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

fix(client): preserve custom Accept headers in StreamableHTTPClientTransport (#1655)

Browse source 
Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com>
Co-authored-by: Felix Weinberger <fweinberger@anthropic.com>
This commit is contained in:
Niels Kaspers 2026-04-02 15:52:53 +03:00 • committed by GitHub
commit 1eb31236e7
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
1 changed files with 106 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

93
packages/client/test/client/streamableHttp.test.ts
View file

@ -628,6 +628,99 @@ describe('StreamableHTTPClientTransport', () => {
expect((actualReqInit.headers as Headers).get('x-custom-header')).toBe('CustomValue');
});
it('should append custom Accept header to required types on POST requests', async () => {
transport = new StreamableHTTPClientTransport(new URL('http://localhost:1234/mcp'), {
requestInit: {
headers: {
Accept: 'application/vnd.example.v1+json'
}
}
});
let actualReqInit: RequestInit = {};
(globalThis.fetch as Mock).mockImplementation(async (_url, reqInit) => {
actualReqInit = reqInit;
return new Response(JSON.stringify({ jsonrpc: '2.0', result: {} }), {
status: 200,
headers: { 'content-type': 'application/json' }
});
});
await transport.start();
await transport.send({ jsonrpc: '2.0', method: 'test', params: {} } as JSONRPCMessage);
expect((actualReqInit.headers as Headers).get('accept')).toBe(
'application/vnd.example.v1+json, application/json, text/event-stream'
);
});
it('should append custom Accept header to required types on GET SSE requests', async () => {
transport = new StreamableHTTPClientTransport(new URL('http://localhost:1234/mcp'), {
requestInit: {
headers: {
Accept: 'application/json'
}
}
});
let actualReqInit: RequestInit = {};
(globalThis.fetch as Mock).mockImplementation(async (_url, reqInit) => {
actualReqInit = reqInit;
return new Response(null, { status: 200, headers: { 'content-type': 'text/event-stream' } });
});
await transport.start();
await transport['_startOrAuthSse']({});
expect((actualReqInit.headers as Headers).get('accept')).toBe('application/json, text/event-stream');
});
it('should set default Accept header when none provided', async () => {
transport = new StreamableHTTPClientTransport(new URL('http://localhost:1234/mcp'));
let actualReqInit: RequestInit = {};
(globalThis.fetch as Mock).mockImplementation(async (_url, reqInit) => {
actualReqInit = reqInit;
return new Response(JSON.stringify({ jsonrpc: '2.0', result: {} }), {
status: 200,
headers: { 'content-type': 'application/json' }
});
});
await transport.start();
await transport.send({ jsonrpc: '2.0', method: 'test', params: {} } as JSONRPCMessage);
expect((actualReqInit.headers as Headers).get('accept')).toBe('application/json, text/event-stream');
});
it('should not duplicate Accept media types when user-provided value overlaps required types', async () => {
transport = new StreamableHTTPClientTransport(new URL('http://localhost:1234/mcp'), {
requestInit: {
headers: {
Accept: 'application/json'
}
}
});
let actualReqInit: RequestInit = {};
(globalThis.fetch as Mock).mockImplementation(async (_url, reqInit) => {
actualReqInit = reqInit;
return new Response(JSON.stringify({ jsonrpc: '2.0', result: {} }), {
status: 200,
headers: { 'content-type': 'application/json' }
});
});
await transport.start();
await transport.send({ jsonrpc: '2.0', method: 'test', params: {} } as JSONRPCMessage);
expect((actualReqInit.headers as Headers).get('accept')).toBe('application/json, text/event-stream');
});
it('should have exponential backoff with configurable maxRetries', () => {
// This test verifies the maxRetries and backoff calculation directly