Introduce compressor option to ActiveRecord::Encryption::Encryptor

[heka1024]

Motivation / Background

There are more performant algorithms than zlib, like zstd or snappy. So I made it possible to configure the compressor to take advantage of these more performant algorithms.

Detail

Make compressor as argument which default value is zlib.

Additional information

• https://facebook.github.io/zstd/

Checklist

Before submitting the PR make sure the following are checked:

• This Pull Request is related to one change. Unrelated changes should be opened in separate PRs.
• Commit message has a detailed description of what changed and why. If this PR fixes a related issue include it in the commit message. Ex: [Fix #issue-number]
• Tests are added or updated if you fix a bug or add a feature.
• CHANGELOG files are updated for the changed libraries if there is a behavior change or additional feature. Minor bug fixes and documentation changes should not be included.

Discussion

What do you thinks about make compressor as property of ActiveRecord::Encryption ?

[flavorjones]

The naming of the custom compressor's methods seems inconsistent to me. Would you consider using Encryptor's convention and name them compress/uncompress instead of ZLib's deflate/inflate?

I also think this PR should update the Rails Guides page on encryption, guides/source/active_record_encryption.md to explain how to implement a custom compressor.

[heka1024]

Hi, @flavorjones ! I changed signature of compressor (compress/uncompress) and make compressor configurable. And add some document about compression. Could you review it? I'd really appreciate it if you could provide feedback!

[zzak]

CI failures seem unrelated, you might want to rebase just to be sure as I think most of those have been fixed

[heka1024]

CI failures seem unrelated, you might want to rebase just to be sure as I think most of those have been fixed

@zzak I just rebased it, and it looks like all CI failures are fixed now. 😄