me.footlights.server.AmazonUploader.java Source code

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Here is the source code for me.footlights.server.AmazonUploader.java

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/*
 * Copyright 2011 Jonathan Anderson
 *
 * 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 me.footlights.server;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.security.AccessControlException;
import java.security.NoSuchAlgorithmException;
import java.util.logging.Logger;

import me.footlights.core.Preferences;
import me.footlights.core.ConfigurationError;
import me.footlights.core.crypto.Fingerprint;

import com.amazonaws.AmazonClientException;
import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.CannedAccessControlList;
import com.amazonaws.services.s3.model.ObjectMetadata;

import com.google.inject.Inject;

/**
 * Uploads user data blocks to Amazon S3.
 */
public final class AmazonUploader implements Uploader {
    @Inject
    public AmazonUploader(Preferences preferences) {
        this.prefs = preferences;
        this.authSecret = getMandatoryPreference("cas.secret");

        final String keyId = getMandatoryPreference("amazon.keyId");
        final String secret = getMandatoryPreference("amazon.secretKey");

        if (keyId.isEmpty())
            throw new ConfigurationError("Amazon key ID not set");
        if (secret.isEmpty())
            throw new ConfigurationError("Amazon secret key not set");

        AWSCredentials cred = new AWSCredentials() {
            @Override
            public String getAWSAccessKeyId() {
                return keyId;
            }

            @Override
            public String getAWSSecretKey() {
                return secret;
            }
        };

        s3 = new AmazonS3Client(cred);
    }

    /**
     * Upload file to Amazon S3, unless there's a reason not to:
     *  - invalid request
     *  - not authorized
     *  - incorrect size
     * 
     * @return the name of the uploaded file (which is a fingerprint)
     */
    @Override
    public String upload(final Block block)
            throws AccessControlException, IOException, NoSuchAlgorithmException, RuntimeException {
        log.entering(AmazonUploader.class.getName(), "upload", block);

        if (!checkAuth(block.getAuthorization()))
            throw new AccessControlException("Authorization failure");

        // Does the actual fingerprint match the expected one (if any)?
        Fingerprint.Builder fingerprintBuilder = Fingerprint.newBuilder().setContent(block.getBytes());

        if (!block.getFingerprintAlgorithm().isEmpty())
            fingerprintBuilder.setAlgorithm(block.getFingerprintAlgorithm());

        final String actualName = fingerprintBuilder.build().encode();
        String expected = block.getExpectedName();
        if (!expected.isEmpty() && !expected.equals(actualName))
            throw new IllegalArgumentException("Block name (" + actualName + ") does not match expected name ("
                    + block.getExpectedName() + ")");

        final ByteBuffer bytes = block.getBytes();

        final ObjectMetadata metadata = new ObjectMetadata();
        metadata.setContentLength(bytes.remaining());

        InputStream stream = new ByteArrayInputStream(bytes.array());

        try {
            s3.putObject(USER_DATA_BUCKET, actualName, stream, metadata);
            s3.setObjectAcl(USER_DATA_BUCKET, actualName, DEFAULT_ACL);
        } catch (AmazonClientException e) {
            throw new RuntimeException(e);
        }

        return actualName;
    }

    /** In the future, this will be much more sophisticated! */
    private boolean checkAuth(String authenticator) {
        return (authenticator.equals(authSecret));
    }

    private String getMandatoryPreference(String name) throws ConfigurationError {
        scala.Option<String> value = prefs.getString(name);
        if (value.isEmpty())
            throw new ConfigurationError(name + " not set");
        else
            return value.get();
    }

    /** User data is public by default (but encrypted!). */
    private static final CannedAccessControlList DEFAULT_ACL = CannedAccessControlList.PublicRead;

    /** The S3 bucket to store user data in. */
    private static final String USER_DATA_BUCKET = "footlights-cas";

    /** Class-specific logger. */
    private static final Logger log = Logger.getLogger(AmazonUploader.class.getCanonicalName());

    /** Configuration data. */
    private final Preferences prefs;

    /** Amazon S3 client. */
    private final AmazonS3Client s3;

    /** Secret used to authenticate uploads. */
    private final String authSecret;
}