Enforce Drive API for Android to work online mode only

问题

Recently, I just manage to migrate Drive API related code from Google APIs Client Library for Java to Google Play services client library

The following code is search a file in appdata folder, then download it as temp file.

private static GoogleCloudFile searchFromGoogleDrive(GoogleApiClient googleApiClient, HandleStatusable h, PublishProgressable p) {
    DriveFolder driveFolder = Drive.DriveApi.getAppFolder(googleApiClient);

    final String titleName = ("my-title");
    Query query = new Query.Builder()
            .addFilter(Filters.and(
                Filters.contains(SearchableField.TITLE, titleName),
                Filters.eq(SearchableField.TRASHED, false)
            ))
            .build();

    DriveApi.MetadataBufferResult metadataBufferResult = driveFolder.queryChildren(googleApiClient, query).await();

    if (metadataBufferResult == null) {
        return null;
    }

    Status status = metadataBufferResult.getStatus();

    if (!status.isSuccess()) {
        h.handleStatus(status);
        return null;
    }

    MetadataBuffer metadataBuffer = null;
    boolean needToReleaseMetadataBuffer = true;

    try {
        metadataBuffer = metadataBufferResult.getMetadataBuffer();
        if (metadataBuffer != null ) {
            long checksum = 0;
            long date = 0;
            int version = 0;
            Metadata metadata = null;

            for (Metadata md : metadataBuffer) {
                if (p.isCancelled()) {
                    return null;
                }

                if (md == null || !md.isDataValid()) {
                    continue;
                }

                final String title = md.getTitle();

                // ...

                metadata = md;

                break;

            }   // for

            if (metadata != null) {
                // Caller will be responsible to release the resource. If release too early,
                // metadata will not readable.
                needToReleaseMetadataBuffer = false;
                return GoogleCloudFile.newInstance(metadataBuffer, metadata, checksum, date, version);
            }
        }   // if
    } finally {
        if (needToReleaseMetadataBuffer) {
            if (metadataBuffer != null) {
                metadataBuffer.release();
            }
        }
    }

    return null;
}

public static CloudFile loadFromGoogleDrive(GoogleApiClient googleApiClient, HandleStatusable h, PublishProgressable p) {
    final java.io.File directory = ...

    GoogleCloudFile googleCloudFile = searchFromGoogleDrive(googleApiClient, h, p);

    if (googleCloudFile == null) {
        return null;
    }

    try {
        DriveFile driveFile = googleCloudFile.metadata.getDriveId().asDriveFile();
        DriveApi.DriveContentsResult driveContentsResult = driveFile.open(googleApiClient, DriveFile.MODE_READ_ONLY, null).await();

        if (driveContentsResult == null) {
            return null;
        }

        Status status = driveContentsResult.getStatus();
        if (!status.isSuccess()) {
            h.handleStatus(status);
            return null;
        }

        final long checksum = googleCloudFile.checksum;
        final long date = googleCloudFile.date;
        final int version = googleCloudFile.version;

        p.publishProgress(MyApplication.instance().getString(R.string.downloading));

        final DriveContents driveContents = driveContentsResult.getDriveContents();

        InputStream inputStream = null;
        java.io.File outputFile = null;
        OutputStream outputStream = null;

        try {
            inputStream = driveContents.getInputStream();
            outputFile = java.io.File.createTempFile("me", ".zip", directory);
            outputFile.deleteOnExit();
            outputStream = new FileOutputStream(outputFile);

            int read = 0;
            byte[] bytes = new byte[1024];

            while ((read = inputStream.read(bytes)) != -1) {
                outputStream.write(bytes, 0, read);
            }
        } catch (IOException ex) {
            Log.e(TAG, "", ex);
        } finally {
            org.yccheok.file.Utils.close(outputStream);
            org.yccheok.file.Utils.close(inputStream);
            driveContents.discard(googleApiClient);
        }

        if (outputFile == null) {
            return null;
        }

        return CloudFile.newInstance(outputFile, checksum, date, version);
    } finally {
        googleCloudFile.metadataBuffer.release();
    }
}

Previously, when I'm using Google APIs Client Library for Java, the similar code will just throw exception, if there's no internet connection.

However, when I'm using Google Play services client library, the above code still work successfully, even though I have my device in airplane mode, and turn off wifi.

It seems that Drive API from Google Play services client library, is able to read the offline file, when there's no internet connection.

Is there any way, to enforce the above code will fail, when there is no internet connection? As, I want to avoid risk of having my users to download outdated cloud file.

回答1:

There's no way to force a failure as you ask.

What you can do is request a sync with the server before your query: https://developers.google.com/android/reference/com/google/android/gms/drive/DriveApi.html#requestSync(com.google.android.gms.common.api.GoogleApiClient)

If there's no connection, the sync will fail with a network error.

来源：https://stackoverflow.com/questions/34735443/enforce-drive-api-for-android-to-work-online-mode-only