156 lines
5.1 KiB
JavaScript
156 lines
5.1 KiB
JavaScript
import { BaseStore } from "@langchain/core/stores";
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/**
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* Class that extends the BaseStore class to interact with a Redis
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* database. It provides methods for getting, setting, and deleting data,
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* as well as yielding keys from the database.
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* @example
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* ```typescript
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* const store = new RedisByteStore({ client: new Redis({}) });
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* await store.mset([
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* [
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* "message:id:0",
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* new TextEncoder().encode(JSON.stringify(new AIMessage("ai stuff..."))),
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* ],
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* [
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* "message:id:1",
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* new TextEncoder().encode(
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* JSON.stringify(new HumanMessage("human stuff...")),
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* ),
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* ],
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* ]);
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* const retrievedMessages = await store.mget(["message:id:0", "message:id:1"]);
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* console.log(retrievedMessages.map((v) => new TextDecoder().decode(v)));
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* const yieldedKeys = [];
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* for await (const key of store.yieldKeys("message:id:")) {
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* yieldedKeys.push(key);
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* }
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* console.log(yieldedKeys);
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* await store.mdelete(yieldedKeys);
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* ```
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*/
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export class RedisByteStore 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, "client", {
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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, "ttl", {
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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, "namespace", {
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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, "yieldKeysScanBatchSize", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: 1000
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});
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this.client = fields.client;
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this.ttl = fields.ttl;
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this.namespace = fields.namespace;
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this.yieldKeysScanBatchSize =
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fields.yieldKeysScanBatchSize ?? this.yieldKeysScanBatchSize;
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}
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_getPrefixedKey(key) {
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if (this.namespace) {
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const delimiter = "/";
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return `${this.namespace}${delimiter}${key}`;
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}
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return key;
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}
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_getDeprefixedKey(key) {
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if (this.namespace) {
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const delimiter = "/";
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return key.slice(this.namespace.length + delimiter.length);
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}
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return key;
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}
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/**
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* Gets multiple keys from the Redis database.
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* @param keys Array of keys to be retrieved.
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* @returns An array of retrieved values.
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*/
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async mget(keys) {
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const prefixedKeys = keys.map(this._getPrefixedKey.bind(this));
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const retrievedValues = await this.client.mgetBuffer(prefixedKeys);
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return retrievedValues.map((value) => {
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if (!value) {
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return undefined;
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}
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else {
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return value;
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}
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});
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}
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/**
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* Sets multiple keys in the Redis database.
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* @param keyValuePairs Array of key-value pairs to be set.
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* @returns Promise that resolves when all keys have been set.
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*/
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async mset(keyValuePairs) {
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const decoder = new TextDecoder();
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const encodedKeyValuePairs = keyValuePairs.map(([key, value]) => [
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this._getPrefixedKey(key),
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decoder.decode(value),
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]);
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const pipeline = this.client.pipeline();
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for (const [key, value] of encodedKeyValuePairs) {
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if (this.ttl) {
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pipeline.set(key, value, "EX", this.ttl);
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}
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else {
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pipeline.set(key, value);
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}
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}
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await pipeline.exec();
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}
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/**
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* Deletes multiple keys from the Redis database.
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* @param keys Array of keys to be deleted.
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* @returns Promise that resolves when all keys have been deleted.
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*/
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async mdelete(keys) {
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await this.client.del(...keys.map(this._getPrefixedKey.bind(this)));
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}
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/**
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* Yields keys from the Redis database.
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* @param prefix Optional prefix to filter the keys.
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* @returns An AsyncGenerator that yields keys from the Redis database.
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*/
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async *yieldKeys(prefix) {
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let pattern;
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if (prefix) {
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const wildcardPrefix = prefix.endsWith("*") ? prefix : `${prefix}*`;
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pattern = this._getPrefixedKey(wildcardPrefix);
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}
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else {
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pattern = this._getPrefixedKey("*");
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}
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let [cursor, batch] = await this.client.scan(0, "MATCH", pattern, "COUNT", this.yieldKeysScanBatchSize);
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for (const key of batch) {
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yield this._getDeprefixedKey(key);
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}
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while (cursor !== "0") {
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[cursor, batch] = await this.client.scan(cursor, "MATCH", pattern, "COUNT", this.yieldKeysScanBatchSize);
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for (const key of batch) {
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yield this._getDeprefixedKey(key);
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}
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}
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}
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}
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