Parsing strings from the datepicker

In my previous post I explained how to create a datepicker with dynamic internationalization. There is one catch though, in different languages the representation of the date can be different, for example, February 5th can be 2/5/2011 in the USA and 5/2/2011 in Portugal. The rails default is the first.

This means that you'll have to take this into account when using the string that you get from the form where you are using the datepicker. You have two options, change the way the dates are displayed, by altering all the languages javascripts, or parse the string as it gets to the controller.

The latter can be achieved with this piece of code:


todo.due_date = DateTime.strptime(params[:date],"%d/%m/%Y").to_time


Note that I've chosen that format for the string, but it can be any format according to the ruby's Time class.

There is one other problem though, the user can, maliciously or by distraction, insert an invalid date. We can strengthen our code to prevent this, by catching the exception thrown.


begin
  todo.due_date = DateTime.strptime(params[:date],"%d/%m/%Y").to_time
rescue ArgumentError
  flash[:error] = t("flash.invalid_date")
  redirect_to somewhere_in_the_app_path
  return
end


So, if the exception occurs, we set the flash error message (using the translation helper), redirect to the appropriate path, and then return, so that it does not complain of having multiple render or redirect calls.