# Select API Quickstart Guide [![Slack](https://slack.min.io/slack?type=svg)](https://slack.min.io)

Traditional retrieval of objects is always as whole entities, i.e GetObject for a 5 GiB object, will always return 5 GiB of data. S3 Select API allows us to retrieve a subset of data by using simple SQL expressions. By using Select API to retrieve only the data needed by the application, drastic performance improvements can be achieved.

		}
	}
}

// Wrapper for calling GetObject API handler tests for both Erasure multiple disks and FS single drive setup.
func TestAPIGetObjectHandler(t *testing.T) {
	globalPolicySys = NewPolicySys()
	defer func() { globalPolicySys = nil }()

	defer DetectTestLeak(t)()
	ExecExtendedObjectLayerAPITest(t, testAPIGetObjectHandler, []string{"GetObject"})
}

        try {
            final GetObjectRequest request = GetObjectRequest.builder().bucket(bucket).key(objectName).build();
            try (InputStream in = s3Client.getObject(request)) {
                in.transferTo(outputStream);
            }
        } catch (final Exception e) {
            throw new StorageException("Failed to download " + objectName, e);
        }
    }

	bucketPolicyTemplateWithoutVersion := `{"Version":"","Statement":[{"Sid":"","Effect":"Allow","Principal":{"AWS":["*"]},"Action":["s3:GetBucketLocation","s3:ListBucket"],"Resource":["arn:aws:s3:::%s"]},{"Sid":"","Effect":"Allow","Principal":{"AWS":["*"]},"Action":["s3:GetObject"],"Resource":["arn:aws:s3:::%s/this*"]}]}`

	// GCS storage decompresses a gzipped object by default and returns the data.
	// Refer to https://cloud.google.com/storage/docs/transcoding#decompressive_transcoding
	// Need to set `Accept-Encoding` header to `gzip` when issuing a GetObject call, to be able
	// to download the object in compressed state.
	// Calling ReadCompressed with true accomplishes that.
	object := gcs.client.Bucket(gcs.Bucket).Object(gcs.getDest(key)).ReadCompressed(true)

			HandlerFunc(s3APIMiddleware(api.GetObjectLegalHoldHandler)).
			Queries("legal-hold", "")
		// GetObject with lambda ARNs
		router.Methods(http.MethodGet).Path("/{object:.+}").
			HandlerFunc(s3APIMiddleware(api.GetObjectLambdaHandler, traceHdrsS3HFlag)).
			Queries("lambdaArn", "{lambdaArn:.*}")
		// GetObject
		router.Methods(http.MethodGet).Path("/{object:.+}").

```bash
helm install --set policies[0].name=mypolicy,policies[0].statements[0].resources[0]='arn:aws:s3:::bucket1',policies[0].statements[0].actions[0]='s3:ListBucket',policies[0].statements[0].actions[1]='s3:GetObject' minio/minio
```

Description of the configuration parameters used above -

- `policies[].name` - name of the policy to create, must be a string with length > 0

		return 0, nil, errors.New("bucket name cannot be empty")
	}

	clnt, err := driver.getMinIOClient(ctx)
	if err != nil {
		return 0, nil, err
	}

	opts := minio.GetObjectOptions{}
	obj, err := clnt.GetObject(context.Background(), bucket, object, opts)
	if err != nil {
		return 0, nil, err
	}
	defer func() {
		if err != nil && obj != nil {
			obj.Close()
		}
	}()

	policy := "mypolicy"
	policyBytes := []byte(`{
 "Version": "2012-10-17",
 "Statement": [
  {
   "Effect": "Allow",
   "Action": [
    "s3:PutObject",
    "s3:GetObject",
    "s3:ListBucket"
   ],
   "Resource": [
    "arn:aws:s3:::BUCKET/*"
   ]
  }
 ]
}`)

	err := s.adm.AddCannedPolicy(ctx, policy, policyBytes)
	if err != nil {

	if bucket == "" {
		return nil, errors.New("bucket name cannot be empty")
	}

	clnt, err := f.getMinIOClient()
	if err != nil {
		return nil, err
	}

	obj, err := clnt.GetObject(context.Background(), bucket, object, minio.GetObjectOptions{})
	if err != nil {
		return nil, err
	}

	_, err = obj.Stat()
	if err != nil {
		return nil, err
	}

	return obj, nil
}