How to introduce change in web api response payload structure without breaking existing integration

Question

In one of our existing .net core web api (REST) end point, one of its property value in response payload is email address which will be changed to alphanumeric id shortly. This change in response payload will break existing integration.

This breaking change impact can be addressed by introducing version to api saying that only v2 version will alphanumeric id in its response payload otherwise v1 version will keep rendering email address in its response payload but is there any other alternative solution to avoid broken existing integration even after introducing the change in existing response payload structure

Existing response payload structure:

{
  customerid: [email protected]
}

Future response payload structure:

{
  customerid: 1123acbd56
}

Answer 1

You can achieve this by creating a AcceptHeaderAttribute and pass Accept:[attrbute value]

Like, in the below code, I create an AcceptHeaderAttribute

[AttributeUsage(AttributeTargets.Method)]
    public class AcceptHeaderAttribute : Attribute, IActionConstraint
    {
        private readonly string _acceptHeader;
        public AcceptHeaderAttribute(string acceptHeader)
        {
            _acceptHeader = acceptHeader;
        }
        public int Order { get; set; }

        public bool Accept(ActionConstraintContext context)
        {
            return context.RouteContext.HttpContext.Request.Headers["Accept"].Any(x => x.IndexOf(_acceptHeader) >= 0);
        }
    }

And here is the use,

[HttpGet]
        public User GetUserName()
        {
            return new User { Name = "Abcd" };
        }

        [HttpGet]
        [AcceptHeader("app/vnd.user")]
        public User GetUserEmail()
        {
            return new User { Name = "[email protected]" };
        }

And here is fiddler response