这里最简单的解决方法是将PDF文件的缓冲区形式转换为可读流，然后将该流传递给S3。

// Add the following import on your module
const { Readable } = require('stream');

public async storeFile({ request }: HttpContextContract) {

     const hash = crypto.randomBytes(32).toString('hex');
     let key = `PDF-${hash}`;

     const file = request.input('file');
     const fileBuffer = Buffer.from(file, 'base64');
     const stream = new Readable();

     stream.push(fileBuffer)   
     stream.push(null);

     await S3Service.uploadManually2(stream, key);
}

public async uploadManually2(stream: Stream, key: string): Promise<string> {
    const params = {
      Bucket: Env.get('AWS_BUCKET_NAME'),
      Body: stream,
      Key: key,
      ContentType: 'application/pdf',
      ACL: 'public-read',
    }
    await s3.send(new PutObjectCommand(params))

    const url = `https://${Env.get('AWS_BUCKET_NAME')}.s3.amazonaws.com/${key}`
    return url
  }

我最初的目标是从react-native发送一个PDF到S3。首先，我尝试将文件发送到服务器，然后发送到s3，但对我来说，它的工作方式是从react-native直接发送到s3。为此，我安装了库“react-native-aws 3”并使用函数“put”。
这是我使用的代码：

import { RNS3 } from "react-native-aws3"

async function enviaPdfS3(uri, fileName){

  const chave = `PDF-${(Math.random() * 100).toString()}-${fileName}`
  //create a single key for each file

  const file = {
    uri: uri,
    name: key,
    type: 'application/pdf'
  }

  const options = {
    bucket: INSERT YOUR BUCKET'S NAME,
    region: INSERT YOUR BUCKET'S REGION,
    accessKey: INSERT YOUR BUCKET'S ACCESS KEY,
    secretKey: INSERT YOUR BUCKET'S SECRET KEY,
    successActionStatus: 201
  }

  await RNS3.put(file, options)

}