Middlewares

Middlewares are a special type of ‘mini app’. It can be embedded in the app to perform some special modifications on every request.

A middleware in Willpyre is fully ASGI compilant, i.e., other frameworks can use Willpyre’s middlewares and vice versa.

A middleware must be an ASGI callable.

It is better to create a middleware as a class. If it is a class, it must have an: async def  __call__`(self, scope, recieve, send)

Other methods such as __init__, etc. can be set if you want to define them.

class Middleware:
    def __init__(self, app, **options):
        self.app = app

    async def __call__(self, scope, receive, send):
        if scope["type"] != "http":
            await self.app(scope, receive, send)
            return
        if scope["path"] == "/middleware":
            await send(
                {
                    "type": "http.response.start",
                    "status": 200,
                    "headers": [(b"content-type", b"text/html")],
                }
            )

            await send(
                {"type": "http.response.body", "body": b"OK", "more_body": False}
            )
        else:
            await self.app(scope, receive, send)

The middleware shown above will edit the response at ‘/middleware’, i.e., no matter what the response is in that path, the middleware will return “OK” with a status of 200.

Note

You should reconsider if you really need a middleware before using one. Maybe you can work without one.