Allow using MRML via MRML-ruby

[pokonski]

This proof of concept change would allow using Rust implementation of MJML called MRML via the mrml-ruby gem.

The benefits:

• no need for JS runtime in production to compile email templates
• MRML boasts better performance and lower memory usage
• MRML-ruby gem comes with precompiled binaries for all architectures so much easier to set up
• no need to write to temp files to feed input into MJML

Would anyone except me find this useful?

References:

• ruby gem: https://github.com/hardpixel/mrml-ruby
• MRML: https://github.com/jdrouet/mrml

MRML isn't 100% compatible with MJML, so I made it optional.

[sighmon]

@pokonski The speed/lower memory use does look amazing. What's your feeling about the compromise of including mrml-ruby binaries when the default is not to use them? Should this be a fork?

If not, it'd be great if you could update the README and write a test when using the use_mrml flag.

I've also fixed the GitHub Action now for Ruby 2.7, so if you merge from master it should all work again.

[pokonski]

What's your feeling about the compromise of including mrml-ruby binaries when the default is not to use them? Should this be a fork?

Good question, I am not opposed but ultimately I can make it a "peer" dependency and check if it's present inside the parser with if defined?(MRML) and raise error in case it is not loaded. MRML makes the whole library simpler, but fragmenting the userbase of mjml-rails with frivolous forking wouldn't be my first choice 😁

If not, it'd be great if you could update the README and write a test when using the use_mrml flag.

Will do, I didn't focus on tests initially because I wasn't sure if such addition is desired :)

[manuelmeurer]

Would be great to see this implemented! 😄

[pokonski]

@sighmon I updated the documentation and made mrml a "peer" dependency. Will add some tests too :)

[pokonski]

I also added tests for MrmlParser, CI is now green in my fork:

https://github.com/pokonski/mjml-rails/actions/runs/7488219746/job/20382217087

let me know if anything else is missing :)

[sighmon]

That works for me! Thanks so much - I'll create a release today.

[pokonski]

Awesome, thank you!