Flask:API的一种简易实现方式——MethodView

FlaskRESTful APIs 提供了一种简易的实现方式,可以针对不同的HTTP方法提供不同的函数。使用也很简单,只需要继承 flask.views.MethodView 然后重写需要的方法:GET POST PUT 等。

下面是官方给的程序示例:

from flask.views import MethodView

class UserAPI(MethodView):

    def get(self):
        users = User.query.all()
        ...

    def post(self):
        user = User.from_form_data(request.form)
        ...

app.add_url_rule('/users/', view_func=UserAPI.as_view('users'))

最下面的 add_url_rule 是添加路由,和用装饰器的效果一样:

@app.route('/users/')
def users(page):
    users = User.query.all()
    return render_template('users.html', users=users)

因为现在是视图类而不是视图函数,对类进行装饰器操作没有意义,如果想对视图函数添加装饰器,比如用户登陆检测,可以对 .as_view() 返回的函数进行装饰:

def user_required(f):
    """Checks whether user is logged in or raises error 401."""
    def decorator(*args, **kwargs):
        if not g.user:
            abort(401)
        return f(*args, **kwargs)
    return decorator

view = user_required(UserAPI.as_view('users'))
app.add_url_rule('/users/', view_func=view)

如何应对多种请求方法,比如用户信息管理:

URL Method Description
/users/ GET Gives a list of all users
/users/ POST Creates a new user
/users/id GET Shows a single user
/users/id PUT Updates a single user
/users/id DELETE Deletes a single user

官方给的实用小例子:

class UserAPI(MethodView):

    def get(self, user_id):
        if user_id is None:
            # return a list of users
            pass
        else:
            # expose a single user
            pass

    def post(self):
        # create a new user
        pass

    def delete(self, user_id):
        # delete a single user
        pass

    def put(self, user_id):
        # update a single user
        pass

user_view = UserAPI.as_view('user_api')
app.add_url_rule('/users/', defaults={'user_id': None},
                 view_func=user_view, methods=['GET',])
app.add_url_rule('/users/', view_func=user_view, methods=['POST',])
app.add_url_rule('/users/', view_func=user_view,
                 methods=['GET', 'PUT', 'DELETE'])

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