Inconsistency in data if file not found between GoogleStorageWrapper and S3StorageWrapper

[hemil-ruparel-blox]

In GoogleStorageWrapper, the bytes function returns null if input is null. Otherwise the raw byte array contents of the given file.

Reference - https://github.com/nmondal/cowj/blob/670c91e64a8a936341eaf03d2cd72fd1222bf25b/app/src/main/java/cowj/plugins/GoogleStorageWrapper.java#L102C5-L109C6

@Override
default byte[] bytes(Blob input) {
    try {
        return input.getContent();
    }catch (Throwable t){
        return null;
    }
}

Meanwhile the S3StorageWrapper bytes function returns empty byte array if input is null. This means we cannot distinguish between the case when the file does not exist and when the file is not empty.

Reference - https://github.com/nmondal/cowj/blob/670c91e64a8a936341eaf03d2cd72fd1222bf25b/app/src/main/java/cowj/plugins/S3StorageWrapper.java#L85C5-L89C6

@Override
default byte[] bytes(Entry<String, ResponseBytes<GetObjectResponse>> input){
    return (input == null || input.getValue() == null) ?
            ArrayUtil.EMPTY_BYTE_ARRAY : input.getValue().asByteArray();
}

[nmondal]

The API :
https://github.com/nmondal/cowj/blob/main/app/src/main/java/cowj/plugins/S3StorageWrapper.java#L104

fileExists works for that purpose.

[hemil-ruparel-blox]

That would be an extra query no? I want to get the contents of file if exists otherwise null?

[nmondal]

No, it is a head call. Under the hood it always does multiple calls.
Exactly what is being broken by this?

[hemil-ruparel-blox]

Nothing major actually. The storage proxy when a file was not found, we used to get 404 because dumpb returned null. Now, it is returning 200 with empty body. The fix is to check if the body is empty before returning which I have done but just wanted to point this out

[nmondal]

@hemil-ruparel-blox take a look around, this is fixed now with protocol change in the Storage ensuring people must conform to this.

[hemil-ruparel-blox]

Working as of 7b783ca. A file that does not exist, returns null