ceph/doc/radosgw/s3/java.rst
Thiago Arrais 3dbb6f7080 doc: Updates Java examples to current AWS SDK
Signed-off-by: Thiago Arrais <thiago.arrais@gmail.com>
2022-12-28 16:21:50 -03:00

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.. _java:
Java S3 Examples
================
Pre-requisites
--------------
All examples are written against AWS Java SDK 2.17.42. You may need
to change some code when using another client.
Setup
-----
The following examples may require some or all of the following java
classes to be imported:
.. code-block:: java
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.ByteBuffer;
import java.nio.file.Paths;
import java.util.List;
import java.util.ListIterator;
import java.time.Duration;
import software.amazon.awssdk.auth.credentials.AwsCredentials;
import software.amazon.awssdk.auth.credentials.AwsBasicCredentials;
import software.amazon.awssdk.auth.credentials.StaticCredentialsProvider;
import software.amazon.awssdk.core.sync.RequestBody;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.Bucket;
import software.amazon.awssdk.services.s3.model.ListBucketsResponse;
import software.amazon.awssdk.services.s3.model.ListObjectsResponse;
import software.amazon.awssdk.services.s3.model.ObjectCannedACL;
import software.amazon.awssdk.services.s3.model.S3Exception;
import software.amazon.awssdk.services.s3.model.S3Object;
import software.amazon.awssdk.services.s3.presigner.S3Presigner;
import software.amazon.awssdk.services.s3.presigner.model.PresignedGetObjectRequest;
If you are just testing the Ceph Object Storage services, consider
using HTTP protocol instead of HTTPS protocol.
First, import the ``AwsBasicCredentials`` and ``S3Client`` classes.
.. code-block:: java
import software.amazon.awssdk.auth.credentials.AwsBasicCredentials;
import software.amazon.awssdk.services.s3.S3Client;
Then, use the client builder to create an S3 client:
.. code-block:: java
AwsBasicCredentials credentials = AwsBasicCredentials.create(accessKey, secretKey);
S3Client client = S3Client.builder()
.endpointOverride(new URI("https://endpoint.com"))
.credentialsProvider(StaticCredentialsProvider.create(credentials))
.serviceConfiguration(srvcConf -> {
srvcConf.pathStyleAccessEnabled();
})
.region(Region.US_EAST_1) // this is not used, but the AWS SDK requires it
.build();
Listing Owned Buckets
---------------------
This gets a list of Buckets that you own.
This also prints out the bucket name and creation date of each bucket.
.. code-block:: java
ListBucketsResponse lbResponse = client.listBuckets();
for (Bucket bucket : lbResponse.buckets()) {
System.out.println(bucket.name() + "\t" + bucket.creationDate());
}
The output will look something like this::
mahbuckat1 2021-09-20T14:12:57.231Z
mahbuckat2 2021-09-20T14:12:59.402Z
mahbuckat3 2021-09-20T14:13:02.288Z
Creating a Bucket
-----------------
This creates a new bucket called ``my-new-bucket``
.. code-block:: java
client.createBucket(req -> {
req.bucket("my-new-bucket");
});
Listing a Bucket's Content
--------------------------
This gets a list of objects in the bucket.
This also prints out each object's name, the file size, and last
modified date.
.. code-block:: java
ListObjectsResponse loResponse = client.listObjects(req -> {
req.bucket("my-bucket");
});
for (S3Object object : loResponse.contents()) {
System.out.println(
object.key() + "\t" +
object.size() + "\t" +
object.lastModified()
);
}
The output will look something like this::
myphoto1.jpg 251262 2021-09-20T17:47:07.317Z
myphoto2.jpg 262518 2021-09-20T17:49:46.872Z
Deleting a Bucket
-----------------
.. note::
The Bucket must be empty! Otherwise it won't work!
.. code-block:: java
client.deleteBucket(req -> {
req.bucket("my-new-bucket");
});
Forced Delete for Non-empty Buckets
-----------------------------------
.. attention::
not available
Creating an Object
------------------
This creates a file ``hello.txt`` with the string ``"Hello World!"``
.. code-block:: java
ByteBuffer input = ByteBuffer.wrap("Hello World!".getBytes());
client.putObject(
req -> {
req.bucket("my-bucket").key("hello.txt");
},
RequestBody.fromByteBuffer(input)
);
Change an Object's ACL
----------------------
This makes the object ``hello.txt`` to be publicly readable, and
``secret_plans.txt`` to be private.
.. code-block:: java
client.putObjectAcl(req -> {
req.bucket("my-bucket").key("hello.txt").acl(ObjectCannedACL.PUBLIC_READ);
});
client.putObjectAcl(req -> {
req.bucket("my-bucket").key("secret_plans.txt").acl(ObjectCannedACL.PRIVATE);
});
Download an Object (to a file)
------------------------------
This downloads the object ``perl_poetry.pdf`` and saves it in
``/home/larry/documents``
.. code-block:: java
client.getObject(
req -> {
req.bucket("my-bucket").key("perl_poetry.pdf");
},
Paths.get("/home/larry/documents/perl_poetry.pdf")
);
Delete an Object
----------------
This deletes the object ``goodbye.txt``
.. code-block:: java
client.deleteObject(req -> {
req.bucket("my-bucket").key("goodbye.txt");
});
Generate Object Download URLs (signed and unsigned)
---------------------------------------------------
This generates an unsigned download URL for ``hello.txt``. This works
because we made ``hello.txt`` public by setting the ACL above.
This then generates a signed download URL for ``secret_plans.txt`` that
will work for 1 hour. Signed download URLs will work for the time
period even if the object is private (when the time period is up, the
URL will stop working).
.. note::
The java library does not have a method for generating unsigned
URLs, so the example below just generates a signed URL.
.. code-block:: java
S3Presigner presigner = S3Presigner.builder()
.endpointOverride(new URI("https://endpoint.com"))
.credentialsProvider(StaticCredentialsProvider.create(credentials))
.region(Region.US_EAST_1) // this is not used, but the AWS SDK requires it
.build();
PresignedGetObjectRequest presignedRequest = presigner.presignGetObject(preReq -> {
preReq.getObjectRequest(req -> {
req.bucket("my-bucket").key("secret_plans.txt");
}).signatureDuration(
Duration.ofMinutes(20)
);
});
System.out.println(presignedRequest.url());
The output will look something like this::
https://endpoint.com/my-bucket/secret_plans.txt?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20210921T151408Z&X-Amz-SignedHeaders=host&X-Amz-Expires=1200&X-Amz-Credential=XXXXXXXXXXXX%2F20210921%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Signature=yyyyyyyyyyyyyyyyyyyyyy