I believe that you should avoid reading the headers in your controller for better separation of concerns (you don't need to read the Customer from request body in the controller right?) and testability.
How I will do it is create a CustomerId
class (this is optional. see note below) and CustomerIdParameterBinding
public class CustomerId
{
public string Value { get; set; }
}
public class CustomerIdParameterBinding : HttpParameterBinding
{
public CustomerIdParameterBinding(HttpParameterDescriptor parameter)
: base(parameter)
{
}
public override Task ExecuteBindingAsync(ModelMetadataProvider metadataProvider, HttpActionContext actionContext, CancellationToken cancellationToken)
{
actionContext.ActionArguments[Descriptor.ParameterName] = new CustomerId { Value = GetIdOrNull(actionContext) };
return Task.FromResult(0);
}
private string GetIdOrNull(HttpActionContext actionContext)
{
IEnumerable<string> idValues;
if(actionContext.Request.Headers.TryGetValues("customerId", out idValues))
{
return idValues.First();
}
return null;
}
}
Writing up the CustomerIdParameterBinding
config.ParameterBindingRules.Add(p =>
{
return p.ParameterType == typeof(CustomerId) ? new CustomerIdParameterBinding(p) : null;
});
Then in my controller
public void Post(CustomerId id, Customer customer)
Testing the Parameter Binding
public void TestMethod()
{
var parameterName = "TestParam";
var expectedCustomerIdValue = "Yehey!";
//Arrange
var requestMessage = new HttpRequestMessage(HttpMethod.Post, "http://localhost/someUri");
requestMessage.Headers.Add("customerId", expectedCustomerIdValue );
var httpActionContext = new HttpActionContext
{
ControllerContext = new HttpControllerContext
{
Request = requestMessage
}
};
var stubParameterDescriptor = new Mock<HttpParameterDescriptor>();
stubParameterDescriptor.SetupGet(i => i.ParameterName).Returns(parameterName);
//Act
var customerIdParameterBinding = new CustomerIdParameterBinding(stubParameterDescriptor.Object);
customerIdParameterBinding.ExecuteBindingAsync(null, httpActionContext, (new CancellationTokenSource()).Token).Wait();
//Assert here
//httpActionContext.ActionArguments[parameterName] contains the CustomerId
}
Note: If you don't want to create a CustomerId
class, you can annotate your parameter with a custom ParameterBindingAttribute
. Like so
public void Post([CustomerId] string customerId, Customer customer)