02-流式输出

query({
    prompt: userMessage,
    options: {
      pathToClaudeCodeExecutable: '/opt/homebrew/bin/claude',
      model: 'claude-haiku-4-5-20251001',
      resume: sessionId,
      
      // 开启 partial 消息，才会收到 type: 'stream_event' 的增量事件
      includePartialMessages: true,
    },
  });

import { query, type SDKMessage } from '@anthropic-ai/claude-agent-sdk';
import { appendFileSync, mkdirSync } from 'fs';
import { dirname, join } from 'path';
import { createInterface } from 'readline';
import { fileURLToPath } from 'url';

const rl = createInterface({ input: process.stdin, output: process.stdout });
const ask = (prompt: string): Promise<string> =>
  new Promise((resolve) => rl.question(prompt, resolve));

const LOG_DIR = join(dirname(fileURLToPath(import.meta.url)), 'logs');
const LOG_FILE = join(LOG_DIR, `sdk-messages-${new Date().toISOString().replace(/[:.]/g, '-')}.jsonl`);
function writeMsgToFile(msg: SDKMessage): void {
  mkdirSync(LOG_DIR, { recursive: true });
  appendFileSync(LOG_FILE, `${JSON.stringify(msg)}\n`, 'utf8');
}

async function sendMessage(userMessage: string, sessionId?: string): Promise<string | undefined> {
  const q = query({
    prompt: userMessage,
    options: {
      pathToClaudeCodeExecutable: '/opt/homebrew/bin/claude',
      model: 'claude-haiku-4-5-20251001',
      resume: sessionId,
      // 开启 partial 消息，才会收到 type: 'stream_event' 的增量事件
      includePartialMessages: true,
    },
  });

  let sid = sessionId;

  for await (const msg of q) {
    switch (msg.type) {
      case 'system': {
        break;
      }
      default: {
        writeMsgToFile(msg);
        break;
      }
    }
    switch (msg.type) {
      case 'stream_event': {
        // 真正的流式增量：content_block_delta + text_delta
        sid = msg.session_id;
        const event = msg.event;
        if (
          event.type === 'content_block_delta' &&
          event.delta.type === 'text_delta'
        ) {
          process.stdout.write(event.delta.text);
        }
        break;
      }
      case 'assistant': {
        // 完整消息会在流结束后再来一次；正文已由 stream_event 打出，这里只记 session
        sid = msg.session_id;
        break;
      }
      case 'result': {
        if (msg.is_error) {
          console.error(`\n[错误] ${msg.subtype}`);
        } else {
          process.stdout.write('\n');
        }
        break;
      }
      default:
        break;
    }
  }

  return sid;
}

export async function streamingOutput(): Promise<void> {
  console.log('====================================');
  console.log('  Claude Agent SDK 流式输出示例');
  console.log('  输入 "exit" 或按 Ctrl+C 退出');
  console.log('====================================\n');

  let sessionId: string | undefined;

  while (true) {
    let userInput: string;
    try {
      userInput = await ask('你: ');
    } catch {
      break;
    }

    userInput = userInput.trim();
    if (!userInput) continue;
    if (userInput.toLowerCase() === 'exit') break;

    process.stdout.write('\nClaude: ');

    try {
      sessionId = await sendMessage(userInput, sessionId);
    } catch (sdkErr) {
      console.error(`\n[SDK 错误] ${(sdkErr as Error).message}`);
    }

    console.log();
  }

  console.log('\n再见！');
  rl.close();
}