Rails 4.0 param is missing or the value is empty

问题

I have an Opportunity model that has a nested resource Link. In my views/opportunities/show page when I click on "DestroY' for one of the links, I get the error:

param is missing or the value is empty: link

The code snippet it is complaining about is:

def link_params
     params.require(:link).permit(:description, :link_url)
end

Here is my destroy code:

def destroy
  @opportunity = Opportunity.find(params[:opportunity_id])
  @link = @opportunity.links.find(link_params)
  @link.destroy
  respond_to do |format|
    format.html { redirect_to links_url, notice: 'Link was successfully destroyed.' }
    format.json { head :no_content }
end

回答1:

Change this:

 @link = @opportunity.links.find(link_params)

To this:

 @link = @opportunity.links.find(params[:id])

You don't have a link in your params, you just have an id and an opportunity_id.

Also, you have this:

respond_to do |format|
   format.html { redirect_to links_url, notice: 'Link was successfully destroyed.' }
...
end

I'm guessing you have your links resource nested inside opportunities. So there is no links_url. You need to use, i.e., opportunities_links_url(@opportunity).

Finally, note that you probably want opportunities_links_path rather than opportunities_links_url unless you explicitly need absolute URLs in this instance.

You can discover your link helper by running rake routes. Everything in the leftmost "prefix" column can be called with _url or _path on the end to generate a url.

回答2:

I had the same error. U must be using before_action :link_params at the top, instead do this before_action :link_params,only: [:create]

来源：https://stackoverflow.com/questions/23984608/rails-4-0-param-is-missing-or-the-value-is-empty

标签

ruby-on-rails

params