Allow custom error handling on input binding error

[sebader]

I'm using an HTTP-triggered function like this:

public static IActionResult GetAllAvailabilityOnDate(
	[HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "availability/{datefilter:regex(^\\d{{4}}-\\d{{2}}-\\d{{2}}$)}")] HttpRequest req,
	[Sql("SELECT * FROM dbo.Availability a " +
	"WHERE a.Date = @DateFilter ",
	CommandType = CommandType.Text,
	Parameters = "@DateFilter={datefilter}",
	ConnectionStringSetting = "DatabaseConnectionString")] IEnumerable<MyResult> res,
	string dateFilter,
	ILogger log)
{

This works all great - until a user provides some bogus input like "0000-00-00". In this case the Function errors out with

System.Private.CoreLib: Exception while executing function: GetAllAvailabilityOnDate. Microsoft.Azure.WebJobs.Host: Exception binding parameter 'res'. Core Microsoft SqlClient Data Provider: Conversion failed when converting date and/or time from character string.

The Function immediately returns a 500 result. However, I would like to be able to insert some custom error handling and for example return a 400-Bad Request instead.

Is this something that's already somehow possible? If not, I would like to make this an enhancement request :)

[jnsvd]

We're facing a similar problem, where we used a Service Bus message property to perform a query. Workarounds exist: you could create another utility function that takes care of all validations and then forwards the message (either through HTTP or another service bus message), but this is highly inconvenient.
More control over bindings would be welcome.