com.sangupta.urn.service.impl.AmazonS3UrnStorageServiceImpl.java Source code

Introduction

Here is the source code for com.sangupta.urn.service.impl.AmazonS3UrnStorageServiceImpl.java

Source

/**
 *
 * urn - Object Storage Library
 * Copyright (c) 2016, Sandeep Gupta
 * 
 * http://sangupta.com/projects/urn
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *       http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 */

package com.sangupta.urn.service.impl;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Date;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.ObjectMetadata;
import com.amazonaws.services.s3.model.PutObjectResult;
import com.amazonaws.services.s3.model.S3Object;
import com.amazonaws.util.IOUtils;
import com.sangupta.jerry.util.AssertUtils;
import com.sangupta.urn.model.UrnObject;
import com.sangupta.urn.service.UrnStorageService;

/**
 * An Amazon-S3 based implementation for {@link UrnStorageService} that helps store
 * objects onto Amazon S3.
 * 
 * @author sangupta
 *
 */
public class AmazonS3UrnStorageServiceImpl extends AbstractUrnStorageServiceImpl {

    private static final Logger LOGGER = LoggerFactory.getLogger(AmazonS3UrnStorageServiceImpl.class);

    /**
     * The client to be used for working with S3
     */
    private final AmazonS3Client client;

    /**
     * The bucket under which all objects will be stored
     */
    private final String bucketName;

    /**
     * Constructor
     * 
     * @param client
     */
    public AmazonS3UrnStorageServiceImpl(AmazonS3Client client, String bucketName) {
        if (client == null) {
            throw new IllegalArgumentException("AmazonS3Client cannot be null");
        }

        if (AssertUtils.isEmpty(bucketName)) {
            throw new IllegalArgumentException("Bucket name cannot be null/empty");
        }

        this.client = client;
        this.bucketName = bucketName;
    }

    @Override
    protected UrnObject get(String objectKey) {
        S3Object object = this.client.getObject(this.bucketName, objectKey);
        if (object == null) {
            return null;
        }

        try {
            InputStream stream = object.getObjectContent();

            byte[] bytes = IOUtils.toByteArray(stream);

            UrnObject urnObject = new UrnObject(objectKey, bytes);

            // TODO: read and populate metadata
            ObjectMetadata metadata = object.getObjectMetadata();
            if (metadata != null) {
                if (metadata.getHttpExpiresDate() != null) {
                    urnObject.expiry = metadata.getHttpExpiresDate().getTime();
                }

                urnObject.mime = metadata.getContentType();
                urnObject.stored = metadata.getLastModified().getTime();

                // TODO:parse the value to extract the filename if available
                urnObject.name = metadata.getContentDisposition();
            }

            // return the object
            return urnObject;
        } catch (IOException e) {
            // happens when we cannot read data from S3
            LOGGER.debug("Exception reading data from S3 for object key: " + objectKey, e);
            return null;
        } finally {
            if (object != null) {
                try {
                    object.close();
                } catch (IOException e) {
                    LOGGER.warn("Unable to close S3 object during/after reading the object");
                }
            }
        }
    }

    @Override
    protected String save(UrnObject urnObject) {
        InputStream stream = new ByteArrayInputStream(urnObject.bytes);

        ObjectMetadata metadata = new ObjectMetadata();
        metadata.setContentLength(urnObject.bytes.length);

        if (AssertUtils.isNotEmpty(urnObject.name)) {
            metadata.setContentDisposition("filename=" + urnObject.name);
        }

        if (AssertUtils.isNotEmpty(urnObject.mime)) {
            metadata.setContentType(urnObject.mime);
        }

        if (urnObject.expiry > 0) {
            metadata.setHttpExpiresDate(new Date(urnObject.expiry));
        }

        PutObjectResult result = this.client.putObject(this.bucketName, urnObject.key, stream, metadata);
        if (result == null) {
            return null;
        }

        return this.client.getResourceUrl(this.bucketName, urnObject.key);
    }

    @Override
    protected boolean remove(String objectKey) {
        this.client.deleteObject(this.bucketName, objectKey);
        return true;
    }

    @Override
    protected boolean has(String objectKey) {
        return this.client.doesObjectExist(this.bucketName, objectKey);
    }

}