When requesting a image thumbnail, If it doesn't exists, WebServerServlet returns a empty image instead of a 404 error

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.3.X, Master
• Fix Version/s: 7.0.X, 7.1.X, 7.2.10 DXP FP18, 7.2.X, 7.3.X, 7.4.3.8 CE GA8, 7.4.13 DXP U4, Master
• Component/s: Core Infrastructure, Documents & Media
• Labels:
  • core-infra-board-out
  • ee-ts
  • liferay-fixpack-dxp-18-7210
  • liferay-fixpack-dxp-27-7110
  • liferay-fixpack-dxp-4-7310
  • liferay-update-dxp-4-7310
  • liferay-update-dxp-4-7413
• Branch Version/s:
  7.3.x, 7.2.x, 7.1.x, 7.0.x
• Backported to Branch:
  Committed
• Story Points: 1
• Fix Priority: 3
• Sprint: LIMA | QA Sprint 17
• Git Pull Request: https://github.com/liferay-lima/liferay-portal/pull/2618
• Bug Type: Default
• QA Test Name:
  • dont-test-again

When requesting a image thumbnail, If it doesn't exists, WebServerServlet returns a empty image with 200 code instead of a 404 error

The customer complains that returning 200 code can cause problems to the CDN and other elements, as they are caching them unless a error code is returned.

It can also cause problems to the user browsers, as we send a wrong image that cannot be rendered.

Steps to reproduce

1. Upload a image to the documents and media section
2. Open the image, click on the button on the upper right side of the page
3. Copy the "Latest Version URL" URL
4. Append &imageThumbnail=1 to the end of the URL and open it in a different tab
5. The thumbnail will be displayed correctly
6. Go to Control Panel => Adaptive Media
7. Deactivate all the defined image resolutions
8. Delete all the defined image resolutions
9. Open again the URL with the &imageThumbnail=1 parameter in a different browser (the image is cached in the browser)
   • Expected behavior: An 404 error "The requested resource could not be found." is displayed
   • Wrong behavior:
     • Firefox returns a "The image xxx cannot be displayed because it contains errors."
     • Chrome returns a empty image