Unable to retrieve/save posts on timeline

[carljenkins]

When working through section 6.4.2 I can't seem to get the timeline.jsp to update with the saved post submitted by the form. The only way to get it to work was to add a post.save(flush:true) after the if(user.save()) statement. If I take the post.save() out the page doesn't update with the newly created post.

I noticed someone else had a similar problem around Dec 2013. Is this still a problem or am I missing something basic?

 def addPost() {
    def user = User.findByLoginId(params.id)
    if (user) {
        def post = new Post(params)

        user.addToPosts(post)
        if (user.save()) {
            post.save(flush: true)
            flash.message = "Successfully created Post"
        } else {
            flash.message = "Invalid or empty post"
        }
    } else {
        flash.message = "Invalid User Id"
    }
    redirect(action: 'timeline', id: params.id)
}

java version 1.7.0_51 grails version 2.4.0

[pledbrook]

Do you have this line in your Post.groovy domain class?

[pledbrook]

To clarify the previous comment, the user.save() call will also save any new posts that have been added to the user as long as Post belongs to User.

[carljenkins]

Hi - thanks for the reply. Yes, I do have that line in my Post.groovy. Here is what my Post domain looks like right now.

package com.grailsinaction

class Post {
  String content
  Date dateCreated

  static constraints = {
  }
  static belongsTo = [user : User]
  static hasMany = [tags : Tag]
  static mapping = {
      sort dateCreated: "desc"
  }
  }

[pledbrook]

Which version of Grails are you using? I remember testing this several times, so unless the Post is failing validation (which it can't be if your post.save() is working) then I can only think of a version issue.

Have you downloaded the chapter source and tested that with ./grailsw run-app?

I'm afraid I don't have time to look at this right now. Maybe later in the week.

[carljenkins]

I am currently running Grails version 2.4.0. I will do as you suggest and try running the chapter source and see what that does; I'll post back here the outcome of running that.

Thanks for your help.

edit: My apologies for taking so long to reply. I ran the chapter code as you suggested and indeed it works correctly. Appears I have some kinks to work out. Thanks for your help!

[thiagoa]

I'm using Grails 2.3.11 and MySQL.

That code sample worked for me when I submitted valid post content.

Instead, a problem happened when the post content was empty. I expected to see "Invalid or empty post", but instead I got a strange error from Hibernate, related to session flush in the event of an exception. I investigated the issue and found out the cause of the exception: validation does not cascade to child objects. When I saved the user, it tried to save the associated post without validation, but it failed badly because content had a NOT NULL constraint in MySQL.

I wrote some tests, and to make the code sample work "as is", I found a workaround in User.groovy:

static constraints = {
    ...
    posts validator: { posts ->
        posts ? posts.every { it.validate() } : true
    }
}

That forces User to validate child Post objects, if any. I expected Grails to do cascade vaildation, so I'm a bit disappointed. Is there a clean workaround for this? Am I missing something?