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fix: cancel disconnected upstream streams #60

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Merged
orangeboyChen merged 1 commit into from
Jul 28, 2026
Merged

fix: cancel disconnected upstream streams #60

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24 changes: 22 additions & 2 deletions lib/server/proxy/anthropic.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -813,10 +813,17 @@ const mapOpenAIStreamToAnthropicSSE = (
});
};

let reader: ReadableStreamDefaultReader<Uint8Array> | null = null;
let cancelled = false;
const releaseReader = (): void => {
reader?.releaseLock();
reader = null;
};
const stream = new ReadableStream<Uint8Array>({
start: (ctrl) => {
controller = ctrl;
const reader = upstreamResponse.body!.getReader();
const upstreamReader = upstreamResponse.body!.getReader();
reader = upstreamReader;
let buffer = '';

const flushFrames = (frames: string[]): void => {
Expand Down Expand Up @@ -845,14 +852,19 @@ const mapOpenAIStreamToAnthropicSSE = (
};

const pump = async (): Promise<void> => {
const { done, value } = await reader.read();
const { done, value } = await upstreamReader.read();

if (cancelled) {
return;
}

if (done) {
if (buffer.trim()) {
flushFrames([buffer]);
}

finalize();
releaseReader();
controller.close();
return;
}
Expand All @@ -866,6 +878,14 @@ const mapOpenAIStreamToAnthropicSSE = (

void pump();
},
async cancel(reason): Promise<void> {
cancelled = true;
try {
await reader?.cancel(reason);
} finally {
releaseReader();
}
},
});

return new Response(stream, {
Expand Down
48 changes: 44 additions & 4 deletions lib/server/proxy/codebuddy.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -222,9 +222,16 @@ const trackResponsesUsageStream = async ({

const decoder = new TextDecoder();
const encoder = new TextEncoder();
let reader: ReadableStreamDefaultReader<Uint8Array> | null = null;
let cancelled = false;
const releaseReader = (): void => {
reader?.releaseLock();
reader = null;
};
const stream = new ReadableStream<Uint8Array>({
start: (controller) => {
const reader = upstreamResponse.body!.getReader();
const upstreamReader = upstreamResponse.body!.getReader();
reader = upstreamReader;
let buffer = '';
let latestUsage = fallbackUsage;

Expand All @@ -250,7 +257,11 @@ const trackResponsesUsageStream = async ({
};

const pump = async (): Promise<void> => {
const { done, value } = await reader.read();
const { done, value } = await upstreamReader.read();

if (cancelled) {
return;
}

if (done) {
if (buffer) {
Expand All @@ -264,6 +275,7 @@ const trackResponsesUsageStream = async ({
route: '/v1/responses',
usage: latestUsage,
});
releaseReader();
controller.close();
return;
}
Expand All @@ -283,6 +295,14 @@ const trackResponsesUsageStream = async ({

void pump();
},
async cancel(reason): Promise<void> {
cancelled = true;
try {
await reader?.cancel(reason);
} finally {
releaseReader();
}
},
});

return new Response(stream, {
Expand Down Expand Up @@ -897,10 +917,17 @@ const normalizeStreamingResponse = ({
mappings: new Map<string, ToolCallMapping>(),
nextIndex: 0,
};
let reader: ReadableStreamDefaultReader<Uint8Array> | null = null;
let cancelled = false;
const releaseReader = (): void => {
reader?.releaseLock();
reader = null;
};

const stream = new ReadableStream<Uint8Array>({
start: (controller) => {
const reader = upstreamResponse.body!.getReader();
const upstreamReader = upstreamResponse.body!.getReader();
reader = upstreamReader;
let buffer = '';
let latestUsage: unknown = null;

Expand Down Expand Up @@ -938,7 +965,11 @@ const normalizeStreamingResponse = ({
};

const pump = async (): Promise<void> => {
const { done, value } = await reader.read();
const { done, value } = await upstreamReader.read();

if (cancelled) {
return;
}

if (done) {
if (buffer.trim()) {
Expand All @@ -952,6 +983,7 @@ const normalizeStreamingResponse = ({
usage: latestUsage,
});

releaseReader();
controller.close();
return;
}
Expand All @@ -965,6 +997,14 @@ const normalizeStreamingResponse = ({

void pump();
},
async cancel(reason): Promise<void> {
cancelled = true;
try {
await reader?.cancel(reason);
} finally {
releaseReader();
}
},
});

return new Response(stream, {
Expand Down
24 changes: 22 additions & 2 deletions lib/server/proxy/responses.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -1011,12 +1011,19 @@ const createResponsesEventStream = async (
const toolCallStates = new Map<string, StreamingToolCallState>();
const toolCallStateKeys = new Map<string, string>();
let nextToolCallOutputIndex = 1;
let reader: ReadableStreamDefaultReader<Uint8Array> | null = null;
let cancelled = false;
const releaseReader = (): void => {
reader?.releaseLock();
reader = null;
};

const stream = new ReadableStream<Uint8Array>({
start: (controller) => {
const encoder = new TextEncoder();
const decoder = new TextDecoder();
const reader = upstreamResponse.body!.getReader();
const upstreamReader = upstreamResponse.body!.getReader();
reader = upstreamReader;
let buffer = '';

const enqueueEvent = (payload: Record<string, unknown>): void => {
Expand Down Expand Up @@ -1129,7 +1136,11 @@ const createResponsesEventStream = async (
};

const pump = async (): Promise<void> => {
const { done, value } = await reader.read();
const { done, value } = await upstreamReader.read();

if (cancelled) {
return;
}

if (done) {
const transcriptToolCalls =
Expand Down Expand Up @@ -1221,6 +1232,7 @@ const createResponsesEventStream = async (
},
});
controller.enqueue(encoder.encode('data: [DONE]\n\n'));
releaseReader();
controller.close();
return;
}
Expand Down Expand Up @@ -1353,6 +1365,14 @@ const createResponsesEventStream = async (

void pump();
},
async cancel(reason): Promise<void> {
cancelled = true;
try {
await reader?.cancel(reason);
} finally {
releaseReader();
}
},
});

return new Response(stream, {
Expand Down
30 changes: 30 additions & 0 deletions tests/server/anthropic.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -565,6 +565,36 @@ describe('anthropic messages api', () => {
expect(text).toContain('event: message_stop');
});

it('cancels the upstream Chat stream when an Anthropic client disconnects', async () => {
const cancel = vi.fn();
vi.spyOn(globalThis, 'fetch').mockResolvedValueOnce(
new Response(
new ReadableStream<Uint8Array>({
cancel,
}),
{
headers: {
'Content-Type': 'text/event-stream; charset=utf-8',
},
},
),
);

const response = await handleMessagesRequest(
makeNextRequest('http://localhost/v1/messages', { method: 'POST' }),
{
model: 'claude-sonnet-4.6',
max_tokens: 1024,
stream: true,
messages: [{ role: 'user', content: 'cancel me' }],
},
);

await response.body?.cancel('client disconnected');

expect(cancel).toHaveBeenCalledWith('client disconnected');
});

it('handles streaming with tool_use blocks', async () => {
vi.spyOn(globalThis, 'fetch').mockResolvedValueOnce(
makeSseResponse([
Expand Down
50 changes: 50 additions & 0 deletions tests/server/units.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -2019,6 +2019,31 @@ describe('server units', () => {
expect(await streamResponse.text()).toContain('response.error');
});

it('cancels the upstream Chat stream when a Responses client disconnects', async () => {
const cancel = vi.fn();
vi.spyOn(globalThis, 'fetch').mockResolvedValueOnce(
new Response(
new ReadableStream<Uint8Array>({
cancel,
}),
{
headers: {
'Content-Type': 'text/event-stream; charset=utf-8',
},
},
),
);

const response = await handleResponsesRequest(
makeNextRequest('http://localhost/v1/responses', { method: 'POST' }),
{ input: 'cancel me', model: 'gpt-5.5', stream: true },
);

await response.body?.cancel('client disconnected');

expect(cancel).toHaveBeenCalledWith('client disconnected');
});

it('maps mcp tool calls back to responses mcp items', async () => {
process.env.CODEBUDDY_AUTH_MODE = 'api_key';
process.env.CODEBUDDY_API_KEY = 'cb-key';
Expand Down Expand Up @@ -2416,6 +2441,31 @@ describe('server units', () => {
});
});

it('cancels the upstream Responses stream when the client disconnects', async () => {
const cancel = vi.fn();
vi.spyOn(globalThis, 'fetch').mockResolvedValueOnce(
new Response(
new ReadableStream<Uint8Array>({
cancel,
}),
{
headers: {
'Content-Type': 'text/event-stream; charset=utf-8',
},
},
),
);

const response = await proxyResponsesUpstream(
makeNextRequest('http://localhost/v1/responses', { method: 'POST' }),
{ input: 'cancel me', model: 'gpt-5.5', stream: true },
);

await response.body?.cancel('client disconnected');

expect(cancel).toHaveBeenCalledWith('client disconnected');
});

it('covers responses passthrough header fallback, raw body passthrough, and upstream errors', async () => {
const createdCredential = await addCredential({
bearer_token: 'token-responses',
Expand Down
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