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Software ObservationsGrails 1.0.4 "no Session" Error
In Grails 1.0.4, there are a few significant changes to how GORM returns Model objects from queries or model traversal.
If you're getting "Could not initialize proxy - no Session" exceptions when trying to access a domain object's collection of child objects, check that you aren't storing the domain object in a HTTP session, as when model objects are stored in the session, they're detached. Prior to version 1.0.3, the detached object had enough information as it was "eagerly fetched". With 1.0.4, this is no longer the case as it's just a proxied object.
If you're getting "Could not initialize proxy - no Session" exceptions when trying to access a domain object's collection of child objects, check that you aren't storing the domain object in a HTTP session, as when model objects are stored in the session, they're detached. Prior to version 1.0.3, the detached object had enough information as it was "eagerly fetched". With 1.0.4, this is no longer the case as it's just a proxied object.
To prevent this problem, before you access the object's child collection do the following:
def user = session.user
user.refresh() // Either refresh the object to attach it back to the session
user = User.get( user.id ) // Or retrieve back the object with its iduser.profiles[0] // Then doing stuff like this won't throw the error anymore
For more discussion and context, read this message thread.
3 comments:
Thanks, this is potentially very helpful. I couldn't find this page when Googling the full exception so to help others, here it is: org.hibernate.LazyInitializationException: could not initialize proxy - no Session
The message thread link above is broken now. Try here:
http://osdir.com/ml/lang.groovy.grails.user/2008-11/msg01092.html
There's a section about this problem in the book Grails Persistence with GORM and GSQL ($14 ebook, $20 book). The section is titled Lazy Initialization and the Grails Session. The recommended solution is this:
def hibSession = sessionFactory.currentSession
user = hibSession.merge(user)
I suppose that using the user.refresh or User.get approach from this blog post results in re-reading the object from the DB and thus losing any changes that have been made to the object.
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