filesharing-ws-proto

Protocol for 2-way WebSocket communication used in our filesharing app.

Messages are sequences of bytes. Strings are encoded in UTF-8, numbers are stored in little-endian.

Messages

• AckMessage
  Type: MessageType.Ack

  • Client <-> Server

  Used as a generic ACK, anywhere it is required.

• InfoRequestMessage
  Type: MessageType.InfoRequest

  • Uploader <- Server
  • Downloader -> Server

  Used to request file information, namely filename and total size in bytes.

• InfoMessage
  Type: MessageType.Info

  • Uploader -> Server
  • Downloader <- Server

  Used to send file information when requested.

• ChunkSizeInfoMessage
  Type: MessageType.ChunkSizeInfo

  • Uploader <- Server

  Used by the server to communicate the chunk size that should be used for transferring the file.

• ChunkRequestMessage
  Type: MessageType.ChunkRequest

  • Uploader <- Server
  • Downloader -> Server

  Used to request a chunk by its number, zero-indexed.

• ChunkMessage
  Type: MessageType.Chunk

  • Uploader -> Server
  • Downloader <- Server

  Used to transfer a file chunk. Contains number and chunk bytes.

Notes

This protocol is to be used by the server (NodeJS) and clients (browser JS). Functionality from NodeJS's Buffer is provided to browsers by https://github.com/feross/buffer.