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

Streamable HTTP: drain SSE frames until the initialize response, ignoring early notifications to prevent handshake timeouts (#467)

Browse source 
Co-authored-by: Min Wei <minwei@microsoft.com>
This commit is contained in:
Min Wei 2025-10-10 03:49:22 -07:00 • committed by GitHub
commit aeeff75e12
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
1 changed files with 23 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

33
crates/rmcp/src/transport/streamable_http_client.rs
View file

@ -5,6 +5,7 @@ pub use sse_stream::Error as SseError;
use sse_stream::Sse; use sse_stream::Sse;
use thiserror::Error; use thiserror::Error;
use tokio_util::sync::CancellationToken; use tokio_util::sync::CancellationToken;
use tracing::debug;
use super::common::client_side_sse::{ExponentialBackoff, SseRetryPolicy, SseStreamReconnect}; use super::common::client_side_sse::{ExponentialBackoff, SseRetryPolicy, SseStreamReconnect};
use crate::{ use crate::{
@ -90,16 +91,28 @@ impl StreamableHttpPostResponse {
match self { match self {
Self::Json(message, session_id) => Ok((message, session_id)), Self::Json(message, session_id) => Ok((message, session_id)),
Self::Sse(mut stream, session_id) => { Self::Sse(mut stream, session_id) => {
let event = while let Some(event) = stream.next().await {
stream let event = event?;
.next() let payload = event.data.unwrap_or_default();
.await if payload.trim().is_empty() {
.ok_or(StreamableHttpError::UnexpectedServerResponse( continue;
"empty sse stream".into(), }
))??;
let message: ServerJsonRpcMessage = let message: ServerJsonRpcMessage = serde_json::from_str(&payload)?;
serde_json::from_str(&event.data.unwrap_or_default())?;
Ok((message, session_id)) if matches!(message, ServerJsonRpcMessage::Response(_)) {
return Ok((message, session_id));
}
debug!(
?message,
"received message before initialize response; continuing to drain stream"
);
}
Err(StreamableHttpError::UnexpectedServerResponse(
"empty sse stream".into(),
))
} }
_ => Err(StreamableHttpError::UnexpectedServerResponse( _ => Err(StreamableHttpError::UnexpectedServerResponse(
"expect initialized, accepted".into(), "expect initialized, accepted".into(),