Find most recent SFTP file with a particular filename using SSH.NET-CodePudding

I have a folder on an SFTP server that has a bunch of files. There are 6 different files, and they are created every 60min. Each with a date and time stamp, and they are held for 3 days.

FilesCodes_Critical.2022-03-17_11-16-22-614.json
FilesCodes_Critical.2022-03-17_12-12-16-818.json
FilesCodes_Critical.2022-03-17_13-11-43-025.json
TransactionAudit.2022-03-14_11-16-23-530.json
TransactionAudit.2022-03-14_12-12-19-764.json
TransactionAudit.2022-03-14_13-11-45-454.json

I am creating a few processes that will run every hour and will pick up a particular file and process it. I know I can use the Name.StartsWith to grab the correct file, but I can't figure out how to grab the most recent of them. I was thinking that LastWriteTime could be used, but I can't figure out how to compare it.

fileNamePat = "FileCodes_Critical";    

try {       
    sftpc.Connect();

    var files = sftpc.ListDirectory(sFTPPath);
    foreach (SftpFile file in files)
    {
        if (file.Name.StartsWith(fileNamePat))
        {
            string jsonData = sftpc.ReadAllText(file.FullName);
            DataSet ds = JsonConvert.DeserializeObject<DataSet>(jsonData);
        }
    }
} catch (Exception ex) {
    Console.WriteLine(ex.Message);
}

I thought of trying something like this to compare and put the final file into targetFile

if (file.Name.StartsWith(fileNamePat))
{
    if (file.LastWriteTime > targetFile.LastWriteTime)
    {
        targetFile = file;
    }
}

But I can't figure out where/how to create the SftpFile targetFile so the comparison will work. I tried SftpFile targetFile = new(); and thought I could check to see if it was blank and then set it, but that doesn't work.

CodePudding user response：

Try using a lambda on your set of files:

foreach (SftpFile file in files.Where(f => f.Name.Contains(fileNamePat))
                                 .OrderByDescending(o => o.LastWriteTime)
                                   .Take(1)) 
{ 
      [...]
}

Actually you didn't need a for each. you can get your 'target' from lambda:

SftpFile targetFile = files.Where(f => f.Name.Contains(fileNamePat))
               .OrderByDescending(o => o.LastWriteTime)
                   .FirstOrDefault();