seems there is no way to "push" events/content.   Is this
>>>>>> accurate?
>>>>>
>>>>> No.
>>>>>
>>>>> For a long time there is the Comet package that provides a "hack" for
>>>>> pushing events from the server to the client. See the Comet examples
>>>>> that come with every Seaside distribution.
>>>>>
>>>>> Also Philippe recently published a WebSocket implementation for
>>>>> Seaside, but that doesn't work with all web browsers yet.
>>>>>
>>>>> Lukas
>>>>>
>>>>> --
>>>>> Lukas Renggli
>>>>> www.lukas-renggli.ch
>>>>> _______________________________________________
>>>>> seaside mailing list
>>>>> seaside at lists.squeakfoundation.org
>>>>> http://lists.squeakfoundation.org/cgi-bin/mailman/listinfo/seaside
>>>>>
>>>>
>>>
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>
>
>
> -- 
> Lukas Renggli
> www.lukas-renggli.ch
> _______________________________________________
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