我试图返回一个状态代码304未修改的web api控制器中的GET方法。
我成功的唯一方法是这样的:
public class TryController : ApiController
{
public User GetUser(int userId, DateTime lastModifiedAtClient)
{
var user = new DataEntities().Users.First(p => p.Id == userId);
if (user.LastModified <= lastModifiedAtClient)
{
throw new HttpResponseException(HttpStatusCode.NotModified);
}
return user;
}
}
这里的问题是,它不是一个异常,它只是没有修改,所以客户端缓存是OK的。
我还希望返回类型是一个用户(所有的web api示例显示与GET)不返回HttpResponseMessage或类似的东西。
我不喜欢改变我的签名来使用HttpCreateResponse类型,所以我提出了一个扩展的解决方案来隐藏它。
public class HttpActionResult : IHttpActionResult
{
public HttpActionResult(HttpRequestMessage request) : this(request, HttpStatusCode.OK)
{
}
public HttpActionResult(HttpRequestMessage request, HttpStatusCode code) : this(request, code, null)
{
}
public HttpActionResult(HttpRequestMessage request, HttpStatusCode code, object result)
{
Request = request;
Code = code;
Result = result;
}
public HttpRequestMessage Request { get; }
public HttpStatusCode Code { get; }
public object Result { get; }
public Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
{
return Task.FromResult(Request.CreateResponse(Code, Result));
}
}
然后你可以添加一个方法到你的ApiController(或者更好的是你的基本控制器),像这样:
protected IHttpActionResult CustomResult(HttpStatusCode code, object data)
{
// Request here is the property on the controller.
return new HttpActionResult(Request, code, data);
}
然后你可以像任何内置方法一样返回它:
[HttpPost]
public IHttpActionResult Post(Model model)
{
return model.Id == 1 ?
Ok() :
CustomResult(HttpStatusCode.NotAcceptable, new {
data = model,
error = "The ID needs to be 1."
});
}