get value from form_for - ruby-on-rails

Question

I'm using rails 4.0.1
<%= form_for #event, :html => { :multipart => true} do |f| %>
<div class="field">
<%= f.label :title %><br>
<%= f.text_field :title %>
</div>
<div class="field">
<%= f.label :content %><br>
<%= f.text_area :content %>
</div>
<div class="field">
<%= f.label :place_id %><br>
<%= f.collection_select(:place_id, #places, :id, :title) %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
And I want to check for current_user.id and Place.user_id (it stores creator id). In Events cotroller i'm trying to use:
def create
#places = Place.all
#event = Event.new(event_params)
#event.user_id = current_user.id
#curplace = Place.find_by(id: params[:place_id])
#event.content = #curplace.id
respond_to do |format|
if #event.save
format.html { redirect_to #event, notice: 'Event was successfully created.' }
format.json { render action: 'show', status: :created, location: #event }
else
format.html { render action: 'new' }
format.json { render json: #event.errors, status: :unprocessable_entity }
end
end
end
But i got an error. I think i'm not getting this Place_id param right or anything else?

Answer 1

Further to the comment from Ankush Kataria, the form_for helper basically creates a form which combines all the params into a hash, as opposed to form_tag, which just makes the params independently
As you've discovered, this means your params will be accessed by:
#form_for
params[:variable][:param]
#form_tag
params[:param]
form_for
The reason why this is important is because if you're using the RESTful routes interface, you'll be able to create / edit / update a variety of records
form_for basically keeps consistency throughout this process, pre-populating your forms with the various values, and keeping your code DRY
To call a form_for helper, you have to define the #varaible the form will populate. This #variable needs to be an ActiveRecord object, and is why you have to build it in the new action before your form shows
form_tag
form_tag is much more independent of the form_for helper, doesn't require any #variable, and creates the params individually
You'd use a form_tag for the likes of a contact us form or similar
Your Code
Your form looks good, but your create action can be dried up:
def create
#places = Place.all
#event = Event.new(event_params)
respond_to do |format|
if #event.save
format.html { redirect_to #event, notice: 'Event was successfully created.' }
format.json { render action: 'show', status: :created, location: #event }
else
format.html { render action: 'new' }
format.json { render json: #event.errors, status: :unprocessable_entity }
end
end
end
private
def event_params
params.require(:event).permit(:title, :content).merge(user_id: current_user.id, place_id: params[:event][:place_id])
end

Answer 2

You are right that params[:place_id] isn't returning the value you expect. It only returns nil. To get the :place_id that's submitted by the form, you have to do this:
#curplace = Place.find(params[:event][:place_id])
Just replace the old line with the code above. It's because your form submits the data in the fields inside an :event key in the params hash since you're using the form_for helper method provided by Rails. That is its default behavior unless you change the 'name' attribute's value in the input fields.
Hope that helps!