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use crate::context::Data;
use crate::http::{GQLError, GQLRequest, GQLResponse};
use crate::{
ConnectionTransport, Error, FieldError, FieldResult, ObjectType, QueryBuilder, QueryError,
QueryResponse, Result, Schema, SubscriptionStreams, SubscriptionType, Variables,
};
use serde::{Deserialize, Serialize};
use std::collections::{HashMap, VecDeque};
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>,
}
/// WebSocket transport for subscription
#[derive(Default)]
pub struct WebSocketTransport {
id_to_sid: HashMap<String, usize>,
sid_to_id: HashMap<usize, String>,
data: Arc<Data>,
init_context_data: Option<Box<dyn Fn(serde_json::Value) -> FieldResult<Data> + Send + Sync>>,
}
impl WebSocketTransport {
/// Creates a websocket transport and sets the function that converts the `payload` of the `connect_init` message to `Data`.
pub fn new<F: Fn(serde_json::Value) -> FieldResult<Data> + Send + Sync + 'static>(
init_context_data: F,
) -> Self {
WebSocketTransport {
init_context_data: Some(Box::new(init_context_data)),
..WebSocketTransport::default()
}
}
}
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);
}
}
#[async_trait::async_trait]
impl ConnectionTransport for WebSocketTransport {
type Error = FieldError;
async fn handle_request<Query, Mutation, Subscription>(
&mut self,
schema: &Schema<Query, Mutation, Subscription>,
streams: &mut SubscriptionStreams,
request: Vec<u8>,
send_buf: &mut VecDeque<Vec<u8>>,
) -> std::result::Result<(), Self::Error>
where
Query: ObjectType + Sync + Send + 'static,
Mutation: ObjectType + Sync + Send + 'static,
Subscription: SubscriptionType + Sync + Send + 'static,
{
match serde_json::from_slice::<OperationMessage>(&request) {
Ok(msg) => match msg.ty.as_str() {
"connection_init" => {
if let Some(payload) = msg.payload {
if let Some(init_context_data) = &self.init_context_data {
self.data = Arc::new(init_context_data(payload)?);
}
}
send_message(
send_buf,
&OperationMessage {
ty: "connection_ack".to_string(),
id: None,
payload: None,
},
);
Ok(())
}
"start" => {
if let (Some(id), Some(payload)) = (msg.id, msg.payload) {
if let Ok(request) = serde_json::from_value::<GQLRequest>(payload) {
let variables = request
.variables
.map(Variables::parse_from_json)
.unwrap_or_default();
match schema
.create_subscription_stream(
&request.query,
request.operation_name.as_deref(),
variables.clone(),
Some(self.data.clone()),
)
.await
{
Ok(stream) => {
let stream_id = streams.add(stream);
self.id_to_sid.insert(id.clone(), stream_id);
self.sid_to_id.insert(stream_id, id);
}
Err(Error::Query { err, .. })
if err == QueryError::NotSupported =>
{
// Is query or mutation
let mut builder =
QueryBuilder::new(&request.query).variables(variables);
if let Some(operation_name) = &request.operation_name {
builder = builder.operation_name(operation_name);
}
match builder.execute(schema).await {
Ok(resp) => {
send_message(
send_buf,
&OperationMessage {
ty: "data".to_string(),
id: Some(id.clone()),
payload: Some(
serde_json::to_value(&GQLResponse(Ok(
resp,
)))
.unwrap(),
),
},
);
send_message(
send_buf,
&OperationMessage {
ty: "complete".to_string(),
id: Some(id),
payload: None,
},
);
}
Err(err) => {
send_message(
send_buf,
&OperationMessage {
ty: "error".to_string(),
id: Some(id),
payload: Some(
serde_json::to_value(GQLError(&err))
.unwrap(),
),
},
);
}
}
}
Err(err) => {
send_message(
send_buf,
&OperationMessage {
ty: "error".to_string(),
id: Some(id),
payload: Some(
serde_json::to_value(GQLError(&err)).unwrap(),
),
},
);
}
}
}
}
Ok(())
}
"stop" => {
if let Some(id) = msg.id {
if let Some(sid) = self.id_to_sid.remove(&id) {
self.sid_to_id.remove(&sid);
streams.remove(sid);
send_message(
send_buf,
&OperationMessage {
ty: "complete".to_string(),
id: Some(id),
payload: None,
},
);
}
}
Ok(())
}
"connection_terminate" => Err("connection_terminate".into()),
_ => Err("Unknown op".into()),
},
Err(err) => Err(err.into()),
}
}
fn handle_response(&mut self, id: usize, res: Result<serde_json::Value>) -> Option<Vec<u8>> {
if let Some(id) = self.sid_to_id.get(&id) {
match res {
Ok(value) => Some(
serde_json::to_vec(&OperationMessage {
ty: "data".to_string(),
id: Some(id.clone()),
payload: Some(
serde_json::to_value(GQLResponse(Ok(QueryResponse {
data: value,
extensions: None,
cache_control: Default::default(),
})))
.unwrap(),
),
})
.unwrap(),
),
Err(err) => Some(
serde_json::to_vec(&OperationMessage {
ty: "error".to_string(),
id: Some(id.to_string()),
payload: Some(serde_json::to_value(GQLError(&err)).unwrap()),
})
.unwrap(),
),
}
} else {
None
}
}
}