如何在React JS中从S3存储桶中获取5个最新文件？

Question

I am using aws-sdk to get object list as below:

 const AWS = require('aws-sdk/global');

 const S3 = require('aws-sdk/clients/s3');

 AWS.config.update({ accessKeyId: 'abc123', secretAccessKey: 'teyb3872312', region: 'eu-west-1' });
 const s3 = new AWS.S3();

const params = {
  Bucket: 'demo-bucket',
  Delimiter: '',
  Prefix: '',
};

  s3.listObjectsV2(params, (err, data) => {
  if (err) throw err;
  console.log(data.Contents);
 })

From this code i am getting all thousand objects from the bucket, but want only 5 latest object from the bucket.

Please suggest if anyone know the solution.

Answer 1

It is not possible to request a listing based upon LastModified .

Instead, your application will need to retrieve the entire list, then sort the objects returned by LastModified and then select the newest 5.

Also, please note that a maximum of 1000 objects will be returned per call. You will need to use the Continuation Token to request the next 1000 objects, and keep repeating until the listing is complete.

If you will be doing this on a regular basis, you might also consider using Amazon S3 Inventory , which can provide a daily listing of all objects in a bucket.

Answer 2

S3 doesn't allow to sort objects by last modified date, so you need to fetch all object and then sort it in your code.

It might cause a performance issue in case of large buckets.

In order to avoid this, you should store object's creation date in some database after upload. You can do it from your code or subscribe to S3 Events and track PUT operations (see https://docs.aws.amazon.com/AmazonS3/latest/API/RESTBucketPUTnotification.html )