How can I handle errors in Ruby EventMachine?

How can I handle errors in Ruby EventMachine?

In Ruby EventMachine, you can handle errors by using the rescue block within your event handlers. This allows you to catch exceptions and manage them gracefully.

Can you give me an example of error handling in an EventMachine server?

Sure! Here's a simple example:

EM.run do
  EM.start_server 'localhost', 8080, MyServer
end

class MyServer < EM::Connection
  def receive_data(data)
    raise 'An error occurred!' if data == 'error'
    send_data "You sent: #{data}"
  rescue => e
    puts "Error: \\#{e.message}"
    send_data "An error occurred: \\#{e.message}"
  end
end

What should I do if I want to log errors instead of just printing them?

You can use a logging library like Logger in Ruby. Replace the puts statement with a logger call:

require 'logger'

class MyServer < EM::Connection
  def initialize
    @logger = Logger.new('error.log')
  end

  def receive_data(data)
    raise 'An error occurred!' if data == 'error'
    send_data "You sent: #{data}"
  rescue => e
    @logger.error(e.message)
    send_data "An error occurred: \\#{e.message}"
  end
end

Is there a way to handle multiple types of errors differently?

Yes, you can use multiple rescue clauses to handle different exceptions separately. For example:

def receive_data(data)
  raise 'Network error' if data == 'network'
  raise 'Timeout error' if data == 'timeout'
  send_data "You sent: #{data}"
rescue NetworkError => e
  @logger.error("Network issue: \\#{e.message}")
  send_data "Network error occurred: \\#{e.message}"
rescue TimeoutError => e
  @logger.error("Timeout issue: \\#{e.message}")
  send_data "Timeout error occurred: \\#{e.message}"
end