# Flashing validation messages

**URL:** <https://www.ruby-forum.com/t/flashing-validation-messages/76717>\
**Category:** Rails\
**Created:** [November 20, 2006, 6:03pm UTC](https://www.ruby-forum.com/t/flashing-validation-messages/76717 "2006-11-20T18:03:15Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Abdullah\_J](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ecccb3/32.png) [@Abdullah\_J](https://www.ruby-forum.com/u/Abdullah_J)\
**Post date:** [November 20, 2006, 6:03pm UTC](https://www.ruby-forum.com/t/flashing-validation-messages/76717/1 "2006-11-20T18:03:15Z")

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Hi,

One thing which I’ve noticed with the default scaffold setup is that  
when validating the model after a post, if there are errors they are  
shown immediately (there is no redirect in between). I think it is  
always better to do a redirect after a post so what is the DRYest way  
to flash my error messages?

Thanks,  
Abdullah

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**Author:** ![Abdullah\_J](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ecccb3/32.png) [@Abdullah\_J](https://www.ruby-forum.com/u/Abdullah_J)\
**Post date:** [November 20, 2006, 6:55pm UTC](https://www.ruby-forum.com/t/flashing-validation-messages/76717/2 "2006-11-20T18:55:36Z")

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@flash[:error] = @object.errors.full\_messages.join(“  
”)

Just a quick hack.

On 11/20/06, Abdullah J. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Abdullah
> 
> >

–  
rm -rf / 2\>/dev/null - [http://null.in](http://null.in)

Dont judge those who try and fail, judge those who fail to try…

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**Author:** ![Abdullah\_J](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ecccb3/32.png) [@Abdullah\_J](https://www.ruby-forum.com/u/Abdullah_J)\
**Post date:** [November 20, 2006, 8:49pm UTC](https://www.ruby-forum.com/t/flashing-validation-messages/76717/3 "2006-11-20T20:49:59Z")

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I don’t see why redirecting after the post is necessary here… the  
record  
insertion failed. Refreshing the page would only result in the same  
error  
message coming back up. Rules like “always redirect after a post”  
should  
depend on the situation and not be requirements.

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<div class="post-metadata">

**Author:** ![Abdullah\_J](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ecccb3/32.png) [@Abdullah\_J](https://www.ruby-forum.com/u/Abdullah_J)\
**Post date:** [November 20, 2006, 11:32pm UTC](https://www.ruby-forum.com/t/flashing-validation-messages/76717/4 "2006-11-20T23:32:39Z")

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Hi Brian,

I think it is almost always necessary because otherwise if the user  
tried to hit refresh after an invalid post the browser will try to  
repost the data (usually giving you an error message first). This  
approach gets rid of that. By the way here is what I decided to use:

def signup  
@user = flash[:user] || User.new  
if request.post?  
@user = User.new(params[:user])  
if @user.save  
flash[:notice] = “User #{@user.name} created”  
redirect\_to home\_url and return  
end  
flash[:user] = @user  
redirect\_to :action =\> ‘signup’  
end  
end

It works great but if anyone knows of a better way please let me know  
(mainly I don’t like how I have to reassign user if it’s a post). And  
the reason I flash user when validation fails is because that instance  
has all the error messages attached to it.

Thanks,  
Abdullah

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<div class="post-metadata">

**Author:** ![Abdullah\_J](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ecccb3/32.png) [@Abdullah\_J](https://www.ruby-forum.com/u/Abdullah_J)\
**Post date:** [November 21, 2006, 4:25am UTC](https://www.ruby-forum.com/t/flashing-validation-messages/76717/5 "2006-11-21T04:25:16Z")

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With that approach you’ve doubled the resource load on your app when  
errors  
occur.

You need to do User.new twice now… because you’ve done it once to  
process  
the error and then once again after the redirect. Plus you’ve invoked  
the  
controller twice.

That’s why it’s not a good method to use in all circumstances. Sure it  
doesn’t matter on small sites, but it matters greatly on sites with lots  
of  
traffic. That’s the reason the default scaffolding uses the approach it  
does.

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<div class="post-metadata">

**Author:** ![Abdullah\_J](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ecccb3/32.png) [@Abdullah\_J](https://www.ruby-forum.com/u/Abdullah_J)\
**Post date:** [November 22, 2006, 5:41am UTC](https://www.ruby-forum.com/t/flashing-validation-messages/76717/6 "2006-11-22T05:41:53Z")

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You have a point, I checked almost every large site I could think of  
(gmail, yahoo, ebay, amazon, youtube, and several others) and the only  
one that redirected after an error (in the login) was ebay. I do feel  
it really helps out with usability though, so I’ll try to test the  
performance once I have time.

Thanks,  
Abdullah