Validate direct transport header key/value types

Co-authored-by: Shri Sukhani <shrisukhani@users.noreply.github.com>

Author: cursoragent

hyperbrowser/transport/async_transport.py

@@ -16,6 +16,11 @@ def __init__(self, api_key: str, headers: Optional[Mapping[str, str]] = None):
             "User-Agent": f"hyperbrowser-python-sdk/{__version__}",
         }
         if headers:
+            if any(
+                not isinstance(key, str) or not isinstance(value, str)
+                for key, value in headers.items()
+            ):
+                raise HyperbrowserError("headers must be a mapping of string pairs")
             merged_headers.update(headers)
         self.client = httpx.AsyncClient(headers=merged_headers)
         self._closed = False

hyperbrowser/transport/sync.py

@@ -16,6 +16,11 @@ def __init__(self, api_key: str, headers: Optional[Mapping[str, str]] = None):
             "User-Agent": f"hyperbrowser-python-sdk/{__version__}",
         }
         if headers:
+            if any(
+                not isinstance(key, str) or not isinstance(value, str)
+                for key, value in headers.items()
+            ):
+                raise HyperbrowserError("headers must be a mapping of string pairs")
             merged_headers.update(headers)
         self.client = httpx.Client(headers=merged_headers)
 

tests/test_custom_headers.py

@@ -23,6 +23,11 @@ def test_sync_transport_accepts_custom_headers():
         transport.close()
 
 
+def test_sync_transport_rejects_non_string_header_pairs():
+    with pytest.raises(HyperbrowserError, match="headers must be a mapping"):
+        SyncTransport(api_key="test-key", headers={"X-Correlation-Id": 123})  # type: ignore[dict-item]
+
+
 def test_async_transport_accepts_custom_headers():
     async def run() -> None:
         transport = AsyncTransport(
@@ -39,6 +44,11 @@ async def run() -> None:
     asyncio.run(run())
 
 
+def test_async_transport_rejects_non_string_header_pairs():
+    with pytest.raises(HyperbrowserError, match="headers must be a mapping"):
+        AsyncTransport(api_key="test-key", headers={"X-Correlation-Id": 123})  # type: ignore[dict-item]
+
+
 def test_sync_client_config_headers_are_applied_to_transport():
     client = Hyperbrowser(
         config=ClientConfig(api_key="test-key", headers={"X-Team-Trace": "team-1"})