c# - 刷新内存缓存 ASP.NET Core 2

Question

我在更新项目后尝试刷新缓存，我尝试了几个不同的选项，但没有一个按预期工作

public class PostApiController : Controller
{
    private readonly IPostService _postService;
    private readonly IPostTagService _postTagService;
    private IMemoryCache _cache;
    private MemoryCacheEntryOptions cacheEntryOptions;
    public PostApiController(IPostService postService, IPostTagService postTagService, IMemoryCache cache)
    {
       _postService = postService;
       _postTagService = postTagService;
       _cache = cache;

      cacheEntryOptions = new MemoryCacheEntryOptions()
          .SetSlidingExpiration(TimeSpan.FromDays(1));
    }

    [HttpGet("{url}", Name = "GetPost")]
    public IActionResult GetById(string url, bool includeExcerpt)
     {
       Post cacheEntry;
       if (!_cache.TryGetValue($"GetById{url}{includeExcerpt}", out cacheEntry))
       {
         cacheEntry = _postService.GetByUrl(url, includeExcerpt);
        _cache.Set($"GetById{url}{includeExcerpt}", cacheEntry, cacheEntryOptions);
      }

      if (cacheEntry == null)
      {
        return NotFound();
      }

      return new ObjectResult(cacheEntry);
    }

    [HttpPut("{id}")]
    public IActionResult Update(int id, [FromBody] Post item)
    {
      if (item == null)
      {
         return BadRequest();
       }

      var todo = _postService.GetById(id);
      if (todo == null)
      {
         return NotFound();
      }

       _postService.Update(item);
       _postTagService.Sync(item.Tags.Select(a => new PostTag { PostId = item.Id, TagId = a.Id }).ToList());
       //Want to flush entire cache here
       return new NoContentResult();
     }

我已尝试在此处 Dispose() MemoryCache，但在下一次 Api 调用时，它仍会被释放。由于 key 有些动态，我不能只获取 key 。我该怎么做呢？

Answer 1

您可以改为存储字典。通过这种方式，您可以为条目使用动态键，为字典容器使用一个静态键，它可以存储在缓存中，而不是单独存储每个条目。

类似的东西:

private const string CachedEntriesKey = "SOME-STATIC-KEY";

[HttpGet("{url}", Name = "GetPost")]
public IActionResult GetById(string url, bool includeExcerpt)
{
    Dictionary<string, Post> cacheEntries;
    if (!_cache.TryGetValue(CachedEntriesKey, out cacheEntries))
    {
        cacheEntries = new Dictionary<string, Post>();
        _cache.Set(CachedEntriesKey, cacheEntries);
    }

    var entryKey = $"GetById{url}{includeExcerpt}";
    if (!cacheEntries.ContainsKey(entryKey))
    {
        return NotFound(); // by the way, why you do that instead of adding to the cache?
    }

    return new ObjectResult(cacheEntries[entryKey]);
}