What's the recommended way to catch errors like this:
NoMethodError in Register#confirm Showing app/views/register/confirm.rhtml where line #4 raised: undefined method `namen' for nil:NilClass
I get this error when someone does somethinh like:
http://…/register/confirm?email=jkdsfadslkjflksd
If I make:
remail = params[:email] @user = Request.find(:first, :conditions => ["email = ?", remail])
the error occurs.
What's the prefered way to react when such an error occurs?
rescue_action_in_public
Here's what it does by default on 1.2.x... not very exciting:
If you're on edge you can manage this a lot easier, defining what type of status you want returned and template you want rendered for each
http://dev.rubyonrails.org/browser/trunk/actionpack/lib/action_controller/rescue.rb#L90
Rails will use rescue_action_in_public for errors in production, unless the the request comes from the same IP as the server. Then, you get the standard dev-mode stack trace screen.
jochen kaechelin wrote:
remail = params[:email] @user = Request.find(:first, :conditions => ["email = ?", remail])
the error occurs.
What's the prefered way to react when such an error occurs?
Briefly, @user might be nil, so you must guard it with "if @user" each time you use it.
I prefer to put that "if @user" line in only one place, for DRY code. I use a kind of Null Object there:
def someone return @user if @user who = OpenStruct.new( :login => '', :namen => '', :user_id => nil) def who.delete_data(r) false end return who end
Instead of using "@user" everywhere, I use "someone". If nobody is logged in, "someone" provides only methods that un-logged-in people can use. For example, if logged-in users can delete data, the line "someone.delete_data(a_record)" will delete the data if a user is logged in, and it won't do anything if nobody is logged in.
The heart of Object Oriented programming is replacing if statements with virtual methods that provide the correct behavior.
undefined method `namen' for nil:NilClass
rescue_action_in_public
Tip: Don't use rescue where you should just use if. The @user is just nil, per the contract of .find(), so use if @user to detect that. Don't let the nil run around loose until something explodes, and then rescue that!