Hi Ashok, 

In the API Gateway, use context.reject not session.reject.  See https://www.ibm.com/docs/en/datapower-gateway/10.5?topic=gateway-apis-manage-messages#context__context.reject for examples, but context.reject will stop API execution.  As for form a generic JSON response and return it back to the consumer if you want something more than the standard default error, you'll need to implement a post-error global policy.  All errors will execute this policy so you'll need to at a minimum a default catch and then an explicit catch for ForbiddenError, UnauthorizedError, and BadRequestError as these require explicit catches to be caught.  That code will still have the context.get('error') object so you can get the details of the error and use whatever else you want to get from the context to augment your response in message.body.  Finally, any catch of an error, even in a post-error global policy, will clear the HTTP status code and reason phrase.  This information should be in the context error object, so you'll need to set those back into message.status or the client will get a HTTP 200 OK.  For more on post-error global policies, see https://www.ibm.com/docs/en/api-connect/10.0.1.x?topic=applications-working-global-policies as a starting point.

Best Regards,

Steve

Hi Steve Linn

We are trying to send custom Error, as suggested we configured Global-Error-Policy, we have faced issued -- 

1. Global-error-policy is not triggered until we put throw action in the API Assembly. Is this how it works ? I assume it should trigger for all errors without a throw in API flow.
2.   if we put throw action, then in context.get('error'); -- we are getting error code as 500 internal error instead of 401 or 400
3.  How to handle below error (this is not available in assembly to configure throw action) and send custom error{
       "httpCode": "400",
       "httpMessage": "Bad Request",
       "moreInformation": "One or more required API parameters are missing in the API request."
   }

Hi Ashok, 

In the API Gateway, use context.reject not session.reject.  See https://www.ibm.com/docs/en/datapower-gateway/10.5?topic=gateway-apis-manage-messages#context__context.reject for examples, but context.reject will stop API execution.  As for form a generic JSON response and return it back to the consumer if you want something more than the standard default error, you'll need to implement a post-error global policy.  All errors will execute this policy so you'll need to at a minimum a default catch and then an explicit catch for ForbiddenError, UnauthorizedError, and BadRequestError as these require explicit catches to be caught.  That code will still have the context.get('error') object so you can get the details of the error and use whatever else you want to get from the context to augment your response in message.body.  Finally, any catch of an error, even in a post-error global policy, will clear the HTTP status code and reason phrase.  This information should be in the context error object, so you'll need to set those back into message.status or the client will get a HTTP 200 OK.  For more on post-error global policies, see https://www.ibm.com/docs/en/api-connect/10.0.1.x?topic=applications-working-global-policies as a starting point.

Best Regards,

Steve