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feat: add closeStandaloneSSEStream for GET stream polling (#1203)

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Felix Weinberger 2025-12-01 17:01:20 +00:00 • committed by GitHub
commit 4b651b8fe1
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1 changed files with 310 additions and 16 deletions
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30
src/server/streamableHttp.ts
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@ -651,13 +651,17 @@ export class StreamableHTTPServerTransport implements Transport {
for (const message of messages) {
// Build closeSSEStream callback for requests when eventStore is configured
let closeSSEStream: (() => void) | undefined;
let closeStandaloneSSEStream: (() => void) | undefined;
if (isJSONRPCRequest(message) && this._eventStore) {
closeSSEStream = () => {
this.closeSSEStream(message.id);
};
closeStandaloneSSEStream = () => {
this.closeStandaloneSSEStream();
};
}
this.onmessage?.(message, { authInfo, requestInfo, closeSSEStream });
this.onmessage?.(message, { authInfo, requestInfo, closeSSEStream, closeStandaloneSSEStream });
}
// The server SHOULD NOT close the SSE stream before sending all JSON-RPC responses
// This will be handled by the send() method when responses are ready
@ -814,6 +818,18 @@ export class StreamableHTTPServerTransport implements Transport {
}
}
/**
* Close the standalone GET SSE stream, triggering client reconnection.
* Use this to implement polling behavior for server-initiated notifications.
*/
closeStandaloneSSEStream(): void {
const stream = this._streamMapping.get(this._standaloneSseStreamId);
if (stream) {
stream.end();
this._streamMapping.delete(this._standaloneSseStreamId);
}
}
async send(message: JSONRPCMessage, options?: { relatedRequestId?: RequestId }): Promise<void> {
let requestId = options?.relatedRequestId;
if (isJSONRPCResponse(message) || isJSONRPCError(message)) {
@ -829,19 +845,21 @@ export class StreamableHTTPServerTransport implements Transport {
if (isJSONRPCResponse(message) || isJSONRPCError(message)) {
throw new Error('Cannot send a response on a standalone SSE stream unless resuming a previous client request');
}
const standaloneSse = this._streamMapping.get(this._standaloneSseStreamId);
if (standaloneSse === undefined) {
// The spec says the server MAY send messages on the stream, so it's ok to discard if no stream
return;
}
// Generate and store event ID if event store is provided
// Store even if stream is disconnected so events can be replayed on reconnect
let eventId: string | undefined;
if (this._eventStore) {
// Stores the event and gets the generated event ID
eventId = await this._eventStore.storeEvent(this._standaloneSseStreamId, message);
}
const standaloneSse = this._streamMapping.get(this._standaloneSseStreamId);
if (standaloneSse === undefined) {
// Stream is disconnected - event is stored for replay, nothing more to do
return;
}
// Send the message to the standalone SSE stream
this.writeSSEEvent(standaloneSse, message, eventId);
return;