1.
Writing code
that lasts.
Rafael Dohms
@rdohms
photo: djandyw.com

2.
Writing code
you won’t hate tomorrow.
Rafael Dohms
@rdohms
photo: djandyw.com

3.
Lead Backend Engineer
Rafael Dohms
jobs.usabilla.com
@rdohms on twitter

4.
Lead Backend Engineer
Rafael Dohms
jobs.usabilla.com
FeedbackFeedback
@rdohms on twitter

5.
photo: Rob Allen (@akrabat)

6.
REWRITE
ALL THE CODE!
image: hyperboleandahalf

7.
Real Developers,
SHIP STUFF.
photo: Glyn Lowe Photoworks

8.
How do we find
balance?
photo: Kalexanderson

9.
Code has an
expiration date
photo: CarbonNYC

10.
Code is
perishable, it rots.
photo by: massdistraction

11.
Code Evolves
photo by: kevin dooley

12.
Languages evolve.
photo by: raneko

13.
You evolve.
photo by: Kaptain Kobold

14.
Complexity
kills
Comprehension
photo: osbornb

15.
Bad Design
photo: miskan

16.
Bad specs

17.
NIH
source: Urban dictionary
photo by: John 'K'

18.
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'

19.
The Solution™
photo: Ian Sane

20.
Improve code

21.
Improve code
make it easier to comprehend

22.
Improve code
make it easier to comprehend
make it flexible

23.
Improve code
make it easier to comprehend
make it flexible
make it tested

24.
Improve code
make it easier to comprehend
make it flexible
make it tested
make it easier to replace, refactor

25.
Improve code
make it easier to comprehend
make it flexible
make it tested
make it easier to replace, refactor
make it not exist

26.
Testing
photo by: jeffkrause

27.
"Refactoring without tests
is just changing stuff."

28.
Good Design
Concepts

29.
Single Responsibility
Open and Close
Liskov substitution
Interface Segregation
Dependency Inversion
Singleton
Tight Coupling
Untestability
Premature Optimization
Indescriptive Naming
Duplication
Solid Stupid
○"

30.
Design Patterns
photo by halloweenstock

31.
Domain Driven Design
with Ubiquitous Language
photo by lwr

32.
Modular Architecture
CQRS, Event Sourcing, Micro Services
photo by medialoog

33.
Package
Managers

34.
PIE
Proudly
Invented
Elsewhere

35.
Readability
photo: Morgenland

36.
photo by: boston_public_library
Object Calisthenics
Jeff Bay

37.
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

38.
These are
exercises, not rules. photo by: david_a_l

39.
#1
Only one
indentation level
per method.
photo by: justinliew

40.
#2
Do not
use else
photo by: justinliew

41.
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";
return array('form' => $form, 'error' => $error);
}
}

42.
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";
return array('form' => $form, 'error' => $error);
}
}
actual goal of function
“Create Post"

43.
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";
return array('form' => $form, 'error' => $error);
}
}
this is all
error
handling

44.
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";
return array('form' => $form, 'error' => $error);
}
}

45.
public function createPost($request)
{
$entity = new Post();
$repository = $this->getRepository('MyBundle:Post');
$form = new MyForm($entity);
$form->bind($request);
if ($form->isValid() === false){
return array('form' => $form, 'error' => 'Invalid fields');
}
if ($repository->exists($entity)){
return array('form' => $form, 'error' => 'Duplicate post
title');
}
$repository->save($entity);
return $this->redirect('create_ok');
}

46.
public function createPost($request)
{
$entity = new Post();
$repository = $this->getRepository('MyBundle:Post');
$form = new MyForm($entity);
$form->bind($request);
if ($form->isValid() === false){
return array('form' => $form, 'error' => 'Invalid fields');
}
if ($repository->exists($entity)){
return array('form' => $form, 'error' => 'Duplicate post
title');
}
$repository->save($entity);
return $this->redirect('create_ok');
}
exit condition 1: invalid form

47.
public function createPost($request)
{
$entity = new Post();
$repository = $this->getRepository('MyBundle:Post');
$form = new MyForm($entity);
$form->bind($request);
if ($form->isValid() === false){
return array('form' => $form, 'error' => 'Invalid fields');
}
if ($repository->exists($entity)){
return array('form' => $form, 'error' => 'Duplicate post
title');
}
$repository->save($entity);
return $this->redirect('create_ok');
}
exit condition 2: duplicated post

48.
public function createPost($request)
{
$entity = new Post();
$repository = $this->getRepository('MyBundle:Post');
$form = new MyForm($entity);
$form->bind($request);
if ($form->isValid() === false){
return array('form' => $form, 'error' => 'Invalid fields');
}
if ($repository->exists($entity)){
return array('form' => $form, 'error' => 'Duplicate post
title');
}
$repository->save($entity);
return $this->redirect('create_ok');
}
this is what the
method actually
does

49.
public function createPost($request)
{
$repository = $this->getRepository('MyBundle:Post');
$entity = new Post();
$repository->save($entity);
return $this->redirect('create_ok');
}

50.
public function createPost($request)
{
$repository = $this->getRepository('MyBundle:Post');
$entity = new Post();
$repository->save($entity);
return $this->redirect('create_ok');
}
FormValidationMiddleware
UniqueEntityMiddleware

51.
public function createPost($request)
{
$repository = $this->getRepository('MyBundle:Post');
$entity = new Post();
$repository->save($entity);
return $this->redirect('create_ok');
}
The power of PSR-7
and middleware
FormValidationMiddleware
UniqueEntityMiddleware

52.
#3
Wrap primitive
types, if they
contain behavior
photo by: justinliew

53.
$component->repaint(false);

54.
$component->repaint( new Animate(false) );

55.
#4
Only one
-> per line
photo by: justinliew

56.
#5
Do not
abbreviate.
photo by: justinliew

57.
if($sx >= $sy) {
if ($sx > $strSysMatImgW) {
$ny = $strSysMatImgW * $sy / $sx;
$nx = $strSysMatImgW;
}
if ($ny > $strSysMatImgH) {
$nx = $strSysMatImgH * $sx / $sy;
$ny = $strSysMatImgH;
}
}

58.
#6
Keep your
classes small.
photo by: justinliew

59.
#7
Limit your
instance
variables to 2
photo by: justinliew

60.
#8
Use first class
collections
photo by: justinliew

61.
#9
Don’t use getters
and setters.
photo by: justinliew

62.
public function getScore($request)
{
return $this->score;
}
public function setScore($score)
{
$this->score = $score;
}
$game->setScore($game->getScore() += 1);

63.
public function collectedCoin()
{
$this->score += 1;
}
$game->collectedCoin();

64.
#10
Document
your code.
photo by: justinliew

65.
Your turn.

66.
Improve
yourself!

67.
Read lots of
code!

68.
Write simpler
code.

69.
Try Object Calisthenics
for a month.

70.
Use someone
else’s code,
and share yours!

71.
Improve your naming,
secure your API, grow
awesome teams, handle
errors, flip out, check out
MySQL 8, Drupal 8 and
HTML 5, go PSR-7, git you
guts and finally, survive.
#phpyorkshire

72.
Improve your naming,
secure your API, grow
awesome teams, handle
errors, flip out, check out
MySQL 8, Drupal 8 and
HTML 5, go PSR-7, git you
guts and finally, survive.
#phpyorkshire

73.
Thank you.
http://slides.doh.ms
http://doh.ms
@rdohms
https://joind.in/talk/89356
jobs.usabilla.com
looking for a job in Amsterdam?

74.
http://l.doh.ms/oc-material
Video recording
Slides
Books
Resources on
Object Calisthenics