node.js - 将本地文件夹中的图像上传到S3

Question

在我的应用程序中，我将图像上传到本地/tmp 文件夹并进行一些转换。图片已正确保存在那里。之后我想将这些图像上传到 S3 存储桶，但到目前为止我只能生成空白图片。

这是我的代码:

//Pick the local image and make it binary
var fs = require('fs');
var bufferedData = '';
fs.readFile(imagePath, function (err, data) {
   if (err) { throw err; }
   bufferedData = new Buffer(data, 'binary');
}


//Send data to s3    
const uploadToS3 = async (idKey: string, modifiers: string, bufferedData) => {
  try {
    return await S3.upload({
      Bucket: 'mirage-thumbnails',
      Key: `${process.env.APP_ENV}/${idKey}/${modifiers}`,
      Body: bufferedData,
      ContentType: 'image/png',
      ACL: 'public-read',
      CacheControl: 'max-age=0',
    }).promise();
  } catch (e) {
    console.error(e.message, e);
  }
};

Answer 1

readFile 是异步的，需要等到完成后才能上传到 S3。但您可以提供 readable stream 而不是使用 readFile到 s3.upload，这将允许您上传大文件而不会耗尽内存，并使代码更容易一些。

S3.upload({
    Bucket: 'mirage-thumbnails',
    Key: `${process.env.APP_ENV}/${idKey}/${modifiers}`,
    Body: fs.createReadStream(imagePath),
    ContentType: 'image/png',
    ACL: 'public-read',
    CacheControl: 'max-age=0',
}).promise();

<小时/>

在您的代码中，调用 uploadToS3 时，bufferedData 未填充。您应该等到文件被读取，然后调用uploadToS3。代码应如下所示:

const fs = require('fs');
const promisify = require('util').promisify;

// Promisify readFile, to make code cleaner and easier.
const readFile = promisify(fs.readFile);

const uploadToS3 = async(idKey, modifiers, data) => {
  return S3.upload({
    Bucket: 'mirage-thumbnails',
    Key: `${process.env.APP_ENV}/${idKey}/${modifiers}`,
    Body: data,
    ContentType: 'image/png',
    ACL: 'public-read',
    CacheControl: 'max-age=0',
  }).promise();
};

const uploadImage = async(path) => {
  const data = await readFile(imagePath);
  // Wait until the file is read
  return uploadToS3('key', 'modifier', data);
};

uploadImage('./some/path/image.png')
  .then(() => console.log('uploaded!'))
  .catch(err => console.error(err));

<小时/>

使用流，只需将 uploadImage 更改为:

const uploadImage = async(path) => {
      const stream = fs.createReadStream(path);
      return uploadToS3('key', 'modifier', stream);
};