Avoid RecordNotFound exception thrown by find method when invalid person_id

app/controllers/people_controller.rb

@@ -141,7 +141,7 @@ class PeopleController < ApplicationController
   end
 
   def contacts
-    @person = Person.find(params[:person_id])
+    @person = Person.find_by_id(params[:person_id])
     if @person
       @contact = current_user.contact_for(@person)
       @aspect = :profile

spec/controllers/people_controller_spec.rb

@@ -322,6 +322,12 @@ describe PeopleController do
       assigns(:contacts_of_contact).should == contacts
       response.should be_success
     end
+
+    it 'shows an error when invalid person id' do
+      get :contacts, :person_id => 'foo'
+      flash[:error].should be_present
+      response.should redirect_to people_path
+    end
   end
 
   describe '#webfinger' do