深入解析OpenAI的Function Calling：原理、应用与实践

1561字
8分钟
2024-06-28
- AI

OpenAI的Function Calling功能是一项强大的工具，它使得开发者能够通过自然语言调用预定义的函数。这篇文章将从what、why、how三个角度详细介绍这一功能，并结合实际应用场景给出案例代码和解释。

什么是Function Calling？

定义

Function Calling是OpenAI API的一项功能，允许开发者通过自然语言指令触发预定义的函数。通过这种方式，我们可以将复杂的操作封装在函数中，然后通过简单的自然语言调用这些函数。

工作原理

Function Calling功能依赖于OpenAI模型的自然语言理解能力。开发者定义一组函数，并将这些函数的描述传递给模型。当用户提供自然语言指令时，模型会解析这些指令并调用相应的函数。

为什么使用Function Calling？

简化复杂操作

Function Calling可以将复杂的操作封装在简单的函数调用中，使得用户无需了解底层实现细节。例如，我们可以定义一个函数来查询数据库，然后通过自然语言指令调用该函数。

提高开发效率

通过Function Calling，开发者可以更快速地构建和扩展应用程序。我们只需定义好函数和描述，剩下的工作交给OpenAI模型来完成。

增强用户体验

Function Calling使得用户可以通过自然语言与应用程序进行交互，提供更直观和友好的用户体验。这在构建聊天机器人、虚拟助手等应用中尤为有用。

如何使用Function Calling？

定义函数

首先，我们需要定义要调用的函数，并为每个函数提供描述。这些描述将帮助模型理解函数的用途和参数。

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export function getWeather(location) {
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  // 假设这是一个查询天气的函数
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  return `The weather in ${location} is sunny.`;
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}
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export function getNews(topic) {
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  // 假设这是一个查询新闻的函数
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  return `Here are the latest news about ${topic}.`;
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}

配置API请求

在API请求中，我们需要传递函数描述和用户输入。模型将根据用户输入调用相应的函数。

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import { OpenAI } from "openai";
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import { getWeather, getNews } from "./functions";
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// 配置 OpenAI API
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const openai = new OpenAI({
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  apiKey: process.env.OPENAI_API_KEY,
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});
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// 定义函数映射
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const functions = {
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  getWeather,
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  getNews,
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};
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// 配置模型
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async function callOpenAIFunction(prompt) {
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  const response = await openai.chat.completions.create({
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    model: "gpt-4-0613", // 使用支持 Function Calling 的模型
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    messages: [
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      { role: "system", content: "You are a helpful assistant." },
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      { role: "user", content: prompt },
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    ],
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    functions: [
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      {
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        name: "getWeather",
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        description: "Get the current weather for a given location.",
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        parameters: {
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          type: "object",
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          properties: {
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            location: {
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              type: "string",
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              description: "The name of the location to get the weather for.",
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            },
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          },
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          required: ["location"],
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        },
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      },
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      {
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        name: "getNews",
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        description: "Get the latest news for a given topic.",
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        parameters: {
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          type: "object",
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          properties: {
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            topic: {
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              type: "string",
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              description: "The topic to get news about.",
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            },
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          },
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          required: ["topic"],
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        },
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      },
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    ],
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  });
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  const message = response.choices[0].message;
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  if (message.tool_calls) {
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    for (const tool_call of message.tool_calls) {
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      const functionName = tool_call.function.name;
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      const functionToCall = functions[functionName];
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      const functionArgs = JSON.parse(tool_call.function.arguments);
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      const functionResult = functionToCall(...Object.values(functionArgs));
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      console.log(
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        `Function ${functionName} called with result: ${functionResult}`,
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      );
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    }
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  } else {
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    console.log(`Model response: ${message.content}`);
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  }
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}
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// 调用示例
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callOpenAIFunction("Get the weather in New York.");
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callOpenAIFunction("Get the latest news about technology.");

实际应用场景

场景1：智能家居控制

在智能家居系统中，我们可以定义函数来控制各个设备，并通过自然语言指令进行控制。

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export function turnOnLight(room) {
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  return `Turning on the light in the ${room}.`;
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}
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export function setThermostat(temperature) {
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  return `Setting thermostat to ${temperature} degrees.`;
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}
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// 配置 OpenAI API
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const openai = new OpenAI({
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  apiKey: process.env.OPENAI_API_KEY,
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});
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// 定义函数映射
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const functions = {
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  turnOnLight,
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  setThermostat,
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};
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// 配置模型
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async function callOpenAIFunction(prompt) {
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  const response = await openai.chat.completions.create({
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    model: "gpt-4-0613", // 使用支持 Function Calling 的模型
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    messages: [
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      { role: "system", content: "You are a helpful assistant." },
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      { role: "user", content: prompt },
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    ],
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    functions: [
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      {
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        name: "turnOnLight",
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        description: "Turn on the light in a specific room.",
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        parameters: {
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          type: "object",
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          properties: {
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            room: {
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              type: "string",
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              description: "The name of the room to turn on the light.",
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            },
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          },
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          required: ["room"],
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        },
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      },
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      {
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        name: "setThermostat",
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        description: "Set the thermostat to a specific temperature.",
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        parameters: {
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          type: "object",
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          properties: {
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            temperature: {
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              type: "number",
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              description: "The temperature to set the thermostat to.",
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            },
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          },
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          required: ["temperature"],
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        },
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      },
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    ],
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  });
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  const message = response.choices[0].message;
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  if (message.tool_calls) {
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    for (const tool_call of message.tool_calls) {
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      const functionName = tool_call.function.name;
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      const functionToCall = functions[functionName];
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      const functionArgs = JSON.parse(tool_call.function.arguments);
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      const functionResult = functionToCall(...Object.values(functionArgs));
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      console.log(
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        `Function ${functionName} called with result: ${functionResult}`,
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      );
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    }
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  } else {
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    console.log(`Model response: ${message.content}`);
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  }
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}
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// 调用示例
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callOpenAIFunction("Turn on the light in the living room.");
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callOpenAIFunction("Set the thermostat to 22 degrees.");

场景2：客户支持

在客户支持系统中，我们可以定义函数来处理常见问题，并通过自然语言指令进行调用。

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export function checkOrderStatus(orderId) {
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  return `Order ${orderId} is currently being processed.`;
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}
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export function cancelOrder(orderId) {
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  return `Order ${orderId} has been cancelled.`;
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}
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// 配置 OpenAI API
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const openai = new OpenAI({
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  apiKey: process.env.OPENAI_API_KEY,
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});
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// 定义函数映射
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const functions = {
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  checkOrderStatus,
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  cancelOrder,
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};
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// 配置模型
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async function callOpenAIFunction(prompt) {
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  const response = await openai.chat.completions.create({
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    model: "gpt-4-0613", // 使用支持 Function Calling 的模型
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    messages: [
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      { role: "system", content: "You are a helpful assistant." },
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      { role: "user", content: prompt },
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    ],
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    functions: [
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      {
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        name: "checkOrderStatus",
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        description: "Check the status of an order.",
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        parameters: {
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          type: "object",
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          properties: {
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            orderId: {
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              type: "string",
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              description: "The ID of the order to check.",
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            },
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          },
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          required: ["orderId"],
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        },
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      },
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      {
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        name: "cancelOrder",
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        description: "Cancel an order.",
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        parameters: {
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          type: "object",
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          properties: {
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            orderId: {
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              type: "string",
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              description: "The ID of the order to cancel.",
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            },
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          },
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          required: ["orderId"],
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        },
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      },
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    ],
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  });
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  const message = response.choices[0].message;
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  if (message.tool_calls) {
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    for (const tool_call of message.tool_calls) {
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      const functionName = tool_call.function.name;
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      const functionToCall = functions[functionName];
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      const functionArgs = JSON.parse(tool_call.function.arguments);
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      const functionResult = functionToCall(...Object.values(functionArgs));
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      console.log(
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        `Function ${functionName} called with result: ${functionResult}`,
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      );
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    }
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  } else {
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    console.log(`Model response: ${message.content}`);
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  }
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}
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// 调用示例
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callOpenAIFunction("Check the status of order 12345.");
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callOpenAIFunction("Cancel order 12345.");