modelcontextprotocol/rust-sdk
Watch
1
0
Fork
You've already forked rust-sdk
 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions 1

Implement SEP-1699: Support SSE Polling via Server-Side Disconnect (#604)

Browse source 
* feat: implement SEP-1699 SSE polling via server-side disconnect

* test: add tests for priming behavior on stream start and close
This commit is contained in:
Dale Seo 2026-01-09 13:22:57 -05:00 • committed by GitHub
commit 971c64c31f
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
1 changed files with 397 additions and 22 deletions
Download patch file Download diff file Expand all files Collapse all files

24
crates/rmcp/src/transport/common/server_side_http.rs
View file

@ -59,8 +59,15 @@ impl sse_stream::Timer for TokioTimer {
#[derive(Debug, Clone)]
pub struct ServerSseMessage {
/// The event ID for this message. When set, clients can use this ID
/// with the `Last-Event-ID` header to resume the stream from this point.
pub event_id: Option<String>,
pub message: Arc<ServerJsonRpcMessage>,
/// The JSON-RPC message content. Set to `None` for priming events.
/// See [SEP-1699](https://github.com/modelcontextprotocol/modelcontextprotocol/issues/1699)
pub message: Option<Arc<ServerJsonRpcMessage>>,
/// The retry interval hint for clients. Clients should wait this duration
/// before attempting to reconnect. This maps to the SSE `retry:` field.
pub retry: Option<Duration>,
}
pub(crate) fn sse_stream_response(
@ -71,9 +78,20 @@ pub(crate) fn sse_stream_response(
use futures::StreamExt;
let stream = stream
.map(|message| {
let data = serde_json::to_string(&message.message).expect("valid message");
let mut sse = Sse::default().data(data);
let mut sse = if let Some(ref msg) = message.message {
let data = serde_json::to_string(msg.as_ref()).expect("valid message");
Sse::default().data(data)
} else {
// Priming event: empty data per SEP-1699 (just "data:\n")
Sse::default().data("")
};
sse.id = message.event_id;
if let Some(retry) = message.retry {
sse.retry = Some(retry.as_millis() as u64);
}
Result::<Sse, Infallible>::Ok(sse)
})
.take_until(async move { ct.cancelled().await });