在ASP.net Web API中设置Owin缓存控制标头

using Microsoft.Owin;
using Owin;

[assembly: OwinStartup(typeof(YourNamespace.Startup))]
namespace YourNamespace
{
    public class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            // 配置Web API
            HttpConfiguration config = new HttpConfiguration();
            WebApiConfig.Register(config);

            // 启用Owin中间件
            app.UseWebApi(config);
        }
    }
}

using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;

public class OwinCacheControlHandler : DelegatingHandler
{
    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        // 执行请求前的逻辑
        HttpResponseMessage response = await base.SendAsync(request, cancellationToken);

        // 设置缓存控制标头
        response.Headers.CacheControl = new System.Net.Http.Headers.CacheControlHeaderValue
        {
            Public = true, // 允许公共缓存
            MaxAge = TimeSpan.FromMinutes(30) // 缓存有效期为30分钟
        };

        return response;
    }
}

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        // 注册OwinCacheControlHandler类
        config.MessageHandlers.Add(new OwinCacheControlHandler());

        // 其他Web API配置代码...
    }
}