2015 ZendCon - Service Oriented Architecture as a Pattern of Development

SERVICE ORIENTED ARCHITECTURE AS A PATTERN OF DEVELOPMENT ZendCon 2015

I AM MIKE WILLBANKS • Father, Husband, Developer • VP
of Development at Packet Power • Twitter: @mwillbanks

Applications much like onions, have multiple layers.

A STORY

ONCE UPON A TIME We wrote procedural code…

<html> <head><title>Recent Books</title></head> <body> <ul class="books"> <?php $books = $db->select('...');
foreach ($books as $book) { echo '<li>' . $book['title'] . '</li>'; } ?> </ul> </body> </html>

<?php if ($_SERVER['REQUEST_METHOD'] == 'POST') { $db->insert('book', array( 'title' =>
$_POST['title'], )); } ?> <html> <head><title>Add Book</title></head> <body> <form method="post"> <input type="text" name="title">  </form> </body> </html>

ALL WAS FINE IN THE WORLD Except for what was
playing out before us…

WE NEED LIBRARY The boss tells you it’s time for
the library feature… and we need to update books.

<html> <head><title>My Libraries</title></head> <body> <ul class="libraries"> <?php $libraries = $db->select('...');
foreach ($libraries as $library) { echo '<li><a href="/library/' . $library['id'] . '">' . $library['name'] . '</a></li>'; } ?> </ul> </body> </html>

<?php if ($_SERVER['REQUEST_METHOD'] == 'POST') { $db->insert('library', array( 'name' =>
$_POST['name'], )); } ?> <html> <head><title>Add Library</title></head> <body> <form method="post"> <input type="text" name="name">  </form> </body> </html>

<?php $rs = $db->select('...'); $book = $rs[0]; if ($book &&
$_SERVER['REQUEST_METHOD'] == 'POST') { $db->update('book', array( 'library_id' => $_POST['library_id'], 'title' => $_POST['title'], ), array( 'book_id' => $book['id'], )); } $libraries = $db->select('...'); ?> <html> <head><title>Update Book</title></head> <body> <form method="post"> <?php displaySelectFromDbResult('library_id', $libraries); ?>

And these things continued…

EVERYTHING IS FALLING APART

BUGS All these little demons came out of the groundwork.

#!/bin/bash grep -lri bookId * | wc -l $ 271

REWRITE! Or I’m done!

MVC Model View Controller Model Controller View

MVC REQUEST LIFECYCLE

CONTROLLERS • Send commands to the model and sends information
to the view. • It’s where your request and response are handled.

<?php class BookController extends AbstractController { public function addAction() {
$book = $this->model->insert(array( 'title' => $this->getPost('title') )); return array( 'book' => $book ); } }

MODELS • Handles the state, persistence, data access and more.
• Might have mappers and entities, it might not.. • It’s a loaded term.

<?php class BookModel extends AbstractModel { public function insert(array $book)
{ $book['id'] = $this->db->insert('book', $book); return $book; } }

<?php class BookModel extends AbstractModel { public function getId(); public
function setId($id); public function getTitle(); public function setTitle($title); }

<?php class BookModelMapper extends AbstractMapper { public function save(BookModel $book);
public function find($id); public function fetchAll(); }

VIEWS • Separating display from business logic • Escaping and
handling what our controller is providing

<?php $this->layout('main'); ?> <ul> <?php foreach ($books as $book): ?>
<li><?php $this->escape($book->getTitle());?></ li> <?php endforeach; ?> </ul>

THERE IS A BETTER WAY.

SOA Service Oriented Architecture Service Layer Controller View Domain Models
Data Mappers Data Access Objects Model

BENEFITS OF A SERVICE LAYER • Better Controllers • Better
Maintainability • Better Parallelism in Development • Better Testing/Fewer Defects • More Reuse

LETS GET BUILDING

BASIC PRINCIPLES

CONTROLLERS Exactly like MVC, but injecting a service layer.

<?php class BookController extends AbstractController { public function addBookAction() {
$book = $this->bookService->addBook( $this->getPost('isbn'), $this->getPost('title'), $this->getPost('description') ); return $this->redirect('/book/' . $book- >getId()); } }

SERVICES • Your application logic / business functionality • The
in-between layer • The internal API to your application

– Wikipedia http://en.wikipedia.org/wiki/Service_(systems_architecture) “A set of related software functionalities that
can be reused for different purposes.”

<?php class BookService extends AbstractService { public function addBook($isbn, $title,
$description) { $book = new BookEntity(); $book->setIsbn($isbn); $book->setTitle($title); $book->setDescription($description); $this->mapper->addBook($book); return $book; } }

DOMAIN MODELS • Describe a “thing” • Data object •
Domain logic • Generally getters, setters

<?php class Book extends AbstractEntity { public function getId(); public
function setId($id); public function getIsbn(); public function setIsbn($isbn); public function getTitle(); public function setTitle($title); public function getDescription(); public function setDescription($description); }

FILTERING AND VALIDATION • Always ﬁlter • User data to
be validated.

<?php class Book extends AbstractEntity { public function getTitle(); public
function setTitle($title) { $trim = new TrimFilter(); $title = $trim->filter($title); $this->title = title; return $this; } }

<?php class Book extends AbstractEntity { pubic function getTitle(); public
function setTitle($title) { $trim = new TrimFilter(); $title = $trim->filter($title); $validate = new AlnumValidator(); if (!$validate->isValid($title)) { throw new InvalidArgumentException($validate->getMessage()); } $this->title = title; return $this; } }

INPUT FILTER PATTERN Merge ﬁlters and validators

<?php class Book extends AbstractEntity { public function getInputFilter() {
$input = new Input('title'); $input->getFilterChain() ->attachByName('stringtrim') ->attachByName('alphanumeric'); $input->getValidatorChain() ->attachByName('not_empty') ->attachByName('string_length', array('min' => 1, 'max' => 45)); $this->inputFilter->addInput($input); return $this->inputFilter; } }

<?php class Book extends AbstractEntity { public function getTitle(); public
function setTitle($title) { $inputFilter = $this->getInputFilter()- >getInput('title'); $inputFilter->setValue($title); if ($inputFilter->isValid()) { $this->title = $title; } throw new InvalidArgumentException($inputFilter- >getMessages()); } }

DATA MAPPERS • Separates mapping data to a data store
as well as your data model. • Data store can be anything or even multiple things.

<?php class BookMapper extends AbstractMapper { public function addBook(BookEntity $book)
{ $this->repository->save($book); return $book; } }

But I have multiple tables for this entity!!!

<?php class Book extends AbstractEntity { public function getId(); public
function setId($id); public function getIsbn(); public function setIsbn($isbn); public function getTitle(); public function setTitle($title); public function getDescription(); public function setDescription($description); } <?php class Book extends AbstractEntity { public function getId(); public function setId($id); public function getIsbn(); public function setIsbn($isbn); public function getTitle(); public function setTitle($title); public function getDescription(); public function setDescription($description); }

<?php class BookMapper extends AbstractMapper { public function addBook(BookEntity $book)
{ $this->bookRepository->save($book); $this->bookDetails->save($book); } }

DUPLICATION?! Not Exactly

We need to lower our database load, let’s cache.

<?php class BookService extends AbstractService { public function findRecent() {
if ($this->cache->has('book.recent')) { return $this->cache->get('book.recent'); } $results = $this->repository->findRecent(); $this->cache->set('book.recent', $results); return $results; } }

But that seems messy.

DATA ACCESS OBJECTS • Or repositories in this case. •
Allow us to target other areas to store data. • Allow for far better decoration • Things are looking up.

<?php class BookRepository extends AbstractRepository { public function save($book) {
if (!$book->getId()) { return $this->insert('book', $book); } return $this->update('book', $book, array( 'id' => $book->getId() )); } }

<?php interface RepositoryInterface { public function save($entity); public function find($id);
public function findBy($criteria); public function findOneBy($criteria); public function delete($entity); }

<?php interface BookRepository { public function findRecent(); }

DECORATION

DECORATOR PATTERN • Used to extend the functionality of a
certain object. • Ultimately wrapping

<?php class BookDbRepository implements BookRepository { public function findRecent() {
$book = $this->gateway->select(...); return $book; } }

<?php class BookCacheRepository implements BookRepository { public function findRecent() {
if ($this->cache->has('book.recent')) { return $this->cache->get('book.recent'); } $results = $this->delegateRepository- >findRecent(); $this->cache->set('book.recent', $results); return $results; } }

WHAT ARE WE ACHIEVING • Discoverability • Maintainability • Readability

DEPENDENCY INJECTION Keeping everything alive.

Dependency injection is the concept of simply injecting anything that
is necessary for that object to operate.

<?php new BookService( new BookMapper( new BookCacheRepository( new BookDbRepository( new
TableGateway('book') ) ) ) );

DI CONTAINERS • Inject dependencies by use of a container.

return array( 'di' => array( 'BookService' => array( 'arguments' =>
array( 'BookMapper', ), ), 'BookMapper' => array( 'arguments' => array( 'BookCacheRepository', ), ), 'BookCacheRepository' => array( 'arguments' => array( 'BookDbRepository', ), ), 'BookDbRepository' => array( 'arguments' => array( 'TableGateway', ),

SO WHAT DOES THAT DO? • Creates an instance of
TableGateway • Creates an instance of BookDbRepository • Then an instance of BookCacheRepository • Then an instance of BookMapper • Finally, an instance of BookService <?php $bookService = $container->get( ‘BookService’ );

CLI? Oh, yes. We can!

<?php require 'bootstrap.php'; $bookService = $container->get('book.service'); $bookService->addBook($argv[0], $argv[1], $argv[2]);

THAT’S SEEMS A LITTLE SLIMY… BUT, there is nothing preventing
us from using controllers.

<?php if (php_sapi_name() == 'cli') { $router = $container->get('cliRouter'); }
else { $router = $container->get('router'); } class BookCliController extends AbstractCliController { public function addBookAction(); }

BUT WHAT BELONGS? • Orchestration • Security • Transactions

DOMAIN EVENTS A kitchen full of examples…

<?php class BookService extends AbstractService { public function addBook($isbn, $title,
$description) { $book = new BookEntity(); $book->setIsbn($isbn); $book->setTitle($title); $book->setDescription($description); $this->mapper->addBook($book); $this->trigger('book.add', array('book' => $book)); return $book; } }

<?php $bookService->attach('book.add', function($e) use ($mq) { $params = $e->getParams(); $book
= $params['book']; $mq->sendMessage('book.add', array('book' => $book)); });

AUTHENTICATION Where does it belong?

STACKING • Routing / Dispatch • Controllers • Services •
Data Access Layer

WEB SERVICES In general, practically free in most libraries, frameworks
and languages.

JEFF BEZOS MANDATE • All teams will henceforth expose their
data and functionality through service interfaces. • Teams must communicate with each other through these interfaces. • There will be no other form of interprocess communication allowed: no direct linking, no direct reads of another team’s data store, no shared-memory model, no back-doors whatsoever. The only communication allowed is via service interface calls over the network. • It doesn’t matter what technology they use. HTTP, Corba, Pubsub, custom protocols — doesn’t matter. • All service interfaces, without exception, must be designed from the ground up to be externalizable. That is to say, the team must plan and design to be able to expose the interface to developers in the outside world. No exceptions. • Anyone who doesn’t do this will be ﬁred. • Thank you; have a nice day!

REST • HTTP with HTTP verbs • Involves collections of
resources.

<?php $app->get('/api/book', 'ApiBookController.recentAction'); $app->put('/api/book', 'ApiBookController.addAction'); class ApiBookController extends RestfulController {
public function recentAction() { return $this->bookService->findRecent(); } public function addAction() { return $this->bookService->addBook(...); } }

SOAP • XML Information Set • Operation under any transport
protocol.

<?php $server = new Zend\Soap\Server(null, array(...)); $server->setClass('BookService'); $server->setObject(new BookService()); $server->handle();

RPC • Request / Response like protocol. • XML /
JSON

<?php $server = new Zend\Json\Server\Server(); $server->setClass('BookService'); $server->handle(); <?php $server =
new Zend\XmlRpc\Server(); $server->setClass('BookService'); echo $server->handle();

DISCOVERY Strategies for discoverability

BLUEPRINTS • API Blueprint • Apiary • ioDocs • Swagger

HYPERMEDIA • HAL • JSON-LD • JSON Hyper Schema

• http://pixabay.com/en/architecture-iron-steel-building-414035/ • http://pixabay.com/en/home-demolition-destroyed-broken-557297/ • http://pixabay.com/en/disassembly-component-parts-336507/ • http://pixabay.com/en/taps-thread-drill-milling-444473/ • http://pixabay.com/en/light-bulb-transparent-light-body-629661/
• http://pixabay.com/en/church-trappist-georgia-monastery-233564/ • http://pixabay.com/en/lego-site-build-replica-516557/ • http://pixabay.com/en/water-tap-wall-outside-exterior-243046/ • http://pixabay.com/en/question-mark-note-duplicate-457453/ • http://pixabay.com/en/door-entry-stone-opening-grid-208081/ • http://pixabay.com/en/onion-cut-fresh-tears-vegetable-161611/ • http://pixabay.com/en/petronas-towers-skyscraper-433081/ • http://pixabay.com/en/carbine-rope-hook-backup-climbing-7104/ • http://pixabay.com/en/code-program-source-computer-pc-113611/ • http://pixabay.com/en/kitchen-cabinets-countertop-granite-670247/ • http://pixabay.com/en/injecting-medical-shot-veins-519389/ • http://pixabay.com/en/books-shelf-retro-black-and-white-635341/ • http://pixabay.com/en/crayons-pencils-blurred-circle-311062/ • http://pixabay.com/en/soap-curd-soap-bathing-cleaning-390300/ • http://pixabay.com/en/helicopter-model-model-helicopter-195660/ • http://pixabay.com/en/bricks-roofing-house-building-420725/ • http://pixabay.com/en/parrot-ara-zoo-bird-beautiful-bill-655777/ • http://pixabay.com/en/gorilla-silverback-animal-448731/ • http://pixabay.com/en/crash-demolition-site-home-floors-214744/ • http://pixabay.com/en/beetle-beasts-field-insect-431125/ • http://en.wikipedia.org/wiki/File:MVC-Process.svg • http://pixabay.com/en/prairie-dog-small-cute-rodent-keep-320836/ • http://pixabay.com/en/key-lock-door-security-home-565607/ • http://pixabay.com/en/library-inside-wood-book-books-428034/ • http://pixabay.com/en/book-old-antique-pages-empty-pages-657637/ • http://pixabay.com/en/dirt-mess-messy-grungy-face-576491/ • http://pixabay.com/en/antique-box-collectible-electronic-21935/ • http://pixabay.com/en/processor-cpu-board-circuits-540254/ • http://pixabay.com/en/slug-shell-animals-wildlife-87037/ • http://pixabay.com/en/colour-pencils-color-paint-draw-450623/ • http://pixabay.com/en/mount-st-helens-volcanic-eruption-164848/ • http://pixabay.com/en/baby-tears-small-child-sad-cry-443393/ • http://pixabay.com/en/children-win-success-video-game-593313/ • http://pixabay.com/en/peas-pod-pea-pod-green-fresh-580333/ • http://pixabay.com/en/site-construction-work-support-592458/ • http://pixabay.com/en/chimney-sweeper-chimney-sweep-14035/ • https://pixabay.com/en/frog-relaxed-fig-funny-rest-914523/ Image Credits THANK YOU! http://joind.in/talk/view/15635

2015 ZendCon - Service Oriented Architecture as...

2015 ZendCon - Service Oriented Architecture as a Pattern of Development

More Decks by Mike Willbanks

Other Decks in Technology

Featured

Transcript