Rails 3，更改或填写控制器中提交的表单值

Question

I have two independent "component" models, contacts and articles. Contacts come in many types (producers, exporters etc...).

In the new article form I have a dropdown selector with contacts (id and title) and want to store the selected value and text in the article table.

In the new article form view:

<%= f.select :producer_id, options_for_select(producers, @article.producer_id) %>

That works and producer_id is stored in article table.

That's clear and logical to me, but in some cases I also need to store the selected contact's title in producer_title .

I have read many different options like "do it in model, before save", or "do it in controller", and I have done it inside controller.

Article controller (only part from update):

#cont_name is producer title from Contacts
def update
  params[:article][:producer_title] = Contact.where(id: params[:article][:producer_id]).pluck(:cont_name).first 
end

This works, but is it the best-practices approach to this problem?

Also, why I can't get it to work if I change the params[producer_id] part to use: id: params[:producer_id] ?

Best regards and thanks.

Answer 1

How about something like the following instead:

def edit
  @article = Article.find(params[:id])
  @producers = Contact.where(type: "producer") # or however you distinguish between producers and other contacts
end

Then in your form change it to:

f.select :producer_id, options_from_collection_for_select(@producers, "cont_name")
# you might need to do (@producers, "cont_name", "cont_name"), can't quite remember

Then your update action will be much simpler:

def update
  @article = Article.find(params[:id])
  if @article.update_attributes(params[:article])
    ...
  else
    ...
  end
end

The reason :id => params[:producer_id] doesn't work is that params is a nested hash, so something like:

params = { :article => { :producer_id => 34, :title => "Cool Article" }, :another_key => { :key => :value } }

So to access the producer_id you first have to retrieve the article hash, otherwise it will only look through the first set of keys which include article and another_key in the example above, but don't include producer_id .