CUST-4514 added handling for non-json responses and tests

CHANGELOG.md

@@ -3,6 +3,7 @@ nylas-python Changelog
 
 v6.10.0
 ----------------
+* Added handling for non-JSON responses
 * Added support for `single_level` query parameter in `ListFolderQueryParams` for Microsoft accounts to control folder hierarchy traversal
 * Added support for `earliest_message_date` query parameter for threads
 * Fixed `earliest_message_date` not being an optional response field

nylas/handler/http_client.py

@@ -18,7 +18,22 @@
 
 
 def _validate_response(response: Response) -> Tuple[Dict, CaseInsensitiveDict]:
-    json = response.json()
+    try:
+        json = response.json()
+    except ValueError as exc:
+        if response.status_code >= 400:
+            raise NylasApiError(
+                NylasApiErrorResponse(
+                    None,
+                    NylasApiErrorResponseData(
+                        type="network_error",
+                        message=f"HTTP {response.status_code}: Non-JSON response received",
+                    ),
+                ),
+                status_code=response.status_code,
+                headers=response.headers,
+            ) from exc
+        return ({}, response.headers)
     if response.status_code >= 400:
         parsed_url = urlparse(response.url)
         try:

nylas/models/errors.py

@@ -28,9 +28,9 @@ def __init__(
             status_code: The HTTP status code of the error response.
             message: The error message.
         """
-        self.request_id: str = request_id
-        self.status_code: int = status_code
-        self.headers: CaseInsensitiveDict = headers
+        self.request_id: Optional[str] = request_id
+        self.status_code: Optional[int] = status_code
+        self.headers: Optional[CaseInsensitiveDict] = headers
         super().__init__(message)
 
 
@@ -70,7 +70,7 @@ class NylasApiErrorResponse:
         error: The error data.
     """
 
-    request_id: str
+    request_id: Optional[str]
     error: NylasApiErrorResponseData
 
 
@@ -169,3 +169,47 @@ def __init__(self, url: str, timeout: int, headers: Optional[CaseInsensitiveDict
         self.url: str = url
         self.timeout: int = timeout
         self.headers: CaseInsensitiveDict = headers
+
+
+class NylasNetworkError(AbstractNylasSdkError):
+    """
+    Error thrown when the SDK receives a non-JSON response with an error status code.
+    This typically happens when the request never reaches the Nylas API due to
+    infrastructure issues (e.g., proxy errors, load balancer failures).
+
+    Note: This error class will be used in v7.0 to replace NylasApiError for non-JSON
+    HTTP error responses. Currently, non-JSON errors still throw NylasApiError with 
+    type="network_error" for backwards compatibility.
+
+    Attributes:
+        request_id: The unique identifier of the request.
+        status_code: The HTTP status code of the error response.
+        raw_body: The non-JSON response body.
+        headers: The headers returned from the server.
+        flow_id: The value from x-fastly-id header if present.
+    """
+
+    def __init__(
+        self,
+        message: str,
+        request_id: Optional[str] = None,
+        status_code: Optional[int] = None,
+        raw_body: Optional[str] = None,
+        headers: Optional[CaseInsensitiveDict] = None,
+        flow_id: Optional[str] = None,
+    ):
+        """
+        Args:
+            message: The error message.
+            request_id: The unique identifier of the request.
+            status_code: The HTTP status code of the error response.
+            raw_body: The non-JSON response body.
+            headers: The headers returned from the server.
+            flow_id: The value from x-fastly-id header if present.
+        """
+        super().__init__(message)
+        self.request_id: Optional[str] = request_id
+        self.status_code: Optional[int] = status_code
+        self.raw_body: Optional[str] = raw_body
+        self.headers: Optional[CaseInsensitiveDict] = headers
+        self.flow_id: Optional[str] = flow_id

tests/handler/test_http_client.py

@@ -432,3 +432,65 @@ def test_execute_with_headers(self, http_client, patched_version_and_sys, patche
             timeout=30,
             data=None,
         )
+
+    def test_validate_response_500_error_html(self):
+        response = Mock()
+        response.status_code = 500
+        response.json.side_effect = ValueError("No JSON object could be decoded")
+        response.text = "<html><body><h1>Internal Server Error</h1></body></html>"
+        response.headers = {"Content-Type": "text/html", "x-fastly-id": "fastly-123"}
+
+        with pytest.raises(NylasApiError) as e:
+            _validate_response(response)
+        assert e.value.type == "network_error"
+        assert str(e.value) == "HTTP 500: Non-JSON response received"
+        assert e.value.status_code == 500
+
+    def test_validate_response_502_error_plain_text(self):
+        response = Mock()
+        response.status_code = 502
+        response.json.side_effect = ValueError("No JSON object could be decoded")
+        response.text = "Bad Gateway"
+        response.headers = {"Content-Type": "text/plain"}
+
+        with pytest.raises(NylasApiError) as e:
+            _validate_response(response)
+        assert e.value.type == "network_error"
+        assert str(e.value) == "HTTP 502: Non-JSON response received"
+        assert e.value.status_code == 502
+
+    def test_validate_response_200_success_non_json(self):
+        response = Mock()
+        response.status_code = 200
+        response.json.side_effect = ValueError("No JSON object could be decoded")
+        response.headers = {"Content-Type": "text/plain"}
+
+        response_json, response_headers = _validate_response(response)
+        assert response_json == {}
+        assert response_headers == {"Content-Type": "text/plain"}
+
+    def test_validate_response_error_empty_response(self):
+        response = Mock()
+        response.status_code = 500
+        response.json.side_effect = ValueError("No JSON object could be decoded")
+        response.text = ""
+        response.headers = {"Content-Type": "text/html"}
+
+        with pytest.raises(NylasApiError) as e:
+            _validate_response(response)
+        assert e.value.type == "network_error"
+        assert str(e.value) == "HTTP 500: Non-JSON response received"
+        assert e.value.status_code == 500
+
+    def test_validate_response_error_long_response_not_truncated(self):
+        response = Mock()
+        response.status_code = 500
+        response.json.side_effect = ValueError("No JSON object could be decoded")
+        response.text = "A" * 600
+        response.headers = {"Content-Type": "text/html"}
+
+        with pytest.raises(NylasApiError) as e:
+            _validate_response(response)
+        assert e.value.type == "network_error"
+        assert str(e.value) == "HTTP 500: Non-JSON response received"
+        assert e.value.status_code == 500