"Polite" UDP File Sharing using Broadcast

Non-serious project to get my feet wet in UDP Datagrams and Electron. Not suitable for use in the real world. Can overload the network with binary UDP packets if large files are transferred.

Features

• Can act as client and/or server in the one running app
• Share variable amount of files as server
• Fetch list of available files as client
• Ask for data broadcasting
• Broadcasting of file chunks
• Transfer progress
• Transferred file checksum verification
• Transferred file opening
• Packet loss simulation
• Lost packets resending
• Detailed configuration support

Downloads

• Windows x64
• Linux x64

Configuration

Configuration can be done using config.json:

• ./resources/app.asar.unpacked/config.json in the packed format
• ./package.json during development

Name	Description	Default
ENABLE_SERVER	Enable server part	true
ENABLE_CLIENT	Enable client part	true
CHUNK_SIZE	Size of the file chunk sent over the network	1000
SERVER_IP	Server IP adress	"localhost"
BROADCAST_ADDRESS	IP address used for data broadcasting	"192.168.1.255"
META_PORT	Port used for meta (plaintext) communication	10000
DATA_PORT	Port used for data (binary) communication	10001
POLITE_REQUEST_WORD	Word used in the end of requests	"PLS"
POLITE_ERROR_WORD	Word used at the beginning of error messages	"SRY"
MAX_FILES	Maximum number of files that can be picked via Server	5
DOWNLOADS_FOLDER	Folder used for downloads	"downloads"
SIMULATE_PACKET_LOSS	Simulate random packet loss	true
PACKET_LOSS_PROBABILITY	Probability that some packets will be lost 0.001 = 0.1% probability packets will be lost 1 = 100% probability packets will be lost 0.001 or less is recommended	0.001
ENABLE_PACKET_LOSS_RECOVERY	Enable recovery of lost packets Lost packets will be requested at the end of receiving	true
ENABLE_DEBUG	Enable debuging Developer tools can be opened using Ctrl+Shift+I	false
ENABLE_DEBUG_LOGGING	Enable logging to console	true
ENABLE_DEBUG_VERBOSE	Enable verbose logging WARNING: Can lead to great number of logged info if large files are used since a lot of repeating messages are logged and all received data objects are logged Please use only on considerably small files which can fit within few packets	false

Development

Requirements:

• Node.js v6 LTS + NPM
• Windows for win32 packaging

Clone this repository and install dependencies:

git clone https://github.com/durasj/Polite-UDP-Transfer.git
cd Polite-UDP-Transfer
npm install

After file changes, run npm start. The project should be built and the app opened. For 64-bit win32 and linux folder packaging, run npm package To create 64-bit win32 and linux installable, run npm dist

See package.json for more available commands

Used

• Electron (Node and Chromium)
• Typescript
• Vue.js
• Material components
• ... and others, see package.json

Code structure

Directory ./src contains raw source code. Directory ./build compiled/copied source code ready to be used by Electron.

File ./main.js is processed as first by Electron to bootstrap the application by creating the main window with ./build/index.html, which loads some ui dependencies and index.js, index.css.

Behind the scenes of the communication

Communicates politely on two ports:

• Meta port default 10000
• Data port default 10001

Meta port

• Plaintext, UTF-8 encoding
• Server listens on predefined port default 10000
• Server responds to these commands:
  • LIST - Get JSON array of file info
  • GET $fileId$ - Request file data broadcasting
  • PARTS $fileId$ $binary list of UInt32 part indexes$ - Request missing specific file data parts broadcasting
• Server error responses:
  • NOT IMPLEMENTED - required command is not implemented
  • UNKNOWN FILE - sent file identifier doesn't match any file on the server

Data port

• Binary data broadcasting
• Client listens on predefined port default 10001
• Server can broadcast file data messages to that port (if asked politely)
  • Message format: $fileId$ $index of chunk$ $binary data chunk$

Politeness

• Only in meta communication
• Every request ends with predefined polite word default PLS, e.g. LIST PLS, with the exception of the PARTS command, which includes polite word before the binary list of the indexes
• Every response error starts with predefined polite word default SRY, e.g. SRY NOT IMPLEMENTED