Error handling in rails

Oddly I'm having a hard time finding good docs about basic error handling in rails. I'd appreciate any good links as well as thoughts on a handling errors in a really basic method like this:

  def self.get_record(id)
    People.first( :conditions => ["id = ?", id] )
  end

1) I could verify that id != nil, and that it's numeric.

2) I could also then verify that a record is found.

Is there anything else?

Are both #1 and #2 recommended practice? In bot开发者_运维技巧h cases would you simply create a flash message with the error and display it, or is that giving away too much information?

As I'm sure you know, this is just like People.find(id), except that find raises an error.

However, People.find_by_id(id) returns nil if no record is found, which I suspect takes care of all you need. You don't need to check that what you put into ActiveRecord is the correct data type and the like; it handles SQL injection risks, so to check ahead of time would not affect actual behavior.

If we're just looking at the show action, though, there's an even more elegant way: rather than using find_by_id and checking for nil, use find, let an error bubble up, and let the controller catch it with rescue_from. (By default, in production, ActiveRecord::RecordNotFound will be caught and rescued by showing a generic 404, but you can customize this behavior if necessary.)

class UsersController < ApplicationController
  rescue_from ActiveRecord::RecordNotFound, :with => :not_found

  def show
    @user = User.find params[:id]
  end

  protected
    def not_found
      flash[:error] = "User not found"
      redirect_to users_path
    end
end

Code untested, for illustrative purposes only ;)

Don't do flash[:notice]'s insted just say that "Record not found"

The two things required by you can be done as follows:

1) I could verify that id != nil, and that it's numeric.

def self.get_record(id)
  People.first( :conditions => ["id = ?", id] ) if id.integer? unless id.blank?
end

2) I could also then verify that a record is found.

def self.get_record(id)
  @people = People.first( :conditions => ["id = ?", id] ) if id.integer? unless id.blank?
  flash[:notice] = @people.blank? # this will print true/false depending on value in @people
end

Hope it works for you. :D