use crate::{http, Data, FieldResult, ObjectType, Request, Response, Schema, SubscriptionType};
use futures::channel::mpsc;
use futures::task::{Context, Poll};
use futures::{Future, Stream, StreamExt};
use serde::{Deserialize, Serialize};
use std::collections::{HashMap, VecDeque};
use std::pin::Pin;
use std::sync::Arc;
#[derive(Serialize, Deserialize)]
struct OperationMessage {
#[serde(rename = "type")]
ty: String,
#[serde(skip_serializing_if = "Option::is_none")]
id: Option<String>,
#[serde(skip_serializing_if = "Option::is_none")]
payload: Option<serde_json::Value>,
}
type SubscriptionStreams = HashMap<String, Pin<Box<dyn Stream<Item = Response> + Send>>>;
type HandleRequestBoxFut<'a> =
Pin<Box<dyn Future<Output = FieldResult<WSContext<'a>>> + Send + 'a>>;
type InitializerFn = Arc<dyn Fn(serde_json::Value) -> FieldResult<Data> + Send + Sync>;
pub fn create<Query, Mutation, Subscription>(
schema: &Schema<Query, Mutation, Subscription>,
) -> (mpsc::UnboundedSender<Vec<u8>>, impl Stream<Item = Vec<u8>>)
where
Query: ObjectType + Send + Sync + 'static,
Mutation: ObjectType + Send + Sync + 'static,
Subscription: SubscriptionType + Send + Sync + 'static,
{
create_with_initializer(schema, |_| Ok(Default::default()))
}
pub fn create_with_initializer<Query, Mutation, Subscription>(
schema: &Schema<Query, Mutation, Subscription>,
initializer: impl Fn(serde_json::Value) -> FieldResult<Data> + Send + Sync + 'static,
) -> (mpsc::UnboundedSender<Vec<u8>>, impl Stream<Item = Vec<u8>>)
where
Query: ObjectType + Send + Sync + 'static,
Mutation: ObjectType + Send + Sync + 'static,
Subscription: SubscriptionType + Send + Sync + 'static,
{
let schema = schema.clone();
let (tx_bytes, rx_bytes) = mpsc::unbounded();
let stream = async_stream::stream! {
let mut streams = Default::default();
let mut send_buf = Default::default();
let mut data = Arc::new(Data::default());
let mut inner_stream = SubscriptionStream {
schema: &schema,
initializer: Arc::new(initializer),
rx_bytes,
handle_request_fut: None,
ctx: Some(WSContext {
streams: &mut streams,
send_buf: &mut send_buf,
ctx_data: &mut data,
}),
};
while let Some(data) = inner_stream.next().await {
yield data;
}
};
(tx_bytes, stream)
}
struct WSContext<'a> {
streams: &'a mut SubscriptionStreams,
send_buf: &'a mut VecDeque<Vec<u8>>,
ctx_data: &'a mut Arc<Data>,
}
fn send_message<T: Serialize>(send_buf: &mut VecDeque<Vec<u8>>, msg: &T) {
if let Ok(data) = serde_json::to_vec(msg) {
send_buf.push_back(data);
}
}
#[allow(missing_docs)]
#[allow(clippy::type_complexity)]
struct SubscriptionStream<'a, Query, Mutation, Subscription> {
schema: &'a Schema<Query, Mutation, Subscription>,
initializer: InitializerFn,
rx_bytes: mpsc::UnboundedReceiver<Vec<u8>>,
handle_request_fut: Option<HandleRequestBoxFut<'a>>,
ctx: Option<WSContext<'a>>,
}
impl<'a, Query, Mutation, Subscription> Stream
for SubscriptionStream<'a, Query, Mutation, Subscription>
where
Query: ObjectType + Send + Sync + 'static,
Mutation: ObjectType + Send + Sync + 'static,
Subscription: SubscriptionType + Send + Sync + 'static,
{
type Item = Vec<u8>;
fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
let this = &mut *self;
loop {
if let Some(ctx) = &mut this.ctx {
if let Some(bytes) = ctx.send_buf.pop_front() {
return Poll::Ready(Some(bytes));
}
}
if let Some(handle_request_fut) = &mut this.handle_request_fut {
match handle_request_fut.as_mut().poll(cx) {
Poll::Ready(Ok(ctx)) => {
this.ctx = Some(ctx);
this.handle_request_fut = None;
continue;
}
Poll::Ready(Err(_)) => return Poll::Ready(None),
Poll::Pending => {}
}
} else {
match Pin::new(&mut this.rx_bytes).poll_next(cx) {
Poll::Ready(Some(data)) => {
let ctx = this.ctx.take().unwrap();
this.handle_request_fut = Some(Box::pin(handle_request(
this.schema.clone(),
this.initializer.clone(),
ctx,
data,
)));
continue;
}
Poll::Ready(None) => return Poll::Ready(None),
Poll::Pending => {}
}
}
if let Some(ctx) = &mut this.ctx {
let mut closed = Vec::new();
for (id, incoming_stream) in ctx.streams.iter_mut() {
match incoming_stream.as_mut().poll_next(cx) {
Poll::Ready(Some(res)) => {
if let Some(err) = &res.error {
closed.push(id.to_string());
send_message(
ctx.send_buf,
&OperationMessage {
ty: "error".to_string(),
id: Some(id.to_string()),
payload: Some(serde_json::to_value(err).unwrap()),
},
);
} else {
send_message(
ctx.send_buf,
&OperationMessage {
ty: "data".to_string(),
id: Some(id.to_string()),
payload: Some(serde_json::to_value(&res).unwrap()),
},
);
}
}
Poll::Ready(None) => {
closed.push(id.to_string());
send_message(
ctx.send_buf,
&OperationMessage {
ty: "complete".to_string(),
id: Some(id.to_string()),
payload: None,
},
);
}
Poll::Pending => {}
}
}
for id in closed {
ctx.streams.remove(&id);
}
if !ctx.send_buf.is_empty() {
continue;
}
}
return Poll::Pending;
}
}
}
async fn handle_request<'a, Query, Mutation, Subscription>(
schema: Schema<Query, Mutation, Subscription>,
initializer: InitializerFn,
ctx: WSContext<'a>,
data: Vec<u8>,
) -> FieldResult<WSContext<'a>>
where
Query: ObjectType + Send + Sync + 'static,
Mutation: ObjectType + Send + Sync + 'static,
Subscription: SubscriptionType + Send + Sync + 'static,
{
match serde_json::from_slice::<OperationMessage>(&data) {
Ok(msg) => match msg.ty.as_str() {
"connection_init" => {
if let Some(payload) = msg.payload {
*ctx.ctx_data = Arc::new(initializer(payload)?);
}
send_message(
ctx.send_buf,
&OperationMessage {
ty: "connection_ack".to_string(),
id: None,
payload: None,
},
);
}
"start" => {
if let (Some(id), Some(payload)) = (msg.id, msg.payload) {
if let Ok(request) = serde_json::from_value::<http::GQLRequest>(payload) {
let request = Request::from(request);
let stream = schema
.execute_stream_with_ctx_data(request, ctx.ctx_data.clone())
.boxed();
ctx.streams.insert(id, stream);
}
}
}
"stop" => {
if let Some(id) = msg.id {
if ctx.streams.remove(&id).is_some() {
send_message(
ctx.send_buf,
&OperationMessage {
ty: "complete".to_string(),
id: Some(id),
payload: None,
},
);
}
}
}
"connection_terminate" => return Err("connection_terminate".into()),
_ => return Err("Unknown op".into()),
},
Err(err) => return Err(err.into()),
}
Ok(ctx)
}