Biglietti, prego! A ticket for the (command) bus

BIGLIETTI, PREGO!a ticket for the (command) bus

@magobaol
UNA SERIE SCRITTA, SCENEGGIATA E NARRATA DA

Giulia è la direttrice
generale di una
compagnia di treni
ad alta velocità

Giulia commissiona a
Roberto un software
per la vendita di
biglietti online.

src
!"" CustomerBundle
!"" TicketBundle
#   !"" Controller
#   !"" DataFixtures
#   !"" Entity
#   !"" Form
#   !"" Listener
#   %"" Service
| %"" Twig
!"" TrainBundle
%"" UserBundle
TicketOffice Project

Ticket.php/**
* @ORMEntity()
* @ORMTable(name="ticket")
*/
class Ticket
{
/**
* @ORMId
* @ORMColumn(type="integer")
* @ORMGeneratedValue(strategy="AUTO")
**/
protected $id;
/**
**/
protected $customerId;
/**
**/
protected $trainNumber;
/**
**/
protected $seatNumber;

Ticket.php
/**
* @return mixed
*/
public function getId()
{
return $this->id;
}
/**
* @return mixed
*/
public function getCustomerId()
{
return $this->customerId;
}
/**
* @return mixed
*/
public function getTrainNumber()
{
return $this->trainNumber;
}

Ticket.php
/**
* @param mixed $id
*/
public function setId($id)
{
$this->id = $id;
}
/**
* @param mixed $customerId
*/
public function setCustomerId($customerId)
{
$this->customerId = $customerId;
}
/**
* @param mixed $trainNumber
*/
public function setTrainNumber($trainNumber)
{
$this->trainNumber = $trainNumber;
}

TicketController.php
public function createTicketAction(Request $request)
{
$seatNumberPicker = $this->get('seat_number_picker');
$seatNumber =
$seatNumberPicker->pickSeat(
$request->get('trainNumber'),
$request->get(‘departure’)
);
$ticket = new Ticket();
$ticket->setCustomerId($request->get('customerId'));
$ticket->setTrainNumber($request->get('trainNumber'));
$ticket->setDeparture($request->get('departure'));
$ticket->setSeatNumber($seatNumber);
$em = $this->get('doctrine.orm.entity_manager');
$em->persist($ticket);
$em->flush();
return $this->render('thank_you_page.html.twig');
}

{
$seatNumber =
);
$em->flush();
}
$seatNumber =
);

{
$seatNumber =
);
$em->flush();
}

{
$seatNumber =
);
$em->flush();
}
$em->flush();

{
$seatNumber =
);
$em->flush();
}

UN PICCOLO
MIGLIORAMENTO
s01e04

{
//pick a seat...
//create ticket...
//save ticket...
$customerRepo = $this->get('customer_repository');
$customer = $customerRepo->find($request->get('customerId'));
$ticketMailer = $this->get('ticket_mailer');
$ticketMailer->sendEmail($customer->getEmail(), $ticket);
}

{
//pick a seat...
$PNRGenerator = $this->get('pnr_generator');
$PNR = $PNRGenerator->generate(
$request->get('departure'),
$seatNumber
);
//create ticket...
$ticket->setPNR($PNR);
//save ticket...
//retrieve customer...
//send email to customer...
}

UN (ALTRO) PICCOLO

MIGLIORAMENTO
s01e06

{
//pick a seat...
//generate PNR...
//create ticket...
//save ticket...
//retrieve customer...
//send email to customer...
$PNRSMSSender = $this->get('pnr_sms_sender');
$PNRSMSSender->send($customer->getMobile(), $PNR);
}

L’INQUIETUDINE DI
ROBERTO
s01e07

{
$seatNumber = $seatNumberPicker->pickSeat(…);
$PNR = $PNRGenerator->generate(…);
$em->flush();
$customerRepository = $this->get('customer_repository');
$customer = $customerRepository->find($request->get('customerId'));
$ticketMailer->sendEmailToCustomer($customer->getEmail(), $ticket);
}

{
$em->flush();
}
s01e03

s01e04
{
$seatNumber = $seatNumberPicker->pickSeat(...);
$em->flush();
$ticketMailer->sendEmailToCustomer(...);
}

s01e05public function createTicketAction(Request $request)
{
$em->flush();
}

{
$em->flush();
}
s01e06

STORIA DI UN
REFACTORING
s01e08

{
$PNR = $PNRGenerator->generate(...);
$em->flush();
}

{
$ticketCreator = $this->get('ticket_creator');
$ticketCreator->createTicket(
$request->get(‘customerId')
);
}

TicketCreatorService.php
class TicketCreatorService
{
public function __construct()
{
}
}

{
public function __construct(
SeatNumberPicker $seatNumberPicker
) {
$this->seatNumberPicker = $seatNumberPicker;
}
}

{
SeatNumberPicker $seatNumberPicker,
PNRGenerator $PNRGenerator
) {
$this->PNRGenerator = $PNRGenerator;
}
}

{
PNRGenerator $PNRGenerator,
EntityRepository $customerRepository
) {
$this->customerRepository = $customerRepository;
}
}

{
EntityRepository $customerRepository,
EntityRepository $ticketRepository
) {
$this->ticketRepository = $ticketRepository;
}
}

{
EntityRepository $ticketRepository,
EntityManager $entityManager
) {
$this->entityManager = $entityManager;
}
}

{
EntityManager $entityManager,
TicketMailer $ticketMailer
) {
$this->ticketMailer = $ticketMailer;
}
}

{
EntityManager $entityManager,
TicketMailer $ticketMailer,
PNRSMSSender $PNRSMSSender
) {
$this->ticketMailer = $ticketMailer;
$this->PNRSMSSender = $PNRSMSSender;
}
}

public function createTicket($trainNumber, $departure, $customerId)
{
$seatNumber = $this->seatNumberPicker->pickSeat(...);
$PNR = $this->PNRGenerator->generate(...);
$ticket->setCustomerId($customerId);
$ticket->setTrainNumber($trainNumber);
$ticket->setDeparture($departure);
$this->entityManager->persist($ticket);
$this->entityManager->flush($ticket);
$customer = $this->customerRepository->find($customerId);
$this->ticketMailer->sendEmailToCustomer(...);
$this->PNRSMSSender->send($customer->getMobile(), $PNR);
}

{
$em->flush();
}

{
$em->flush();
}
{
$em->flush();
}

{
$em->flush();
}

{
public function createTicket($trainNumber, $departure, $customerId)
{
$seatNumber = $this->seatNumberPicker->pickSeat($trainNumber, $departure);
$PNR = $this->PNRGenerator->generate($trainNumber, $departure, $seatNumber);
$ticket->setCustomerId($customerId);
$ticket->setTrainNumber($trainNumber);
$ticket->setDeparture($departure);
$this->entityManager->flush($ticket);
$customer = $this->customerRepository->find($customerId);
$this->ticketMailer->sendEmailToCustomer($customer->getEmail(), $ticket);
$this->PNRSMSSender->send($customer->getMobile(), $PNR);
}
}

Disclaimer: @agilegigi non ha mai detto questa
cosa, ma secondo me potrebbe farlo.

{
$request->get('customerId'));
$ticketRepository = $this->get('ticket_repository');
$ticketInADay =
$ticketRepository->countTicketForADay($request->get('departure'));
if ($ticketInADay == 100) {
$winnerMailer = $this->get(‘winner_mailer');
$winnerMailer->send($customer);
}
}

{
$request->get('customerId'));
$ticketInADay =
}
}
$ticketInADay =
}

PRIMA O POI

C’È SEMPRE UN LUNEDì
s01e10

TRA LA PRIMA E LA
SECONDA STAGIONE...

thanks to @leopro for the inspiring picture
COMMAND BUS

È un canale di comunicazione che
consente di inviare e ricevere messaggi in
un'applicazione
MESSAGE BUS

I messaggi possono essere
comandi ed eventi
MESSAGE BUS

COSA È UN COMANDO?
È un messaggio
tramite il quale si
comunica al sistema
che si vuole fare
qualcosa
[ request ]
[ command ]
[ command bus ]
[ command handler ]
(non restituisce nulla)

COSA È UN EVENTO?
È un messaggio
tramite il quale il
sistema comunica
che è accaduto
qualcosa
[ tipicamente in un
command handler ]
[ event ]
[ event bus ]
[ subscriber 1 ] [ subscriber 2 ]

TACTICIANhttps://tactician.thephpleague.com/

SIMPLEBUShttp://simplebus.github.io/MessageBus/

.
!"" app
#   !"" Resources
#   #   %"" views
#   #   %"" default
#   %"" config
!"" bin
!"" src
#   %"" AppBundle
#   %"" Controller
!"" tests
#   %"" AppBundle
#   %"" Controller
!"" var
#   !"" cache
#   !"" logs
#   %"" sessions
%"" web
Symfony 3 folders

.
!"" app
#   !"" Resources
#   #   %"" views
#   #   %"" default
#   %"" config
!"" bin
!"" src
#   %"" AppBundle
#   %"" Controller
!"" tests
#   %"" AppBundle
#   %"" Controller
!"" var
#   !"" cache
#   !"" logs
#   %"" sessions
%"" web
Symfony 3 folders
!"" src
#   %"" AppBundle
#   %"" Controller

src
%"" AppBundle
Domain folder

src
!"" AppBundle
%"" TicketOffice
Domain folder

src
!"" AppBundle
%"" TicketOffice
%"" Sale
Domain folder

src
!"" AppBundle
%"" TicketOffice
%"" Sale
%"" Entity
Domain folder

src
!"" AppBundle
%"" TicketOffice
%"" Sale
%"" Entity
%"" Ticket.php
Domain folder

Ticket.php
class Ticket
{
private $id;
private $customerId;
private $trainNumber;
private $departure;
private $seatNumber;
private $PNR;
$id, $customerId, $trainNumber, $departure, $seatNumber, $PNR)
{
$this->id = $id;
$this->departure = $departure;
$this->seatNumber = $seatNumber;
$this->PNR = $PNR;
}
}

Rectangle.php
class Rectangle
{
private $width;
private $height;
public function getWidth()
{
return $this->width;
}
public function setWidth($width)
{
$this->width = $width;
}
public function getHeight()
{
return $this->height;
}
public function setHeight($height)
{
$this->height = $height;
}
}

Somewhere.php
$rectangle = new Rectangle();
$rectangle->setWidth(100);
$rectangle->setHeight(50);

Somewhere.php
$rectangle->setWidth(100);
$rectangle->setHeight(50);
NON È UN RETTANGOLO!

Rectangle.php
class Rectangle
{
private $width;
private $height;
public function __construct($width, $height)
{
$this->width = $width;
$this->height = $height;
}
public function getWidth()
{
return $this->width;
}
public function getHeight()
{
return $this->height;
}
}

Somewhere.php
$rectangle = new Rectangle(100, 50);
QUESTO SÌ

Ticket.php
class Ticket
{
private $id;
private $customerId;
private $trainNumber;
private $departure;
private $seatNumber;
private $PNR;
$id, $customerId, $trainNumber,
$departure, $seatNumber, $PNR
) {
$this->id = $id;
$this->seatNumber = $seatNumber;
$this->PNR = $PNR;
}
}

app
!"" DoctrineMigrations
!"" Resources
%"" config
%"" config.yml
config.yml

config.yml
doctrine:
orm:
auto_generate_proxy_classes: "%kernel.debug%"
naming_strategy:
doctrine.orm.naming_strategy.underscore
auto_mapping: false
mappings:
ticket_office.sale:
type: yml
dir: '%kernel.root_dir%/../src/AppBundle/
Resources/config/doctrine/Sale'
is_bundle: false
prefix: TicketOfficeSaleEntity
alias: AppSale

config.yml
doctrine:
orm:
naming_strategy:
auto_mapping: false
mappings:
ticket_office.sale:
type: yml
is_bundle: false
alias: AppSale
auto_mapping: false

config.yml
doctrine:
orm:
naming_strategy:
auto_mapping: false
mappings:
ticket_office.sale:
type: yml
is_bundle: false
alias: AppSale
mappings:
ticket_office.sale:
type: yml

src
!"" AppBundle
#   !"" Controller
#   !"" Entity
#   %"" Resources
#   %"" config
#   %"" doctrine
#   %"" Sale
#   %"" Ticket.orm.yml
%"" TicketOffice
Ticket.orm.yml

Ticket.orm.yml
TicketOfficeSaleEntityTicket:
type: entity
table: ticket
id:
id:
type: string
generator: { strategy: NONE }
fields:
customerId:
type: integer
trainNumber:
type: integer
departure:
type: datetime
seatNumber:
type: integer
PNR:
type: string

src
!"" AppBundle
%"" TicketOffice
%"" Sale
%"" Entity
!"" Ticket.php
%"" TicketRepository.php
TicketRepository.php

TicketRepository.php
interface TicketRepository
{
public function save(Ticket $ticket);
/**
* @param $id
* @return Ticket
*/
public function findById($id);
}

src
!"" AppBundle
#   !"" Controller
#   !"" Entity
#   #   %"" DoctrineTicketRepository.php
#   %"" Resources
%"" TicketOffice
DoctrineTicketRepository.php

class DoctrineTicketRepository implements TicketRepository
{
private $entityRepository;
private $entityManager;
public function __construct(EntityManager $entityManager)
{
$this->entityRepository =
$this->entityManager->getRepository('AppSale:Ticket');
}
public function save(Ticket $ticket)
{
$this->entityManager->flush();
}
public function findById($id)
{
return $this->entityRepository->find($id);
}
}

class DoctrineTicketRepository implements TicketRepository
{
{
$this->entityManager->getRepository('AppSale:Ticket');
}
public function save(Ticket $ticket)
{
$this->entityManager->flush();
}
{
}
}
implements TicketRepository

app
!"" DoctrineMigrations
!"" Resources
%"" config
%"" services.yml
services.yml

services:
ticket_office.sale.entity.ticket_repository:
class: AppBundleEntityDoctrineTicketRepository
arguments: ["@doctrine.orm.default_entity_manager"]
services.yml

src
!"" AppBundle
%"" TicketOffice
%"" Sale
!"" Entity
%"" Service
%"" SeatPicker.php
SeatPicker.php

class SeatPicker
{
public function pick($trainNumber, $departure)
{
return rand(1, 1000);
}
}
SeatPicker.php

src
!"" AppBundle
%"" TicketOffice
%"" Sale
!"" Entity
%"" Service
!"" PNRGenerator.php
%"" SeatPicker.php
PNRGenerator.php

class PNRGenerator
{
public function generate(
$trainNumber,
$departure,
$seatNumber
) {
return uniqid();
}
}
PNRGenerator.php

services:
ticket_office.sale.seat_picker:
class: TicketOfficeSaleServiceSeatPicker
ticket_office.sale.pnr_generator:
class: TicketOfficeSaleServicePNRGenerator
services.yml

composer require simple-bus/symfony-bridge
@command_bus
@event_bus

AppKernel.php
public function registerBundles()
{
$bundles = [
//...
new SimpleBusSymfonyBridgeSimpleBusCommandBusBundle(),
new SimpleBusSymfonyBridgeSimpleBusEventBusBundle(),
];
//...
}

src
!"" AppBundle
%"" TicketOffice
%"" Sale
!"" Command
# %"" SellTicket.php
!"" Entity
%"" Service
SellTicket.php

SellTicket.php
class SellTicket
{
//private properties declaration...
$id, $customerId, $trainNumber, $departure
) {
$this->id = $id;
}
public function getCustomerId() {...}
public function getTrainNumber() {...}
public function getDeparture() {...}
public function getId() {...}
}

src
!"" AppBundle
%"" TicketOffice
%"" Sale
!"" Command
# !"" SellTicket.php
# %"" SellTicketHandler.php
!"" Entity
%"" Service
SellTicketHandler.php

class SellTicketHandler
{
SeatPicker $seatPicker,
TicketRepository $ticketRepository
) {
$this->seatPicker = $seatPicker;
}
}

{
) {
}
}

public function handle(SellTicket $command)
{
$seat = $this->seatPicker->pick(
$command->getTrainNumber(), $command->getDeparture()
);
$pnr = $this->PNRGenerator->generate(
$command->getTrainNumber(), $command->getDeparture(),
$seat
);
$ticket = new Ticket(
$command->getId(),
$command->getCustomerId(),
$command->getTrainNumber(),
$command->getDeparture(),
$seat,
$pnr
);
$this->ticketRepository->save($ticket);
}

{
);
$seat
);
$command->getId(),
$seat,
$pnr
);
}

{
);
$seat
);
$command->getId(),
$seat,
$pnr
);
}
);

{
);
$seat
);
$command->getId(),
$seat,
$pnr
);
}
$seat
);

{
);
$seat
);
$command->getId(),
$seat,
$pnr
);
}
$command->getId(),
$seat,
$pnr
);

{
);
$seat
);
$command->getId(),
$seat,
$pnr
);
}

services.yml
services:
ticket_office.commands.sell_ticket_handler:
class: TicketOfficeSaleCommandSellTicketHandler
arguments:
- "@ticket_office.sale.seat_picker"
- "@ticket_office.sale.pnr_generator"
- "@ticket_office.sale.entity.ticket_repository"
tags:
- { name: command_handler,
handles: TicketOfficeSaleCommandSellTicket }

services.yml
services:
arguments:
tags:

services.yml
services:
arguments:
tags:
tags:

src
!"" AppBundle
#   !"" Controller
#   #   %"" TicketController.php
#   !"" Entity
#   %"" Resources
%"" TicketOffice

/**
* @Route("tickets/new", name="tickets.new")
*/
public function sellTicketAction(Request $request)
{
$id = Uuid::uuid4();
$command = new SellTicket(
$id,
$request->get('customerId'),
new DateTime($request->get('departure'))
);
$this->get('command_bus')->handle($command);
return new JsonResponse(['id' => $id], 201);
}

/**
*/
{
$id,
);
}

/**
*/
{
$id,
);
}
$id,
);

/**
*/
{
$id,
);
}

src
!"" AppBundle
%"" TicketOffice
%"" Sale
!"" Command
!"" Entity
# !"" Customer.php
# !"" Ticket.php
# %"" TicketRepository.php
%"" Service
Customer.php

Customer.php
class Customer
{
private $id;
private $email;
public function __construct($id, $email)
{
$this->id = $id;
$this->email = $email;
}
public function getId() {...}
public function getEmail() {...}
}

src
!"" AppBundle
#   !"" Controller
#   !"" Entity
#   %"" Resources
#   %"" config
#   %"" doctrine
#   %"" Sale
#   %"" Customer.orm.yml
%"" TicketOffice
Customer.orm.yml

Customer.orm.yml
TicketOfficeSaleEntityCustomer:
type: entity
table: customer
id:
id:
type: integer
generator: { strategy: AUTO }
fields:
email:
type: string

src
!"" AppBundle
%"" TicketOffice
%"" Sale
!"" Command
!"" Entity
# !"" Customer.php
#   !"" CustomerRepository.php
#   !"" Ticket.php
#   %"" TicketRepository.php
%"" Service
CustomerRepository.php

CustomerRepository.php
interface CustomerRepository
{
/**
* @param $id
* @return Customer
*/
public function findById($id);
}

src
!"" AppBundle
#   !"" Controller
#   !"" Entity
#   #   %"" DoctrineCustomerRepository.php
#   %"" Resources
%"" TicketOffice
DoctrineCustomerRepository.php

DoctrineCustomerRepository.php
class DoctrineCustomerRepository implements CustomerRepository
{
{
$this->entityManager->getRepository('AppSale:Customer');
}
{
}
}

src
!"" AppBundle
%"" TicketOffice
%"" Sale
!"" Command
!"" Entity
!"" Event
# %"" TicketSold.php
%"" Service
TicketSold.php

TicketSold.php
class TicketSold
{
//private properties declarations...
public function __construct($trainNumber, $customerId, $ticketId)
{
$this->ticketId = $ticketId;
}
public function getCustomerId() {...}
public function getTicketId() {...}
public function getTrainNumber() {...}
}

{
TicketRepository $ticketRepository,
MessageBus $eventBus
) {
$this->eventBus = $eventBus;
}
}

{
) {
}
}

{
$seat = $this->seatPicker->pick(...);
$pnr = $this->PNRGenerator->generate(...);
$ticket = new Ticket(...);
$event = new TicketSold(
$command->getId()
);
$this->eventBus->handle($event);
}

{
$command->getId()
);
}
$command->getId()
);

{
$command->getId()
);
}

src
!"" AppBundle
%"" TicketOffice
%"" Sale
!"" Command
!"" Entity
!"" Event
!"" Service
%"" Subscriber
%"" SendEmailWhenTicketSold.php
SendEmailWhenTicketSold.php

class SendEmailWhenTicketSold
{
private $mailer;
private $ticketRepository;
private $customerRepository;
Mailer $mailer,
CustomerRepository $customerRepository
) {
$this->mailer = $mailer;
}
public function notify(...) {...}
}

class SendEmailWhenTicketSold
{
private $mailer;
private $ticketRepository;
private $customerRepository;
Mailer $mailer,
) {
$this->mailer = $mailer;
}
}

public function notify(TicketSold $event)
{
$customer =
$this->customerRepository->findById(
$event->getCustomerId()
);
$mailMessage = $this->mailer->createMessage();
$mailMessage->setTo($customer->getEmail());
$mailMessage->setSubject('Dettagli biglietto');
$mailMessage->setFrom($this->sender_address);
$mailMessage->setBody($body,
sprintf(
'Hai acquistato il biglietto %s
per il treno %s',
$event->getTicketId(),
$event->getTrainNumber()
);
$this->mailer->send($mailMessage);
}

{
$customer =
);
sprintf(
per il treno %s',
);
}
TicketSold $event

{
$customer =
);
sprintf(
per il treno %s',
);
}
$customer =
);

{
$customer =
);
sprintf(
per il treno %s',
);
}
sprintf(
per il treno %s',
);

{
$customer =
);
sprintf(
per il treno %s',
);
}

services.yml
ticket_office.sale.subscriber.send_email_when_ticket_sold:
class:
TicketOfficeSaleSubscriberSendEmailWhenTicketSold
arguments:
- "@mailer"
- "@ticket_office.sale.entity.customer_repository"
tags:
- { name: event_subscriber,
subscribes_to: TicketOfficeSaleEventTicketSold }

services.yml
ticket_office.sale.subscriber.send_email_when_ticket_sold:
class:
TicketOfficeSaleSubscriberSendEmailWhenTicketSold
arguments:
- "@mailer"
tags:
tags:

src
!"" AppBundle
%"" TicketOffice
%"" Sale
!"" Command
!"" Entity
!"" Event
!"" Service
%"" Subscriber
!"" SendEmailWhenTicketSold.php
%"" SendPNRWhenTicketSold.php
SendPNRWhenTicketSold.php

class SendPNRWhenTicketSold
{
SMSGateway $SMSGateway,
) {
$this->SMSGateway = $SMSGateway;
}
}

{
$ticket =
$this->ticketRepository->findById(
$event->getTicketId()
);
$customer =
);
$this->SMSGateway->send(
$customer->getMobile(),
sprintf('Il tuo PNR è %s', $ticket->getPNR())
);
}

{
$ticket =
);
$customer =
);
);
}
TicketSold $event

{
$ticket =
);
$customer =
);
);
}
$ticket =
);

{
$ticket =
);
$customer =
);
);
}
$customer =
);

{
$ticket =
);
$customer =
);
);
}
);

services.yml
ticket_office.sale.subscriber.send_pnr_when_ticket_sold:
class: TicketOfficeSaleSubscriberSendPNRWhenTicketSold
arguments:
- "@logger"
tags:

services.yml
ticket_office.sale.subscriber.send_pnr_when_ticket_sold:
class: TicketOfficeSaleSubscriberSendPNRWhenTicketSold
arguments:
- "@logger"
tags:
tags:

src
!"" AppBundle
!"" Basic
# %"" TicketOfficeException.php
%"" TicketOffice
TicketOfficeException.php

TicketOfficeException.php
class TicketOfficeException extends Exception
{
public static function createWithDetails($details)
{
$e = new static();
$e->setDetails($details);
return $e;
}
public function toArray()
{
$a['error']['code'] = $this->getCode();
$a['error']['message'] = $this->getMessage();
$a['error']['details'] = $this->getDetails();
return $a;
}
public function toJson()
{
return json_encode($this->toArray());
}
public function setDetails($details) {...}
public function getDetails() {...}
}

src
!"" AppBundle
!"" Basic
%"" TicketOffice
%"" Sale
!"" Command
!"" Entity
!"" Event
!"" Exception
# %"" CustomerNotAllowedException.php
!"" Service
%"" Subscriber
CustomerNotAllowedException.php

CustomerNotAllowedException.php
class CustomerNotAllowedException extends TicketOfficeException
{
protected $code = 666;
protected $message =
'Customer is not allowed to use this service.';
}

{
if ($command->getCustomerId() == 42) {
throw new CustomerNotAllowedException();
}
$event = new TicketSold(...);
}

{
}
$event = new TicketSold(...);
}
}

{
$id,
);
try {
} catch (CustomerNotAllowedException $e) {
return new Response($e->toJson(), 400);
}
}

{
$id,
);
try {
}
}
try {
}

COMMAND
‣Si usa per muovere il dominio
‣Va a buon ﬁne per deﬁnizione
‣Non restituisce nessun risultato

COMMAND HANDLER
‣ Gestisce il comando
‣ Effettua validazioni di dominio
‣ Muove concretamente il dominio
‣ Solleva eccezioni in caso di problemi

EVENT
‣ Viene sollevato a fronte di qualcosa accaduto nel
dominio (es: UserRegistered)
‣ Contiene informazioni arbitrarie

SUBSCRIBER
‣ Viene usato per eseguire azioni in risposta a
degli eventi
‣ Non può muovere il dominio, al massimo
inoltra la richiesta ad un comando
‣ Può operare autonomamente se la sua azione
è destinata all'esterno del dominio

Giulia ha continuato
a chiedere nuove
funzionalità perché
un software non è
mai ﬁnito

Roberto ha potuto
implementarle
senza scrivere
controller o servizi
di 2000 righe

I comandi, gli eventi
e i subscriber sono
piccoli e perciò
facilmente testabili

Quindi Roberto ha
potuto consegnare
nuove funzionalità
più velocemente e
con meno errori

(anche) grazie al
software di
Roberto, l'azienda
di Giulia prospera e
vende biglietti

Francesco Face
@magobaol
Senior Developer

Approfondimenti
A wave of command buses by Matthias Noback
http://php-and-symfony.matthiasnoback.nl/2015/01/a-wave-of-command-buses/
SimpleBus Library 
http://simplebus.github.io/MessageBus/
Martin Eckardt Bachelor Thesis on CQRS and Event Sourcing
https://drive.google.com/file/d/0B_enB2DMKeyzbF96VjdKdjIzOHc/view
Bounded Context by Martin Fowler
https://martinfowler.com/bliki/BoundedContext.html
Ticket Office Sample Project
https://github.com/magobaol/ticket-office

Biglietti, prego! A ticket for the (command) bus

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