import { zodToJsonSchema } from "zod-to-json-schema"; import { Validator } from "@langchain/core/utils/json_schema"; import { ChatOpenAI } from "@langchain/openai"; import { BaseLLMOutputParser, OutputParserException, } from "@langchain/core/output_parsers"; import { LLMChain } from "../llm_chain.js"; import { OutputFunctionsParser } from "../../output_parsers/openai_functions.js"; function isJsonSchema7Type(x) { return (x.jsonSchema === undefined && x.zodSchema === undefined); } /** * Class that extends the BaseLLMOutputParser class. It provides * functionality for parsing the structured output based on a JSON schema. */ export class FunctionCallStructuredOutputParser extends BaseLLMOutputParser { constructor(fieldsOrSchema) { let fields; if (isJsonSchema7Type(fieldsOrSchema)) { fields = { jsonSchema: fieldsOrSchema }; } else { fields = fieldsOrSchema; } if (fields.jsonSchema === undefined && fields.zodSchema === undefined) { throw new Error(`Must provide at least one of "jsonSchema" or "zodSchema".`); } super(fields); Object.defineProperty(this, "lc_namespace", { enumerable: true, configurable: true, writable: true, value: ["langchain", "chains", "openai_functions"] }); Object.defineProperty(this, "functionOutputParser", { enumerable: true, configurable: true, writable: true, value: new OutputFunctionsParser() }); Object.defineProperty(this, "jsonSchemaValidator", { enumerable: true, configurable: true, writable: true, value: void 0 }); Object.defineProperty(this, "zodSchema", { enumerable: true, configurable: true, writable: true, value: void 0 }); if (fields.jsonSchema !== undefined) { this.jsonSchemaValidator = new Validator(fields.jsonSchema, "7"); } if (fields.zodSchema !== undefined) { this.zodSchema = fields.zodSchema; } } /** * Method to parse the result of chat generations. It first parses the * result using the functionOutputParser, then parses the result against a * zod schema if the zod schema is available which allows the result to undergo * Zod preprocessing, then it parses that result against the JSON schema. * If the result is valid, it returns the parsed result. Otherwise, it throws * an OutputParserException. * @param generations Array of ChatGeneration instances to be parsed. * @returns The parsed result if it is valid according to the JSON schema. */ async parseResult(generations) { const initialResult = await this.functionOutputParser.parseResult(generations); const parsedResult = JSON.parse(initialResult, (_, value) => { if (value === null) { return undefined; } return value; }); if (this.zodSchema) { const zodParsedResult = this.zodSchema.safeParse(parsedResult); if (zodParsedResult.success) { return zodParsedResult.data; } else { throw new OutputParserException(`Failed to parse. Text: "${initialResult}". Error: ${JSON.stringify(zodParsedResult.error.errors)}`, initialResult); } } else if (this.jsonSchemaValidator !== undefined) { const result = this.jsonSchemaValidator.validate(parsedResult); if (result.valid) { return parsedResult; } else { throw new OutputParserException(`Failed to parse. Text: "${initialResult}". Error: ${JSON.stringify(result.errors)}`, initialResult); } } else { throw new Error("This parser requires an input JSON Schema or an input Zod schema."); } } } /** * @deprecated Use {@link https://api.js.langchain.com/functions/langchain.chains_openai_functions.createStructuredOutputRunnable.html | createStructuredOutputRunnable} instead * Create a chain that returns output matching a JSON Schema. * @param input Object that includes all LLMChainInput fields except "outputParser" * as well as an additional required "outputSchema" JSON Schema object. * @returns OpenAPIChain */ export function createStructuredOutputChain(input) { const { outputSchema, llm = new ChatOpenAI({ modelName: "gpt-3.5-turbo-0613", temperature: 0 }), outputKey = "output", llmKwargs = {}, zodSchema, ...rest } = input; if (outputSchema === undefined && zodSchema === undefined) { throw new Error(`Must provide one of "outputSchema" or "zodSchema".`); } const functionName = "output_formatter"; return new LLMChain({ llm, llmKwargs: { ...llmKwargs, functions: [ { name: functionName, description: `Output formatter. Should always be used to format your response to the user.`, parameters: outputSchema, }, ], function_call: { name: functionName, }, }, outputKey, outputParser: new FunctionCallStructuredOutputParser({ jsonSchema: outputSchema, zodSchema, }), ...rest, }); } /** @deprecated Use {@link https://api.js.langchain.com/functions/langchain.chains_openai_functions.createStructuredOutputRunnable.html | createStructuredOutputRunnable} instead */ export function createStructuredOutputChainFromZod(zodSchema, input) { return createStructuredOutputChain({ ...input, outputSchema: zodToJsonSchema(zodSchema), zodSchema, }); }