An FTP secure client library for C#

Download source code - 10.1 KB

Introduction

The purpose of this article is to create a C # FTP client in Secure mode, so if you don’t have much knowledge of FTPS, I advise you to take a look at this: FTPS.

In the .NET Framework, to upload a file in FTPS mode, we generally use the FtpWebRequest class, but you can not send commands with « quote » arguments, and even if you search on the web, you will not find a concrete example of a secured C# FTP client.

It’s for those reasons I decided to create this article.

SSL Stream?

To send a socket in Secure Socket Layer (SSL) mode, we use the class System.Net.Security.SslStream.

“Provides a stream used for client-server communication that uses the Secure Socket Layer (SSL) security protocol to authenticate the server and optionally the client”.

For more information, refer to MSDN.

Using the Code

1. Pre-Authenticate

FTPFactory ftp = new FTPFactory();
ftp.setDebug(true);
ftp.setRemoteHost(Settings.Default.TargetFtpSource);

//Connect to SSL Port (990)
ftp.setRemotePort(990);
ftp.loginWithoutUser();

//Send "AUTH SSL" Command
string cmd = "AUTH SSL";
ftp.sendCommand(cmd);

Before connecting to the FTP server in SSL mode, you have to define the 990 SSL port and send the « AUTH SSL » command authentication using SSL.

2. Create SSL Stream

//Create SSL Stream
ftp.getSslStream();
ftp.setUseStream(true);
//Login to FTP Secure
ftp.setRemoteUser(Settings.Default.TargetFtpSecureUser);
ftp.setRemotePass(Settings.Default.TargetFtpSecurePass);
ftp.login();

ftp.getSslStream() creates an SSL stream from client socket which will be used for exchange between the client and the server FTPS. Then, you have to enter a login and password to authenticate on the FTPS server.

Note: if the SSL stream is well established, then I display all the information about the server certificate.

3. Upload File

//Set ASCII Mode
ftp.setBinaryMode(false);

//Send Arguments if you want
//cmd = "site arg1 arg2";
//ftp.sendCommand(cmd);

//Upload file
ftp.uploadSecure(@"Filepath", false);

ftp.close();

Before uploading a file, you have to specify the mode: ftp.setBinaryMode(bool value).

value is false --> ASCII mode
value is true --> Binary mode

By default, it’s binary. Now, you upload the file using:

ftp.uploadSecure(@"Filepath", false)

Note: you can upload in non secured mode using ftp.upload().

Points of Interest

I learned how an SSL stream and the RAW FTP communication works between a client and an FTP server. Searching on the web, I found many who were stuck on the issue of SSL communication with an FTP server, so I hope this article will be of great help.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

About the Author

kadaoui el mehdi

Technical Lead

Belgium

Member

in 2005, I started my career. Net and I could improve in this technology through the project WinFroms. Net 2.0 / MVC2 for "Nestle".

After obtaining my diploma MASTER "MBDS" from the University of Nice Sophia Anti-police, I left to Belguim to work as Expert .Net Analyst Developer.

Currently I specialize in architecture Asp.net to the lowest level.

Meanwhile I remain very active in the community. Net, I created the 1st community. Net Morocco "on Facebook and LinkedIn and twitter, called "Morocco .Net User Group (MONUG)"

Article Top

Poor

Excellent

Add a reason or comment to your vote: x
Votes of 3 or less require a comment