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 FileInfo _tempFile;
        private MemoryStream _stream;
        private ILJClient _ljPool;
        private static object _syncRoot = new object();
        private string _token;
        public L1SvrFileInfo(string fullFilepath, string subpath, ILJClient ljPool,string token)
        {
            _fullFilepath = fullFilepath;
            _subpath = subpath;
            _ljPool = ljPool;
            _token = token;
            _stream = new MemoryStream(); ;
            if (File.Exists(_fullFilepath))
            {
                _tempFile = new FileInfo(_fullFilepath);
                CheckAuthorizationOrGetRemoteFile(_tempFile.LastWriteTime, true);
            }
            else
            {
                lock (_syncRoot)
                {
                    if (File.Exists(_fullFilepath))
                    {
                        _tempFile = new FileInfo(_fullFilepath);
                        CheckAuthorizationOrGetRemoteFile(_tempFile.LastWriteTime,true);
                    }
                    else
                    {
                        CheckAuthorizationOrGetRemoteFile(null);
                    }

                }
            }
        }
        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 CheckAuthorizationOrGetRemoteFile(DateTime? lastWriteTime, bool checkAuthorization=false)
        {
            var getFileReq = new GetFileRequest() {
                Filepath = _subpath,
                token = _token,
                checkAuthorization = checkAuthorization,
                lastWriteTime = lastWriteTime
            };
            var responseStr = _ljPool.DoExcute(getFileReq.GetApiName(),JsonConvert.SerializeObject(getFileReq));
            var response = JsonConvert.DeserializeObject<GetFileResponse>(responseStr);
            if (response.AppErrCode == "900")
            {
                if (!checkAuthorization)
                {
                    var fileDir = Path.GetDirectoryName(_fullFilepath);
                    if (!Directory.Exists(fileDir))
                    {
                        Directory.CreateDirectory(fileDir);
                    }
                    File.WriteAllBytes(_fullFilepath, response.FileData);
                }
                else
                {
                    if(response.FileData!=null && response.FileData.Length > 0)
                    {
                        var fileDir = Path.GetDirectoryName(_fullFilepath);
                        if (!Directory.Exists(fileDir))
                        {
                            Directory.CreateDirectory(fileDir);
                        }
                        File.WriteAllBytes(_fullFilepath, response.FileData);
                    }
                }
                _file = new FileInfo(_fullFilepath);
                byte[] buff = new byte[1024];
                using(var fs = _file.OpenRead())
                {
                    int readCount = fs.Read(buff, 0, buff.Length);
                    while (readCount > 0)
                    {
                        _stream.Write(buff, 0, readCount);
                        readCount = fs.Read(buff, 0, buff.Length);
                    }
                }                
            }
        }

    }
}