In Azure Functions 3+ how can I change the Response message for invalid parameter binding

Question

When we setup an Azure Function (3) with bind parameter of DateTime, if someone calling the API has the wrong DateTime they just get a "500 Internal Server Error".

In the backend we get an error like this:

System.Private.CoreLib: Exception while executing function: XXX. Microsoft.Azure.WebJobs.Host: One or more errors occurred. (Exception binding parameter 'dateTime'). System.Private.CoreLib: String '2020-5-13T12:0t' was not recognized as a valid DateTime.

I want to return a BadRequestObject with the specific parameters at fault.

The only way I can find to do this is make all parameters strings, and then try and parse them in code, and through an error if there is an issue.

Is there a better way?

Answer 1

Below code helps you in returning the 500 Internal server error to BadRequestObject with the specified parameters

[Microsoft.AspNetCore.Mvc.NonAction]
public  virtual System.Web.Http.BadRequestErrorMessageResult BadRequest (string message);

Check apicontroller.badrequestmethod for further details.

Update:

Also, I would like to suggest you, use ArgumentException, ArgumentNullException, and ArgumentOutOfRangeException.

• ArgumentExcepton - For something is wrong with the argument
• ArgumentNullException - Argument is null
• ArgumentOutOfRangeException - when the value of an argument is outside the allowable range of values as defined by the invoked method