fix(client): handle graceful SSE stream termination without error rep…#1349
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hassan123789 wants to merge 4 commits intomodelcontextprotocol:mainfrom
Open
fix(client): handle graceful SSE stream termination without error rep…#1349hassan123789 wants to merge 4 commits intomodelcontextprotocol:mainfrom
hassan123789 wants to merge 4 commits intomodelcontextprotocol:mainfrom
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…orting Fixes modelcontextprotocol#1211 When a server closes an SSE connection gracefully (e.g., due to timeout or polling), the client would incorrectly report 'TypeError: terminated' as an error. This is expected behavior for long-polling scenarios where the server periodically closes connections. This change detects graceful termination (TypeError with message 'terminated' or 'body stream') and suppresses unnecessary error reporting while still allowing the reconnection logic to proceed.
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Motivation and Context
This fixes Issue #1211 where SSE streams report
TypeError: terminatedas an error every ~5 minutes.When a server closes an SSE connection gracefully (e.g., due to timeout or long-polling), Node.js's
fetchAPI throws aTypeErrorwith message "terminated" or "body stream already read". This is expected behavior, not an error condition. The client was incorrectly reporting this to users viaonerror, causing confusion and noisy logs.How Has This Been Tested?
Breaking Changes
None. This change only suppresses unnecessary error reporting. The reconnection logic remains unchanged.
Types of changes
Checklist
Additional context
The fix detects graceful termination by checking for:
error instanceof TypeErrorerror.message === 'terminated'ORerror.message.includes('body stream')This approach is consistent with how other libraries handle this Node.js behavior. The reconnection logic (lines 400+) continues to work normally after graceful termination.