com.sxthsenseapp.api.s3propertyloader.S3ResourceLoader.java Source code

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Here is the source code for com.sxthsenseapp.api.s3propertyloader.S3ResourceLoader.java

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package com.sxthsenseapp.api.s3propertyloader;

/*
 * #%L
 * S3Property Loader
 * $Id:$
 * $HeadURL:$
 * %%
 * Copyright (C) 2014 SixthSenseApp
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public
 * License along with this program.  If not, see
 * <http://www.gnu.org/licenses/gpl-3.0.html>.
 * #L%
 */

import org.jets3t.service.S3Service;
import org.jets3t.service.S3ServiceException;
import org.jets3t.service.impl.rest.httpclient.RestS3Service;
import org.jets3t.service.model.S3Object;
import org.jets3t.service.security.AWSCredentials;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.io.ByteArrayResource;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;

import java.io.InputStream;

public class S3ResourceLoader implements ResourceLoader {

    private static final String LOCATION_PREFIX = "s3://";
    private static final String ENVIRONMENT_VARIABLE_PREFIX = "S3_CONFIG_RES_";
    private final Logger log = LoggerFactory.getLogger(getClass());

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

    private String awsAccessKey;
    private String awsSecretKey;
    private AWSCredentials credentials;
    private S3Service s3Service;

    public S3ResourceLoader() {
        this.awsAccessKey = getRequiredSystemProperty("S3_CONFIG_AWS_ACCESS_KEY_ID");
        this.awsSecretKey = getRequiredSystemProperty("S3_CONFIG_AWS_SECRET_KEY");
        this.setupAWSCredentials();
    }

    public S3ResourceLoader(String awsAccessKey, String awsSecretKey) {
        this.awsAccessKey = awsAccessKey;
        this.awsSecretKey = awsSecretKey;
        this.setupAWSCredentials();
    }

    private void setupAWSCredentials() {
        this.credentials = new AWSCredentials(awsAccessKey, awsSecretKey);
        try {
            this.s3Service = new RestS3Service(credentials);
        } catch (S3ServiceException e) {
            throw new S3ResourceException("could not initialize s3 service", e);
        }

    }

    public ClassLoader getClassLoader() {
        return this.getClassLoader();
    }

    public Resource getResource(String location) {
        try {
            S3Path s3Path = parseS3Path(location);
            S3Object s3Object = s3Service.getObject(s3Path.bucket, s3Path.key);
            byte[] buf = readS3Object(s3Object);
            return new ByteArrayResource(buf, location);

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

    private String getRequiredSystemProperty(String propertyName) {
        String value = System.getProperty(propertyName);
        if (value == null || "".equals(value.trim())) {
            throw new S3ResourceException("no " + propertyName + " property found in system");
        }
        return value;
    }

    private S3Path parseS3Path(String location) {

        String path = getLocationPath(location);
        String bucketName = path.substring(0, path.indexOf("/"));
        String keyName = path.substring(path.indexOf("/") + 1);

        log.debug("S3 Resource from bucket: " + bucketName + " and key: " + keyName);

        S3Path s3Path = new S3Path();

        s3Path.bucket = bucketName;
        s3Path.key = keyName;
        return s3Path;
    }

    private String getLocationPath(String location) {

        if (location == null || "".equals(location.trim())) {
            throw new S3ResourceException("location cannot be empty or null");
        }

        String resolvedLocation = location;

        if (resolvedLocation.startsWith(LOCATION_PREFIX)) {
            return resolvedLocation.substring(LOCATION_PREFIX.length(), resolvedLocation.length());
        } else if (resolvedLocation.startsWith(ENVIRONMENT_VARIABLE_PREFIX)) {
            return getRequiredSystemProperty(resolvedLocation);
        } else {
            throw new S3ResourceException(resolvedLocation + " does not begin with " + LOCATION_PREFIX);
        }

    }

    private byte[] readS3Object(S3Object s3Object) throws Exception {
        InputStream inputStream = s3Object.getDataInputStream();
        int size = 1024;
        byte[] buf = new byte[size];

        int readedSize = inputStream.read(buf);
        while (readedSize == 1024) {
            byte[] tmpBuf = new byte[size];
            readedSize = inputStream.read(tmpBuf);
            byte[] newBuf = new byte[buf.length + readedSize];
            System.arraycopy(buf, 0, newBuf, 0, buf.length);
            System.arraycopy(tmpBuf, 0, newBuf, buf.length, readedSize);
            buf = newBuf;
        }
        return buf;
    }
}