Getting 403 while downloading files from a certain folder in an Amazon S3 bucket in Spring boot application - spring

Question

I am using one S3 bucket for my Spring boot application.
Here I have created the folder and uploaded files within this in S3 bucket from my Spring boot application with the help of the following upload function. Now, while I am listing the files within the folder, I am able to see them. But I cannot download them, getting 403 always.
Code snippet for uploading, listing the objects and downloading thereafter:
//Download is failing
public File downloadObject(String filePath) {
File file = null;
log.info("Downloading object {} from s3 bucket {}", filePath, bucketName);
try {
file = File.createTempFile(filePath, "");
file.deleteOnExit();
amazonS3.getObject(new GetObjectRequest(bucketName, filePath), file);
} catch (Exception exception) {
exception.stackTrace();
}
return file;
}
//Following function is working perfectly fine
public List<String> listObjects(String pathPrefix) {
final ListObjectsV2Result listingResponse = amazonS3.listObjectsV2(new ListObjectsV2Request()
.withPrefix(pathPrefix)
.withBucketName(bucketName));
if (Objects.nonNull(listingResponse)) {
List<String> result = listingResponse.getObjectSummaries().stream().map(
S3ObjectSummary::getKey).collect(
Collectors.toList());
result.remove(pathPrefix);
return result;
}
return Collections.emptyList();
}
//uploading is also working fine
public void uploadFile(InputStream inputStream, String filePath)
{
try {
amazonS3.putObject(new PutObjectRequest(bucketName, filePath, inputStream, null));
} catch (SdkClientException exception) {
exception.stackTrace();
}
}
S3 bucket permission is as follows:
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "AllowAReadWriteAccessToBucket",
"Effect": "Allow",
"Principal": {
"AWS": "arn:aws:iam::123456:role/abcd"
},
"Action": "s3:*",
"Resource": "arn:aws:s3:::test-bucket/*"
}
]
}
You can see, as per the bucket policy, I have given every permission. Even after this, why the download is failing, not able to figure out. Please help.

Answer 1

First thing I am noticing is you are using the old V1 S3 API. Amazon strongly recommends moving to the AWS SDK for Java V2.
The AWS SDK for Java 2.x is a major rewrite of the version 1.x code base. It’s built on top of Java 8+ and adds several frequently requested features. These include support for non-blocking I/O and the ability to plug in a different HTTP implementation at run time.
The Amazon S3 V2 Java API work nicely in a Spring application. There is a multi service example that shows use of the S3 V2 Java API within a Spring BOOT app. In this use case, we get a byte[] to pass to the Amazon Rekognition service.
To get a byte[] from an object in an Amazon S3 bucket (which is what i assume you mean when you use the word download), you can use V2 code like this:
public byte[] getObjectBytes (String bucketName, String keyName) {
s3 = getClient();
try {
// Create a GetObjectRequest instance
GetObjectRequest objectRequest = GetObjectRequest
.builder()
.key(keyName)
.bucket(bucketName)
.build();
// Get the byte[] from this S3 object
ResponseBytes<GetObjectResponse> objectBytes = s3.getObjectAsBytes(objectRequest);
byte[] data = objectBytes.asByteArray();
return data;
} catch (S3Exception e) {
System.err.println(e.awsErrorDetails().errorMessage());
System.exit(1);
}
return null;
}
Refer to this end to end example that shows you how to perform this use case in a Spring app. Look at the code in the S3Service class.
Creating an example AWS photo analyzer application using the AWS SDK for Java
I just ran this app and it works perfectly...