mcp: fix cancellation for HTTP transport #293
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In modelcontextprotocol#202, I added the checkRequest helper to validate incoming requests, and invoked it in the stremable transports to preemptively reject invalid HTTP requests, so that a jsonrpc error could be translated to an HTTP error. However, this introduced a bug: since cancellation was handled in the jsonrpc2 layer, we never had to validate it in the mcp layer, and therefore never added methodInfo. As a result, it was reported as an invalid request in the http layer. Add a test, and a fix. The simplest fix was to create stubs that are placeholders for cancellation. This was discovered in the course of investigating modelcontextprotocol#285.
samthanawalla
approved these changes
Aug 14, 2025
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In #202, I added the checkRequest helper to validate incoming requests, and invoked it in the stremable transports to preemptively reject invalid HTTP requests, so that a jsonrpc error could be translated to an HTTP error.
However, this introduced a bug: since cancellation was handled in the jsonrpc2 layer, we never had to validate it in the mcp layer, and therefore never added methodInfo. As a result, it was reported as an invalid request in the http layer.
Add a test, and a fix. The simplest fix was to create stubs that are placeholders for cancellation.
This was discovered in the course of investigating #285.