NIGHTGATE Plugin

@odatano/nightgate ties a SAP CAP runtime directly to the Midnight blockchain. A built-in crawler indexes blocks from a Substrate RPC node into CAP entities; a worker-thread-isolated wallet stack handles ZK-aware transaction submission — deploy/call Compact contracts, send NIGHT and custom tokens, fee sponsoring, dust generation. The whole surface is standard OData V4: no GraphQL, no SDK lock-in for consumers.

Highlights

• Block-level indexing: Live + catch-up crawler with reorg detection
• Wallet sessions: Read-only (viewing key) + signing (seed), AES-256-GCM at rest; deriveWalletInfo creates wallets programmatically (multi-account via accountIndex) — no Lace needed
• Contract deploy / call: Compact-compiled contracts via deployContract / submitContractCall; submitContractCallBatch bundles up to 8 dependent calls in one tx with deterministic apply order
• In-process WASM proving: NIGHTGATE_PROVING_MODE=wasm is the zero-config default — no proof-server container for dev/test/CI (external proof server recommended for production)
• Fee sponsoring: sponsorSessionId on all submission actions — the caller wallet needs neither NIGHT nor dust
• ZK predicate attestations: issuePredicateAttestation / issueFieldPredicateAttestation prove value ≤/≥ threshold without revealing the value; verifyAttestationState / verifyPredicateState verify crawler-free, cross-network
• Document anchoring: anchorDocument / verifyDocument — hash on-chain, caller-managed storage
• Disclosure ACLs: grantDisclosure / revokeDisclosure + registerGranteeIdentity gate who can read disclosed values
• Passport registrar: registerPassport with bind-takeover guard
• Token transfers: sendNight auto-detects the receiver ledger and moves NIGHT or custom tokens (tokenTypeHex); getWalletBalance / estimateSendNightFee for diagnostics
• Browser connector surface: @odatano/nightgate/browser + /zk-config + /contract-manifest for wallet-driven (Lace) contract calls
• Offline mode: the CAP app starts even if the upstream node is unreachable
• AI agents: @odatano/nightgate-mcp exposes the attestation layer (anchor, prove, verify, grant) as MCP tools — scoped by ngat_… agent-grant tokens

Stack

Architecture

Main thread                       Worker thread
┌────────────────────┐            ┌────────────────────────┐
│ Crawler            │            │ Wallet SDK             │
│ - BlockProcessor   │            │ - facade.start (sync)  │
│ - reorg detection  │            │ - transferTransaction  │
└────────┬───────────┘            │ - deployContract       │
         ▼  atomic writes         │ - submitContractCall   │
┌────────────────────┐            └───────────┬────────────┘
│ CAP DB             │◄────state-save─────────┘
└────────┬───────────┘
         ▼  OData V4
4 services on /api/v1/{nightgate, indexer, analytics, admin}

The wallet SDK lives in worker_threads because Midnight’s Effect.ts fiber scheduler saturates the microtask queue during sync — isolation keeps the main CAP request pipeline responsive.

Service Surface

Submit actions are async: they return { jobId, status }; poll getJobStatus(jobId, sessionId) for the result. The job model is a durable, restart-safe state machine — idempotency keys, lease/heartbeat, on-chain chainStatus tracked separately from the job status, Prometheus job gauges.

Use as a CAP Plugin

{
  "cds": {
    "requires": {
      "db": { "kind": "sqlite" },
      "nightgate": { "network": "preprod" }
    }
  }
}

Then cds watch — network is the only required key; defaults use the public RPC + hosted indexer.

Quick Start

npm install @odatano/nightgate @cap-js/sqlite
npm ci
npm run dev            # connects to public preprod RPC + hosted indexer

# wallet signing + submission — proving runs in-process by default (WASM):
npm run serve:sync     # sets the ~12 GB heap (override via NIGHTGATE_HEAP_MB)

# optional, recommended for production — external proof server:
docker compose -f docker/docker-compose.yml up -d proof-server

Sourcecode

github.com/ODATANO/NIGHTGATE