How do I write a conditional redirect into a model's create method, in a Rails app?

I'm allowing users to create a 'Question' from different pages in the app, and want them to be redirected to the right page after the开发者_高级运维 new question is saved. Since one page has a params[:id] and one doesn't, I thought I'd use that to differentiate between the different redirects.

Here's what I was trying to do in my Questions controller:

respond_to do |format|  
if @question.save
    if params[:id].nil?
      format.html {redirect_to :controller => 'home', :action => 'show', :username => question.directed_to}  
    else
      format.html {redirect_to :controller => 'mentions', :action => 'show', :id => question.topic}
    end    
else
    ...
end

Thanks very much, I'm still new to this.

---

Relying on params beings nil is super awkward. You have control of the forms being submitted, so just sent an extra parameter yourself which identifies where it's coming from.

A few other things:

If you're only responding with html, don't bother doing the respond_to block.

if @question.save
  redirect_to :controller => 'home', :action => 'show', :username => question.directed_to
else
  redirect_to :controller => 'mentions', :action => 'show', :id => question.topic
end

@question.save doesn't run validations. It's pretty unusual that you'd want to have a create action that doesn't run validations. You should probably having something like:

def create
  @question = Question.new(params[:question])
  @question.save!
  flash[:notice] = "Question saved successfully"
  # Do your redirects here
rescue ActiveRecord::RecordInvalid
  flash[:error] = "There were errors saving your question"
  render :action => :new
end