Function middleware

tests/test_web_middleware.py:17–22

(request, handler: Handler)

    @web.middleware
    async def middleware(request, handler: Handler):
        resp = await handler(request)
        assert 200 == resp.status
        resp.set_status(201)
        resp.text = resp.text + "[MIDDLEWARE]"
        return resp

    app = web.Application()
    app.middlewares.append(middleware)