Fix duplicate OPTIONS method error for paths with trailing slash #3844
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Fixes aws#3816 When CORS is enabled on an API with paths that differ only by a trailing slash (e.g., /datasets and /datasets/), API Gateway would throw an error: 'Duplicate method OPTIONS found for resource /datasets. Only one is allowed.' This occurs because API Gateway treats /path and /path/ as the same resource, but SAM was adding OPTIONS methods to both paths separately. Solution: - Added path normalization in ApiGenerator._add_cors() method - Paths are normalized by removing trailing slashes (except for root '/') - Track normalized paths in a set to skip duplicates - Ensures only one OPTIONS method is added per normalized path Testing: - Added unit test test_add_cors_with_trailing_slash_paths to verify fix - All existing CORS integration tests (68 tests) pass without regression - Tested with real-world production templates with multiple HTTP methods
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Description
Fixes #3816
This PR fixes the issue where enabling CORS on an API with paths that differ only by a trailing slash (e.g.,
/datasetsand/datasets/) causes API Gateway to throw an error:Problem
When CORS is enabled, SAM adds OPTIONS methods to all paths. However, API Gateway treats
/pathand/path/as the same resource. If both paths exist in the template, SAM was adding OPTIONS to both separately, causing a duplicate method error.Solution
The fix normalizes paths before adding CORS OPTIONS methods:
/)Changes
Modified files:
samtranslator/model/api/api_generator.py: Added path normalization in_add_cors()methodtests/model/api/test_api_generator.py: Added unit testtest_add_cors_with_trailing_slash_pathsTesting
✅ Unit Tests
test_add_cors_with_trailing_slash_pathsthat verifies:/datasets(POST) and/datasets/(PUT) are correctly handled✅ Integration Tests
✅ Real-world Validation
Related Issues
Closes #3816
Checklist:
developbranch