dotnet

chat-xdk example bot (.NET)

An encrypted chat bot built on the ChatXdk .NET binding (P/Invoke over the Rust core). It reads incoming DMs, decrypts them, generates a reply, encrypts + signs it, and sends it back. Keys come from a local blob (or are generated + registered on first run); conversation state is in memory.

Layout

File	Purpose
ChatBot/ChatCore.cs	All encryption logic — the only file that touches ChatXdk.
ChatBot/XChatClient.cs	The X Chat API I/O layer (plain HTTP).
ChatBot/Bot.cs	The receive → decrypt → reply → encrypt → send loop.
ChatBot/Program.cs	Entrypoint: config, key load/generate, run (and the register dispatch).
ChatBot/Register.cs	One-time public-key registration (dotnet run --project ChatBot register).
ChatBot.Tests/ChatCoreTests.cs	Offline test driving the real binding (no mocks).

Prerequisites

• .NET 8+ SDK
• The native chat_xdk_dotnet library, built once from the repo root:

cargo build -p chat-xdk-dotnet --release

Place the resulting libchat_xdk_dotnet.dylib / .so / chat_xdk_dotnet.dll next to the built app (or on the loader path) so P/Invoke can find it.

Run it

cp .env.example .env
# First run with no keys prints a registration payload + a private blob:
dotnet run --project ChatBot
# Paste CHAT_PRIVATE_KEYS_B64 into .env, register the public key with the X API,
# set X_ACCESS_TOKEN + CHAT_CONVERSATION_ID, then re-run.
dotnet run --project ChatBot

The bot echoes messages back (pong for ping, otherwise You said: …). Customize Bot.GenerateReply in ChatBot/Bot.cs to change the reply logic.

Registering your key (one-time)

Before a bot can send or receive, its public key must be registered on the account. This is a rate-limited write (only a few per 24h), so run it once:

X_ACCESS_TOKEN=... dotnet run --project ChatBot register --confirm

It generates the identity, saves the private-key blob under state/ (mode 600) before the network call, then POSTs the public key. If it is interrupted, re-running resumes the same saved identity rather than minting a new one; if the key is already on the account it adopts that version and skips the POST; on HTTP 429 it stops and tells you when the window resets rather than retrying. Set CHAT_PIN to additionally back the keys up in Juicebox (best-effort — the local blob is already saved). When it finishes it prints the CHAT_PRIVATE_KEYS_B64 and CHAT_SIGNING_KEY_VERSION lines to paste into .env. state/ is gitignored — never commit key blobs.

Test it (offline, no credentials)

cargo build -p chat-xdk-dotnet --release   # build the native lib first
dotnet test

The test imports the fixture private keys, checks the binding reproduces the committed public-key/signature vectors, and runs a real encrypt → decrypt round-trip plus a conversation-key ECIES round-trip.

License

MIT