From: Matthias Reitinger <reitinge@...>
Date: 2009-03-22T03:09:28+09:00
Subject: Re: how to know where ERB stopped?

matt neuburg wrote:
> Let's say I've got an ERB template:
> 
> text1
> <%= thing1() %>
> text2
> <%= thing2() %>
> text3
> <%= thing3() %>
> text4
> 
> But let's say we get an error (exception) during the execution of
> thing2(). How can I find out that this is where the error occurred? I
> don't want to instrument thing1, thing2, thing3, etc; I'm hoping I can
> just find out what ERB was doing when we errored out. Thx - m.

The following code illustrates how this could be accomplished (also 
available as a pastie[1]):

  require 'erb'

  def thing1(); "foo" end
  def thing2(); raise Exception.new("Something went wrong") end
  def thing3(); "bar" end

  template = <<ERB
    text1
    <%= thing1() %>
    text2
    <%= thing2() %>
    text3
    <%= thing3() %>
    text4
  ERB

  erb = ERB.new(template)

  begin
    erb.run
  rescue Exception => e
    puts "Exception: #{e}"
    line = e.backtrace.grep(/^\(erb\)/)[0].split(':')[1].to_i
    puts "While evaluating line #{line} of the template:"
    puts template.split("\n")[line-1]
    puts "Backtrace: ", e.backtrace
  end

Hope that helps!

-Matthias

[1]: http://www.pastie.org/422933
-- 
Posted via http://www.ruby-forum.com/.