Crate nexo_pairing 

Phase 26 — pairing protocol.

Two coexisting protocols:

• DM challenge — opt-in inbound allowlist. A plugin (whatsapp, telegram, …) calls PairingGate::should_admit before publishing to the broker. Unknown senders get a one-time human-friendly code and the operator approves them via CLI / admin-ui.
• Setup-code — operator-initiated. agent pair start issues a short-lived HMAC-signed bearer token + a gateway URL, packs them into a base64url payload, and renders a QR. A companion app scans, opens the WS, presents the token, and gets a session token in return.

This crate is a leaf: it does not depend on nexo-core or any plugin crate. The bin (src/main.rs) wires the store + the gate into the plugins, and registers the CLI subcommand.

Re-exports

pub use adapter::PairingChannelAdapter;

pub use gate::PairingGate;

pub use registry::PairingAdapterRegistry;

pub use session_store::PairingSessionStore;

pub use session_store::SessionRow;

pub use setup_code::SetupCodeIssuer;

pub use store::PairingStore;

pub use types::AllowedSender;

pub use types::ApprovedRequest;

pub use types::Decision;

pub use types::PairingError;

pub use types::PairingPolicy;

pub use types::PendingRequest;

pub use types::SetupCode;

pub use types::TokenClaims;

pub use types::UpsertOutcome;

Modules

adapter

Per-channel adapter the plugins implement.

code

Human-friendly pairing code generator.

gate

Hot-path inbound gate.

qr

QR rendering for the setup-code payload.

registry

Lookup table mapping channel_id → adapter implementation.

session_store

Companion session tokens — issued after a successful WS handshake.

setup_code

HMAC-SHA256 bearer-token issuer.

store

SQLite-backed pairing storage.

telemetry

Phase 26.y — Prometheus telemetry for the pairing flow.

types

Public types shared by store / gate / setup-code.

url_resolver

Resolve the gateway URL for agent pair start.