org.tiogasolutions.lib.spring.amazon.S3ResourceLoader.java Source code

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Here is the source code for org.tiogasolutions.lib.spring.amazon.S3ResourceLoader.java

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/*
 * Copyright 2012 Jacob D Parr
 *
 * 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 org.tiogasolutions.lib.spring.amazon;

import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.model.S3Object;
import java.io.InputStream;
import org.tiogasolutions.dev.common.IoUtils;
import org.tiogasolutions.dev.common.exceptions.ExceptionUtils;
import org.springframework.core.io.*;

public class S3ResourceLoader implements ResourceLoader {

    private static final String LOCATION_PREFIX = "s3://";

    public static class S3Path {
        public String bucket;
        public String key;
    }

    private AmazonS3 client;

    public S3ResourceLoader() {
        this.client = AwsUtils.newAmazonS3Client();
    }

    @Override
    public ClassLoader getClassLoader() {
        return getClass().getClassLoader();
    }

    @Override
    public Resource getResource(String location) {
        try {
            S3Path s3Path = parseS3Path(location);
            S3Object s3Object = client.getObject(s3Path.bucket, s3Path.key);

            InputStream inputStream = s3Object.getObjectContent();
            byte[] bytes = IoUtils.toBytes(inputStream);
            return new ByteArrayResource(bytes, location);

        } catch (Exception e) {
            throw new S3ResourceException("could not load resource from " + location, e);
        }
    }

    private S3Path parseS3Path(String location) {
        ExceptionUtils.assertNotZeroLength(location, "location");

        if (location.startsWith(LOCATION_PREFIX) == false) {
            String msg = String.format("AWS S3 resource locations must start with \"%s\": %s.", LOCATION_PREFIX,
                    location);
            throw new IllegalArgumentException(msg);
        }

        S3Path s3Path = new S3Path();
        String path = location.substring(LOCATION_PREFIX.length());
        int pos = path.indexOf("/");

        if (pos < 0) {
            String msg = String.format("The path does not specify a bucket name: %s.", path);
            throw new IllegalArgumentException(msg);
        }

        s3Path.bucket = path.substring(0, pos);
        s3Path.key = path.substring(pos + 1, path.length());

        return s3Path;
    }
}