Add custom header to all responses in Web API

Question

Simple question, and I am sure it has a simple answer but I can\'t find it.

I am using WebAPI and I would like to send back a custom header to all responses (server

Answer 1

For that you can use a custom ActionFilter (System.Web.Http.Filters)

public class AddCustomHeaderFilter : ActionFilterAttribute
{
    public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
    {
       actionExecutedContext.Response.Headers.Add("customHeader", "custom value date time");
    }
}

You can then apply the filter to all your controller's actions by adding this in the configuration in Global.asax for example :

GlobalConfiguration.Configuration.Filters.Add(new AddCustomHeaderFilter());

You can also apply the filter attribute to the action that you want without the global cofiguration line.