{"record":{"id":"0823aa80b864d23e","repo":"microsoft/semantic-kernel","slug":"error-building-the-url-for-the-operation-self-id","errorCode":null,"errorMessage":"Error building the URL for the operation {self.id}: {e!s}","messagePattern":"Error building the URL for the operation (.+?): (.+?)","errorType":"exception","errorClass":"FunctionExecutionException","httpStatus":null,"severity":"error","filePath":"python/semantic_kernel/connectors/openapi_plugin/models/rest_api_operation.py","lineNumber":229,"sourceCode":"                if parameter.is_required:\n                    raise FunctionExecutionException(\n                        f\"No argument is provided for the `{parameter.name}` \"\n                        f\"required parameter of the operation - `{self.id}`.\"\n                    )\n                continue\n\n            headers[parameter.name] = str(argument)\n\n        return headers\n\n    def build_operation_url(self, arguments, server_url_override=None, api_host_url=None):\n        \"\"\"Build the URL for the operation.\"\"\"\n        server_url = self.get_server_url(server_url_override, api_host_url, arguments)\n        path = self.build_path(self.path, arguments)\n        try:\n            request_url = urljoin(server_url, path.lstrip(\"/\"))\n        except Exception as e:\n            raise FunctionExecutionException(f\"Error building the URL for the operation {self.id}: {e!s}\") from e\n        self._ensure_request_target_matches_server(server_url, request_url)\n        return request_url\n\n    @staticmethod\n    def _ensure_request_target_matches_server(server_url: str, request_url: str) -> None:\n        \"\"\"Verify URL construction did not move the request off the configured server.\n\n        A selected operation path must resolve to a request on the same scheme, host, and port and\n        within the server's base path. Otherwise an absolute or authority-changing operation path\n        (for example \"https://another-host/admin\") could redirect a credential-bearing request to an\n        unintended target even though it carries no dot-segment. This complements\n        `_validate_path_segments` so operation selection, path validation, and request construction\n        share one canonical target.\n        \"\"\"\n        server = urlparse(server_url)\n        request = urlparse(request_url)\n\n        if (request.scheme, request.username, request.password, request.hostname, request.port) != (","sourceCodeStart":211,"sourceCodeEnd":247,"githubUrl":"https://github.com/microsoft/semantic-kernel/blob/c028a0c7dc4f0814cdcbaba9d998f187a41197bf/python/semantic_kernel/connectors/openapi_plugin/models/rest_api_operation.py#L211-L247","documentation":"The `build_operation_url` method joins the server URL with the operation path to construct the request URL, wrapped in a try/except. If `urljoin` raises any exception (malformed server URL, path, or argument interpolation result), it is caught and re-raised as this FunctionExecutionException with the original error stringified. This is a catch-all for URL construction failures.","triggerScenarios":"The server URL or interpolated operation path is malformed in a way that causes `urljoin` to fail, or an argument value produces an invalid path segment. This is a low-level URL parsing failure during request construction.","commonSituations":"Server URL override contains invalid characters or scheme. Path template argument values contain characters that break URL parsing. Misconfigured server URL environment variable. Extremely rare under normal conditions since most malformed inputs are caught by earlier validation.","solutions":["Inspect the inner exception (`__cause__`) for the specific URL parsing error.","Validate the server URL and all path argument values for valid URL characters before calling.","Ensure the server URL override (if used) is a well-formed absolute URL with a scheme.","URL-encode any path argument values that may contain special characters."],"exampleFix":"// before\nawait api.call_op(server_url_override=\"not a url\")\n// after\nawait api.call_op(server_url_override=\"https://api.example.com/\")","handlingStrategy":"try-catch","validationCode":"from urllib.parse import urljoin, urlparse\ndef validate_url_construction(server_url: str, path: str):\n    if not urlparse(server_url).scheme:\n        raise ValueError(f\"Server URL has no scheme: {server_url}\")\n    try:\n        urljoin(server_url, path.lstrip('/'))\n    except Exception as e:\n        raise ValueError(f\"URL construction would fail: {e}\")","typeGuard":null,"tryCatchPattern":"try:\n    result = await api.my_operation(**args)\nexcept FunctionExecutionException as e:\n    if \"Error building the URL\" in str(e):\n        cause = e.__cause__  # inspect the original URL parsing error\n        # validate server_url and path argument values\n        ...","preventionTips":["Validate the server URL has a valid scheme before invoking.","URL-encode path argument values that may contain special characters.","Inspect the __cause__ of the exception for the specific URL parsing error."],"tags":["openapi","rest-api","url","semantic-kernel"],"backgroundTag":null,"analyzedSha":"c028a0c7dc4f0814cdcbaba9d998f187a41197bf","analyzedAt":"2026-08-13T13:48:05.040Z","schemaVersion":2},"datasetVersion":"2026-08-13T14:17:21.547Z"}