FTP - how to overwrite older files OR files with different size

Question

I'd like to use the FTP component to download different files only. I can see there is an option to download (and overwrite) EITHER files with different size OR older files:

client.Download(remote, local, traversal, transfer, ActionOnExistingFiles.OverwriteDifferentSize);

or

client.Download(remote, local, traversal, transfer, ActionOnExistingFiles.OverwriteOlder);

How can I combine these two conditions together?

Answer 1

To accomplish your need, you have to handle the overwriting manually in the ProblemDetected event handler.

Create a handler method like this:

static void client_ProblemDetected(object sender, FtpProblemDetectedEventArgs e)  
{ 
   // if the file does not exist, we cannot resolve what to do, so do nothing
   if (e.ProblemType != TransferProblemType.FileExists) 
         return;

   // first handle the file size
   if (e.RemoteItem.Length != e.LocalItem.Length)  
   { 
         e.Overwrite();             // overwrite unconditionally
         return; 
   }

   // then let the Overwrite method decide the file date and time
   // (the same as using ActionOnExistingFiles.OverwriteOlder in Download method)
   e.Overwrite(OverwriteCondition.Older); // overwrite conditionally, otherwise skip the file
}

Then assign this method to the ProblemDetected event of your FTP object before calling the Download method:

// connect and login
var client = new Ftp();
client.Connect("server");
client.Login("username", "password");

// assign the event handler
ftp.ProblemDetected += client_ProblemDetected;

// perform the file transfers
// you can (or rather should) omit the ActionOnExistingFiles argument now
ftp.Download(remotePath, localPath);

Note: This article can be used for the Rebex SFTP component as well - just replace the first line of the code with:

var client = new Sftp();