La programmation fonctionnelle
pour les développeuses·eurs web
@ThibaudDauce | https://thibaud.dauce.fr
Co-fondateur de Quantic Telecom
https://www.quantic-telecom.net
Thibaud Dauce sur YouTube
https://www.apprendre-laravel.frLa programmation fonctionnelle
pour les développeuses·eurs web
@ThibaudDauce | https://thibaud.dauce.frIl y a 3 ans…
Haskell c'est quoi ?
- pas de conditions
- pas de boucles
- pas de variables
function getStudents() {
$customers = Customer::all();
$students = [];
foreach($customers as $customer) {
if ($customer->isStudent()) {
$students[] = $customer;
}
}
return $students;
}
function getStudents() {
$customers = Customer::all();
return array_filter($customers, function ($customer) {
return $customer->isStudent();
});
}
function getStudents() {
return Customer::all()
->filter(function ($customer) {
return $customer->isStudent();
});
}
function getStudents() {
$customers = Customer::all();
return array_filter(array_filter($customers, function ($customer) {
return $customer->isStudent();
}), function ($student) {
return $student->isValid();
});
}
function getStudents() {
return Customer::all()
->filter(function ($customer) {
return $customer->isStudent();
});
->filter(function ($student) {
return $customer->isValid();
});
}
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()]++;
}
}
}
$meanRevenue = [];
foreach ($totalRevenue as $month => $total) {
$meanRevenue[$month] = $total / $counts[$month];
}
return $meanRevenue;
}
function getMonthlyMeanRevenueForStudents() {
return Customer::all()
// [
// 'Étudiant John',
// 'Étudiante Jane',
// 'Entreprise Google',
// ]
->filter(function ($customer) {
return $customer->isStudent();
})
// [
// 'Étudiant John',
// 'Étudiante Jane',
// ]
->map(function ($student) {
return $student->invoices();
})
// [
// ['2019-03-001', '2019-04-001'],
// ['2019-03-002'],
// ]
->flatten()
// [ '2019-03-001', '2019-04-001', '2019-03-002']
->groupBy(function ($invoice) {
return $invoice->month();
})
// [
// '2019-03' => ['2019-03-001', '2019-03-002'],
// '2019-04' => ['2019-04-001'],
// ]
->map(function ($invoices) {
// = ['2019-03-001', '2019-03-002']// = [80, 100]// = 180// = 90
return $invoices->map(function ($invoice) {
return $invoice->total();
})->sum() / $invoices->count();
});
// [
// '2019-03' => 90,
// '2019-04' => 150,
// ]
}
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()]++;
}
}
}
$meanRevenue = [];
foreach ($totalRevenue as $month => $total) {
$meanRevenue[$month] = $total / $counts[$month];
}
return $meanRevenue;
}
PHP RFC: Arrow Functions 2.0
function getMonthlyMeanRevenueForStudents() {
return Customer::all()
->filter(fn($customer) => $customer->isStudent())
->flatMap(fn($student) => $student->invoice())
->groupBy(fn($invoice) => $invoice->month())
->map(function ($invoices) {
$total = $invoices
->map(fn($invoice) => $invoice->total())
->sum();
return $total / $invoices->count();
});
}
Middlewares
Gestion d'une Chaîne de traitement
Requête HTTP → Réponse HTTP
3 problèmes
- Vérifiez que la personne est connectée
- Ajouter un header HTTP à toutes les réponses
(Content-Language: fr) - Enregistrer le temps de traitement d'une requête
function myMiddleware(Request $request, $next): Response
{
// $next = function (Request $request): Response {
// return new Response(200, 'All good!');
// };
$response = $next($request);
return $response;
}
Vérifiez que la personne est connectée
function authMiddleware(Request $request, $next): Response
{
if (! $request->session()->has('user')) {
return new Response(302, '/login');
}
$response = $next($request);
return $response;
}
Ajouter un header HTTP à chaque réponse
function contentLanguageMiddleware(Request $request, $next): Response
{
$response = $next($request);
$response->headers()->add('Content-Language', 'fr');
return $response;
}
Enregistrer le temps de traitement d'une requête
function timeMiddleware(Request $request, $next): Response
{
$start = microtime(true);
$response = $next($request);
$time = microtime(true) - $start;
$text = "Request {$request->url()} took {$time}s \n";
file_put_content('timings.txt', $text, FILE_APPEND);
return $response;
}
Exemples de middlewares avec Laravel
$middlewares = [
CheckForMaintenanceMode::class,
EncryptCookies::class,
StartSession::class,
ThrottleRequests::class,
ConvertEmptyStringsToNull::class,
];
L'ordre des middlewares
$middlewares = [
'authMiddleware',
'contentLanguageMiddleware',
'timeMiddleware',
];
$middlewares = [
'timeMiddleware',
'authMiddleware',
'contentLanguageMiddleware',
];
function otherMiddleware(ClasseA $classeA, $next): ClasseB
{
// $next = function (ClasseA $classeA): ClasseB {
// return new ClasseB;
// };
$classeB = $next($classeA);
return $classeB;
}
Un peu de Front-End
Elm
MVU
Model View Update
Model
type alias Model = String
init : Model
init = "Thibaud"
Update
type Event = NewName String | Reverse
update : Event -> Model -> Model
update event oldName = case event of
NewName newName -> newName
Reverse -> String.reverse oldName
View
view : Model -> Html Event
view name =
div []
[ input [ placeholder "New Name", onInput NewName, value name ] []
, button [ onClick Reverse ] [ text "Reverse Name" ]
, div [] [ text name ]
]