A worse file transfer protocol.

• Author: Diamond Dinh [email protected]
• Repository: libdb.so/wftp
• Documentation: package libdb.so/wftp

Requirements:

• Go 1.21 or later.

To build the project, run:

go build ./cmd/wftp

Then invoke the binary as ./wftp. Alternatively, you may install it by first setting up your GOPATH and GOBIN environment variables, then running:

go install ./cmd/wftp

Then invoke the binary as wftp.

wftp assumes one peer is trying to talk to another peer. At least one of the peers must be listening for a connection. The other peer must connect to the listening peer.

To listen for a connection, run:

wftp -l :8080 # no authentication
wftp -l :8080 -s supersecret # with authentication

Otherwise, if you're not hosting a server, run:

wftp

Once in the wftp shell, to connect to a listening peer, run:

connect 1.2.3.4:8080

The peer may require authentication. If so, request to be prompted for a password by including the -s flag:

connect 1.2.3.4:8080 -s

The user may also choose to give each connection a nickname to refer to:

nick 1.2.3.4:8080 frill-mole

Otherwise, it is whatever the other peer wishes to call itself:

> connect 1.2.3.4:8080
12:38AM INF authenticated with peer peer=frill-mole addr=[::1]:49284 state=ready

It is possible to connect to multiple peers at once. To do so, simply run connect again. The user must choose the connection to send commands to by running use:

use frill-mole
use "[::1]:49284" # also works

By default, the latest connection is used.

Once connected, the user may run the following commands:

# List files
ls
ls directory_name
# Download a file to a directory
get path/to/file directory_name
# Upload a file to the other peer's directory
put path/to/file directory_name
# List all active peers
peers

Below is a sequence diagram of how these messages are used:

sequenceDiagram
    Note over A, B: Handshake
    A->>B: Hello
    B->>A: Welcome
    Note over A, B: Chatting
    A->>B: Chat
    B->>A: Chat
    Note over A, B: Listing a directory
    A->>B: ListDirectory
    B->>A: DirectoryList
    Note over A, B: Downloading a file from B
    A->>B: GetFile
    B->>A: GetFileAgree
    B->>A: FileTransferData
    B->>A: 
    B->>A: 
    B->>A: FileTransferEnd
    Note over A, B: Uploading a file to B
    A->>B: PutFile
    B->>A: PutFileAgree
    A->>B: FileTransferData
    A->>B: 
    A->>B: 
    A->>B: FileTransferEnd
    Note over A, B: Connection termination
    A->>B: Terminate
    B->>A: 
    A--xB: [connection closed]
    B--xA: 

Unlike FTP, wftp more resembles a peer-to-peer file transfer protocol. Specifically, it differs in the following ways:

• wftp allows both peers to send and receive files from each other, whereas FTP only allows the client to download files from the server.
  • In wftp, any peer can be a "listening" peer, which allows other peers to connect to it. After the initial handshake, both peers act the same.
• wftp multiplexes data transfer and commands over the same connection, whereas FTP uses separate connections for each.
  • This is more of an oversight in my part, since I did not realize that I can just open two connections from the same source to the same port.
  • FTP has the server connect back to the client for data transfer; wftp never does this.
• wftp assumes UTF-8 encoding for all text, whereas FTP does not specify an encoding.
• wftp does not try to be secure. It does not support TLS, and it does not support authentication. It is meant to be used over a VPN like Tailscale or SSH.