fix: Allow OPTIONS requests on /openapi.json for CORS preflight #1518
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This change exempts OPTIONS requests from authentication on documentation endpoints (/docs, /redoc, /openapi.json) to support CORS preflight requests. Issue: Browser-based OpenAPI integrations (like Open WebUI) were failing because CORS preflight OPTIONS requests cannot include Authorization headers per RFC 7231 Section 4.3.7, but the DocsAuthMiddleware was enforcing authentication on all requests including OPTIONS. Solution: Check request.method == 'OPTIONS' before applying authentication, allowing CORS preflight to succeed while still requiring authentication for GET requests to actually fetch the OpenAPI spec. This maintains security (GET still requires auth) while enabling proper CORS support for browser-based integrations. Fixes browser-based OpenAPI tool integration (Open WebUI, Swagger UI, etc.) when AUTH_REQUIRED=false or when using proper authentication flows.
Fix minor style issue with double blank line after OPTIONS check. Signed-off-by: Mihai Criveti <crivetimihai@gmail.com>
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Summary
This PR fixes CORS preflight authentication issues that prevent browser-based OpenAPI integrations (Open WebUI, Swagger UI, etc.) from successfully fetching the OpenAPI specification.
DocsAuthMiddleware.dispatch()to allow CORS preflight requestsChanges
mcpgateway/main.py: Added OPTIONS bypass in DocsAuthMiddleware before authentication checkTesting
Security Considerations
Closes #1493
Co-authored-by: Jason Sievert jsievert@gmail.com