Files
ocas/packages/core/README.md
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xiaoju 1edb09a8b0 feat: rebrand json-cas → OCAS (Object Content Addressable Store)
- Rename packages: @uncaged/json-cas → @ocas/core, @uncaged/json-cas-fs → @ocas/fs, @uncaged/cli-json-cas → @ocas/cli
- Rename dirs: packages/json-cas → core, json-cas-fs → fs, cli-json-cas → cli
- CLI binary: ocas (removed json-cas and ucas aliases)
- Default store: ~/.ocas (was ~/.uncaged/json-cas)
- Update all imports, tsconfig, biome, docs, tests, snapshots
- Changeset config targets @ocas org and shazhou-ww/ocas GitHub

Closes #3, Closes #4, Closes #5, Closes #6, Closes #7
2026-06-01 06:21:56 +00:00

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# @ocas/core
Core CAS engine — hashing, schema, store, verify, bootstrap.
## Overview
`@ocas/core` is the foundation of the ocas monorepo. It defines content-addressed nodes (`CasNode`), the `Store` interface, XXH64-based hashing with deterministic CBOR, JSON Schema registration and validation (including `cas_ref` links between nodes), bootstrap seeding, and integrity verification.
Other packages build on this layer: `ocas-fs` provides persistence, and `cli-ocas` exposes store operations on the command line.
**Dependencies:** `ajv`, `cborg`, `xxhash-wasm`
## Installation
```bash
bun add @ocas/core
```
## API
All symbols below are exported from `src/index.ts`.
### Types
```typescript
/** 13-character uppercase Crockford Base32 (XXH64) */
type Hash = string;
type CasNode<T = unknown> = {
type: Hash;
payload: T;
timestamp: number; // Unix epoch ms
};
type Store = {
put(typeHash: Hash, payload: unknown): Promise<Hash>;
get(hash: Hash): CasNode | null;
has(hash: Hash): boolean;
listByType(typeHash: Hash): Hash[];
};
type JSONSchema = Record<string, unknown>;
type BootstrapCapableStore = Store & {
[BOOTSTRAP_STORE](payload: unknown): Promise<Hash>;
};
```
### Hashing
```typescript
function computeHash(typeHash: Hash, payload: unknown): Promise<Hash>;
function computeSelfHash(payload: unknown): Promise<Hash>;
function cborEncode(value: unknown): Uint8Array;
```
`computeHash``XXH64(utf8(typeHash) ++ CBOR(payload))` for normal nodes.
`computeSelfHash``XXH64(CBOR(payload))` for bootstrap nodes where `type === hash`.
### Bootstrap
```typescript
const BOOTSTRAP_STORE: unique symbol;
async function bootstrap(store: Store): Promise<Hash>;
```
Writes the meta-schema seed node (idempotent). Requires a `BootstrapCapableStore` (e.g. from `createMemoryStore()`).
### Schema
```typescript
class SchemaValidationError extends Error;
async function putSchema(store: Store, jsonSchema: JSONSchema): Promise<Hash>;
function getSchema(store: Store, typeHash: Hash): JSONSchema | null;
function validate(store: Store, node: CasNode): boolean;
function refs(store: Store, node: CasNode): Hash[];
function walk(
store: Store,
rootHash: Hash,
visitor: (hash: Hash, node: CasNode) => void,
): void;
```
- `putSchema` — stores a schema typed by the meta-schema; returned hash is the `typeHash` for conforming payloads.
- `refs` — collects all `format: "cas_ref"` values in the payload per schema shape.
- `walk` — BFS from `rootHash`, following `cas_ref` edges; cycles are visited once.
### Store
```typescript
function createMemoryStore(): BootstrapCapableStore;
```
In-memory `Store` with type indexing, suitable for tests and ephemeral use.
### Verify
```typescript
async function verify(hash: Hash, node: CasNode): Promise<boolean>;
```
Recomputes hash from `node` and compares to `hash` (self-referencing vs normal rules).
### Example
```typescript
import {
bootstrap,
createMemoryStore,
putSchema,
refs,
validate,
walk,
} from "@ocas/core";
const store = createMemoryStore();
const metaHash = await bootstrap(store);
const personType = await putSchema(store, {
type: "object",
properties: {
name: { type: "string" },
friend: { type: "string", format: "cas_ref" },
},
required: ["name"],
additionalProperties: false,
});
const aliceHash = await store.put(personType, { name: "Alice" });
const bobHash = await store.put(personType, {
name: "Bob",
friend: aliceHash,
});
const bob = store.get(bobHash)!;
console.log(validate(store, bob)); // true
console.log(refs(store, bob)); // [aliceHash]
walk(store, bobHash, (h) => console.log(h)); // bobHash, aliceHash
```
## Internal Structure
| File | Purpose |
|------|---------|
| `types.ts` | `Hash`, `CasNode`, `Store` |
| `hash.ts` | `computeHash`, `computeSelfHash` |
| `cbor.ts` | Deterministic CBOR encoding |
| `bootstrap-capable.ts` | `BOOTSTRAP_STORE` symbol and capability check |
| `bootstrap.ts` | Meta-schema seed and `bootstrap()` |
| `store.ts` | `createMemoryStore()` |
| `mem-store.ts` | Alternate in-memory store (tests only; not exported) |
| `schema.ts` | Schema put/get/validate, `refs`, `walk` |
| `verify.ts` | Node integrity verification |
| `index.ts` | Public exports |
Tests live in `src/*.test.ts` and `tests/`.