Compress middleware should not compress image/* content types

[nyurik]

Expected Behavior

Most image/* mime types such as png and jpeg are already pre-compressed, so when using .wrap(middleware::Compress::default()), the expectation is that the well known images would not be compressed.

Current Behavior

Currently the compression middleware only looks at the content-encoding of the response (which should not be set for images), and thus compresses images again.

Possible Solution

• Check against a list of well known image types
• Offer a way to set a callback so that the user can check themselves
• all of the above?

Your Environment

• Rust Version: 1.67.1
• Actix Web Version: 4.3.0

[robjtede]

I am surprised that browsers send Accept-Encoding headers for image assets so this appears to be a legitimate issue.

[cptrodolfox]

Hey @robjtede , I am interested in working on this issue. I will start working on a solution. I might have some questions though.