SAP CAP plugin: Midnight blockchain indexer + transaction submission, exposed as OData V4.
@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 or custom tokens on both the shielded and the unshielded ledger, dust generation, fee sponsoring). The whole surface is exposed through standard OData V4.
┌──────────────────────────────────────┐
│ Midnight Preview / Preprod │
│ Substrate Node GraphQL Indexer │
└──────────────┬──────────────┬────────┘
│ │
wss:// │ Substrate │ GraphQL
JSON-RPC │ RPC │ HTTP + WS
▼ ▼
┌───────────────────────────────────────────────────────────────────────────┐
│ NIGHTGATE │
│ │
│ Main thread Worker thread │
│ ┌──────────────────────┐ ┌──────────────────────────┐ │
│ │ Crawler │ │ Wallet SDK │ │
│ │ - BlockProcessor │ │ │ │
│ │ - reorg detection │ │ - facade.start (sync) │ │
│ └─────────┬────────────┘ │ - transferTransaction │ │
│ │ atomic writes │ - finalize (ZK prove) │ │
│ ▼ │ - registerForDustGen │ │
│ ┌──────────────────────┐ │ - deployContract │ │
│ │ CAP DB │◄────state-save──┤ - submitContractCall │ │
│ │ (SQLite / HANA) │ periodic save │ │ │
│ └─────────┬────────────┘ │ - private-state-rpc │ │
│ │ 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; isolating it keeps the main CAP request pipeline responsive.
npm ci
npm run dev Or standalone with Docker, no Node installation and no host app required (published on every release, see docs/docker.md):
docker pull ghcr.io/odatano/nightgate:latest
docker run -d -p 4004:4004 \
-e ENCRYPTION_KEY=$(openssl rand -hex 32) \
-e NIGHTGATE_HTTP_PASSWORD=change-me \
-v nightgate-data:/data \
ghcr.io/odatano/nightgate:latestConfigure the .env file (see .env.example) to point to a Substrate RPC node and a GraphQL indexer.
# target network
NIGHTGATE_NETWORK=preprod
# Substrate RPC node
NIGHTGATE_NODE_URL=wss://rpc.preprod.midnight.network/
# GraphQL indexer (HTTP only; WS derived from it)
NIGHTGATE_INDEXER_HTTP_URL=https://indexer.preprod.midnight.network/api/v4/graphql
# Proving defaults to fully in-process (wasm): no proof server needed.
# For production, run the proof-server container (compose:
# midnightntwrk/proof-server on :6300) and point at it; configuring the URL
# selects server proving automatically.
# NIGHTGATE_PROOF_SERVER_URL=http://localhost:6300
NIGHTGATE_CRAWLER_ENABLED=false
ENCRYPTION_KEY=<random secret> For the full first-time-sync walkthrough see docs/quickstart.md.
Four OData V4 services: NightgateService (/api/v1/nightgate: chain data, wallet sessions, all token / contract / attestation actions), NightgateIndexerService (/api/v1/indexer: sync state, health, metrics, crawler control), NightgateAnalyticsService (/api/v1/analytics: aggregate counts), NightgateAdminService (/api/v1/admin: session administration).
Submit actions are async: they return { jobId, status }; poll getJobStatus(jobId, sessionId) for the result. Exhaustive signatures, error codes, and curl examples: docs/actions.md.
| Capability | Surface |
|---|---|
| Block indexing | Live + catch-up crawler with reorg detection (srv/crawler/); standard OData ($filter, $orderby, $top, $expand) on Blocks, Transactions, ContractActions, UnshieldedUtxos, NightBalances |
| Wallet sessions | connectWallet (viewing key, read-only) upgraded via connectWalletForSigning (BIP39 mnemonic, HD-derived to match Lace); AES-256-GCM at rest, sessions bound to the requesting user |
| Token ops | sendNight (receiver ledger auto-detected; optional tokenTypeHex sends any custom token instead of NIGHT, shielded or unshielded depending on the receiver address), registerForDustGeneration / deregisterFromDustGeneration |
| Fee sponsoring | Generation delegation (registerForDustGeneration with a foreign dustReceiverAddress, own dust address via deriveWalletInfo) and per-tx sponsorship (optional sponsorSessionId on all submit actions: a second session pays the dust fee; cross-user use gated via NIGHTGATE_FEE_SPONSOR_SESSION) |
| Pre-flight | getWalletBalance, estimateSendNightFee, deriveWalletInfo |
| Compact contracts | deployContract / submitContractCall on registered compiled artifacts |
| Proving modes | wasm (default when no proof server is configured: fully in-process for wallet AND contract circuits, no Docker needed) or server (proof-server container, selected automatically by configuring proofServerUrl; recommended for production). Explicit override via NIGHTGATE_PROVING_MODE. |
| Document anchoring | anchorDocument / verifyDocument: sha256 hash on-chain, storage stays with the caller |
| Document ingestion | prepareDocumentProof: canonical JSON -> payloadHash + depth-4 Merkle content root with per-field inclusion paths (numeric and, since 0.15.0, kind: 'bytes' string fields), ready for the field-proof actions; prepareMembershipSet builds the canonical allow-list set root (compute-only, nothing persisted) |
| AI-agent access | createAgentGrant / revokeAgentGrant: scoped bearer tokens (x-agent-token) with action allowlist, daily job budget and pinned session/sponsor (fundless agents); attestAgentOutput anchors third-party-verifiable agent-output provenance. MCP companion: @odatano/nightgate-mcp |
| ZK predicate attestations | issueFieldPredicateAttestation (field-bound via salted content root) / issueFieldPredicateAttestationBatch (up to 8 field proofs in ONE tx, mixed kinds): prove value ≤/≥ threshold without revealing the value; verifyPredicateAttestation to check. (The commitment-only issuePredicateAttestation lane was removed in 0.16.0.) |
| Bytes equality + membership proofs | issueFieldEqualityAttestation (field carries exactly the value behind a public digest) and issueFieldMembershipAttestation (hidden value is ONE OF a public allow-list of up to 64 values, without revealing which), batchable alongside numeric claims (0.15.0) |
| Cross-root document proofs | issueDocumentIntegrityAttestation (document B differs from document A ONLY in a public 16-bit slot mask) and issueDocumentDiffAttestation (at least k of 16 aligned slots differ): one proof relating TWO anchored salted content roots, values hidden, schema ids proven in-circuit (0.16.0) |
| Crawler-free verification | verifyAttestationState / verifyPredicateState / reindexDisclosures read live contract state from the public indexer (per-call network override, no wallet, no local index) |
| Tiered disclosure (RBAC) | grantDisclosure / revokeDisclosure (+ registerGranteeIdentity), on-chain DisclosureGrants index, AttestationService mixin with EU Battery Reg tiers |
| Cross-server fee sponsoring | @odatano/nightgate/txbuilder (or the slim standalone package @odatano/nightgate-tx, under 1 MB): build, prove and sign a contract call on YOUR machine with YOUR key (wasm proving, prover keys fetched from a public /zk-config and cached), then hand the ~5 KB fee-unpaid transaction to sponsorFinalizedTransaction, which pays the dust and submits. The attestation carries the caller's identity; the sponsor never sees a key, witness or preimage (0.17.0) |
| Browser / connector | @odatano/nightgate/browser (providers, witnesses, prepareAttest / prepareGrantDisclosure / prepareRevokeDisclosure) + GET /zk-config/<contract>/… + GET /contract-manifest: a wallet-driven dApp (Lace) needs neither the Compact toolchain nor managed/ artifacts |
| Operations | Health / liveness / readiness, Prometheus metrics, pauseCrawler / resumeCrawler / reindexFromHeight, offline start (boots without upstream node), optional local indexer via docker-compose |
- Quickstart: get from zero to first wallet-signed transaction
- Actions reference: every OData action + function with examples
- Architecture: worker-thread design, submission flow, persistence model
- Operations: running NIGHTGATE day to day, scripts, local indexer, troubleshooting
- Docker: standalone container (
ghcr.io/odatano/nightgate), configuration, schema upgrades - Transaction builder: build sponsorable transactions locally, without a NIGHTGATE server
- Reference: full configuration matrix + project structure
- Changelog: notable changes by version
cd my-cap-app
npm install @odatano/nightgate @cap-js/sqlite{
"cds": {
"requires": {
"db": { "kind": "sqlite" },
"nightgate": { "network": "preprod" }
}
}
}Then cds watch. network is the only required key; everything else defaults to fully public endpoints: Preprod's public RPC, the hosted indexer, and in-process (wasm) proving, so no local container is required. Configure a proof-server URL to switch to server proving (recommended for production). Override via env vars or CDS config, see docs/reference.md#configuration.
npm run dev # cds watch with 12 GB heap (scripts/dev.mjs)
npm run serve:sync # cds-serve with 12 GB heap, use this for long sync runs
npm run sync:start # bootstrap a wallet session against the running server
npm run typecheck # tsc --noEmit
npm run lint # ESLint
npm test # full Vitest suite with coverage
npm run build # Compile CDS types + TypeScript to JS
# Integration scripts (real SDK, no chain access required)
npm run smoke:sdk # all SDK packages load
npm run integration:providers # + wallet-keys, wallet-facade, contract-registry,
# connector-routes, attestation-vault, derive-wallet-info
# Live e2e against preprod (funded wallet required)
npm run deploy:e2e # + predicate:e2e, disclosure:e2e, state-verify:e2e,
# wasm-proving:e2e, wasm-contract:e2e, wasm-zswap:e2e