LJProxy/Providers/L1SvrFileInfo.cs

using LJLib.Net.SPI.Client;
using LJProxy.Models;
using Microsoft.Extensions.FileProviders;
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;

namespace LJProxy.Providers
{
    public class L1SvrFileInfo : IFileInfo
    {
        private string _fullFilepath;
        private string _subpath;
        private FileInfo _file;
        private Stream _stream;
        private ILJClient _ljPool;
        private static object _syncRoot = new object();
        public L1SvrFileInfo(string fullFilepath, string subpath, ILJClient ljPool)
        {
            _fullFilepath = fullFilepath;
            _subpath = subpath;
            _ljPool = ljPool;
            if (File.Exists(_fullFilepath))
            {
                _file = new FileInfo(_fullFilepath);
                _stream = _file.OpenRead();
            }
            else
            {
                lock (_syncRoot)
                {
                    if (File.Exists(_fullFilepath))
                    {
                        _file = new FileInfo(_fullFilepath);
                        _stream = _file.OpenRead();
                    }
                    else
                    {
                        GetRemoteFile();
                        if (File.Exists(_fullFilepath))
                        {
                            _file = new FileInfo(_fullFilepath);
                            _stream = _file.OpenRead();
                        }
                    }

                }
            }
        }
        public bool Exists => _file!=null;

        public bool IsDirectory => false;

        public DateTimeOffset LastModified => _file.LastWriteTime;

        public long Length => _stream.Length;

        public string Name => _file.Name;

        public string PhysicalPath => _file.FullName;

        public Stream CreateReadStream()
        {
            return _stream;
        }

        public void GetRemoteFile()
        {
            var getFileReq = new GetFileRequest() {
                Filepath = _subpath
            };
            var responseStr = _ljPool.DoExcute(getFileReq.GetApiName(),JsonConvert.SerializeObject(getFileReq));
            var response = JsonConvert.DeserializeObject<GetFileResponse>(responseStr);
            if (string.IsNullOrEmpty(response.ErrMsg))
            {
                var fileDir = Path.GetDirectoryName(_fullFilepath);
                if (!Directory.Exists(fileDir)){
                    Directory.CreateDirectory(fileDir);
                }
                File.WriteAllBytes(_fullFilepath, response.FileData);
            }
        }
    }
}