Preview for MUCH more formats

[acosonic]

Since NODEJS is becoming inescapable :) even some popular Redmine themes like PurpleMine2 use it...

I am suggesting to use this (server side) https://www.npmjs.com/package/filepreview
which can easily be triggered from ruby, and ending result displayed or cached,
in a same way like multiple other supported formats...

[tofi86]

Nice idea! However, I would need help from a professional rails developer for implementing this, I'm only writing ruby/rails code once or twice in a year ;-)

Contributions are welcome!

[tofi86]

refs #59

[acosonic]

I'll help with node, and coordinate with @bilel-kedidi