60 lines
2.4 KiB
JavaScript
60 lines
2.4 KiB
JavaScript
import { getEnv } from "@langchain/core/utils/env";
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import { BaseDocumentLoader } from "../base.js";
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/**
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* Abstract class that extends the `BaseDocumentLoader` class. It
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* represents a document loader that loads documents from a buffer. The
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* `load()` method is implemented to read the buffer contents and metadata
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* based on the type of `filePathOrBlob`, and then calls the `parse()`
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* method to parse the buffer and return the documents.
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*/
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export class BufferLoader extends BaseDocumentLoader {
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constructor(filePathOrBlob) {
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super();
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Object.defineProperty(this, "filePathOrBlob", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: filePathOrBlob
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});
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}
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/**
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* Method that reads the buffer contents and metadata based on the type of
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* `filePathOrBlob`, and then calls the `parse()` method to parse the
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* buffer and return the documents.
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* @returns Promise that resolves with an array of `Document` objects.
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*/
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async load() {
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let buffer;
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let metadata;
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if (typeof this.filePathOrBlob === "string") {
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const { readFile } = await BufferLoader.imports();
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buffer = await readFile(this.filePathOrBlob);
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metadata = { source: this.filePathOrBlob };
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}
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else {
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buffer = await this.filePathOrBlob
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.arrayBuffer()
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.then((ab) => Buffer.from(ab));
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metadata = { source: "blob", blobType: this.filePathOrBlob.type };
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}
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return this.parse(buffer, metadata);
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}
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/**
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* Static method that imports the `readFile` function from the
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* `fs/promises` module in Node.js. It is used to dynamically import the
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* function when needed. If the import fails, it throws an error
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* indicating that the `fs/promises` module is not available in the
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* current environment.
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* @returns Promise that resolves with an object containing the `readFile` function.
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*/
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static async imports() {
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try {
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const { readFile } = await import("node:fs/promises");
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return { readFile };
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}
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catch (e) {
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console.error(e);
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throw new Error(`Failed to load fs/promises. TextLoader available only on environment 'node'. It appears you are running environment '${getEnv()}'. See https://<link to docs> for alternatives.`);
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}
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}
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}
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