mcp_transcoder: add sse server response support.#45374
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Signed-off-by: Yilin Guo <guoyilin@google.com>
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CC @envoyproxy/api-shepherds: Your approval is needed for changes made to |
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/gemini review cc @paulhong01 |
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Code Review
This pull request introduces support for Server-Sent Events (SSE) responses in the MCP JSON-RPC REST bridge filter. It adds an SseResponseExtractor to parse incoming text/event-stream chunks on the fly and wrap completed event payloads into distinct text items within the JSON-RPC content array. The review feedback highlights two critical robustness and security concerns: first, nlohmann::json::dump() could throw an exception and crash Envoy if it encounters invalid UTF-8 in the untrusted upstream payload, which should be mitigated by using a safe error-handling replacement strategy; second, the unbounded buffering of incomplete SSE events poses a memory exhaustion (DoS) risk, necessitating a maximum buffer size limit.
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Signed-off-by: Yilin Guo <guoyilin@google.com>
Signed-off-by: Yilin Guo <guoyilin@google.com>
Signed-off-by: Yilin Guo <guoyilin@google.com>
3 participants
Commit Message: mcp_transcoder: add sse server response support.
Additional Description:
This PR introduces Server-Sent Events (SSE) server response support to the MCP JSON REST bridge filter. When the upstream server responds with a
text/event-streamcontent type, the filter will now parse the stream and wrap each extracted complete event payload into a distinct text content item within the JSON-RPCcontentarray on the fly.Key Changes:
SseResponseExtractor: Introducedsse_response_extractor.ccand its header to process incoming chunks of an SSE stream and return completed event payloads.McpJsonRestBridgeFilter: Modified the encoding path to check for thetext/event-streamcontent type. It now delegates chunk processing to the new SSE extractor and formats the results into the JSON-RPC streaming envelope.sse_response_extractor_test.ccto verify the handling of single/multiple events, multiline data, incomplete chunked events, and CRLF line endings. Also addedToolsCallSseStreamingTranscodingto integration tests.Risk Level: Low
Testing: Unit and Integration tests.
Docs Changes: N/A
Release Notes: N/A
Platform Specific Features: N/A