FileDownloader doesn't work with ExternalResource

Vaadin 6 / 7 / 8
1

Hi,
I’m using Vaadin 8.
I want to preview image and provide a way to save it to disk with a button.
I have a Window with content of Image and a Button

String resourceURL = // any link of PNG image from google
Button downloadBtn = new Button("download");
ExternalResource source = new ExternalResource(resourceURL); 
FileDownloader downloader = new FileDownloader(source);

downloader.extend(downloadBtn);

After clicking on button downloading does not start, instead of this I have ultrafast browser loading action. I mean Chrome shows spinner like while loading page, it’s lasts less than a second.

If I use StreamResource as source (ie. from
https://vaadin.com/docs/-/part/framework/application/application-resources.html#application.resources.stream
) downloading works.
Can i create a StreamResource from URL? Later I want to download files with other type than Image, also using URL.

2

FileDownloader will only serve resources associated with a connector (typically a component), i.e. ClassResource, FileResource or StreamResource. However, its client side should still make requests to the correct URL for other types of resources such as ExternalResource. You can try to check what the browser is doing using e.g. Chrome developer tools, and looking at the network requests made.

If it doesn’t work, please
create an issue at GitHub
 with version information and the code to reproduce the issue.