I've read lots of posts about caching already, but none of them actually match my needs exactly. In my mvc 3 app I have an action method GetImage() that returns a File of image type. Then I use this method in a view to display image:

我已经阅读了很多关于缓存的帖子，但其中没有一篇确实符合我的需求。在我的mvc 3应用程序中，我有一个动作方法GetImage（），它返回一个图像类型的文件。然后我在视图中使用此方法来显示图像：

<img width="75" height="75" src="@Url.Action("GetImage", "Store", new {productId = item.ProductId})"/>

I want to cache images on a Server. So, what I've already tried:

我想在服务器上缓存图像。所以，我已经尝试过：

1) to use OutputCacheAttribute:

1）使用OutputCacheAttribute：

    [HttpGet, OutputCache(Duration = 10, VaryByParam = "productId", Location = OutputCacheLocation.Server, NoStore = true)]
    public FileContentResult GetImage(int productId)
    {
        var p = _productRepository.GetProduct(productId);
        if (p != null)
        {
            if (System.IO.File.Exists(GetFullProductImagePath(productId)))
            {
                var image = Image.FromFile(GetFullProductImagePath(productId));
                return File(GetFileContents(image), "image/jpeg");
            }
        }
        var defaultPath = AppDomain.CurrentDomain.BaseDirectory +
                             ConfigurationManager.AppSettings["default-images-directory"];

        var defaultImage = Image.FromFile(Path.Combine(defaultPath, "DefaultProductImage.jpg"));
        return File(GetFileContents(defaultImage), "image/jpeg");
    }

Images are not cached (I get status: 200 OK)

图像没有缓存（我得到状态：200 OK）

2) to use the following Response.Cache methods in a GetImage() method:

2）在GetImage（）方法中使用以下Response.Cache方法：

    public FileContentResult GetImage(int productId)
    {
        Response.Cache.SetCacheability(HttpCacheability.Public);
        Response.Cache.SetMaxAge(new TimeSpan(0, 0, 0, 10));
        Response.Cache.SetExpires(DateTime.Now.Add(new TimeSpan(0, 0, 0, 10)));
        Response.Cache.AppendCacheExtension("must-revalidate, proxy-revalidate");        
        // other code is the same
    }

Images are not cached

图像未缓存

3) Here I get: 304 Not Modified, but the GetImage() method returns nothing (empty image)

3）我得到：304 Not Modified，但GetImage（）方法什么都不返回（空图像）

    public FileContentResult GetImage(int productId)
    {
        Response.StatusCode = 304;
        Response.StatusDescription = "Not Modified";
        Response.AddHeader("Content-Length", "0");     
        // other code is the same
    }

Question: How to cache the output of this action method on a server?

问题：如何在服务器上缓存此操作方法的输出？

1 个解决方案

[HttpGet]
[OutputCache(
    Duration = 10, 
    VaryByParam = "productId", 
    Location = OutputCacheLocation.ServerAndClient)]
public ActionResult GetImage(string productId)
{
    ...
}