Why your code suxx

Why Your Code SuxxAnd why you should care about it ?

www.blubird.eu

Started mid 2013

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ABOUT BLUBIRD

Web & Mobile apps

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SMAC the pictureSecurity, Mobility, Apps & Cloud

Nicolas De Boose

➢ Freelancer

➢ PHP, Symfony2, (Node) Js, Css

➢ 10 yrs pro

➢ A wonderful fiancee <3

➢@NicoDeBoose

➢ Blog: mechantblog.com

ABOUT ME

http://www.mechantblog.com/

WHY THIS SUBJECT?

1. Laravel vs Symfony2 vs Zend Framework2 ? Google it!

2. “Clean code” is a subject I like– Pull request– Gave lots of reviews– Read/watch Clean coders (book & website)

3. Every year, new coders must learn best practices, solid principles, patterns, ... And it’s a good booster shot

HOW ?

1. Presentation of code that smells

2. Your opinion

3. Refactoring

//Let's go to the bar

interface Human{public function getAge();public function getFullName();

}

interface Drink{public function getPrice();

}

interface Bar{public function removeFromStock(Drink $drink);public function hasInStock(Drink $drink);

}

class BarMan{private $bar;

public function command(Human $human, Drink $drink){if ($this->bar->hasInStock($drink) == true) {

if ($drink->doesNotContainAlcohol()) {$this->prepare($human, $drink);

} else {if ($human->getAge() >= 18){

$this->prepare($human, $drink);} else {

$this->errorMessage = 'Too young :(';return false;

}}

} else {$this->errorMessage = 'Not in stock :(';

}return true;

}}

class BarMan{private $bar;

public function command(Human $human, Drink $drink){if ($this->bar->hasInStock($drink) == true) {

if ($drink->doesNotContainAlcohol()) {$this->prepare($human, $drink);

} else {if ($human->getAge() >= 18){



}}

} else {$this->errorMessage = 'Not in stock :(';

}return true;

}}

Focus on this code

//In Barman::command(Human $human, Drink $drink)

if ($this->bar->hasInStock($drink) == true) {if ($drink->doesNotContainAlcohol()) {


if ($human->getAge() >= 18){$this->prepare($human, $drink);

} else {$this->errorMessage = 'Too young :(';return false;

}}

} else {$this->errorMessage = 'Not in stock :(';return false;

}return true;


if ($this->bar->hasInStock($drink) == true) {if ($drink->doesNotContainAlcohol()) {




}}


}return true;

== true) == true) ...


if ($this->bar->hasInStock($drink)) {if ($drink->doesNotContainAlcohol()) {




}}


}return true;






}}


}return true;

Nested if’s






}}


}return true;


if (!$this->bar->hasInStock($drink)) {$this->errorMessage = 'Not in stock :(';return false;

}if ($drink->doesNotContainAlcohol()) {




}}return true;



}if ($drink->doesNotContainAlcohol()) {




}}return true;

call to “prepare()” here

And here + nested if



}if (!$drink->doesNotContainAlcohol()

&& $human->getAge() < 18) {


}

$this->prepare($human, $drink);return true;



}if (!$drink->doesNotContainAlcohol()



}


NOT doesNot… My head hurts!



}if ($drink->containsAlcohol()



}







}


can we be more explicit?




&& $human->isYoungerThan(18)) {


}







}


It’s not my job to keep the error message

It’s not my job to keep the error message


if (!$this->bar->hasInStock($drink)) {throw new DrinkNotInStockException($drink);



return new CommandResult(false,'Too young :(');}


Solution 1: Throw an exception

Solution 2: Return a “Result” object

Solution 1: Return nothingSolution 2: Return a “Result” object





throw new TooYoungToDrinkAlcoholException();}

$this->prepare($human, $drink);





throw new TooYoungToDrinkAlcoholException();}


What is “18”? It’s a magic number!




&& $human->isYoungerThan(self::MINIMUM_AGE_FOR_ALCOHOL)

) {throw new TooYoungToDrinkAlcoholException();

}


Better but not the best place to store the constant




&& $human->isYoungerThan(BarLegislation::MINIMUM_AGE_FOR_ALCOHOL)

) {throw new TooYoungToDrinkAlcoholException();

}


There, it’s good enough for the moment


if (!$this->bar->hasInStock($drink))throw new DrinkNotInStockException($drink);

if ($drink->containsAlcohol() && $human->isYoungerThan

(BarLegislation::MINIMUM_AGE_FOR_ALCOHOL))

throw new TooYoungToDrinkAlcoholException();


interface Human{// public function getAge(); => deleted

public function isYoungerThan($age); //New public function getFullName();

}

interface Drink{public function getPrice();public function containsAlcohol(); //Rename

}

interface Bar{public function removeFromStock(Drink $drink);public function hasInStock(Drink $drink);

}

//In Barman::prepare(Human $human, Drink $drink)

$tmp = explode(" ", $human->getFullName());$ac = "";foreach ($tmp as $w) {

$ac .= $w[0];}$human->addToBill($drink);$this->bar->removeFromStock($drink);

/* ... Prepare the drink ... */

$drink->setAcronym($ac);SmsSender::send(

$human->getMobilePhoneNumber(),sprintf('Drink %s ready', $ac)

);


$tmp = explode(" ", $human->getFullName());$ac = "";foreach ($tmp as $w) {

$ac .= $w[0];}$human->addToBill($drink);$this->bar->removeFromStock($drink);


$drink->setAcronym($ac);SmsSender::send(

$human->getMobilePhoneNumber(),sprintf('Drink %s ready', $ac)

);

What does “tmp” mean?

What does “ac” mean?


$nameParts = explode(" ",$human->getFullName());$acronym = "";foreach ($nameParts as $w) {

$acronym .= $w[0];}$human->addToBill($drink);$this->bar->removeFromStock($drink);


$drink->setAcronym($acronym);SmsSender::send(

$human->getMobilePhoneNumber(),sprintf('Drink %s ready', $acronym)

);


$nameParts = explode(" ",$human->getFullName());$acronym = "";foreach ($nameParts as $w) {

$acronym .= $w[0];}$human->addToBill($drink);$this->bar->removeFromStock($drink);




);

Can we compute the acronym elsewhere?


$acronym = $this->getHumanAcronym($human);$human->addToBill($drink);$this->bar->removeFromStock($drink);




);

That’s better, but ...


$acronym = $human->getAcronym();$human->addToBill($drink);$this->bar->removeFromStock($drink);




);


$acronym = $human->getAcronym();$human->addToBill($drink);$this->bar->removeFromStock($drink);




);

Now let’s remove $acronym var


$human->addToBill($drink);$this->bar->removeFromStock($drink);


$drink->setAcronym($human->getAcronym());SmsSender::send(

$human->getMobilePhoneNumber(),sprintf('Drink %s ready',$human->getAcronym())

);


$human->addToBill($drink);$this->bar->removeFromStock($drink);




);

A bill for a “simple” human?


$client = new Client($human);$client->addDrink($drink);$this->bar->removeFromStock($drink);




);

Create a “Client” class: He knows what he’s drinking






);

A drink should not be more than a drink.




$labeledDrink = new LabeledDrink($drink,$human->getAcronym());

SmsSender::send($human->getMobilePhoneNumber(),sprintf('Drink %s ready',

$labeledDrink->getLabel()));

Create a class that symbolizes the drink with an acronym

Take the label from the new object







Is there a better place to instantiate the object?







Is there a better place to instantiate the object?

Maybe here?


$client = new Client($human);$labeledDrink = $client->addDrink($drink);$this->bar->removeFromStock($drink);









Not all human have a phone number




SmsSender::send($client->getMobilePhoneNumber(),sprintf('Drink %s ready',


Our clients have a phone number!






Human becomes useless here

//In Barman::prepare(Client $client, Drink $drink)

$labeledDrink = $client->addDrink($drink);$this->bar->removeFromStock($drink);









Hello ugly hard coded content!






Hello ugly hard coded content!

We actually send a message here...




SmsSender::send(new DrinkIsReadyMessage($labeledDrink, $client););

//FYI

class DrinkIsReadyMessage implements Message{public function getPhoneNumber(){

return $this->client->getMobilePhoneNumber();}public function getMessage(){/* … */}

}









Static is not testable!





/* Should the bar manage the sms messaging system? */






/* Should the bar manage the sms messaging system? Why not, but it already manages the drinks stock.*/






/* Should the bar manage the sms messaging system? Why not, but it already manages the drinks stock.Maybe the bar should be a facade?*/





$this->bar->sendMessage(new DrinkIsReadyMessage($labeledDrink, $client););

Simplest solution...




$this->bar->sendMessage(new DrinkIsReadyMessage($labeledDrink, $client););

Simplest solution...

Voilà! Let's not over engineering for the moment :)

interface Bar{public function removeFromStock(Drink $drink);public function hasInStock(Drink $drink);public function sendMessage(Message $message);//New

}

interface Client{public function addDrink(Drink $drink);public function getMobilePhoneNumber();

}interface labeledDrink extends Drink{ //New class

public function getLabel();}

interface Message{ //New interfacepublic function getPhoneNumber();public function getMessage();

}interface DrinkIsReadyMessage extends Message{} //New

class BillPrinter{ //Let's print the bill!public function __construct(string $type) {

$this->type = $type;}public function renderClientBill(Client $client){

if ($this->type === 'xml') {$this->renderAsXml($client);

} elseif ($this->type === 'html') {$this->renderAsHtml($client);

} else {throw new \Exception('Invalid input');

}}

public function renderAsHtml(Client $client){}public function renderAsXml(Client $client){}

}

class BillPrinter{public function __construct(string $type) {




} else {throw new \Exception('Invalid input');

}}


}

Generic exception





} else {throw new \InvalidTypeException();

}}


}






}}


}

Render an xml

Render an html

2 responsabilities



if ($this->type === 'xml') {(new XmlBillPrinter())->render($client);



}}

public function renderAsHtml(Client $client){}}

Render an html

Delegate xml




} elseif ($this->type === 'html') {(new HtmlBillPrinter())->render($client);


}}

}

Delegate html

Delegate xml






}}

}






}}

}interface BillPrinterInterface{

public function render(Client $client);}

NB: The same interface is used






}}

} It’s not my job to find what instantiate!I just want to render a bill!






}}

} It’s not my job to find what instantiate!I just want to render a bill!

Delegate to a private method first...



$this->getPrinterInstance()->render($client);}public function getPrinterInstance(){

if ($this->type === 'xml') {return new XmlBillPrinter();

} elseif ($this->type === 'html') {return new HtmlBillPrinter();


}}

}







}}

}

It’s really not my job to find what instantiate!







}}

}

It’s really not my job to find what instantiate!

It’s a factory job!



BillPrinterFactory::create($this->type)->render($client);

}}class BillPrinterFactory{

public static function create(string $type){if ($type === 'xml') {

return new XmlBillPrinter();} else //...

}}







}}

What is the purpose of this class again?







}}

What is the purpose of this class again?







}}

Remove the unnecessary class :)

//What about the render of the bill in HTML?class HtmlBillPrinter

implements BillPrinterInterface{

public function render(Client $client){foreach($client->getDrinks() as $drink){

$render .= '<div class="drink-line"';

if ($drink->containsAlcohol()) {$render .= ' data-alcohol="1"';

}

$render.= '>'. $drink->getPrice() .'</div>';}return $render;

}}

class HtmlBillPrinterimplements BillPrinterInterface{




}


}}

It renders lines





}


}}

It manages HTML and its attributes

It renders lines





}


}}


And who’s gonna escape string if necessary?

It renders lines





}


}}


And who’s gonna escape string if necessary?

It renders lines

It’s bibi!



return '<div class="drink-line"';$div = new HtmlTag('div');$div->addAttribute('class', 'drink-line');


}


}}



$div = new HtmlTag('div');$div->addAttribute('class', 'drink-line');


}


}}




if ($drink->containsAlcohol()) {return ' data-alcohol="1"'; $div->addAttribute('data-alcohol', '1');

}$render.= '>'. $drink->getPrice() .'</div>';

}return $render;

}}




if ($drink->containsAlcohol()) {$div->addAttribute('data-alcohol', '1');

}$render.= '>'. $drink->getPrice() .'</div>';

}return $render;

}}





}$render.= '>'. $drink->getPrice() .'</div>';$div->setHtml($drink->getPrice());return $div;

}}

}





}$div->setHtml($drink->getPrice());return $div;

}}

}

It’s all about making

Your code comprehensible

WRAPPING UP

Books

Thank you ☺Questions?

[email protected]

+32 2 880 05 41

Spiritual

Why your code suxx