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adhearsion-ivr

IVR building blocks for Adhearsion apps

Installing

Simply add to your Gemfile like any other Adhearsion plugin:

gem 'adhearsion-ivr'

Configuration

Adhearsion IVR currently has no configurable options.

Examples

A bare-bones example of creating a prompt. This menu has a single message, "Please enter a number 1 through 3." By default, the caller has 3 attempts to enter any of 1, 2 or 3 (though the actual grammar is left as an exercise to the developer). If 1 is pressed, the caller is sent to the OneController; if 2 is pressed the caller is sent to the TwoController; if 3 is pressed the caller hears a poor impersonation of the Three Stooges and is hung up.

If the caller fails to provde input within 3 attempts, he hears a taunting message and is then transferred to a waiting kindergarten teacher.

class SimplePrompt < Adhearsion::IVRController
  prompts << "Please enter a number 1 through 3"

  on_complete do |result|
    case result.nlsml.interpretations.first[:instance] # FIXME?
    when 1
      pass OneController
    when 2
      pass TwoController
    when 3
      say "Yuk yuk yuk"
      hangup
    end
  end

  on_failure do
    say "Sorry you failed kindergarten. Let us transfer you to our trained staff of kindergarten teachers."
    dial 'sip:[email protected]'
  end

  def grammar
    RubySpeech::GRXML.draw do
      # ... put a valid GRXML grammar here
    end
  end
end

An example with escalating prompts:

class EscalatedPrompt < Adhearsion::IVRController
  prompts << "First attempt: enter a number"
  prompts << "Second attempt: enter a number 1 through 3"
  prompts << "Third attempt: enter a number 1 through 3. That would be the top row of your DTMF keypad. Don't get it wrong again."
  prompts << "Fourth attempt: really? Was I not clear the first 3 times? Last chance, dunce."

  max_attempts 4

  on_complete do |result|
    case result.nlsml.interpretations.first[:instance] # FIXME?
    when 1
      pass OneController
    when 2
      pass TwoController
    when 3
      say "Yuk yuk yuk"
      hangup
    end
  end

  on_failure do
    say "Sorry you failed kindergarten. Let us transfer you to our trained staff of kindergarten teachers."
    dial 'sip:[email protected]'
  end

  def grammar
    RubySpeech::GRXML.draw do
      # ... put a valid GRXML grammar here
    end
  end
end

An example with input validation:

class InputValidation < Adhearsion::IVRController
  prompts << "Please enter your favorite fruit"

  on_complete do |result|
    case result.interpretation
    when "apple"
      pass AppleController
    when "orange"
      pass OrangeController
    else
      pass OtherController
    end
  end

  on_failure do
    say "Sorry you failed kindergarten. Let us transfer you to our trained staff of kindergarten teachers."
    dial 'sip:[email protected]'
  end

  validate do
    ["apple", "orange", "banana", "tomato"].include? @result.interpretation
  end

  def grammar
    RubySpeech::GRXML.draw do
      # ... put a valid GRXML grammar here
    end
  end
end

A slightly more involved example showing integration with I18n:

class I18nEscalatedPrompts < Adhearsion::IVRController
  # Note that by deferring prompt resolution we can take advantage of per-call variables such as language selection
  prompts << -> { t(:first_attempt) }
  prompts << -> { t(:second_attempt) }
  prompts << -> { t(:third_attempt) }
  prompts << -> { [ t(:fourth_attempt), t(:this_is_your_final_attempt) ] }
  # Future improvement: we could potentially also include the previous input
  # in the re-prompts, but that isn't implemented now

  max_attempts 4
  timeout 30

  on_complete do |result|
    case result.nlsml.interpretations.first[:instance] # FIXME?
    when 1
      pass OneController
    when 2
      pass TwoController
    when 3
      say "Yuk yuk yuk"
      hangup
    end
  end

  on_failure do
    say "Sorry you failed kindergarten. Let us transfer you to our trained staff of kindergarten teachers."
    dial 'sip:[email protected]'
  end

  def grammar
    RubySpeech::GRXML.draw do
      # ... put a valid GRXML grammar here
    end
  end
end

Passing URLs for prompts

You might want to pass an URL to an SSML document as a prompt. In that case, wrap the URL in the #from_url method and the rendering engine will fetch the prompt over HTTP instead of sending the full prompt over the wire.

# ...
 prompts << -> { from_url('http://foobar.com/doc.ssml') }
# ...

Use cases for #from_url include supporting long prompts on Asterisk, serving the SSML via Adhearsion's built-in HTTP server and caching.

Method overriding in subclasses

If you need to set the configuration for the menu at runtime, #prompts, #timeout, #max_attempts and renderer can be defined on the subclass to provide the needed values, as you can see in the following example.

The examples assumes the values have been placed in call variables by an earlier controller, which is also a practical use case for overriding methods.

renderer values are the same accepted by the various Adhearsion output methods.

class OverriddenPrompt < Adhearsion::IVRController
  prompts << "Please enter a number 1 through 3"

  on_complete do |result|
    case result.nlsml.interpretations.first[:instance] # FIXME?
    when 1
      pass OneController
    when 2
      pass TwoController
    when 3
      say "Yuk yuk yuk"
      hangup
    end
  end

  on_failure do
    say "Sorry you failed kindergarten. Let us transfer you to our trained staff of kindergarten teachers."
    dial 'sip:[email protected]'
  end

  def prompts
    ["Please enter a number 1 through 3", "You should enter a number 1 through 3"]
  end

  def timeout
    call[:menu_timeout]
  end

  def renderer
    :unimrcp
  end

  def max_attempts
    call[:menu_retries]
  end

  def grammar
    RubySpeech::GRXML.draw do
      # ... put a valid GRXML grammar here
    end
  end
end

Available Callbacks

  • on_response - Called each time a response is generated, whether valid, invalid, or no input at all.
  • on_validate - Called to verify that the matched input is valid, for example, if additional validation is needed beyond the grammar. Returning false here is treated like a nomatch result. Returning true will continue into the on_success callback.
  • on_success - Called whenever an input matches the supplied grammar.
  • on_failure - Called after all retries have been exhausted and the IVR is giving up. Useful for transferring to an operator, for example.
  • on_error - Called if an exception is encountered during execution. Also useful for transferring to an operator or other fail-safe logic.

Credits

Copyright (C) 2014 The Adhearsion Foundation

adhearsion-ivr is released under the MIT license. Please see the LICENSE file for details.

adhearsion-ivr was created by Ben Klang with support from Mojo Lingo and their clients.