Backend Types

Backend

type Backend = {
  metadata: MetadataClient
  data: DataClient
  on_event?: EventHandler
}

---

MetadataClient

type MetadataClient = {
  get: (store_id: string, version: string) => Promise<Result<SnapshotMeta, CorpusError>>
  put: (meta: SnapshotMeta) => Promise<Result<void, CorpusError>>
  delete: (store_id: string, version: string) => Promise<Result<void, CorpusError>>
  list: (store_id: string, opts?: ListOpts) => AsyncIterable<SnapshotMeta>
  get_latest: (store_id: string) => Promise<Result<SnapshotMeta, CorpusError>>
  get_children: (parent_store_id: string, parent_version: string) => AsyncIterable<SnapshotMeta>
  find_by_hash: (store_id: string, content_hash: string) => Promise<SnapshotMeta | null>
}

---

DataClient

type DataClient = {
  get: (data_key: string) => Promise<Result<DataHandle, CorpusError>>
  put: (data_key: string, data: ReadableStream<Uint8Array> | Uint8Array) => Promise<Result<void, CorpusError>>
  delete: (data_key: string) => Promise<Result<void, CorpusError>>
  exists: (data_key: string) => Promise<boolean>
}

---

DataHandle

type DataHandle = {
  stream: () => ReadableStream<Uint8Array>
  bytes: () => Promise<Uint8Array>
}

---

CorpusEvent

type CorpusEvent =
  | { type: 'meta_get'; store_id: string; version: string; found: boolean }
  | { type: 'meta_put'; store_id: string; version: string }
  | { type: 'meta_delete'; store_id: string; version: string }
  | { type: 'meta_list'; store_id: string; count: number }
  | { type: 'data_get'; store_id: string; version: string; found: boolean }
  | { type: 'data_put'; store_id: string; version: string; size_bytes: number; deduplicated: boolean }
  | { type: 'snapshot_put'; store_id: string; version: string; content_hash: string; deduplicated: boolean }
  | { type: 'snapshot_get'; store_id: string; version: string; found: boolean }
  | { type: 'error'; error: CorpusError }

type EventHandler = (event: CorpusEvent) => void

---

Configuration Types

type MemoryBackendOptions = { on_event?: EventHandler }

type FileBackendConfig = { base_path: string; on_event?: EventHandler }

type CloudflareBackendConfig = { d1: D1Database; r2: R2Bucket; on_event?: EventHandler }

type LayeredBackendOptions = { read: Backend[]; write: Backend[]; list_strategy?: 'merge' | 'first' }