Router simule

En production avec DRF, tu ne definis pas les URLs a la main. Tu enregistres tes ViewSets dans un Router, et il genere automatiquement toutes les routes REST. C'est un gain de temps enorme sur les vrais projets.

Par exemple, si tu enregistres un ArticleViewSet sous le prefix 'articles', le Router cree :

GET /articles/ -> list
POST /articles/ -> create
GET /articles/1/ -> retrieve (pk=1)
PUT /articles/1/ -> update (pk=1)
DELETE /articles/1/ -> destroy (pk=1)

Tu vas créer une classe SimpleRouter qui :

register(prefix, viewset) : enregistre un ViewSet sous un prefix d'URL. Plusieurs ViewSets peuvent etre enregistres.

resolve(method, path) : prend une méthode HTTP et un chemin d'URL, et retourne le résultat du bon ViewSet. Le chemin est de la forme '/prefix/' pour les collections et '/prefix/id/' pour les details. L'id est toujours un entier. Si le chemin ne correspond a aucun ViewSet, retourne {'status': 404, 'error': 'Route non trouvee'}.

Exemple :

router = SimpleRouter()
router.register('articles', ArticleViewSet())

router.resolve('POST', '/articles/', data={'title': 'Hello'})
renvoie {'status': 201, 'data': {'id': 1, 'title': 'Hello'}}

router.resolve('GET', '/articles/1/')
renvoie {'status': 200, 'data': {'id': 1, 'title': 'Hello'}}

Tu peux reutiliser la classe ArticleViewSet de l'exercice précédent (elle est fournie dans le starter code).

Tests (4/5)

router = SimpleRouter()
router.register('articles', ArticleViewSet())
r = router.resolve('GET', '/articles/')
assert r['status'] == 200 and r['data'] == []

Create via router

router = SimpleRouter()
router.register('articles', ArticleViewSet())
r = router.resolve('POST', '/articles/', data={'title': 'Hello'})
assert r['status'] == 201 and r['data']['title'] == 'Hello'

Retrieve via router

router = SimpleRouter()
vs = ArticleViewSet()
router.register('articles', vs)
vs.create({'title': 'Test'})
r = router.resolve('GET', '/articles/1/')
assert r['status'] == 200 and r['data']['title'] == 'Test'

Route inconnue

router = SimpleRouter()
router.register('articles', ArticleViewSet())
r = router.resolve('GET', '/unknown/')
assert r['status'] == 404

+ 0 tests cachés

Indices (3 disponibles)

Solution officielle

class ArticleViewSet:
    def __init__(self):
        self.db = {}
        self.next_id = 1

    def list(self):
        return {'status': 200, 'data': list(self.db.values())}

    def create(self, data):
        article = dict(data)
        article['id'] = self.next_id
        self.db[self.next_id] = article
        self.next_id += 1
        return {'status': 201, 'data': article}

    def retrieve(self, pk):
        if pk not in self.db:
            return {'status': 404, 'error': 'Non trouve'}
        return {'status': 200, 'data': self.db[pk]}

    def update(self, pk, data):
        if pk not in self.db:
            return {'status': 404, 'error': 'Non trouve'}
        self.db[pk].update(data)
        self.db[pk]['id'] = pk
        return {'status': 200, 'data': self.db[pk]}

    def destroy(self, pk):
        if pk not in self.db:
            return {'status': 404, 'error': 'Non trouve'}
        del self.db[pk]
        return {'status': 204, 'data': None}

    def dispatch(self, method, data=None, pk=None):
        if method == 'GET' and pk is None:
            return self.list()
        elif method == 'POST' and pk is None:
            return self.create(data)
        elif method == 'GET' and pk is not None:
            return self.retrieve(pk)
        elif method == 'PUT' and pk is not None:
            return self.update(pk, data)
        elif method == 'DELETE' and pk is not None:
            return self.destroy(pk)
        return {'status': 405, 'error': 'Méthode non autorisee'}


class SimpleRouter:
    def __init__(self):
        self.routes = {}

    def register(self, prefix, viewset):
        self.routes[prefix] = viewset

    def resolve(self, method, path, data=None):
        parts = path.strip('/').split('/')
        if not parts:
            return {'status': 404, 'error': 'Route non trouvee'}
        prefix = parts[0]
        if prefix not in self.routes:
            return {'status': 404, 'error': 'Route non trouvee'}
        viewset = self.routes[prefix]
        pk = None
        if len(parts) >= 2 and parts[1].isdigit():
            pk = int(parts[1])
        return viewset.dispatch(method, data=data, pk=pk)

← ViewSet simule Serializer avec champs calcules →

solution.py

class ArticleViewSet:
    def __init__(self):
        self.db = {}
        self.next_id = 1

def list(self):
        return {'status': 200, 'data': list(self.db.values())}

def create(self, data):
        article = dict(data)
        article['id'] = self.next_id
        self.db[self.next_id] = article
        self.next_id += 1
        return {'status': 201, 'data': article}

def retrieve(self, pk):
        if pk not in self.db:
            return {'status': 404, 'error': 'Non trouve'}
        return {'status': 200, 'data': self.db[pk]}

def update(self, pk, data):
        if pk not in self.db:
            return {'status': 404, 'error': 'Non trouve'}
        self.db[pk].update(data)
        self.db[pk]['id'] = pk
        return {'status': 200, 'data': self.db[pk]}

def destroy(self, pk):
        if pk not in self.db:
            return {'status': 404, 'error': 'Non trouve'}
        del self.db[pk]
        return {'status': 204, 'data': None}

def dispatch(self, method, data=None, pk=None):
        if method == 'GET' and pk is None:
            return self.list()
        elif method == 'POST' and pk is None:
            return self.create(data)
        elif method == 'GET' and pk is not None:
            return self.retrieve(pk)
        elif method == 'PUT' and pk is not None:
            return self.update(pk, data)
        elif method == 'DELETE' and pk is not None:
            return self.destroy(pk)
        return {'status': 405, 'error': 'Méthode non autorisee'}

class SimpleRouter:
    def __init__(self):
        self.routes = {}

def register(self, prefix, viewset):
        pass

def resolve(self, method, path, data=None):
        pass

Bravo!

Router simule

Tests (4/5)

Indices (3 disponibles)

Solution officielle