Problem with continuations/flow.

> Hi.
>
>
> Calling the following:
>
> testCC
>
> self inform: 'A'.  
> self wait: [ :cc |
> self inform: 'B: ', ( self session actionUrlForContinuation: cc).
> self answer].
> self inform: 'C'.
> self answer.  
>
>
> allways results in an error:
>

> Error: This block accepts 1 argument, but was called with 0 arguments.
>
> In WASession>>handleFiltered:
>
> handleFiltered: aRequestContext
> | key continuation |
> key := aRequestContext request fields
> at: self actionField
> ifAbsent: [ ^ self start ].
>
> continuation := continuations
> at: key
> ifAbsent: [ ^ self unknownRequest ].
> continuation value
>
> at the last line.
> Continuation is
> outerContext: GRPharoPlatform>>seasideSuspendFlowDo: startpc: 54 numArgs: 1
>
>
> So Long,
> -Tobias
>
> _______________________________________________
> seaside mailing list
> [hidden email]
> http://lists.squeakfoundation.org/cgi-bin/mailman/listinfo/seaside

>
> Am 2011-05-20 um 09:49 schrieb Tobias Pape:
>
>> Hi.
>>
>>
>> Calling the following:
>>
>> testCC
>>
>> self inform: 'A'.  
>> self wait: [ :cc |
>> self inform: 'B: ', ( self session actionUrlForContinuation: cc).
>> self answer].
>> self inform: 'C'.
>> self answer.  
>>
>>
>> allways results in an error:
>>
>
> Ok, this is incorret,
> Calling the url generated by ( self session actionUrlForContinuation: cc)
> results in the error.
>
>> Error: This block accepts 1 argument, but was called with 0 arguments.
>>
>> In WASession>>handleFiltered:
>>
>> handleFiltered: aRequestContext
>> | key continuation |
>> key := aRequestContext request fields
>> at: self actionField
>> ifAbsent: [ ^ self start ].
>>
>> continuation := continuations
>> at: key
>> ifAbsent: [ ^ self unknownRequest ].
>> continuation value
>>
>> at the last line.
>> Continuation is
>> outerContext: GRPharoPlatform>>seasideSuspendFlowDo: startpc: 54 numArgs: 1
>>
>>
>> So Long,
>> -Tobias
>>
>> _______________________________________________
>> seaside mailing list
>> [hidden email]
>> http://lists.squeakfoundation.org/cgi-bin/mailman/listinfo/seaside
>
> _______________________________________________
> seaside mailing list
> [hidden email]
> http://lists.squeakfoundation.org/cgi-bin/mailman/listinfo/seaside

> *humble bump*
>
> Am 2011-05-20 um 10:03 schrieb Tobias Pape:
>
>>
>> Am 2011-05-20 um 09:49 schrieb Tobias Pape:
>>
>>> Hi.
>>>
>>>
>>> Calling the following:
>>>
>>> testCC
>>>
>>>      self inform: 'A'.
>>>      self wait: [ :cc |
>>>              self inform: 'B: ', ( self session actionUrlForContinuation: cc).
>>>              self answer].
>>>      self inform: 'C'.
>>>      self answer.
>>>
>>>
>>> allways results in an error:
>>>
>>
>> Ok, this is incorret,
>> Calling the url generated by ( self session actionUrlForContinuation: cc)
>> results in the error.
>>
>>> Error: This block accepts 1 argument, but was called with 0 arguments.
>>>
>>> In WASession>>handleFiltered:
>>>
>>> handleFiltered: aRequestContext
>>>      | key continuation |
>>>      key := aRequestContext request fields
>>>              at: self actionField
>>>              ifAbsent: [ ^ self start ].
>>>
>>>      continuation := continuations
>>>              at: key
>>>              ifAbsent: [ ^ self unknownRequest ].
>>>      continuation value
>>>
>>> at the last line.
>>> Continuation is
>>>      outerContext: GRPharoPlatform>>seasideSuspendFlowDo: startpc: 54 numArgs: 1
>>>
>>>
>>> So Long,
>>>      -Tobias
>>>
>>> _______________________________________________
>>> seaside mailing list
>>> [hidden email]
>>> http://lists.squeakfoundation.org/cgi-bin/mailman/listinfo/seaside
>>
>> _______________________________________________
>> seaside mailing list
>> [hidden email]
>> http://lists.squeakfoundation.org/cgi-bin/mailman/listinfo/seaside
>
> _______________________________________________
> seaside mailing list
> [hidden email]
> http://lists.squeakfoundation.org/cgi-bin/mailman/listinfo/seaside
>

> #actionUrlForContinuation: doesn't expect a first-class continuation
> but rather a CPS continuation (a subclass of WASessionContinuation).
> Actually, to be more accurate, WASession>>handleFiltered: expects that
> to be so. Actually, to be more accurate, it expects something that
> responds to successfully to #value.
>
> Technically, I think you could avoid the error by doing:
>
> testCC
>     self inform: 'A'.
>     self wait: [ :cc |
>             self inform: 'B: ', ( self session
> actionUrlForContinuation: [ cc value: nil ]) greaseString.
>             self answer].
>     self inform: 'C'.
>     self answer.
>
> However, I doubt you'll be happy with the results: part of the
> implementation of WASessionContinuation>>value is to restore
> backtracked state, and its subclasses do things like processing
> callbacks and starting rendering. Without the handling that deals with
> callbacks, for example, your call to #answer inside the block won't
> work.

>
> Am 2011-05-24 um 09:50 schrieb Julian Fitzell:
>
>> #actionUrlForContinuation: doesn't expect a first-class continuation
>> but rather a CPS continuation (a subclass of WASessionContinuation).
>> Actually, to be more accurate, WASession>>handleFiltered: expects that
>> to be so. Actually, to be more accurate, it expects something that
>> responds to successfully to #value.
>>
>> Technically, I think you could avoid the error by doing:
>>
>> testCC
>>     self inform: 'A'.
>>     self wait: [ :cc |
>>             self inform: 'B: ', ( self session
>> actionUrlForContinuation: [ cc value: nil ]) greaseString.
>>             self answer].
>>     self inform: 'C'.
>>     self answer.
>>
>> However, I doubt you'll be happy with the results: part of the
>> implementation of WASessionContinuation>>value is to restore
>> backtracked state, and its subclasses do things like processing
>> callbacks and starting rendering. Without the handling that deals with
>> callbacks, for example, your call to #answer inside the block won't
>> work.
>
>
> In the original Squeaksource Code, this facility was used to
> generate Password-reset links like this (in seaside 2.7*):
>
>  1 sendPasswordToUserWithLogin: login
>  2     | member url |
>  3     member := self model memberAt: login.
>  4
>  5     " validation here "
>  6     Continuation currentDo: [ :cc |
>  7             url := self session actionUrlForContinuation: cc.
>  8             url := SSRepository rootUrl , url copyWithoutFirst.
>  9             self sendMailWithUrl: url toMember: member. "exception handling here"
>  10             self inform: 'An e-mail has been successfully sent to you.'.
>  11             self answer ].
>  12     self callEditMemberForm. "shortened for brevity"
>  13     self answer.
>
> with the effect, that on the website the ‘link to the continuation’ was
> generated (7/8) and sent as email to se user (9). The user was informed
> that the email had been sent (10) and was returned where he came from (11)
>  Now when the user clicked on the link in the email, the continuation
> continued from 12, effectively allowing the user to change her/his password.
>
> I think this is one of the most elegant ways to implement a secure
> password reset. Yet, this no longer works with Seaside 3.0,
> Neither using
>        WAComponent>>#wait: ,
>        GRPlatform>>#seasideSuspendFlowDo: ,
>        WAContinuation>>#currentDo: , nor
>        WAPartialContinuation>>#currentDo:
> (I tried the last with various marker setups)
>
> I hope you can enlighten me there.
>
> Best
>        -Tobias
>
>
>
> * for reference, the same from SqueakSource2 with Seaside 2.8, but
>  the differences are minor.
>
> sendPasswordToUserWithLogin: login
>        | member url |
>        member := self model memberAt: login.
>        " " validation here "
>        WAContinuation currentDo: [ :cc |
>                url := self session actionUrlForContinuation: cc.
>                url := self repository rootUrl , url copyWithoutFirst.
>                self sendMailWithUrl: url toMember: member. "exception handling here"
>                self inform: 'An e-mail has been successfully sent to you.'.
>                self answer ].
>        self editMember: 'Change your password'.
>        self answer_______________________________________________
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>

> I'm pretty sure that code would have suffered from the same bugs, i.e.
> state would not be backtracked, so the user would be running in a
> session assuming it was in the condition of a particular request but
> actually in the state of whatever request happened to have been
> processed by that session most recently. However, the move to partial
> continuations means that it is now more overtly broken.
>
> So... instead of using #inform: to tell the user an email has been
> sent to them, you could #call: a component. Inside that component's
> render method, you can use "url := html urlForAction [ self
> verifyAccount. self answer ]" to get a URL and then send the email.
> This isn't a *great* solution either, since we don't recommend
> performing actions (like sending an email) during the render phase,
> but currently you have no way of setting up callbacks in a task, so it
> may be the best you can easily do.
>
> The other option is to create your own subclass of
> WASessionContinuation, which is a bit heavier-weight but probably a
> better idea. I'm actually in the middle of working on some code in
> Seaside that introduces a pluggable action continuation, which should
> make this kind of thing easier since you wouldn't have to create your
> own class. It should be possible to implement what you're trying to do
> in a task by wrapping the first class continuation in a CPS
> continuation, but I'll need to think a bit more about that - I'm
> meeting Nick to work on related stuff this afternoon anyway so I'll
> see what I can come up with.