Access S3 Bucket by using key

Question

I have a S3 bucket and one Elastic Beanstalk express server on AWS.

There is folder named data and there is another folder named images in that S3 bucket. In data folder I have some strict data that I want to access only from ELB express server.

In images folder there are content images that I upload manually and I want to access these images via my mobile app in <Image /> tag by using some secret key. And even if I do not provide that secret key it should not be accessible.

Is there any way to do that? I am junior on AWS! :/

Answer 1

Yess, it took my time however I fixed that issue.

For data folder I created IAM user and role to connect S3 bucket from ELB app and added some policies;

{
    "Version": "2012-10-17",
    "Id": "Policy1528702071704",
    "Statement": [
        {
            "Sid": "Stmt1528702067249",
            "Effect": "Allow",
            "Principal": "*",
            "Action": "s3:GetObject",
            "Resource": "arn:aws:s3:::my-bucket-name/*"
        }
    ]
}

For getting images from mobile app by using key was the hard one because either I will need to make by bucket public or I will need to use preSignedUrl feature from AWS. And I followed the second way. I generated keys from IAM user panel to access S3 bucket by using those keys from app. I decided to access and create preSignedUrl in ELB app since I provide data from ELB app to mobile app. And I created this function;

const getImageURL = () => {
  const params = {
    Bucket: "my-s3-bucket",
    Key: "images/pretty.jpg",
    Expires: 60 * 5,
  };

  const url = await new Promise((resolve, reject) => {
    s3.getSignedUrl("getObject", params, (err, url) => {
      err ? reject(err) : resolve(url);
    });
  });
  return url ?? 'some-public-image';
}

I hope it helps someone else too.