Attached files are rendered as text

[nmagedman]

Description:

PR #16232 introduced a BREAKING CHANGE even though it was labelled as a bugfix.
That PR adds the HTTP header x-content-type-options: nosniff which is a good security move, however it breaks installations that do not yet set the Content-Type. Had it been labelled a BREAKING CHANGE, I could have ensured that we were setting our MIME types properly before upgrading.

Steps to reproduce:

1. Upload an image to a chat room (or find a pre-existing one)
2. Click on the image title (not the image itself).
3. The image will load in a new tab.

Expected behavior:

The image to be displayed properly in the new browser tab.

Actual behavior:

The contents of the image file are displayed as plain text. e.g. a PNG file is displayed as

‰PNG
�
���
IHDR�������_�����
...

Server Setup Information:

• Version of Rocket.Chat Server: 3.4.2
• Operating System: Linux
• Deployment Method: tar
• Number of Running Instances: 15
• DB Replicaset Oplog: enabled
• NodeJS Version: 12.16.1
• MongoDB Version: 4.0.18

Client Setup Information

• Desktop App or Browser Version: Chrome 83.0.4103.116
• Operating System: MacOS Catalina 10.15.5

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[milton-rucks]

@rodrigok , I believe we can close this one. @damian-centrone tested and now it's working fine.