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The OpenTripPlanner multimodal journey planning system
There is a newer version: 2.5.0
package org.opentripplanner.ext.datastore.gs;


import com.google.auth.oauth2.GoogleCredentials;
import com.google.cloud.storage.Blob;
import com.google.cloud.storage.BlobId;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageOptions;
import org.opentripplanner.datastore.CompositeDataSource;
import org.opentripplanner.datastore.DataSource;
import org.opentripplanner.datastore.FileType;
import org.opentripplanner.datastore.base.DataSourceRepository;
import org.opentripplanner.datastore.base.ZipStreamDataSourceDecorator;

import java.io.FileInputStream;
import java.io.IOException;
import java.net.URI;
import java.util.Collections;

/**
 * This data store uses the local file system to access in-/out- data files.
 */
public class GsDataSourceRepository implements DataSourceRepository {
    private final String credentialsFilename;
    private Storage storage;

    public GsDataSourceRepository(String credentialsFilename) {
        this.credentialsFilename = credentialsFilename;
    }

    @Override
    public void open() {
        this.storage = connectToStorage();
    }

    @Override
    public String description() {
        return "Google Cloud Storage";
    }

    @Override
    public DataSource findSource(URI uri, FileType type) {
        if(skipUri(uri)) { return null; }
        BlobId blobId = GsHelper.toBlobId(uri);
        return createSource(blobId, type);
    }

    @Override
    public CompositeDataSource findCompositeSource(URI uri, FileType type) {
        if(skipUri(uri)) { return null; }
        return createCompositeSource(GsHelper.toBlobId(uri), type);
    }

    /* private methods */

    private static boolean skipUri(URI uri) {
        return !"gs".equals(uri.getScheme());
    }

    private DataSource createSource(BlobId blobId, FileType type) {
        Blob blob = storage.get(blobId);

        if(blob != null) {
            return new GsFileDataSource(blob, type);
        }
        else {
            return new GsOutFileDataSource(storage, blobId, type);
        }
    }

    private CompositeDataSource createCompositeSource(BlobId blobId, FileType type) {
        if(GsHelper.isRoot(blobId)) {
            return new GsDirectoryDataSource(storage, blobId, type);
        }

        if(blobId.getName().endsWith(".zip")) {
            Blob blob = storage.get(blobId);

            if(blob == null) {
                throw new IllegalArgumentException(
                        type.text() +  " not found: " + GsHelper.toUriString(blobId)
                );
            }
            DataSource gsSource = new GsFileDataSource(blob, type);
            return new ZipStreamDataSourceDecorator(gsSource);
        }
        return new GsDirectoryDataSource(storage, blobId, type);
    }

    private Storage connectToStorage() {
        try {
            StorageOptions.Builder builder = StorageOptions.getDefaultInstance().toBuilder();

            if(credentialsFilename != null) {
                GoogleCredentials credentials = GoogleCredentials
                        .fromStream(new FileInputStream(credentialsFilename))
                        .createScoped(Collections.singletonList(
                                "https://www.googleapis.com/auth/cloud-platform"));
                builder.setCredentials(credentials);
            }
            return builder.build().getService();
        }
        catch (IOException e) {
            throw new RuntimeException(e.getLocalizedMessage(), e);
        }
    }
}