Mp4 files are downloading instead of displaying inline

[david (David Taylor)]

Continuing the discussion from Make PDFs open directly (not via download) by default

@david

In theory, mp4 should be served inline:

discourse/lib/file_helper.rb at 2d615863d2613a7237451b8997c3c8c6583e7ae8 · discourse/discourse · GitHub

which uses:

discourse/lib/file_helper.rb at 2d615863d2613a7237451b8997c3c8c6583e7ae8 · discourse/discourse · GitHub

@Canapin

On meta, discourse forces mp4 downloads as well: https://d11a6trkgmumsb.cloudfront.net/original/4X/3/f/0/3f09f895d21cf0ae897d90c947abb816830b00a2.mp4

Something is causing mp4 files to still be served with content-disposition: attachment. We need to investigate and fix.

[Canapin (Coin-coin le Canapin)]

For the record, there was a topic about it and Nat worked on the matter:

Incorrect mime-types (content-type header) for mp4 and js

Just a quick update - The ext_mime_db above that we use follows IANA Media Types defined here - https://www.iana.org/assignments/media-types/media-types.xhtml. Unfortunately, this means that mp4 is correctly application/mp4 [Screenshot 2025-01-03 at 12.51.40 AM] Though, looking into our S3 uploader implementation further, I do see that we are adding Content-Disposition header "attachment" for pretty much every upload that is not an image, but it feels like it was only intended…