@langchain/core/dist/callbacks/base.js

Core LangChain.js abstractions and schemas

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");
};