fix: add Accept-Encoding: identity to OAuth discovery fetch requests - #277
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fix: add Accept-Encoding: identity to OAuth discovery fetch requests#277clouatre wants to merge 1 commit into
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Node built-in fetch (undici) sends Accept-Encoding: gzip, deflate, br by default. Servers that honor this (e.g. mcp.atlassian.com) return gzip-compressed bodies. Both fetchAuthorizationServerMetadata and fetchProtectedResourceMetadata call response.json() on the raw bytes, causing a fatal SyntaxError before any OAuth flow begins. Add Accept-Encoding: identity to suppress compression on these two discovery requests. The --header CLI arg does not help here because custom headers are only applied to MCP transport requests, not to the upstream OAuth discovery fetch. Fixes geelen#276 Signed-off-by: Hugues Clouâtre <hugues@linux.com>
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Closing -- submitted prematurely without proper review. |
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Summary
Node's built-in
fetch(undici) sendsAccept-Encoding: gzip, deflate, brby default on every request. Servers that honor this header -- includingmcp.atlassian.com-- return gzip-compressed response bodies.fetchAuthorizationServerMetadataandfetchProtectedResourceMetadataboth callresponse.json()on the raw compressed bytes, causing a fatal crash before any OAuth flow begins:The
--headerCLI arg does not help here because custom headers are only applied to MCP transport requests, not to the upstream OAuth discovery fetches.Changes
src/lib/authorization-server-metadata.ts: addAccept-Encoding: identityto the discovery fetchsrc/lib/protected-resource-metadata.ts: same fix for consistencyTest plan
mcp-remote https://mcp.atlassian.com/v1/mcp --resource https://<org>.atlassian.net/proceeds past OAuth discovery on Node 18+Fixes #276