const awaitWriteStream = require('await-stream-ready').write;
const sendToWormhole = require('stream-wormhole');
...
const stream = await ctx.getFileStream();

// 文件生成绝对路径
const filename =
  md5(stream.filename) + path.extname(stream.filename).toLocaleLowerCase();

const target = path.join(this.config.baseDir, 'app/public/uploads', filename);

// 生成一个文件写入文件流
const writeStream = fs.createWriteStream(target);
try {
  // 异步把文件流写入
  await awaitWriteStream(stream.pipe(writeStream));
} catch (err) {
  // 如果出现错误，关闭管道
  await sendToWormhole(stream);
  throw err;
}
...