“Writing code that lasts” … or writing code you won’t hate tomorrow. - PHPKonf

Writing code
that lasts.
Rafael Dohms 
@rdohms
photo: djandyw.com

Writing code  
you won’t hate tomorrow.
Rafael Dohms 
@rdohms
photo: djandyw.com

Lead Backend Engineer
Rafael Dohms
jobs.usabilla.com
@rdohms on twitter

Lead Backend Engineer
Rafael Dohms
jobs.usabilla.com
FeedbackFeedback
@rdohms on twitter

REWRITE
ALL THE CODE!
image: hyperboleandahalf

Real Developers,
SHIP STUFF.
photo: Glyn Lowe Photoworks

How do we ﬁnd
balance?
photo: Kalexanderson

Code has an
expiration date
photo: CarbonNYC

Code is
perishable, it rots.
photo by: massdistraction

Code Evolves
photo by: kevin dooley

Languages evolve.
photo by: raneko

You evolve.
photo by: Kaptain Kobold

Complexity  
kills
Comprehension
photo: osbornb

NIH
source: Urban dictionary
photo by: John 'K'

NIH
| nɒt ɪnˈventɪd hɪə | 
Not Invented Here —The German art of humiliating any technology,
agricultural product, or (medical) scientiﬁc work that has not been
invented or produced in Germany, Switzerland, or Austria.
source: Urban dictionary
photo by: John 'K'

The Solution™
photo: Ian Sane

Improve code
make it easier to comprehend

Improve code
make it ﬂexible

Improve code
make it ﬂexible
make it tested

Improve code
make it ﬂexible
make it tested
make it easier to replace, refactor

Improve code
make it ﬂexible
make it tested
make it easier to replace, refactor
make it not exist

"Refactoring without tests
is just changing stuﬀ."

Single Responsibility 
Open and Close 
Liskov substitution 
Interface Segregation 
Dependency Inversion
Singleton 
Tight Coupling 
Untestability 
Premature Optimization 
Indescriptive Naming 
Duplication
Solid Stupid
○"

Design Patterns
photo by halloweenstock

Domain Driven Design
with Ubiquitous Language
photo by lwr

Modular Architecture
CQRS, Event Sourcing, Micro Services
photo by medialoog

PIE
Proudly 
Invented 
Elsewhere

photo by: boston_public_library
Object Calisthenics
Jeff Bay

Calisthenics
/ˌkaləsˈTHeniks/
Calisthenics are a form of dynamic exercise consisting of a variety of
simple, often rhythmical, movements, generally using minimal
equipment or apparatus.
photo by: boston_public_library

These are
exercises, not rules. photo by: david_a_l

#1
Only one
indentation level
per method.
photo by: justinliew

#2
Do not  
use else

public function createPost($request)
{
$entity = new Post();
$form = new MyForm($entity);
$form->bind($request);
if ($form->isValid()){
$repository = $this->getRepository('MyBundle:Post');
if (!$repository->exists($entity) ) {
$repository->save($entity);
return $this->redirect('create_ok');
} else {
$error = "Post Title already exists";
return array('form' => $form, 'error' => $error);
}
} else {
$error = "Invalid fields";
}
}

{
} else {
}
} else {
}
}
actual goal of function
“Create Post"

{
} else {
}
} else {
}
}
this is all
error
handling

{
if ($form->isValid() === false){
return array('form' => $form, 'error' => 'Invalid fields');
}
if ($repository->exists($entity)){
return array('form' => $form, 'error' => 'Duplicate post
title');
}
}

{
}
title');
}
}
exit condition 1: invalid form

{
}
title');
}
}
exit condition 2: duplicated post

{
}
title');
}
}
this is what the
method actually
does

{
}

{
}
FormValidationMiddleware
UniqueEntityMiddleware

{
}
The power of PSR-7
and middleware
FormValidationMiddleware
UniqueEntityMiddleware

#3
Wrap primitive
types, if they
contain behavior

$component->repaint( new Animate(false) );

use MoneyMoney;
$fiveEur = Money::EUR(500);
$tenEur = $fiveEur->add($fiveEur);

#4
Only one  
-> per line

$user = $this->get('security.token_storage')->getToken()->getUser();

$user = $this->get('security.token_storage')->getToken()->getUser();
null

#5
Do not
abbreviate.

if($sx >= $sy) {
if ($sx > $strSysMatImgW) {
$ny = $strSysMatImgW * $sy / $sx;
$nx = $strSysMatImgW;
}
if ($ny > $strSysMatImgH) {
$nx = $strSysMatImgH * $sx / $sy;
$ny = $strSysMatImgH;
}
}

#6
Keep your
classes small.

#7
Limit your
instance
variables to 2

class MyRegistrationService
{
protected $userService;
protected $passwordService;
protected $logger;
protected $translator;
protected $entityManager;
protected $imageCropper;
// ...
}

#8
Use ﬁrst class
collections

#9
Don’t use getters
and setters.

public function getScore($request)
{
return $this->score;
}
public function setScore($score)
{
$this->score = $score;
}
$game->setScore($game->getScore() += 1);

public function collectedCoin()
{
$this->score += 1;
}
$game->collectedCoin();

#10
Document
your code.

Try Object Calisthenics
for a month.

Use someone  
else’s code, 
and share yours!

Thank you.
http://slides.doh.ms
http://doh.ms
@rdohms
jobs.usabilla.com
looking for a job in Amsterdam?

http://l.doh.ms/object-calisthenics-links
Books

“Writing code that lasts” … or writing code you won’t hate tomorrow. - PHPKonf

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