100 lines
3.6 KiB
JavaScript
100 lines
3.6 KiB
JavaScript
import { Document } from "@langchain/core/documents";
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import { BaseStore } from "@langchain/core/stores";
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/**
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* Class that provides a layer of abstraction over the base storage,
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* allowing for the encoding and decoding of keys and values. It extends
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* the BaseStore class.
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*/
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// eslint-disable-next-line @typescript-eslint/no-explicit-any
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export class EncoderBackedStore extends BaseStore {
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constructor(fields) {
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super(fields);
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Object.defineProperty(this, "lc_namespace", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: ["langchain", "storage"]
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});
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Object.defineProperty(this, "store", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "keyEncoder", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "valueSerializer", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "valueDeserializer", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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this.store = fields.store;
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this.keyEncoder = fields.keyEncoder;
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this.valueSerializer = fields.valueSerializer;
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this.valueDeserializer = fields.valueDeserializer;
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}
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/**
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* Method to get multiple keys at once. It works with the encoded keys and
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* serialized values.
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* @param keys Array of keys to get
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* @returns Promise that resolves with an array of values or undefined for each key
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*/
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async mget(keys) {
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const encodedKeys = keys.map(this.keyEncoder);
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const values = await this.store.mget(encodedKeys);
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return values.map((value) => {
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if (value === undefined) {
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return undefined;
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}
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return this.valueDeserializer(value);
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});
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}
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/**
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* Method to set multiple keys at once. It works with the encoded keys and
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* serialized values.
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* @param keyValuePairs Array of key-value pairs to set
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* @returns Promise that resolves when the operation is complete
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*/
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async mset(keyValuePairs) {
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const encodedPairs = keyValuePairs.map(([key, value]) => [this.keyEncoder(key), this.valueSerializer(value)]);
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return this.store.mset(encodedPairs);
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}
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/**
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* Method to delete multiple keys at once. It works with the encoded keys.
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* @param keys Array of keys to delete
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* @returns Promise that resolves when the operation is complete
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*/
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async mdelete(keys) {
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const encodedKeys = keys.map(this.keyEncoder);
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return this.store.mdelete(encodedKeys);
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}
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/**
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* Method to yield keys. It works with the encoded keys.
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* @param prefix Optional prefix to filter keys
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* @returns AsyncGenerator that yields keys
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*/
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async *yieldKeys(prefix) {
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yield* this.store.yieldKeys(prefix);
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}
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}
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export function createDocumentStoreFromByteStore(store) {
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const encoder = new TextEncoder();
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const decoder = new TextDecoder();
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return new EncoderBackedStore({
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store,
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keyEncoder: (key) => key,
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valueSerializer: (doc) => encoder.encode(JSON.stringify({ pageContent: doc.pageContent, metadata: doc.metadata })),
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valueDeserializer: (bytes) => new Document(JSON.parse(decoder.decode(bytes))),
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});
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}
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