async-graphql-poem 7.2.1

use std::{io::Error as IoError, str::FromStr, time::Duration};

use async_graphql::{
    Data, Executor,
    http::{
        ALL_WEBSOCKET_PROTOCOLS, DefaultOnConnInitType, DefaultOnPingType, WebSocketProtocols,
        WsMessage, default_on_connection_init, default_on_ping,
    },
};
use futures_util::{
    Future, Sink, SinkExt, Stream, StreamExt,
    future::{self},
    stream::{SplitSink, SplitStream},
};
use poem::{
    Endpoint, Error, FromRequest, IntoResponse, Request, RequestBody, Response, Result,
    http::StatusCode,
    web::websocket::{Message, WebSocket},
};

/// A GraphQL protocol extractor.
///
/// It extract GraphQL protocol from `SEC_WEBSOCKET_PROTOCOL` header.
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub struct GraphQLProtocol(pub WebSocketProtocols);

impl<'a> FromRequest<'a> for GraphQLProtocol {
    async fn from_request(req: &'a Request, _body: &mut RequestBody) -> Result<Self> {
        req.headers()
            .get(http::header::SEC_WEBSOCKET_PROTOCOL)
            .and_then(|value| value.to_str().ok())
            .and_then(|protocols| {
                protocols
                    .split(',')
                    .find_map(|p| WebSocketProtocols::from_str(p.trim()).ok())
            })
            .map(Self)
            .ok_or_else(|| Error::from_status(StatusCode::BAD_REQUEST))
    }
}

/// A GraphQL subscription endpoint.
///
/// # Example
///
/// ```
/// use async_graphql::{EmptyMutation, Object, Schema, Subscription};
/// use async_graphql_poem::GraphQLSubscription;
/// use futures_util::{Stream, stream};
/// use poem::{Route, get};
///
/// struct Query;
///
/// #[Object]
/// impl Query {
///     async fn value(&self) -> i32 {
///         100
///     }
/// }
///
/// struct Subscription;
///
/// #[Subscription]
/// impl Subscription {
///     async fn values(&self) -> impl Stream<Item = i32> {
///         stream::iter(vec![1, 2, 3, 4, 5])
///     }
/// }
///
/// type MySchema = Schema<Query, EmptyMutation, Subscription>;
///
/// let schema = Schema::new(Query, EmptyMutation, Subscription);
/// let app = Route::new().at("/ws", get(GraphQLSubscription::new(schema)));
/// ```
pub struct GraphQLSubscription<E> {
    executor: E,
}

impl<E> GraphQLSubscription<E> {
    /// Create a GraphQL subscription endpoint.
    pub fn new(executor: E) -> Self {
        Self { executor }
    }
}

impl<E> Endpoint for GraphQLSubscription<E>
where
    E: Executor,
{
    type Output = Response;

    async fn call(&self, req: Request) -> Result<Self::Output> {
        let (req, mut body) = req.split();
        let websocket = WebSocket::from_request(&req, &mut body).await?;
        let protocol = GraphQLProtocol::from_request(&req, &mut body).await?;
        let executor = self.executor.clone();

        let resp = websocket
            .protocols(ALL_WEBSOCKET_PROTOCOLS)
            .on_upgrade(move |stream| GraphQLWebSocket::new(stream, executor, protocol).serve())
            .into_response();
        Ok(resp)
    }
}

/// A Websocket connection for GraphQL subscription.
pub struct GraphQLWebSocket<Sink, Stream, E, OnConnInit, OnPing> {
    sink: Sink,
    stream: Stream,
    executor: E,
    data: Data,
    on_connection_init: OnConnInit,
    on_ping: OnPing,
    protocol: GraphQLProtocol,
    keepalive_timeout: Option<Duration>,
}

impl<S, E>
    GraphQLWebSocket<
        SplitSink<S, Message>,
        SplitStream<S>,
        E,
        DefaultOnConnInitType,
        DefaultOnPingType,
    >
where
    S: Stream<Item = Result<Message, IoError>> + Sink<Message>,
    E: Executor,
{
    /// Create a [`GraphQLWebSocket`] object.
    pub fn new(stream: S, executor: E, protocol: GraphQLProtocol) -> Self {
        let (sink, stream) = stream.split();
        GraphQLWebSocket::new_with_pair(sink, stream, executor, protocol)
    }
}

impl<Sink, Stream, E> GraphQLWebSocket<Sink, Stream, E, DefaultOnConnInitType, DefaultOnPingType>
where
    Sink: futures_util::sink::Sink<Message>,
    Stream: futures_util::stream::Stream<Item = Result<Message, IoError>>,
    E: Executor,
{
    /// Create a [`GraphQLWebSocket`] object with sink and stream objects.
    pub fn new_with_pair(
        sink: Sink,
        stream: Stream,
        executor: E,
        protocol: GraphQLProtocol,
    ) -> Self {
        GraphQLWebSocket {
            sink,
            stream,
            executor,
            data: Data::default(),
            on_connection_init: default_on_connection_init,
            on_ping: default_on_ping,
            protocol,
            keepalive_timeout: None,
        }
    }
}

impl<Sink, Stream, E, OnConnInit, OnConnInitFut, OnPing, OnPingFut>
    GraphQLWebSocket<Sink, Stream, E, OnConnInit, OnPing>
where
    Sink: futures_util::sink::Sink<Message>,
    Stream: futures_util::stream::Stream<Item = Result<Message, IoError>>,
    E: Executor,
    OnConnInit: FnOnce(serde_json::Value) -> OnConnInitFut + Send + 'static,
    OnConnInitFut: Future<Output = async_graphql::Result<Data>> + Send + 'static,
    OnPing: FnOnce(Option<&Data>, Option<serde_json::Value>) -> OnPingFut + Clone + Send + 'static,
    OnPingFut: Future<Output = async_graphql::Result<Option<serde_json::Value>>> + Send + 'static,
{
    /// Specify the initial subscription context data, usually you can get
    /// something from the incoming request to create it.
    #[must_use]
    pub fn with_data(self, data: Data) -> Self {
        Self { data, ..self }
    }

    /// Specify a callback function to be called when the connection is
    /// initialized.
    ///
    /// You can get something from the payload of [`GQL_CONNECTION_INIT` message](https://github.com/apollographql/subscriptions-transport-ws/blob/master/PROTOCOL.md#gql_connection_init) to create [`Data`].
    /// The data returned by this callback function will be merged with the data
    /// specified by [`with_data`].
    #[must_use]
    pub fn on_connection_init<F, R>(
        self,
        callback: F,
    ) -> GraphQLWebSocket<Sink, Stream, E, F, OnPing>
    where
        F: FnOnce(serde_json::Value) -> R + Send + 'static,
        R: Future<Output = async_graphql::Result<Data>> + Send + 'static,
    {
        GraphQLWebSocket {
            sink: self.sink,
            stream: self.stream,
            executor: self.executor,
            data: self.data,
            on_connection_init: callback,
            on_ping: self.on_ping,
            protocol: self.protocol,
            keepalive_timeout: self.keepalive_timeout,
        }
    }

    /// Specify a ping callback function.
    ///
    /// This function if present, will be called with the data sent by the
    /// client in the [`Ping` message](https://github.com/enisdenjo/graphql-ws/blob/master/PROTOCOL.md#ping).
    ///
    /// The function should return the data to be sent in the [`Pong` message](https://github.com/enisdenjo/graphql-ws/blob/master/PROTOCOL.md#pong).
    ///
    /// NOTE: Only used for the `graphql-ws` protocol.
    #[must_use]
    pub fn on_ping<F, R>(self, callback: F) -> GraphQLWebSocket<Sink, Stream, E, OnConnInit, F>
    where
        F: FnOnce(Option<&Data>, Option<serde_json::Value>) -> R + Clone + Send + 'static,
        R: Future<Output = async_graphql::Result<Option<serde_json::Value>>> + Send + 'static,
    {
        GraphQLWebSocket {
            sink: self.sink,
            stream: self.stream,
            executor: self.executor,
            data: self.data,
            on_connection_init: self.on_connection_init,
            on_ping: callback,
            protocol: self.protocol,
            keepalive_timeout: self.keepalive_timeout,
        }
    }

    /// Sets a timeout for receiving an acknowledgement of the keep-alive ping.
    ///
    /// If the ping is not acknowledged within the timeout, the connection will
    /// be closed.
    ///
    /// NOTE: Only used for the `graphql-ws` protocol.
    #[must_use]
    pub fn keepalive_timeout(self, timeout: impl Into<Option<Duration>>) -> Self {
        Self {
            keepalive_timeout: timeout.into(),
            ..self
        }
    }

    /// Processing subscription requests.
    pub async fn serve(self) {
        let stream = self
            .stream
            .take_while(|res| future::ready(res.is_ok()))
            .map(Result::unwrap)
            .filter_map(|msg| {
                if msg.is_text() || msg.is_binary() {
                    future::ready(Some(msg))
                } else {
                    future::ready(None)
                }
            })
            .map(Message::into_bytes);

        let stream =
            async_graphql::http::WebSocket::new(self.executor.clone(), stream, self.protocol.0)
                .connection_data(self.data)
                .on_connection_init(self.on_connection_init)
                .on_ping(self.on_ping.clone())
                .keepalive_timeout(self.keepalive_timeout)
                .map(|msg| match msg {
                    WsMessage::Text(text) => Message::text(text),
                    WsMessage::Close(code, status) => Message::close_with(code, status),
                });

        let sink = self.sink;
        futures_util::pin_mut!(stream, sink);

        while let Some(item) = stream.next().await {
            if sink.send(item).await.is_err() {
                break;
            }
        }
    }
}