I have some engineering users who wish to attach some data files with uncommon file extensions to their posts. They are essentially plain text files but include extended ASCII characters. I tried to update Discourse’s NGINX config to specify MIME media types for these files but it didn’t work. I …

Yes, that’s right – like in my screenshot above I’m not suggesting you do the modification. However, if you can’t wait, you could certainly test that change. For a temporary change (gone after rebuild): cd /var/discourse ./launcher enter app sed -i "s/FastImage.new(@file)/FastImage.new(@fi…

[image] xyzzy: Alternatively, I could configure Discourse to allow zip files and tell the users to zip up their files before uploading them, but I’d rather not open up the site to random zip file uploads. That seems like a security issue. Another work around is adoption an extension for those…

Thanks for the quick response! However, I tried that and it doesn’t work. Discourse is definitely looking at the file contents, not the extension, to determine if it’s an image or not.

Does anyone have any thoughts on this? This seems like a pretty significant bug.

I did some digging around this issue. In short, your file is being detected as JPEG because it starts with the same signature as this type of file. Fixing this behavior in Discourse is possible, but it requires a modification. (see at the end) Here some technical stuff. This issue starts here: …

Wow! This ia a phenomenal analysis! Thank you! Some quick questions: So with these changes, the file won’t be detected as an image and will be uploaded like a non-image and displayed to the right of the post? If I understand correctly, you’re suggesting I make these tweaks in my local Disco…

@Arkshine – Thank you very much for these details. I was able to test out both fixes separately (each one on a freshly restored VM) and they both worked! Notes: For the temporary fix, I needed to run “./launcher restart app” for the changes to take effect. It looks like “spec/models/optimize…

I’m glad it works. :slight_smile: This is just for testing purposes, so you don’t have to worry about it.

Great! Thanks! Now that I’ve tested this out in my dev env, I’ll deploy this to the test and prod envs. BTW, if you have time, I’d love to get your thoughts on a related problem ( How to customize MIME media type emitted for certain attachments? ).

Discourse détecte incorrectement le fichier téléchargé comme une image

Soutien

Falco (Falco) Octobre 26, 2023, 5:47 2

Une autre solution de contournement consiste à adopter une extension pour ces fichiers étranges, comme .bin, .data ou vraiment .anythinggoes, ce qui devrait suffire à Discourse pour laisser ces fichiers tranquilles.

Sujet		Réponses	Vues
Security checks on uploads Support	35	7876	Décembre 2, 2018
Incorrect mime-types (content-type header) for mp4 and js Bug	10	1276	Janvier 7, 2025
Something missing in "Select images or files from your device ()"? Bug	5	1193	Octobre 22, 2015
Faster (and smaller) uploads in Discourse with Rust, WebAssembly and MozJPEG \| Blog Blog	35	5705	Mai 13, 2025
Add the .svg file extension to "image files" Feature	18	1692	Octobre 10, 2025

Discourse détecte incorrectement le fichier téléchargé comme une image

Sujets connexes