La programmation fonctionnelle
pour les développeuses·eurs web
@ThibaudDauce | https://thibaud.dauce.fr
Co-fondateur de Quantic Telecom
https://www.quantic-telecom.net
Formations Laravel
https://www.formations-laravel.frLa programmation fonctionnelle
pour les développeuses·eurs web
@ThibaudDauce | https://thibaud.dauce.frEuh… J'en fais déjà, non ?
// Get invoices
$api = new API()
$result = $api->post('/invoices', []);
$invoices = json_decode($result);
// Get students
$customers = Customer::all();
$students = [];
foreach ($customers as $customer) {
if ($customer->isStudent()) {
$students[] = $customer;
}
}
Euh… J'en fais déjà, non ?
// Get invoices
$invoices = getInvoices();
// Get students
$students = getStudents();
Votre serveur web est une fonction
Requête HTTP → Réponse HTTP
// 1. Vérifiez que la personne est connectée
// 2. Enregistrer le début du traitement de la requête
// 3. Faire ce que tu as à faire
// (retourne une chaîne de caractères)
// 4. Transformer la chaîne de caractères en réponse HTTP
// 5. Enregistrer le temps de traitement grâce à 2.
$tasks = [
new CheckAuthentication,
new LogRequestTime,
new TransformToResponse,
];
Pipelines / Middlewares
(new Pipeline)
->send(Request::createFromGlobals())
->through([
new CheckAuthentication,
new LogRequestTime,
new TransformToResponse,
])
->then(function ($request) {
return "Welcome {$request->session('customer')}!";
});
class CheckAuthentication
{
public function handle($request, $next)
{
if (! $request->session()->has('customer')) {
return new RedirecResponse('/login', 302);
}
return $next($request);
}
}
class LogRequestTime
{
public function handle($request, $next)
{
$start = microtime(true);
$response = $next($request);
$time = microtime(true) - $start;
$text = "Request {$request->requestUri} took {$time}s \n";
file_put_content('timings.txt', $text, FILE_APPEND);
return $response;
}
}
class TransformToResponse
{
public function handle($request, $next)
{
$response = $next($request);
if ($response instanceof Response) {
return $response;
}
return new Response((string) $response, 200);
}
}
function ($request) {
return "Welcome {$request->session('customer')}!";
}
Votre serveur web est une fonction
(Le retour)
- Requête HTTP → Identifiant client
- Identifiant client → Client
- Client → Total des comptes
- Total des comptes → Page HTML
- Page HTML → Réponse
Collections
function getMonthlyMeanRevenueForStudents() {
$customers = Customer::all();
$totalRevenue = [];
$counts = [];
foreach($customers as $customer) {
if ($customer->isStudent()) {
foreach($customer->invoices() as $invoice) {
$totalRevenue[$invoice->month()] +=
$invoice->total();
$counts[$invoice->month()]++;
}
}
}
$meanRevenue = [];
foreach ($revenues as $month => $total) {
$meanRevenue[$month] = $totalRevenue[$month] / $counts[$month];
}
return $meanRevenue;
}
Collections
function getMonthlyMeanRevenueForStudents() {
return Customer::all()
// [
// 'Étudiant John',
// 'Étudiante Jane',
// 'Entreprise Google',
// ]
->filter(function ($customer) {
return $customer->isStudent();
})
// [
// 'Étudiant John',
// 'Étudiante Jane',
// ]
->map(function ($customer) {
return $customer->invoices();
})
// [
// ['2017-07-001', '2017-08-001'],
// ['2017-07-002'],
// ]
->flatten()
// [ '2017-07-001', '2017-08-001', '2017-07-002' ]
->groupBy(function ($invoice) {
return $invoice->month();
})
// [
// '2017-07' => ['2017-07-001', '2017-07-002'],
// '2017-08' => ['2017-08-001'],
// ]
->map(function ($invoices) {
// = ['2017-07-001', '2017-07-002']// = [80, 100]// = 180// = 90
return $invoices->map(function ($invoice) {
return $invoice->total();
})->sum() / $invoices->count();
});
// [
// '2017-07' => 90,
// '2017-08' => 150,
// ]
}
Collections
function getMonthlyMeanRevenueForStudents() {
return Customer::all()
->filter->isStudent()
->flatMap->invoices()
->groupBy->month()
->map(function ($invoices) {
return $invoices->map->total()->sum() / $invoices->count();
});
}
Un peu de Front-End
Elm
MVU
Model View Update
Model
type alias Model = String
init : Model
init = ""
Update
type Event = Typed String
update : Event -> Model -> Model
update (Typed textTyped) oldTextTyped = textTyped
View
view : Model -> Html Event
view textTyped =
div []
[ input [ placeholder "Text to reverse", onInput Typed ] []
, div [] [ text (String.reverse textTyped) ]
]