import * as uuid from "uuid"; import { Serializable, get_lc_unique_name, } from "../load/serializable.js"; import { getEnvironmentVariable } from "../utils/env.js"; /** * Abstract class that provides a set of optional methods that can be * overridden in derived classes to handle various events during the * execution of a LangChain application. */ class BaseCallbackHandlerMethodsClass { } export function callbackHandlerPrefersStreaming(x) { return "lc_prefer_streaming" in x && x.lc_prefer_streaming; } /** * Abstract base class for creating callback handlers in the LangChain * framework. It provides a set of optional methods that can be overridden * in derived classes to handle various events during the execution of a * LangChain application. */ export class BaseCallbackHandler extends BaseCallbackHandlerMethodsClass { get lc_namespace() { return ["langchain_core", "callbacks", this.name]; } get lc_secrets() { return undefined; } get lc_attributes() { return undefined; } get lc_aliases() { return undefined; } get lc_serializable_keys() { return undefined; } /** * The name of the serializable. Override to provide an alias or * to preserve the serialized module name in minified environments. * * Implemented as a static method to support loading logic. */ static lc_name() { return this.name; } /** * The final serialized identifier for the module. */ get lc_id() { return [ ...this.lc_namespace, get_lc_unique_name(this.constructor), ]; } constructor(input) { super(); Object.defineProperty(this, "lc_serializable", { enumerable: true, configurable: true, writable: true, value: false }); Object.defineProperty(this, "lc_kwargs", { enumerable: true, configurable: true, writable: true, value: void 0 }); Object.defineProperty(this, "ignoreLLM", { enumerable: true, configurable: true, writable: true, value: false }); Object.defineProperty(this, "ignoreChain", { enumerable: true, configurable: true, writable: true, value: false }); Object.defineProperty(this, "ignoreAgent", { enumerable: true, configurable: true, writable: true, value: false }); Object.defineProperty(this, "ignoreRetriever", { enumerable: true, configurable: true, writable: true, value: false }); Object.defineProperty(this, "ignoreCustomEvent", { enumerable: true, configurable: true, writable: true, value: false }); Object.defineProperty(this, "raiseError", { enumerable: true, configurable: true, writable: true, value: false }); Object.defineProperty(this, "awaitHandlers", { enumerable: true, configurable: true, writable: true, value: getEnvironmentVariable("LANGCHAIN_CALLBACKS_BACKGROUND") === "false" }); this.lc_kwargs = input || {}; if (input) { this.ignoreLLM = input.ignoreLLM ?? this.ignoreLLM; this.ignoreChain = input.ignoreChain ?? this.ignoreChain; this.ignoreAgent = input.ignoreAgent ?? this.ignoreAgent; this.ignoreRetriever = input.ignoreRetriever ?? this.ignoreRetriever; this.ignoreCustomEvent = input.ignoreCustomEvent ?? this.ignoreCustomEvent; this.raiseError = input.raiseError ?? this.raiseError; this.awaitHandlers = this.raiseError || (input._awaitHandler ?? this.awaitHandlers); } } copy() { return new this.constructor(this); } toJSON() { return Serializable.prototype.toJSON.call(this); } toJSONNotImplemented() { return Serializable.prototype.toJSONNotImplemented.call(this); } static fromMethods(methods) { class Handler extends BaseCallbackHandler { constructor() { super(); Object.defineProperty(this, "name", { enumerable: true, configurable: true, writable: true, value: uuid.v4() }); Object.assign(this, methods); } } return new Handler(); } } export const isBaseCallbackHandler = (x) => { const callbackHandler = x; return (callbackHandler !== undefined && typeof callbackHandler.copy === "function" && typeof callbackHandler.name === "string" && typeof callbackHandler.awaitHandlers === "boolean"); };