Query string parameter with WebAPI routing

Question

If I have an endpoint

public class OrdersController : ApiController
{
    [Route("customers/{customerId}/orders")]
    [HttpPatch]
    public IEnumerable<Order> UpdateOrdersByCustomer(int customerId) { ... }
}

I can make the calls like this:

http://localhost/customers/1/orders
http://localhost/customers/bob/orders
http://localhost/customers/1234-5678/orders

But what if I want to send a date as part of the query string?

For example I want to send the following: http://localhost/customers/1234-5678/orders?01-15-2019

How can I set my endpoint?

public class OrdersController : ApiController
{
    [Route("customers/{customerId}/orders")]
    [HttpPatch]
    public IEnumerable<Order> UpdateOrdersByCustomer(int customerId, DateTime? effectiveDate) { ... }
}

Answer 1

In a [HttpPatch] type of request, only primitive types are can be used as query strings. And DateTime is not a primitive type.

As your example suggests that you need to pass just the date part to the query string, therefore, you can use string datatype instead and convert it to date inside the action method. Something like this:

public IEnumerable<Order> UpdateOrdersByCustomer(int customerId, string effectiveDate)  //changed datatype of effectiveDate to string
{
    //converting string to DateTime? type
    DateTime? effDate = string.IsNullOrEmpty(effectiveDate) ? default(DateTime?) : DateTime.Parse(str);

    // do some logic with date obtained above
}

Answer 2

You could modify your route attribute to the following:

public class OrdersController : ApiController
{
    [Route("customers/{customerId}/orders/{effectiveDate?}")]
    [HttpPost]
    public IEnumerable<Order> UpdateOrdersByCustomer(int customerId, DateTime? effectiveDate) { ... }
}