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this PR blob v2 field helpers and reads to the Node SDK.
`blob()` marks a field as blob v2 and lets you set the storage
thresholds. Inputs can be bytes, a URI, or a data/uri struct.
Queries return descriptors. `fetchBlobs()` reads the bytes by row ID,
and `fetchBlobFiles()` gives you lazy handles for full or range reads.
`blobColumns()` lists the blob fields, including nested ones.
Fetch uses the table’s current checkout. It preserves order, duplicates,
and nulls. Holding row IDs across compaction still requires stable row
IDs.
```javascript
const db = await connect("./data");
const video = await readFile("clip.mp4");
const table = await db.createTable(
"videos",
[{ id: 1n, video }],
{
schema: new Schema([
new Field("id", new Int64()),
blob("video"),
]),
},
);
const rows = await table.query().select(["id"]).withRowId().toArray();
const rowIds = rows.map((row) => row._rowid as bigint);
const bytes = await table.fetchBlobs("video", rowIds);
const [handle] = await table.fetchBlobFiles("video", rowIds);
const header = await handle!.readRange(0n, 65536n);
```
### Testing
- cover input validation, thresholds, nested fields, fetch ordering,
nulls, and range reads.
186 lines
5.8 KiB
TypeScript
186 lines
5.8 KiB
TypeScript
// SPDX-License-Identifier: Apache-2.0
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// SPDX-FileCopyrightText: Copyright The LanceDB Authors
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import { Field, Int64, List, Schema, Struct, Utf8 } from "apache-arrow";
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import { makeArrowTable } from "../lancedb/arrow";
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import { BlobFile, blob, coerceBlobValue, isBlobField } from "../lancedb/blob";
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describe("blob()", () => {
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it("marks the field as lance.blob.v2", () => {
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const field = blob("image", { nullable: false });
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expect(field.nullable).toBe(false);
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expect(isBlobField(field)).toBe(true);
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expect(field.metadata.get("ARROW:extension:name")).toBe("lance.blob.v2");
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});
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it("writes encoding thresholds as field metadata", () => {
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const field = blob("video", {
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inlineSizeThreshold: 1024,
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dedicatedSizeThreshold: 2 * 1024 * 1024,
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packFileSizeThreshold: 64 * 1024 * 1024,
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});
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expect(
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field.metadata.get("lance-encoding:blob-inline-size-threshold"),
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).toBe("1024");
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expect(
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field.metadata.get("lance-encoding:blob-dedicated-size-threshold"),
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).toBe(String(2 * 1024 * 1024));
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expect(
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field.metadata.get("lance-encoding:blob-pack-file-size-threshold"),
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).toBe(String(64 * 1024 * 1024));
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});
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it("rejects invalid thresholds", () => {
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expect(() => blob("image", { inlineSizeThreshold: -1 })).toThrow(
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/inlineSizeThreshold must be non-negative/,
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);
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expect(() => blob("image", { dedicatedSizeThreshold: 0 })).toThrow(
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/dedicatedSizeThreshold must be positive/,
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);
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expect(() => blob("image", { packFileSizeThreshold: 1.5 })).toThrow(
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/packFileSizeThreshold must be a safe integer/,
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);
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expect(() =>
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blob("image", { dedicatedSizeThreshold: Number.MAX_SAFE_INTEGER + 1 }),
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).toThrow(/dedicatedSizeThreshold must be a safe integer/);
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});
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});
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describe("coerceBlobValue", () => {
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it.each([
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["Buffer", Buffer.from("x"), { data: Buffer.from("x"), uri: null }],
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[
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"Uint8Array",
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new Uint8Array([120]),
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{ data: new Uint8Array([120]), uri: null },
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],
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["URI string", "s3://bucket/key", { data: null, uri: "s3://bucket/key" }],
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[
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"data struct",
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{ data: Buffer.from("y") },
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{ data: Buffer.from("y"), uri: null },
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],
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[
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"uri struct",
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{ uri: "s3://bucket/key" },
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{ data: null, uri: "s3://bucket/key" },
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],
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["null", null, null],
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])("accepts %s", (_name, input, expected) => {
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expect(coerceBlobValue(input)).toEqual(expected);
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});
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it.each([
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["empty URI", "", /uri cannot be empty/],
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["object without data or uri", { position: 0 }, /data' or 'uri/],
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[
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"Int16Array",
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new Int16Array([1]),
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/Blob data must be Buffer or Uint8Array/,
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],
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[
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"both data and uri",
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{ data: Buffer.from("y"), uri: "s3://bucket/key" },
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/exactly one of 'data' or 'uri'/,
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],
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[
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"neither data nor uri",
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{ data: null, uri: null },
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/exactly one of 'data' or 'uri'/,
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],
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])("rejects %s", (_name, input, message) => {
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expect(() => coerceBlobValue(input)).toThrow(message);
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});
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});
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describe("BlobFile", () => {
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it("rejects constructing BlobFile without a native handle", () => {
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expect(() => new (BlobFile as unknown as { new (): BlobFile })()).toThrow(
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/fetchBlobFiles/,
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);
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});
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});
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describe("makeArrowTable blob columns", () => {
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it("coerces Buffer input onto a blob field", () => {
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const schema = new Schema([
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new Field("id", new Int64(), true),
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blob("image"),
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]);
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const table = makeArrowTable([{ id: 1n, image: Buffer.from("hello") }], {
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schema,
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});
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expect(isBlobField(table.schema.fields[1])).toBe(true);
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const image = table.getChild("image")!;
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expect(image.nullCount).toBe(0);
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expect(image.getChild("uri")!.get(0)).toBeNull();
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expect(image.getChild("data")!.nullCount).toBe(0);
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expect(Buffer.from(image.getChild("data")!.get(0)!).toString()).toBe(
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"hello",
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);
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});
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it("coerces Buffer elements inside a list and keeps null slots", () => {
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const schema = new Schema([
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new Field("id", new Int64(), true),
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new Field("images", new List(blob("image")), true),
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]);
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const table = makeArrowTable(
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[
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{ id: 1n, images: [Buffer.from("a"), Buffer.from("bb")] },
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{ id: 2n, images: null },
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{ id: 3n, images: [Buffer.from("c"), null] },
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{ id: 4n, images: [] },
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],
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{ schema },
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);
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const images = table.getChild("images")!;
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expect(images.nullCount).toBe(1);
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const rows = images.toArray();
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expect(rows[1]).toBeNull();
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expect(Array.from(rows[3] as Iterable<unknown>)).toHaveLength(0);
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const first = Array.from(rows[0] as Iterable<{ data: Uint8Array | null }>);
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expect(Buffer.from(first[0].data!).toString()).toBe("a");
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expect(Buffer.from(first[1].data!).toString()).toBe("bb");
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const third = Array.from(
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rows[2] as Iterable<{ data: Uint8Array | null } | null>,
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);
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expect(Buffer.from(third[0]!.data!).toString()).toBe("c");
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expect(third[1]).toBeNull();
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});
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it("coerces Buffer fields inside list structs", () => {
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const schema = new Schema([
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new Field("id", new Int64(), true),
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new Field(
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"items",
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new List(
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new Field(
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"item",
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new Struct([new Field("name", new Utf8(), true), blob("image")]),
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true,
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),
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),
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true,
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),
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]);
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const table = makeArrowTable(
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[
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{
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id: 1n,
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items: [{ name: "one", image: Buffer.from("alpha") }],
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},
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],
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{ schema },
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);
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const items = Array.from(
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table.getChild("items")!.toArray()[0] as Iterable<{
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name: string;
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image: { data: Uint8Array | null };
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}>,
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);
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expect(items[0].name).toBe("one");
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expect(Buffer.from(items[0].image.data!).toString()).toBe("alpha");
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});
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});
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