Class: Volt::Tasks

Inherits:
Object show all
Defined in:
lib/volt/page/tasks.rb

Overview

The tasks class provides an interface to call tasks on the backend server. This class is setup as page.task (as a singleton)

Instance Method Summary collapse

Constructor Details

#initialize(page) ⇒ Tasks

Returns a new instance of Tasks.



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# File 'lib/volt/page/tasks.rb', line 7

def initialize(page)
  @page       = page
  @promise_id = 0
  @promises   = {}

  page.channel.on('message') do |*args|
    received_message(*args)
  end
end

Instance Method Details

#call(class_name, method_name, meta_data, *args) ⇒ Object 



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# File 'lib/volt/page/tasks.rb', line 17

def call(class_name, method_name, meta_data, *args)
  promise_id            = @promise_id
  @promise_id += 1

  # Track the callback
  promise               = Promise.new
  @promises[promise_id] = promise

  # TODO: Timeout on these callbacks
  @page.channel.send_message([promise_id, class_name, method_name, meta_data, *args])

  promise
end

#notify_query(method_name, collection, query, *args) ⇒ Object

Called when the backend sends a notification to change the results of a query.



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# File 'lib/volt/page/tasks.rb', line 61

def notify_query(method_name, collection, query, *args)
  query_obj = Persistors::ArrayStore.query_pool.lookup(collection, query)
  query_obj.send(method_name, *args)
end

#received_message(name, promise_id, *args) ⇒ Object 



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# File 'lib/volt/page/tasks.rb', line 31

def received_message(name, promise_id, *args)
  case name
    when 'added', 'removed', 'updated', 'changed'
      notify_query(name, *args)
    when 'response'
      response(promise_id, *args)
    when 'reload'
      reload
  end
end

#reload ⇒ Object 



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# File 'lib/volt/page/tasks.rb', line 66

def reload
  # Stash the current page value
  value = EJSON.stringify($page.page.to_h)

  # If this browser supports session storage, store the page, so it will
  # be in the same state when we reload.
  `sessionStorage.setItem('___page', value);` if `sessionStorage`

  $page.page._reloading = true
  `window.location.reload(false);`
end

#response(promise_id, result, error) ⇒ Object

When a request is sent to the backend, it can attach a callback, this is called from the backend to pass to the callback.



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# File 'lib/volt/page/tasks.rb', line 44

def response(promise_id, result, error)
  promise = @promises.delete(promise_id)

  if promise
    if error
      # TODO: full error handling
      Volt.logger.error('Task Response:')
      Volt.logger.error(error.inspect)
      promise.reject(error)
    else
      promise.resolve(result)
    end
  end
end