eft - effective file transfer tool.

Copy file between two computers within a single tcp connection, based on akka stream. This is also an example of akka stream.

Problems:

Akka stream tcp problems encountered.

For now, sometimes, eft cannot complete for reason/problem 2. use --debug option to see if the transfer is done, and ctrl + C to close eft, the file transfer will have been done.

Max chunkSize is Short.maximum, because Framing layer use 16 bit length field.

Motivation:

I need to pass file between two PCs. Where all the common ports like 22/445/139 are not available. Plus, a unidirectional filewall resides between.

      Unidirectional
        Firewall
          >|>
NodeA     >|>     NodeB
          >|>

eft comes to solve the problem.

Usage:

Setup push on node where you want to send a file:

$eft push file1.txt
Connection info: XXXXXX

Then, on node where you want to receive this file:

$eft pull -n XXXXXX

file1.txt will be saved to current dir on pull node.

Tip: Vice versa, one can setup pull first and then push.

Download:

Download zip from Releases, shell/bat files have already been created, running it requires java8 runtime.

Design:

• Symmetric.

  +----------------------------------------+          +-------
  |NodeA          Translation    Framing   |   Tcp    |NodeB
  |                  Layer        Layer    |          |
  |                                        |          |
  |  +--------+   ~>   I     ~>     I      O=   ~>   =I
  |  |  Flow  |        I            I      |          |
  |  +--------+   <~   I     <~     I      I=   <~   =O
  +----------------------------------------+          +-------

Where NodeA = NodeB in topology.

• Reactive.

                       (Filters as Router)
  ------+      +-----------+
        |      |           O=   ~>   Test/Log  
        |      |           |  
      a O= ~> =I BroadCast O=   ~>   ControlMerge ~>  FileSink
        |      |           |         
        |      |           |        +-------- +
        |      |         b O=  ~>  =I c       |
  TL    |      +-----------+        |   Msg   |     
  Bidi  |                           | Process |
        |      +--------+           |(Reactor)|
        |      |      e I=    <~   =O d       |
      f I= <~ =O Mearge |           +---------+
        |      |        |        
        |      |        I=  <~ InitialMsg
  ------+      +--------+

Where ~> a-b-c-d-e-f ~> forms a reactive chain. Which means protocol process completes in a single loop within a single Tcp connection.

ControlMerge see problems below.

Implementation detail: LoopTcpMan

Build:

under sbt console:

>assembly

jar and executable sh/bat file will be packed into cross target dir.