ntex-mqtt 0.10.1

Client and Server framework for MQTT v5 and v3.1.1 protocols
Documentation
use std::{fmt, marker::PhantomData, rc::Rc};

use ntex::codec::{Decoder, Encoder};
use ntex::io::{DispatchItem, Filter, Io, IoBoxed};
use ntex::service::{Service, ServiceFactory};
use ntex::time::{Deadline, Seconds};
use ntex::util::{select, BoxFuture, Either};

use crate::io::Dispatcher;

type ResponseItem<U> = Option<<U as Encoder>::Item>;

pub struct MqttServer<St, C, T, Codec> {
    connect: C,
    handler: Rc<T>,
    disconnect_timeout: Seconds,
    _t: PhantomData<(St, Codec)>,
}

impl<St, C, T, Codec> MqttServer<St, C, T, Codec> {
    pub(crate) fn new(connect: C, service: T, disconnect_timeout: Seconds) -> Self {
        MqttServer { connect, disconnect_timeout, handler: Rc::new(service), _t: PhantomData }
    }
}

impl<St, C, T, Codec> MqttServer<St, C, T, Codec>
where
    C: ServiceFactory<IoBoxed, Response = (IoBoxed, Codec, St, Seconds)>,
{
    async fn create_service(
        &self,
    ) -> Result<MqttHandler<St, C::Service, T, Codec>, C::InitError> {
        // create connect service and then create service impl
        Ok(MqttHandler {
            handler: self.handler.clone(),
            disconnect_timeout: self.disconnect_timeout,
            connect: self.connect.create(()).await?,
            _t: PhantomData,
        })
    }
}

impl<St, C, T, Codec> ServiceFactory<IoBoxed> for MqttServer<St, C, T, Codec>
where
    St: 'static,
    C: ServiceFactory<IoBoxed, Response = (IoBoxed, Codec, St, Seconds)> + 'static,
    C::Error: fmt::Debug,
    T: ServiceFactory<
            DispatchItem<Codec>,
            St,
            Response = ResponseItem<Codec>,
            Error = C::Error,
            InitError = C::Error,
        > + 'static,
    Codec: Decoder + Encoder + Clone + 'static,
{
    type Response = ();
    type Error = C::Error;
    type InitError = C::InitError;
    type Service = MqttHandler<St, C::Service, T, Codec>;
    type Future<'f> = BoxFuture<'f, Result<Self::Service, Self::InitError>>;

    fn create(&self, _: ()) -> Self::Future<'_> {
        Box::pin(self.create_service())
    }
}

impl<F, St, C, T, Codec> ServiceFactory<Io<F>> for MqttServer<St, C, T, Codec>
where
    F: Filter,
    St: 'static,
    C: ServiceFactory<IoBoxed, Response = (IoBoxed, Codec, St, Seconds)> + 'static,
    C::Error: fmt::Debug,
    T: ServiceFactory<
            DispatchItem<Codec>,
            St,
            Response = ResponseItem<Codec>,
            Error = C::Error,
            InitError = C::Error,
        > + 'static,
    Codec: Decoder + Encoder + Clone + 'static,
{
    type Response = ();
    type Error = C::Error;
    type InitError = C::InitError;
    type Service = MqttHandler<St, C::Service, T, Codec>;
    type Future<'f> = BoxFuture<'f, Result<Self::Service, Self::InitError>>;

    fn create(&self, _: ()) -> Self::Future<'_> {
        Box::pin(self.create_service())
    }
}

impl<St, C, T, Codec> ServiceFactory<(IoBoxed, Deadline)> for MqttServer<St, C, T, Codec>
where
    St: 'static,
    C: ServiceFactory<IoBoxed, Response = (IoBoxed, Codec, St, Seconds)> + 'static,
    C::Error: fmt::Debug,
    T: ServiceFactory<
            DispatchItem<Codec>,
            St,
            Response = ResponseItem<Codec>,
            Error = C::Error,
            InitError = C::Error,
        > + 'static,
    Codec: Decoder + Encoder + Clone + 'static,
{
    type Response = ();
    type Error = C::Error;
    type InitError = C::InitError;
    type Service = MqttHandler<St, C::Service, T, Codec>;
    type Future<'f> = BoxFuture<'f, Result<Self::Service, Self::InitError>>;

    fn create(&self, _: ()) -> Self::Future<'_> {
        Box::pin(self.create_service())
    }
}

pub struct MqttHandler<St, C, T, Codec> {
    connect: C,
    handler: Rc<T>,
    disconnect_timeout: Seconds,
    _t: PhantomData<(St, Codec)>,
}

impl<St, C, T, Codec> Service<IoBoxed> for MqttHandler<St, C, T, Codec>
where
    St: 'static,
    C: Service<IoBoxed, Response = (IoBoxed, Codec, St, Seconds)> + 'static,
    C::Error: fmt::Debug,
    T: ServiceFactory<
            DispatchItem<Codec>,
            St,
            Response = ResponseItem<Codec>,
            Error = C::Error,
            InitError = C::Error,
        > + 'static,
    Codec: Decoder + Encoder + Clone + 'static,
{
    type Response = ();
    type Error = C::Error;
    type Future<'f> = BoxFuture<'f, Result<(), Self::Error>>;

    ntex::forward_poll_ready!(connect);
    ntex::forward_poll_shutdown!(connect);

    #[inline]
    fn call(&self, req: IoBoxed) -> Self::Future<'_> {
        let handler = self.handler.clone();
        let timeout = self.disconnect_timeout;
        let handshake = self.connect.call(req);

        Box::pin(async move {
            let (io, codec, session, keepalive) = handshake.await.map_err(|e| {
                log::trace!("Connection handshake failed: {:?}", e);
                e
            })?;
            log::trace!("Connection handshake succeeded");

            let handler = handler.create(session).await?;
            log::trace!("Connection handler is created, starting dispatcher");

            Dispatcher::new(io, codec, handler)
                .keepalive_timeout(keepalive)
                .disconnect_timeout(timeout)
                .await
        })
    }
}

impl<F, St, C, T, Codec> Service<Io<F>> for MqttHandler<St, C, T, Codec>
where
    F: Filter,
    St: 'static,
    C: Service<IoBoxed, Response = (IoBoxed, Codec, St, Seconds)> + 'static,
    C::Error: fmt::Debug,
    T: ServiceFactory<
            DispatchItem<Codec>,
            St,
            Response = ResponseItem<Codec>,
            Error = C::Error,
            InitError = C::Error,
        > + 'static,
    Codec: Decoder + Encoder + Clone + 'static,
{
    type Response = ();
    type Error = C::Error;
    type Future<'f> = BoxFuture<'f, Result<(), Self::Error>>;

    ntex::forward_poll_ready!(connect);
    ntex::forward_poll_shutdown!(connect);

    #[inline]
    fn call(&self, io: Io<F>) -> Self::Future<'_> {
        Service::<IoBoxed>::call(self, IoBoxed::from(io))
    }
}

impl<St, C, T, Codec> Service<(IoBoxed, Deadline)> for MqttHandler<St, C, T, Codec>
where
    St: 'static,
    C: Service<IoBoxed, Response = (IoBoxed, Codec, St, Seconds)> + 'static,
    C::Error: fmt::Debug,
    T: ServiceFactory<
            DispatchItem<Codec>,
            St,
            Response = ResponseItem<Codec>,
            Error = C::Error,
            InitError = C::Error,
        > + 'static,
    Codec: Decoder + Encoder + Clone + 'static,
{
    type Response = ();
    type Error = C::Error;
    type Future<'f> = BoxFuture<'f, Result<(), Self::Error>>;

    ntex::forward_poll_ready!(connect);
    ntex::forward_poll_shutdown!(connect);

    #[inline]
    fn call(&self, (io, delay): (IoBoxed, Deadline)) -> Self::Future<'_> {
        let handler = self.handler.clone();
        let timeout = self.disconnect_timeout;
        let handshake = self.connect.call(io);

        Box::pin(async move {
            let (io, codec, ka, handler) = {
                let res = select(
                    delay,
                    Box::pin(async {
                        let (io, codec, st, ka) = handshake.await.map_err(|e| {
                            log::trace!("Connection handshake failed: {:?}", e);
                            e
                        })?;
                        log::trace!("Connection handshake succeeded");

                        let handler = handler.create(st).await?;
                        log::trace!("Connection handler is created, starting dispatcher");

                        Ok::<_, C::Error>((io, codec, ka, handler))
                    }),
                )
                .await;

                match res {
                    Either::Left(_) => {
                        log::warn!("Handshake timed out");
                        return Ok(());
                    }
                    Either::Right(item) => item?,
                }
            };

            Dispatcher::new(io, codec, handler)
                .keepalive_timeout(ka)
                .disconnect_timeout(timeout)
                .await
        })
    }
}