form_for, need to modify the :url based on if it is persisted or not

rubyonrails-talk
1

My have a form in a partial like this:

form_for @article, :url => articles_path, …

Now currently it posts to the create action.

I want it to post to comment_article_path under certain conditions, how can I do this?

Can I put in a expression like:

@article.persisted? comment_article_path : articles_path

Is this good practice?

2

It can certainly be done easy enough, but I’d question the problem you are trying to solve if you want to do something like that.

3

You can create a helper method (in helpers/articles_helper.rb): def correct_post_path     @article.persisted? comment_article_path : articles_path end

And then use this helper in your form builder   form_for @article, correct_post_path do ... end

That helps ? Maybe you can tell us under what conditions you need to change post url, maybe you over-engineer somewhere...

4

Thanks.

When you add something to a helper like articles_helper, does it have the request object in there also?

How does it get the @articles object when I call it like:

form_for @article, correct_post_path, …

I would have though it would be:

form_for @article, correct_post_path(@article), …

5

Thanks.

When you add something to a helper like articles_helper, does it have the request object in there also?

How does it get the @articles object when I call it like:

Controller instance variables are copied across to the view object so that just works (although you can of course pass parameters into your helpers explicitly)

Fred