Tasks

Sometimes you need to explicitly execute some code on the server. Volt solves this problem through tasks. You can define your own tasks by inheriting from Volt::Task. Ruby files in a tasks folder, which end with _tasks.rb, will be required automatically.

# app/main/tasks/logging_tasks.rb

class LoggingTasks < Volt::Task
  def log(message)
    puts message
  end
end

Volt will automatically generate wrappers for you on the client side which will return a promise.

Note that the classes on the server side use instance methods while the wrapper classes represent those methods as class methods. For more information on using promises in Ruby see here.

class Contacts < Volt::ModelController
  def hello
    promise = LoggingTasks.log('Hello World!')
  end
end

You can use the #then method of the returned promise to get the result of the call. You can use the #fail method on the promise to get any thrown errors.

MathTasks.add(23, 5).then do |result|
  # result should be 28
  alert result
end.fail do |error|
  puts "Error: #{error}"
end

Timeout

Tasks by default run with a 60 second timeout. You can change the global timeout for all tasks by setting config.worker_timeout in config/app.rb. You can also change the timeout per task class by calling the timeout method in the class:

class SampleTask < Volt::Task
  timeout 200

  # ...
end

You can also set the timeout to 0 to disable the timeout.

Cookies

You can set new cookies using the cookies repo from inside of tasks. Any cookie set will be sent and set on the client. NOTE: You can not read cookies from tasks, only set. (This was a performance decision)