使用ASP.NET Core 3.0，我有一个PostService，可以读取一些Markdown文件的内容：

public class PostService : IPostService {

  private String _basePath;

  public PostService(IWebHostEnvironment _webHostEnvironment) {
    _basePath = _webHostEnvironment.WebRootPath;      
  }

  public async Task<IList<Post>> GetallAsync() {

    IList<Post> _posts = new List<Post>();

    String[] files = Directory.GetFiles($"{_basePath}/posts","*",SearchOption.AllDirectories);

    foreach (String file in files) {

      String content = await File.ReadAllTextAsync(file);

      // Process content and create 'post' from content 

      _posts.Add(post);

    }

    return _posts;

  }

}

然后在控制器上按如下方式使用它：

public class PostController : ControllerBase {   

    public PostController(IPostService postService) {
      _postService = postService;      
    }

    [HttpGet("posts/{id}")]
    public async Task<IactionResult> Get(Int32 id) {

      Post post = _postService.GetallAsync().FirstOrDefault(x => x.Id == id);

      // Remaining code
    } 
}

我不想在每个请求中都加载文件，因为它们不会更改。

我应该将PostService添加为Singleton吗？

services.AddSingleton<IPostService,PostService>();   

我应该将帖子存储在PostService中的静态变量中吗？

避免始终加载和读取文件的最佳方法是什么？

更新

在PostService中使用静态字段将类似于：

public class PostService : IPostService {

  private static List<Post>() _posts;

  private String _basePath;

  public PostService(IWebHostEnvironment _webHostEnvironment) {
    _basePath = _webHostEnvironment.WebRootPath;      
  }

  public async Task<IList<Post>> GetallAsync() {

    // Check if Posts were already loaded.
    if (_posts != null)
      return _posts; // If yes then return _posts and do not load files

    String[] files = Directory.GetFiles($"{_basePath}/posts",SearchOption.AllDirectories);

    foreach (String file in files) {

      String content = await File.ReadAllTextAsync(file);

      // Process content and create 'post' from content 

      _posts.Add(post);

    }

    return _posts;

  }

}

这是要走的路吗？我应该在构造函数中加载帖子吗？