Encoding magic

Weird encoding problems are usually solved with a magic comment.

# coding: UTF-8

I don’t think I’ve used it since ruby 1.8.

Since 1.9 encoding is derived from environment. Here’s what you probably see.

export LANG='en_US.UTF-8'
export LC_CTYPE='UTF-8'

If you’re trying to avoid fiddling with the environment of the entire server, try the gemfile.

Ruby Docker image

As for December 2019 There’s still some frankly repulsive encoding bullshit when using official ruby Docker image.

By default, Ruby inherits the locale of the environment in which it is run. For most users running Ruby on their desktop systems, that means it’s likely using some variation of *.UTF-8 (en_US.UTF-8, etc). In Docker however, the default locale is C, which can have unexpected results. If your application needs to interact with UTF-8, it is recommended that you explicitly adjust the locale of your image/container via -e LANG=C.UTF-8 or ENV LANG C.UTF-8.

Add this to your run command

-e LANG=C.UTF-8

Or to you image Dockerfile

ENV LANG C.UTF-8