fix(webhook): case-insensitive X-Lark-* signature header lookup - #13
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wz-heng wants to merge 2 commits into
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fix(webhook): case-insensitive X-Lark-* signature header lookup#13wz-heng wants to merge 2 commits into
wz-heng wants to merge 2 commits into
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_verify_sign and _has_signature_headers in EventDispatcherHandler and CardActionHandler looked up X-Lark-Request-Timestamp, X-Lark-Request-Nonce, and X-Lark-Signature case-sensitively. ASGI servers (Starlette/FastAPI) hand handlers lowercase header names per the ASGI spec, so every legitimately signed request behind such a server hit `None + None + encrypt_key` and 500'd with a confusing TypeError instead of verifying. Add a small case-insensitive header lookup used by both handlers. Fixes larksuite#12 (bug 1 of 2).
The lowercase-ASGI-header regression coverage added for this fix exercised the event plaintext, event encrypted, and card encrypted paths, but missed CardActionHandler's plaintext-signed path even though _verify_sign there uses the same fixed lookup. Addresses review feedback from this run's required Snape pass.
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Fixes part 1 of #12.
Bug
EventDispatcherHandler._verify_sign/_has_signature_headers(and theidentical duplicated logic in
CardActionHandler) look upX-Lark-Request-Timestamp,X-Lark-Request-Nonce, andX-Lark-Signaturecase-sensitively via a plain
dict.get(...).ASGI servers (Starlette/FastAPI) hand the application lowercase header
names, per the ASGI spec. Behind such a server, the case-sensitive lookup
returns
Nonefor all three headers, and_verify_signimmediatelyraises
TypeError: unsupported operand type(s) for +: 'NoneType' and 'NoneType'when it triestimestamp + nonce + encrypt_key— everylegitimately signed request 500s.
Fix
Add a small case-insensitive header lookup (
_get_header), used by bothEventDispatcherHandlerandCardActionHandler(the card callback pathhas the exact same duplicated verification code and the exact same bug).
Falls back to a case-insensitive scan only when the exact-case key isn't
found, so behavior for exact-case callers (e.g. plain WSGI) is unchanged.
Testing
Added regression tests exercising both handlers with lowercased headers
(matching what Starlette/FastAPI would hand the SDK) for both plaintext
and encrypted+signed payloads — they 500'd before this change, they pass
now. Full suite:
python -m pytest -q→ 1101 passed.🤖 Generated with Claude Code