SERVICE ORIENTED ARCHITECTURE Midwest PHP 2015 

I AM MIKE WILLBANKS • Father, Husband, Developer • VP of Development at Packet Power • Twitter: @mwillbanks • ZF Contributor, ZF CR Team, ZF Certification Advisory Group 

Applications much like onions, have multiple layers. 

A STORY 

ONCE UPON A TIME We wrote procedural code… 

Recent Books

select('...'); foreach ($books as $book) { echo '
• ' . $book['title'] . '
'; } ?>



insert('book', array( 'title' => $_POST['title'], )); } ?> Add Book 

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. 

My Libraries

select('...'); foreach ($libraries as $library) { echo '
• ' . $library['name'] . '
'; } ?>



insert('library', array( 'name' => $_POST['name'], )); } ?> Add Library 

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('...'); ?> Update Book 

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. 

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. 

db->insert('book', $book); return $book; } } 

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

layout('main'); ?>

• escape($book->getTitle());?>



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. 

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.” 

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 

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

filter($title); $this->title = title; return $this; } } 

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 

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; } } 

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. 

repository->save($book); return $book; } } 

But I have multiple tables for this entity!!! 

bookRepository->save($book); $this->bookDetails->save($book); } } 

DUPLICATION?! Not Exactly 

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

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. 

getId()) { return $this->insert('book', $book); } return $this->update('book', $book, array( 'id' => $book->getId() )); } } 

DECORATION 

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

gateway->select(...); return $book; } } 

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. 

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 get( ‘BookService’ ); 

CLI? Oh, yes. We can! 

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. 

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… 

setIsbn($isbn); $book->setTitle($title); $book->setDescription($description); $this->mapper->addBook($book); $this->trigger('book.add', array('book' => $book)); return $book; } } 

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

WEB SERVICES Practically Free! 

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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 

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 

setClass('BookService'); $server->setObject(new BookService()); $server->handle(); 

RPC 

setClass('BookService'); $server->handle(); setClass('BookService'); echo $server->handle(); 

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