[Lift] Re: NPE Problem with User.current in CRUDify action

2009-07-13 Thread David Pollak 
On Sun, Jul 12, 2009 at 2:00 PM, Jeppe Nejsum Madsen je...@ingolfs.dkwrote:


 On Fri, Jul 10, 2009 at 8:12 PM, David
 Pollakfeeder.of.the.be...@gmail.com wrote:
  Okay... I just checked in a change to Lift that allows RequestVars to be
  reset once the session is known.
 
  Please do a build with the latest (if you're not building locally, please
  wait until Hudson finishes spinning the build) and let me know if it
 works.
 
  Thanks,
 
  David

 Thanks, I tried with these changes and it seems to work! Butthis
 solution feels a bit hackish to me, maybe out of lack of knowledge
 about the inner workings of Lift (ie what is a Session transition, and
 what does it transition from/to :-)


There's a huge tension in Lift between the re-writing phase (which happens
very, very early) and the session-related servicing phase.

The reason that we do rewriting before figuring out how to service the
request is because it's important to allow sessionless services to be able
to intercept the request.  It's also super duper important to have the
request normalized for as long as possible during the whole servicing
cycle.  Thus, I've made sure that the URL rewriting happens before the
session is part of the request.

It turns out that there is a very good reason to extend the life of the
RequestVar to include the re-writing phase.  This allows us to cache an
RDBMS lookup in the request var.

The problem in your case is that your model object caused the RequestVar
that holds the current user record to be populated.  But it was populated by
the sessionvar the holds the primary key to the User.

So, there needed to be a mechanism for flushing cached RequestVars that are
dependent on SessionVars when the session identifier changes.   Thus, the
new trait that signals to the RequestVar mechanism that a RequestVar is
dependent on a SessionVar and needs to be recalculated if the SessionVar
changes.  I don't think it's a hack as much as another way to resolve the
tension between where the request is demarked, the rewriting/caching
happens, and when the session is recognized.




 When are you supposed to apply the CleanRequestVarOnSessionTransition
 for instance? Is it Lift internals only or?

 Of course I could just ignore this and be happy that it works, but I
 like to know how stuff works underneath the covers :-)

 /Jeppe

 



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[Lift] Re: NPE Problem with User.current in CRUDify action

2009-07-13 Thread Jeppe Nejsum Madsen 

David Pollak feeder.of.the.be...@gmail.com writes:

[...]

 So, there needed to be a mechanism for flushing cached RequestVars that are
 dependent on SessionVars when the session identifier changes.   Thus, the
 new trait that signals to the RequestVar mechanism that a RequestVar is
 dependent on a SessionVar and needs to be recalculated if the SessionVar
 changes.  I don't think it's a hack as much as another way to resolve the
 tension between where the request is demarked, the rewriting/caching
 happens, and when the session is recognized.

Ok, makes sense. Thanks for the thorough explanation!

/Jeppe


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[Lift] Re: NPE Problem with User.current in CRUDify action

2009-07-10 Thread Jeppe Nejsum Madsen 

On Thu, Jul 9, 2009 at 11:44 PM, David
Pollakfeeder.of.the.be...@gmail.com wrote:

 If it's still a problem, a reproducible example would be great!

It's not a showstopper, since I can workaround it by reading the User again:

 def findMap[T](f: CustomCategory = Box[T]) : List[T] = {
Log.info(User %s, id=%s.format(User.currentUser, User.currentUserId))
// HACK
val curUser = User.currentUserId.flatMap(id = getSingleton.find(id))
findMap(By(account, curUser.open_!.account.is))(f)
  }

I tried to reproduce it with the Lift basic example, but was unable to
reproduce it here. This is probably good in that it's not a problem
that everybody sees, but bad in the sense that I'll need to do some
more digging. I'll see if I can find some time do work through the
Lift processing cycle :-)

/Jeppe

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[Lift] Re: NPE Problem with User.current in CRUDify action

2009-07-10 Thread David Pollak 
On Fri, Jul 10, 2009 at 9:28 AM, Jeppe Nejsum Madsen je...@ingolfs.dkwrote:


 On Fri, Jul 10, 2009 at 10:35 AM, Jeppe Nejsum Madsenje...@ingolfs.dk
 wrote:
  On Thu, Jul 9, 2009 at 11:44 PM, David
  Pollakfeeder.of.the.be...@gmail.com wrote:
 
  If it's still a problem, a reproducible example would be great!


 I've added some logging statements at various places. The statements
 below are from the beginning of a request to an CRUDify edit page from
 an CRUDify list page. It seems your hunch was correct in that CRUDify
 does seem to do some rewriting in it's Locs

 In CRUDify, it tries to load the selected object and therefore create
 a new instance. This creation needs the User.currentUser requestVar.
 But when the requestvars are being initialized, S.session is empty, so

 I'm not really sure what the correct order is and when S.session
 should be available, so let me know if you need more info.


The re-writing happens before the session is available.  Lemme see if I can
make the loading of the objects lazy... that might help a lot.




 /Jeppe

 INFO - RequestVarHandler.apply
 INFO - S.init req=null session=net.liftweb.http.liftsess...@40391ae4
 INFO - RequestVarHandler.apply
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.mapper.DB$$anon$1$DepthCnt$__inited_?=true
 INFO - AnyVar.is: Value not found set default value
 _lift_sv_net.liftweb.mapper.DB$$anon$1$DepthCnt$_=0
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.mapper.DB$$anon$1$DepthCnt$__inited_?=true
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.mapper.DB$$anon$1$DepthCnt$_=0
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.mapper.DB$$anon$1$DepthCnt$__inited_?=true
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.mapper.DB$$anon$1$DepthCnt$_=1
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.http.S$postFuncs$__inited_?=true
 INFO - AnyVar.is: Value not found set default value
 _lift_sv_net.liftweb.http.S$postFuncs$_=ListBuffer()
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.http.S$postFuncs$__inited_?=true
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.http.S$postFuncs$_=ListBuffer()
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.mapper.DB$$anon$1$DepthCnt$__inited_?=true
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.mapper.DB$$anon$1$DepthCnt$_=0
 INFO - S.init done
 INFO - New RewriteRequest parsePath=ParsePath(List(assets, edit,
 2875),,true,false)
 INFO - findForParam in=2875 S.session=Empty
 INFO - Set default user
 INFO - SessionVar.findFunc
 _lift_sv_net.liftweb.mapper.MetaMegaProtoUser$curUserId$_.
 Session=Empty
 INFO - AnyVar.is: Value not found set default value
 _lift_sv_net.liftweb.mapper.MetaMegaProtoUser$curUserId$_=Empty
 INFO - Sessionvar.setFunc
 _lift_sv_net.liftweb.mapper.MetaMegaProtoUser$curUserId$_=Empty
 INFO - Set curUser, id=Empty

 



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Beginning Scala http://www.apress.com/book/view/1430219890
Follow me: http://twitter.com/dpp
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[Lift] Re: NPE Problem with User.current in CRUDify action

2009-07-10 Thread David Pollak 
Okay... I just checked in a change to Lift that allows RequestVars to be
reset once the session is known.

Please do a build with the latest (if you're not building locally, please
wait until Hudson finishes spinning the build) and let me know if it works.

Thanks,

David

On Fri, Jul 10, 2009 at 9:56 AM, David Pollak feeder.of.the.be...@gmail.com
 wrote:



 On Fri, Jul 10, 2009 at 9:28 AM, Jeppe Nejsum Madsen je...@ingolfs.dkwrote:


 On Fri, Jul 10, 2009 at 10:35 AM, Jeppe Nejsum Madsenje...@ingolfs.dk
 wrote:
  On Thu, Jul 9, 2009 at 11:44 PM, David
  Pollakfeeder.of.the.be...@gmail.com wrote:
 
  If it's still a problem, a reproducible example would be great!


 I've added some logging statements at various places. The statements
 below are from the beginning of a request to an CRUDify edit page from
 an CRUDify list page. It seems your hunch was correct in that CRUDify
 does seem to do some rewriting in it's Locs

 In CRUDify, it tries to load the selected object and therefore create
 a new instance. This creation needs the User.currentUser requestVar.
 But when the requestvars are being initialized, S.session is empty, so

 I'm not really sure what the correct order is and when S.session
 should be available, so let me know if you need more info.


 The re-writing happens before the session is available.  Lemme see if I can
 make the loading of the objects lazy... that might help a lot.




 /Jeppe

 INFO - RequestVarHandler.apply
 INFO - S.init req=null session=net.liftweb.http.liftsess...@40391ae4
 INFO - RequestVarHandler.apply
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.mapper.DB$$anon$1$DepthCnt$__inited_?=true
 INFO - AnyVar.is: Value not found set default value
 _lift_sv_net.liftweb.mapper.DB$$anon$1$DepthCnt$_=0
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.mapper.DB$$anon$1$DepthCnt$__inited_?=true
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.mapper.DB$$anon$1$DepthCnt$_=0
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.mapper.DB$$anon$1$DepthCnt$__inited_?=true
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.mapper.DB$$anon$1$DepthCnt$_=1
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.http.S$postFuncs$__inited_?=true
 INFO - AnyVar.is: Value not found set default value
 _lift_sv_net.liftweb.http.S$postFuncs$_=ListBuffer()
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.http.S$postFuncs$__inited_?=true
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.http.S$postFuncs$_=ListBuffer()
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.mapper.DB$$anon$1$DepthCnt$__inited_?=true
 INFO - RequestVarHandler.set
 _lift_sv_net.liftweb.mapper.DB$$anon$1$DepthCnt$_=0
 INFO - S.init done
 INFO - New RewriteRequest parsePath=ParsePath(List(assets, edit,
 2875),,true,false)
 INFO - findForParam in=2875 S.session=Empty
 INFO - Set default user
 INFO - SessionVar.findFunc
 _lift_sv_net.liftweb.mapper.MetaMegaProtoUser$curUserId$_.
 Session=Empty
 INFO - AnyVar.is: Value not found set default value
 _lift_sv_net.liftweb.mapper.MetaMegaProtoUser$curUserId$_=Empty
 INFO - Sessionvar.setFunc
 _lift_sv_net.liftweb.mapper.MetaMegaProtoUser$curUserId$_=Empty
 INFO - Set curUser, id=Empty

 



 --
 Lift, the simply functional web framework http://liftweb.net
 Beginning Scala http://www.apress.com/book/view/1430219890
 Follow me: http://twitter.com/dpp
 Git some: http://github.com/dpp




-- 
Lift, the simply functional web framework http://liftweb.net
Beginning Scala http://www.apress.com/book/view/1430219890
Follow me: http://twitter.com/dpp
Git some: http://github.com/dpp

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[Lift] Re: NPE Problem with User.current in CRUDify action

2009-07-07 Thread David Pollak 
Are you doing this as part of an HTTP request or at some other point in the
execution of your code (e.g., a background processing thread)?

On Tue, Jul 7, 2009 at 5:53 AM, Jeppe Nejsum Madsen je...@ingolfs.dkwrote:


 Hi,

 I get an Empty box when using the value of User.current when trying to
 populate the valid select values for use in a CRUDify edit form:

 I have this mapped object which I'm trying to edit using CRUDify:

 class Vehicle extends LongKeyedMapper[Vehicle] with IdPK {
[...]
object customCategory extends MappedLongForeignKey(this, CustomCategory)
 {
  override def validSelectValues = Full(CustomCategory.findMap{cc :
 CustomCategory = Full(cc.id.is, cc.description.is)})
}
  [...]

 I then have this, that uses the current user to populate the valid
 values:

 object CustomCategory extends CustomCategory with
 LongKeyedMetaMapper[CustomCategory] {
  def findMap[T](f: CustomCategory = Box[T]) : List[T] = {
Log.info(User %s, id=%s.format(User.currentUser, User.currentUserId))
findMap(By(id, User.currentUser.open_!.account.is))(f)
  }

 When navigating to the edit page for Vehicle, I get this in the log:

 INFO - User Empty, id=Full(2)

 So it seems the user id is stored ok, but the RequestVar is not set.

 Any clues??

 /Jeppe

 



-- 
Lift, the simply functional web framework http://liftweb.net
Beginning Scala http://www.apress.com/book/view/1430219890
Follow me: http://twitter.com/dpp
Git some: http://github.com/dpp

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[Lift] Re: NPE Problem with User.current in CRUDify action

2009-07-07 Thread Jeppe Nejsum Madsen 
Just a normal request from a link in a CRUDify list

Sendt fra min iPhone

Den 07/07/2009 kl. 18.49 skrev David Pollak feeder.of.the.be...@gmail.com 
 :

 Are you doing this as part of an HTTP request or at some other point  
 in the execution of your code (e.g., a background processing thread)?

 On Tue, Jul 7, 2009 at 5:53 AM, Jeppe Nejsum Madsen  
 je...@ingolfs.dk wrote:

 Hi,

 I get an Empty box when using the value of User.current when trying to
 populate the valid select values for use in a CRUDify edit form:

 I have this mapped object which I'm trying to edit using CRUDify:

 class Vehicle extends LongKeyedMapper[Vehicle] with IdPK {
[...]
object customCategory extends MappedLongForeignKey(this,  
 CustomCategory) {
  override def validSelectValues = Full(CustomCategory.findMap 
 {cc : CustomCategory = Full(cc.id.is, cc.description.is)})
}
  [...]

 I then have this, that uses the current user to populate the valid
 values:

 object CustomCategory extends CustomCategory with LongKeyedMetaMapper 
 [CustomCategory] {
  def findMap[T](f: CustomCategory = Box[T]) : List[T] = {
Log.info(User %s, id=%s.format(User.currentUser,  
 User.currentUserId))
findMap(By(id, User.currentUser.open_!.account.is))(f)
  }

 When navigating to the edit page for Vehicle, I get this in the log:

 INFO - User Empty, id=Full(2)

 So it seems the user id is stored ok, but the RequestVar is not set.

 Any clues??

 /Jeppe





 -- 
 Lift, the simply functional web framework http://liftweb.net
 Beginning Scala http://www.apress.com/book/view/1430219890
 Follow me: http://twitter.com/dpp
 Git some: http://github.com/dpp

 

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[Lift] Re: NPE Problem with User.current in CRUDify action

2009-07-07 Thread David Pollak 
Okay... I see the code path that could cause this issue.

Are you doing any re-writing?  Are you accessing User.currentUser in your
re-writes?

On Tue, Jul 7, 2009 at 5:53 AM, Jeppe Nejsum Madsen je...@ingolfs.dkwrote:


 Hi,

 I get an Empty box when using the value of User.current when trying to
 populate the valid select values for use in a CRUDify edit form:

 I have this mapped object which I'm trying to edit using CRUDify:

 class Vehicle extends LongKeyedMapper[Vehicle] with IdPK {
[...]
object customCategory extends MappedLongForeignKey(this, CustomCategory)
 {
  override def validSelectValues = Full(CustomCategory.findMap{cc :
 CustomCategory = Full(cc.id.is, cc.description.is)})
}
  [...]

 I then have this, that uses the current user to populate the valid
 values:

 object CustomCategory extends CustomCategory with
 LongKeyedMetaMapper[CustomCategory] {
  def findMap[T](f: CustomCategory = Box[T]) : List[T] = {
Log.info(User %s, id=%s.format(User.currentUser, User.currentUserId))
findMap(By(id, User.currentUser.open_!.account.is))(f)
  }

 When navigating to the edit page for Vehicle, I get this in the log:

 INFO - User Empty, id=Full(2)

 So it seems the user id is stored ok, but the RequestVar is not set.

 Any clues??

 /Jeppe

 



-- 
Lift, the simply functional web framework http://liftweb.net
Beginning Scala http://www.apress.com/book/view/1430219890
Follow me: http://twitter.com/dpp
Git some: http://github.com/dpp

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