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fix: accept 200 with empty body in response to notifications in addition to 202 (#849)

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Alex Hancock 2026-05-14 14:52:11 -04:00 • committed by GitHub
commit cc66e3091e
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14
crates/rmcp/src/transport/common/reqwest/streamable_http_client.rs
View file

@ -178,11 +178,25 @@ impl StreamableHttpClient for reqwest::Client {
.headers()
.get(reqwest::header::CONTENT_TYPE)
.map(|ct| String::from_utf8_lossy(ct.as_bytes()).to_string());
let content_length = response.content_length();
let session_id = response
.headers()
.get(HEADER_SESSION_ID)
.and_then(|v| v.to_str().ok())
.map(|s| s.to_string());
// Spec requires 202 Accepted for these, but some servers return an empty 200.
// Treat empty success responses as equivalent to Accepted.
if status.is_success()
&& content_length == Some(0)
&& matches!(
message,
ClientJsonRpcMessage::Notification(_)
| ClientJsonRpcMessage::Response(_)
| ClientJsonRpcMessage::Error(_)
)
{
return Ok(StreamableHttpPostResponse::Accepted);
}
// Non-success responses may carry valid JSON-RPC error payloads that
// should be surfaced as McpError rather than lost in TransportSend.
if !status.is_success() {

17
crates/rmcp/src/transport/common/unix_socket.rs
View file

@ -257,12 +257,29 @@ impl StreamableHttpClient for UnixSocketHttpClient {
}
let content_type = response.headers().get(http::header::CONTENT_TYPE).cloned();
let content_length = response
.headers()
.get(http::header::CONTENT_LENGTH)
.and_then(|v| v.to_str().ok())
.and_then(|v| v.parse::<u64>().ok());
let session_id = response
.headers()
.get(HEADER_SESSION_ID)
.and_then(|v| v.to_str().ok())
.map(|s| s.to_string());
if status.is_success()
&& content_length == Some(0)
&& matches!(
message,
ClientJsonRpcMessage::Notification(_)
| ClientJsonRpcMessage::Response(_)
| ClientJsonRpcMessage::Error(_)
)
{
return Ok(StreamableHttpPostResponse::Accepted);
}
match content_type {
Some(ref ct) if ct.as_bytes().starts_with(EVENT_STREAM_MIME_TYPE.as_bytes()) => {
let sse_stream = SseStream::new(response.into_body()).boxed();