P2P File Sharing

A simple P2P file sharing application, allowing multiple peers running separate instances of this application to send and recieve files over a network using TCP. The application features a client to provide a simple text-based UI and a server to handle ingoing and outgoing requests. A list of the features of this application are given below:

• Allows for files of any file type to be shared between peers.
• Directories in which to download and share files are configurable.
• Provide a dynamic list of current peers on the network and request a list of downloadable files from each peer.
• Reliably closes connections with clients which exit the network undexpectedly.
• Search over all peers in the network for a file by its file name and return a list of peers sharing the file.

Usage

The application can be compiled and ran using the following commands inside the /src directory.

javac FileShareMain.java

Then ran with the following command:

java FileShareMain

The program has default saved and shared directories at the directories ../p2p-files/saved and ../p2p-files/shared respectively. Files are saved and shared here. Therefore in order to share a file, the file must be present within the peers shared directory.

The program supports file transfer of any file type since it sends the file over in byte arrays.

A peer that is running an instance of the same application can be connected to as follows:

connect "255.255.255.255"
connect "ffff::ffff::ffff::ffff::ffff"
connect "host.cs.st-andrews.ac.uk"

Where 255.255.255.255 and xxxx::xxxx::xxxx::xxxx::xxxx can be any IPv4 and IPv6 address respectively. Either way of connecting is acceptable, however assure that you have included either single or double quotation marks around the peer address for it to be accepted as an argument.

All arguments, in fact, should be wrapped in quotation marks, this allows the application to parse them correctly.

To cleanly exit the application the exit command can be ran.

Commands

To see a list of available commands and a description of their function, type list into the command line. The commands shown by list will change between connecting and disconnecting to a peer. For instance the disconnect command will only be available if connected to a peer.

Base commands (can be ran at any point)

Command	Usage	Function
exit		Quit the application.
downloads		List all files downloaded that are present in the saved directory.
dirs		Show the location of the shared and saved directories.
change-dirs	change-dirs "../saved_dir" "../shared_dir"	Changes the location where files are saved and shared.
serving		List peers that are currently connected to this client.
peers		List all peers on the local network.
search	search "file.ext"	List all peers on the network hosting a specific file.
list		list all commands available to the user.

Connected commands (can only be ran when connected to a peer)

Command	Usage	Function
disconnect		Disconnect the peer currently connected to.
get	get "file.ext"	Download the specified file from the peer currently connected to.
available		List files shared by the peer and are available to download.

Disconnected commands (can only be ran when disconnected)

Command	Usage	Function
connect	connect "255.255.255.255"	Connect to a peer with the specified address.

Notes

The search and peers commands scan for instances of the application of files on the local network. It only scans computers the netmask 255.255.255.0. Therefore, when running these commands, make sure that the application is running on two computers with the same IPv4 address up to the last byte.