使用 fetch() handler

非常常见的用例是通过 function calling 为 LLM 提供执行 API 调用的能力。

在本示例中，LLM 将获取未来 5 天的天气预报。为此定义了 getWeather 函数，并将其作为 tool 传递给 LLM。

getWeather 函数从请求中提取用户位置，通过 Workers 的 Fetch API 调用外部天气 API 并返回结果。

Embedded function calling example with fetch()ts

import { runWithTools } from '@cloudflare/ai-utils';

type Env = {
	AI: Ai;
};

export default {
	async fetch(request, env, ctx) {
		// Define function
		const getWeather = async (args: { numDays: number }) => {
			const { numDays } = args;
      // Location is extracted from request based on
      // https://developers.cloudflare.com/workers/runtime-apis/request/#incomingrequestcfproperties
      const lat = request.cf?.latitude
      const long = request.cf?.longitude

      // Interpolate values for external API call
			const response = await fetch(
				`https://api.open-meteo.com/v1/forecast?latitude=${lat}&longitude=${long}&daily=temperature_2m_max,precipitation_sum&timezone=GMT&forecast_days=${numDays}`
			);
			return response.text();
		};
		// Run AI inference with function calling
		const response = await runWithTools(
			env.AI,
			// Model with function calling support
			'@hf/nousresearch/hermes-2-pro-mistral-7b',
			{
				// Messages
				messages: [
					{
						role: 'user',
						content: 'What the weather like the next 5 days? Respond as text',
					},
				],
				// Definition of available tools the AI model can leverage
				tools: [
					{
						name: 'getWeather',
						description: 'Get the weather for the next [numDays] days',
						parameters: {
							type: 'object',
							properties: {
								numDays: { type: 'numDays', description: 'number of days for the weather forecast' },
							},
							required: ['numDays'],
						},
						// reference to previously defined function
						function: getWeather,
					},
				],
			}
		);
		return new Response(JSON.stringify(response));
	},
} satisfies ExportedHandler<Env>;