如何将Rails对象作为参数发送到POST请求

Question

I have an rails object named app, when i send it to controller by following method then i get params[:app] as array in the controller. I have already tried a lot on stack overflow but did not found what i was looking for

assert_difference("Tagging.count", 3) do
      put "/candidates/#{app.id}", {id: app.id, assigned_tags: " #{tag_one.name} #{tag_two.name} #{tag_three.name} " ,  app: app.to_json }
    end

how can i get the app as hash in controller through params[:app] ??

Answer 1

There are two data structures you can build with the name attribute of a form field.

foo[] will put the value into an array called foo

foo[bar] will put the value into a hash called foo , using the key bar .

eg

  <input type="text" name="foo[]" value="bacon">
  <input type="text" name="foo[]" value="chicken">
  => params = {:foo => ["bacon", "chicken"]}

  <input type="text" name="foo[bar]" value="bacon">
  <input type="text" name="foo[baz]" value="chicken">
  => params = {:foo => {:bar => "bacon", :baz => "chicken"}}

These can be combined:

  <input type="text" name="foo[bar][]" value="bacon">
  <input type="text" name="foo[baz][]" value="chicken">
  => params = {:foo => {:bar => ["bacon"], :baz => ["chicken"]}}

  <input type="text" name="foo[][bar]" value="bacon">
  <input type="text" name="foo[][baz]" value="chicken">
  => params = {:foo => [{:bar => "bacon", :baz => "chicken"}]}

Answer 2

You can't send an object through params. Normally you should send the ID of that object in params and in receiving end you should lookup in the controller.

user = User.find(params[:user_id])

If you send an object as params, it'll be converted to array automatically.