Conversion from S3ObjectInputStream to AbstractStreamResource-CodePudding

I am getting an AWS S3 image resource as a S3ObjectInputStream and want to put it into a Vaadin image HTML Component. The Vaadin Image only has two ways of initialization. The first is through a string indicating a filepath, which would mean writing the S3 image to disk, which I cannot do because of data security reasons and the second one is through something implementing "AbstractStreamResource". The question now is, how do I get the S3ObjectInputStream converted to something implementing "AbstractStreamResource" to keep the file only in memory.

CodePudding user response：

Based on S3ObjectInputStream API doc S3ObjectInputStream is sub class of java.io.InputStream. In that case you should be able to do

    S3ObjectInputStream s3ImageResource = ... 
    StreamResource res = new StreamResource("filename.jpg", () -> {
        InputStream is = s3ImageResource;
        return is;
    });
    Image image = new Image(res,"Image");

Alternatively if that does not work, based on other questions here in StackOverflow, I assume you can convert S3ObjectInputStream to byte array.

    byte[] bytes = // get bytes from S3ObjectInputStream 
    StreamResource res = new StreamResource("filename.jpg", () -> {
        InputStream is = new ByteArrayInputStream(bytes);
        return is;
    });
    Image image = new Image(res,"Image");