UndirectedOrderedUnchunkedChannel

The peers start by displaying a "broadcast" message with no read receipt and once they meet each other, exchange messages and read receipts. The peers always assume the one counterparty they met first is the only other peer in the line of sight and error on meeting new peers.

The channel is undirected, so the read receipts do not have recipient names on them, a sole counterpart is assumed and expected.

The channel is ordered, so the sequential order of the received messages is verified and enforced, erroring on irregularities.

The channel is unchunked, so the entirety of the passed-in message is displayed in the QR code alongside the protocol metadata.

Building

parcel build index.ts --target=node

Contributing

Protocol Metadata Structure

`${name}|${number}|${counterpartyNumber}|${message}`

Flow Example

• A shows A|1||Hello from A and scans
• B shows B|1||Hi from B and scans
• B sees A|1||Hello from A and processes it
• B knows A haven't seen any of it's messages yet because it lacks counterpartyNumber
• B shows B|1|1|Hello from B letting A know it saw its message (by adding read receipt)
• If B sees A's missing counterpartyNumber it knows it already shows the read receipt
• A sees B|1|1|Hello from B and processes it
• A knows B has seen A|1||Hello from A and so switches to A|2|1|Next from A with RR
• If A sees B's counterpartyNumber=1 again it ignores it as it already shows the RR
• And so on…

Testing

With one device:

• Open two tabs side by side:
  • index.html#A
  • index.html#B
• Alternate the webcam between the QR codes in the two tabs (use an external webcam and hold it or sit the device in front of a mirror)
• Observe as messages are exchanged and acknowledged

With two devices:

• Position the two devices against one another
• Tweak their tilt angle so that they see each other's QR codes
• Observe as messages are exchanged and acknowledged

Publishing

• Bump version in package.json
• Document changes in CHANGELOG.md
• Update contents of README.md
• Verify npm whoami or npm login if needed
• npm publish