Rails: passing arguments through controller methods

Question

Say I've got a standard new method in a controller:

def new
  @doc = Doc.new
  respond_to do |format|
    format.html
    format.json { render json: @doc }
  end
end

How would I facilitate passing an argument through it, i.e.:

def new(i)
  ...
end

To permit me to write something like this in the view:

<%= link_to(e.name, new_doc_path(e.id)) %>

Cheers!

Mischa · Accepted Answer · 2013-01-07 02:15:05Z

7

Rails doesn't work like that. If you want to pass anything to the controller you have to use the params hash. In your example:

View:

<%= link_to(e.name, new_doc_with_parameter_path(e.id)) %>

Controller:

def new
  id = params[:id]
  # do something with `id`
end

For this to work you have to change your routes so that you can pass an id via the URL to your new action:

get "/docs/new/:id" => "docs#new", :as => :new_doc_with_parameter

Although the above should work, in your case it may be better to have a look at Nested Resources.

answered Jan 7, 2013 at 1:06

Mischa

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6 Comments

That seems like it'll work, but new_doc_path(e.id) gives me a URL that looks like .../doc/new.3. Any thoughts?

What are you trying to do exactly? What kind of object is e? You may want to have a look at Nested Resources.

@mileorsohigh, I updated my answer, but it may be better to use Nested Resources. Not sure if that's appropriate in your situation though.

e loops through records from a different model and each doc record has to record which e was selected. Does that makes sense?

So Doc belongs_to :e in your model? If so, you can use nested resources. See my link above. If not, try my updated answer.

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