How do I pass in a parameter to a hidden_field_tag in my form in Rails 3?

Question

I'm trying to get a messaging feature working (using the acts-as-messageable gem) and I want a user to send a message without having to enter a ':to' field.

In my /users/show.html.erb I have:

<%= link_to 'Send a message', new_message_path %>

And in my /messages/new.html.erb:

<%= simple_form_for @message, :url => messages_path, :method => :post do |f| %>
   <%= hidden_field_tag :user_id %> 
   <%= f.input :body %>
   <%= f.submit %>
 <% end %>

And my messages controller:

def new
  @message = ActsAsMessageAble::Message.new
 end

 def create
   @to = User.find(params[:user_id])
   current_user.send_message(@to, params[:body])
 end

At the moment when I submit the form, Rails obviously can't find a user with id= nothing since there is no param[:user_id] present.

I can't figure out how to pass the param into that hidden_field_tag in the form?

Appreciate your help.

Answer 1

So what I wanted to do was visit a users profile, click send message, and be able to write the the message and let it send automatically to the user without explicitly stipulating a :to field.

The problem was that :user_id in <%= hidden_tag_field :user_id %> wasn't being set. In other words, I couldn't get :user_id from the params while in that form.

Some of the solutions we tried were to include the params in the link_to but that didn't sit well with the form which saw the object as nil.

What I ended up doing was creating a nested resource like so:

resources :users do
   resources :messages do
   end
 end

And this ultimately gave me the url: users/:id/messages/new (new_user_message_path)

My controller ended up looking like this:

def new
   @message = ActsAsMessageable::Message.new
   @user = params[:user_id]
 end

 def create
   @to = User.find params[:id]
   if current_user.send_message(@to, params[:acts_as_messageable_message][:body]
     flash[:notice] = "Success"
   else 
     flash[:error] = "Fail"
   end
 end

In the form I was able to leave <%= hidden_tag_field :user_id %> as is.

But basically that solved the problem of finding the user (whose profile I was visiting) and setting the @to in my create action.

Answer 2

I'm on my iPhone so sorry for the brief reply, you just need to pass in the user id into the hidden field, you can find the syntax in the answer here:

rails - what exactly does hidden_field and hidden_field_tag do?

Edit: just noticed - this    <%= hidden_field_tag :user_id %>

Should be this:    <%= f.hidden_field_tag :user_id %>

Try passing the params into the create method like this:

User.find(params[:message][:user_id])