Skip to content

Continue OAuth discovery on non-JSON metadata responses #2171

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
FU-max-boop wants to merge 1 commit into
base: main
Choose a base branch
from
+26 −3
Open

Continue OAuth discovery on non-JSON metadata responses #2171

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
5 changes: 5 additions & 0 deletions .changeset/non-json-oauth-discovery.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,5 @@
---
'@modelcontextprotocol/client': patch
---

Continue authorization server metadata discovery when a candidate well-known endpoint returns HTTP 200 with a non-JSON body, allowing fallback to the next OAuth/OIDC discovery URL.
12 changes: 9 additions & 3 deletions packages/client/src/client/auth.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1262,10 +1262,16 @@ export async function discoverAuthorizationServerMetadata(
);
}

let metadata: unknown;
try {
metadata = await response.json();
} catch {
await response.body?.cancel().catch(() => {});
continue;
}

// Parse and validate based on type
return type === 'oauth'
? OAuthMetadataSchema.parse(await response.json())
: OpenIdProviderDiscoveryMetadataSchema.parse(await response.json());
return type === 'oauth' ? OAuthMetadataSchema.parse(metadata) : OpenIdProviderDiscoveryMetadataSchema.parse(metadata);
}

return undefined;
Expand Down
12 changes: 12 additions & 0 deletions packages/client/test/client/auth.test.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -945,6 +945,18 @@ describe('OAuth Authorization', () => {
expect(mockFetch).toHaveBeenCalledTimes(2);
});

it('continues when an authorization metadata endpoint returns non-JSON', async () => {
mockFetch.mockResolvedValueOnce(new Response('<html>not metadata</html>', { status: 200 }));
mockFetch.mockResolvedValueOnce(Response.json(validOpenIdMetadata, { status: 200 }));

const metadata = await discoverAuthorizationServerMetadata('https://auth.example.com/tenant1');

expect(metadata).toEqual(validOpenIdMetadata);
expect(mockFetch).toHaveBeenCalledTimes(2);
expect(mockFetch.mock.calls[0]![0].toString()).toBe('https://auth.example.com/.well-known/oauth-authorization-server/tenant1');
expect(mockFetch.mock.calls[1]![0].toString()).toBe('https://auth.example.com/.well-known/openid-configuration/tenant1');
});

it('throws on non-502 5xx errors', async () => {
mockFetch.mockResolvedValueOnce({
ok: false,
Expand Down
Loading