how do I make my rails 3 app handle exceptions when accessing remote data

in several places in my current code I do this (or something like it such as check for a file on Amazon S3):

def
  success_flag = open(the_url, "UserAgent" => "Ruby-OpenURI").read
  ... do something else...
  return success_flag
end

if open() or read() fails for ANY reason I want to gracefully return false, not throw an exception. For example, if the app is running locally and there is no internet connection, I don't want the app to throw the "host unavailable" exception

I assume I want to use a begin/do/rescue but I'm not sure how to do that, and in particular, I'm not sure if I need to separate the 'open' from the 'read' in order to be able to catch both errors. For example, if I keep open(url).read and the open is what fails, would the begin/do开发者_C百科/rescue catch that, or will an exception still be thrown if 'open' fails because the begin/do/rescue applies only to the read?

Absolutely right, catch the Exception via begin/rescue/end, like this:

def
  begin
    success_flag = open(the_url, "UserAgent" => "Ruby-OpenURI").read
    ... do something else...
    return success_flag
  rescue Exception => e
    # log(e) here, maybe?
    return false
  end
end

It will catch any exception thrown inside the begin/rescue block.