async-graphql/integrations/axum/src/subscription.rs

266 lines
8.7 KiB
Rust

use std::{borrow::Cow, convert::Infallible, future::Future, str::FromStr};
use async_graphql::{
futures_util::task::{Context, Poll},
http::{WebSocketProtocols, WsMessage, ALL_WEBSOCKET_PROTOCOLS},
Data, ObjectType, Result, Schema, SubscriptionType,
};
use axum::{
body::{boxed, BoxBody, HttpBody},
extract::{
ws::{CloseFrame, Message},
FromRequest, RequestParts, WebSocketUpgrade,
},
http::{self, Request, Response, StatusCode},
response::IntoResponse,
Error,
};
use futures_util::{
future,
future::{BoxFuture, Ready},
stream::{SplitSink, SplitStream},
Sink, SinkExt, Stream, StreamExt,
};
use tower_service::Service;
/// A GraphQL protocol extractor.
///
/// It extract GraphQL protocol from `SEC_WEBSOCKET_PROTOCOL` header.
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub struct GraphQLProtocol(WebSocketProtocols);
#[async_trait::async_trait]
impl<B: Send> FromRequest<B> for GraphQLProtocol {
type Rejection = StatusCode;
async fn from_request(req: &mut RequestParts<B>) -> Result<Self, Self::Rejection> {
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(StatusCode::BAD_REQUEST)
}
}
/// A GraphQL subscription service.
pub struct GraphQLSubscription<Query, Mutation, Subscription> {
schema: Schema<Query, Mutation, Subscription>,
}
impl<Query, Mutation, Subscription> Clone for GraphQLSubscription<Query, Mutation, Subscription>
where
Query: ObjectType + 'static,
Mutation: ObjectType + 'static,
Subscription: SubscriptionType + 'static,
{
fn clone(&self) -> Self {
Self {
schema: self.schema.clone(),
}
}
}
impl<Query, Mutation, Subscription> GraphQLSubscription<Query, Mutation, Subscription>
where
Query: ObjectType + 'static,
Mutation: ObjectType + 'static,
Subscription: SubscriptionType + 'static,
{
/// Create a GraphQL subscription service.
pub fn new(schema: Schema<Query, Mutation, Subscription>) -> Self {
Self { schema }
}
}
impl<B, Query, Mutation, Subscription> Service<Request<B>>
for GraphQLSubscription<Query, Mutation, Subscription>
where
B: HttpBody + Send + 'static,
Query: ObjectType + 'static,
Mutation: ObjectType + 'static,
Subscription: SubscriptionType + 'static,
{
type Response = Response<BoxBody>;
type Error = Infallible;
type Future = BoxFuture<'static, Result<Self::Response, Self::Error>>;
fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Poll::Ready(Ok(()))
}
fn call(&mut self, req: Request<B>) -> Self::Future {
let schema = self.schema.clone();
Box::pin(async move {
let mut parts = RequestParts::new(req);
let protocol = match GraphQLProtocol::from_request(&mut parts).await {
Ok(protocol) => protocol,
Err(err) => return Ok(err.into_response().map(boxed)),
};
let upgrade = match WebSocketUpgrade::from_request(&mut parts).await {
Ok(protocol) => protocol,
Err(err) => return Ok(err.into_response().map(boxed)),
};
let schema = schema.clone();
let resp = upgrade
.protocols(ALL_WEBSOCKET_PROTOCOLS)
.on_upgrade(move |stream| GraphQLWebSocket::new(stream, schema, protocol).serve());
Ok(resp.into_response().map(boxed))
})
}
}
type DefaultOnConnInitType = fn(serde_json::Value) -> Ready<async_graphql::Result<Data>>;
fn default_on_connection_init(_: serde_json::Value) -> Ready<async_graphql::Result<Data>> {
futures_util::future::ready(Ok(Data::default()))
}
/// A Websocket connection for GraphQL subscription.
pub struct GraphQLWebSocket<Sink, Stream, Query, Mutation, Subscription, OnConnInit> {
sink: Sink,
stream: Stream,
schema: Schema<Query, Mutation, Subscription>,
data: Data,
on_connection_init: OnConnInit,
protocol: GraphQLProtocol,
}
impl<S, Query, Mutation, Subscription>
GraphQLWebSocket<
SplitSink<S, Message>,
SplitStream<S>,
Query,
Mutation,
Subscription,
DefaultOnConnInitType,
>
where
S: Stream<Item = Result<Message, Error>> + Sink<Message>,
Query: ObjectType + 'static,
Mutation: ObjectType + 'static,
Subscription: SubscriptionType + 'static,
{
/// Create a [`GraphQLWebSocket`] object.
pub fn new(
stream: S,
schema: Schema<Query, Mutation, Subscription>,
protocol: GraphQLProtocol,
) -> Self {
let (sink, stream) = stream.split();
GraphQLWebSocket::new_with_pair(sink, stream, schema, protocol)
}
}
impl<Sink, Stream, Query, Mutation, Subscription>
GraphQLWebSocket<Sink, Stream, Query, Mutation, Subscription, DefaultOnConnInitType>
where
Sink: futures_util::sink::Sink<Message>,
Stream: futures_util::stream::Stream<Item = Result<Message, Error>>,
Query: ObjectType + 'static,
Mutation: ObjectType + 'static,
Subscription: SubscriptionType + 'static,
{
/// Create a [`GraphQLWebSocket`] object with sink and stream objects.
pub fn new_with_pair(
sink: Sink,
stream: Stream,
schema: Schema<Query, Mutation, Subscription>,
protocol: GraphQLProtocol,
) -> Self {
GraphQLWebSocket {
sink,
stream,
schema,
data: Data::default(),
on_connection_init: default_on_connection_init,
protocol,
}
}
}
impl<Sink, Stream, Query, Mutation, Subscription, OnConnInit, OnConnInitFut>
GraphQLWebSocket<Sink, Stream, Query, Mutation, Subscription, OnConnInit>
where
Sink: futures_util::sink::Sink<Message>,
Stream: futures_util::stream::Stream<Item = Result<Message, Error>>,
Query: ObjectType + 'static,
Mutation: ObjectType + 'static,
Subscription: SubscriptionType + 'static,
OnConnInit: FnOnce(serde_json::Value) -> OnConnInitFut + Send + 'static,
OnConnInitFut: Future<Output = async_graphql::Result<Data>> + 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`].
pub fn on_connection_init<OnConnInit2, Fut>(
self,
callback: OnConnInit2,
) -> GraphQLWebSocket<Sink, Stream, Query, Mutation, Subscription, OnConnInit2>
where
OnConnInit2: FnOnce(serde_json::Value) -> Fut + Send + 'static,
Fut: Future<Output = async_graphql::Result<Data>> + Send + 'static,
{
GraphQLWebSocket {
sink: self.sink,
stream: self.stream,
schema: self.schema,
data: self.data,
on_connection_init: callback,
protocol: self.protocol,
}
}
/// Processing subscription requests.
pub async fn serve(self) {
let input = self
.stream
.take_while(|res| future::ready(res.is_ok()))
.map(Result::unwrap)
.filter_map(|msg| {
if let Message::Text(_) | Message::Binary(_) = msg {
future::ready(Some(msg))
} else {
future::ready(None)
}
})
.map(Message::into_data);
let stream =
async_graphql::http::WebSocket::new(self.schema.clone(), input, self.protocol.0)
.connection_data(self.data)
.on_connection_init(self.on_connection_init)
.map(|msg| match msg {
WsMessage::Text(text) => Message::Text(text),
WsMessage::Close(code, status) => Message::Close(Some(CloseFrame {
code,
reason: Cow::from(status),
})),
});
let sink = self.sink;
futures_util::pin_mut!(stream, sink);
while let Some(item) = stream.next().await {
let _ = sink.send(item).await;
}
}
}