Validating form data without saving

Rails
1

Hello,

I got a form that feeds data to 2 models: Topic and Post.

@topic = Topic.new(params[:topic])
@post = Post.new(params[:post])

if @topic.save

@post.topic_id = @topic.id
@post.save

end

Now if there is an error in the Topic data RoR will catch it. But if
the Post fails validation the Topic still gets created. So what would
like to do is doing a test on each object and then save.

Did google the topic but did not hit the nail on the head.

Best regards.
Asbjørn Morell.

2

On 24 Aug 2008, at 19:35, atmorell [email protected] wrote:

@post.topic_id = @topic.id
@post.save

end

Now if there is an error in the Topic data RoR will catch it. But if
the Post fails validation the Topic still gets created. So what would
like to do is doing a test on each object and then save.

Just call the valid? method

Fred

3

Hmmm just gave it a try:

if @post.valid? and @topic.valid?

@topic.save
@post.topic_id = @topic.id
@post.save

end

The “if” condition does not seem to care about the Post validation.
Topic validation works as it should :confused:

Any ideas?

On Aug 24, 8:53 pm, Frederick C. [email protected]

4

On Sun, Aug 24, 2008 at 8:35 PM, atmorell [email protected] wrote:

end

Now if there is an error in the Topic data RoR will catch it. But if
the Post fails validation the Topic still gets created. So what would
like to do is doing a test on each object and then save.

You could for example add

validates_associated :topic

to the Post model and then:

post = Post.new(params[:post])
post.build_topic(params[:topic])
if post.save
# both post and topic are valid
else
# at least one of them is invalid, you got all errors in one shot
end

That said, in AR I normally work from the parent downwards:

topic = Topic.new(params[:topic])
topic.posts.build(params[:post])
topic.save

In any case, if the associated object is invalid you have an error in
the “root” object telling so, and the particular errors in the child.

5

On Sun, Aug 24, 2008 at 11:40 PM, Xavier N. [email protected] wrote:

That said, in AR I normally work from the parent downwards:

topic = Topic.new(params[:topic])
topic.posts.build(params[:post])
topic.save

I forgot to mention in that alternative you put

validates_associated :posts

in the Topic model.

6

Problem solved. valid? was the method I was looking for.

Thanks.

7

Watch out: “and” is not the same as “&&”

if @post.valid? and @topic.valid? # equivalent to @post.valid?; if
@topic.valid?

See http://www.pjhyett.com/posts/201-using-or-and-in-ruby for more
details.

8

I think you really just want a transaction here. If you don’t want
the Topic created when the post fails, you can do the following:

Post.transaction do
@topic = Topic.new(params[:topic])
@post = Post.new(params[:post])

if @topic.save
@post.topic_id = @topic.id
@post.save
end
end

If one fails, all fail and you don’t get the unwanted saves.

-Kevin

9

On Tue, Aug 26, 2008 at 5:38 PM, Kevin W.
[email protected] wrote:

If one fails, all fail and you don’t get the unwanted saves.
Problem is if @topic.save fails and @post is invalid you are not able
to show @post’s validation errors to the user in the same view.