ruby - Rails form_for own action routes -

i want modify action (submit) form_for helper

<%= form_for(@rating, :as => :post, :url => demo_create_rating_path(@rating)) |f| %>   <div class="field">     <%= f.label :value %><br />     <%= f.select :value, %w(1 2 3 4 5) %>   </div>     <%= f.hidden_field :article_id, :value => @article.id%>     <%= f.hidden_field :user_id, :value => current_user.id %>   <div class="field">     <%= f.label :description %><br />     <%= f.text_area :description, size: "100x5" %>   </div>   <div class="actions">     <%= f.submit %>   </div> <% end %> 

this view , not work.

all want is, can redirekt action after submit button error:

actioncontroller::routingerror (no route matches {:controller=>"demo_ratings", :action=>"create", :article_id=>#<rating id: nil, value: nil, description: nil, article_id: nil, user_id: nil, created_at: nil, updated_at: nil>}):   app/views/demo_ratings/_form.html.erb:1:in `_app_views_demo_ratings__form_html_erb__1912848844925280312_70155649546120'   app/views/demo_ratings/new.html.erb:13:in `_app_views_demo_ratings_new_html_erb__27525029454473720_70155632487040' 

what doing wrong?

update

all funktion need form_for helper:

def new     @rating = rating.new     @article = article.find(params[:article_id])   end    def edit     @rating = rating.find(params[:id])     @article = article.find(params[:article_id])   end    def create     @rating = rating.new(params[:rating])     if @rating.save       @article= article.find(params[:article_id])       puts @article.name       puts @rating.id       @rating.article = @article       puts @rating.article.name       redirect_to demo_rating_path(@rating, :article_id => @article.id), notice: 'rating created.'     else       render action: "new"     end   end    def update     @rating = rating.find(params[:id])     if @rating.update_attributes(params[:rating])       @article = @rating.article       redirect_to demo_rating_path(@rating), notice: 'rating updated.'     else       render action: "edit"     end   end 

try this:

<%= form_for(@rating, :as => :post, :url => demo_create_rating_path) |f| %> 

the @rating in url providing nil object id, , don't have id yet.

if want share form between create , update, use following:

<% form_for(@rating, :as => :post) |f| %> 

for reference, review output of rails generated scaffold's _form.html.erb.

in controller, saving new/ updated record before processing. statement if @rating.save should come after @rating.article = @article.

  def create     @rating = rating.new(params[:post])     @article= article.find(params[:article_id])     @rating.article_id = @article.id     if @rating.save       redirect_to demo_rating_path(@rating, :article_id => @article.id), notice: 'rating created.'     else       render action: "new"     end   end