StreamRegistration::getResourceUri result URI doesn't take into account Portlet's resource url

[mshabarov]

• Description of the bug As a developer, I want to use StreamResource API with a Button component to download a resource file in a portlet application. But in a portlet world, the dynamic resources url should be embedded into portlet parameters part. For instance, regular servlet dynamic resource url: http://localhost:8080/VAADIN/dynamic/resource/0/82c11682-792d-4d74-b323-aeb26fe3ce6a/pom.xml, should be embedded as: http://localhost:8080/en/web/guest/home?p_p_id=my_portlet_id&p_p_lifecycle=2&p_p_state=normal&p_p_mode=view&p_p_resource_id=%2FVAADIN%2Fdynamic%2Fresource%2F0%2F82c11682-792d-4d74-b323-aeb26fe3ce6a%2Fpom.xml&p_p_cacheability=cacheLevelPage.

Proposition: create a custom implementation of StreamResource for portlets, which would return correct "wrapped" resource url, like it's already done here https://github.com/vaadin/portlet/blob/b545000cbf32c50131fb663f901caa2d1c438d6d/vaadin-portlet/src/main/java/com/vaadin/flow/portal/PortletStreamResourceRegistry.java#L51.

• Minimal reproducible example Take https://github.com/vaadin/addressbook-portlet starter project as an example and add a download button:

  File file = new File("/path/to/file");
  InputStream inputStream = new FileInputStream(file);
  StreamResource streamResource = new StreamResource(fileName, () -> inputStream );
  final StreamRegistration registration = VaadinPortletSession.getCurrent().getResourceRegistry().registerResource(streamResource );
  UI.getCurrent().getPage().open(registration.getResourceUri().toString());

• Expected and actual behavior Expected: file is downloaded in browser, actual: The requested resource could not be found. http://localhost:8080/en/web/guest/VAADIN/dynamic/resource/0/deced29f-e427-45be-b587-4520a6c0fdcc/pom.xml is shown (http code 404).
• Versions:
  • Vaadin Portlet version: snapshot from feature/liferay branch
  • Vaadin version: 14.8.0
  • Liferay version: 7.3
  • Java version: 11
  • OS version: Windows 10
  • Browser version (if applicable) Chrome 95

[mshabarov]

Included into feature branch.