Is it possible for the output of FRB to be directly called by Android/iOS Native?

[lwj1994]

Thanks for this lib. our project is flutter-module mode. we want share code with android&ios&dart. we want reuse the output of FRB. the dartbinding-fork of uniffi-rs is unactive.

[welcome]

Hi! Thanks for opening your first issue here! 😄

[fzyzcjy]

Hi, frb does not directly support Rust to Android/iOS native. But may I know a bit more details about the project - why is the code shared betweeen android/ ios and dart? (we may discuss e.g. if it is possible to be shared only to dart)

[lwj1994]

Our project is a hybrid Flutter application based on flutter_boost, with Flutter making up approximately 65% of the codebase. We need to maintain three parts: Android Native, iOS Native, and Flutter.

Currently, we have some common logic processing, such as obtaining image metadata, which returns the image format, width, and height: getImageMeta(). We've implemented getImageMeta separately on both Android and iOS, and Flutter calls these native implementations through channels.
Modifying three platforms—Android, iOS, and Flutter，requires a significant amount of work, making it very costly.

There are many similar scenarios like getImageMeta, and we don't want to repeat the logic implementation every time. Therefore, we want to use Rust to share this logic.

I've looked into mozilla/uniffi-rs. However, it doesn't have official Dart bindings, and the third-party implementations are not very complete. On the other hand, frb is more actively maintained, so I prefer to choose frb. Therefore, I hope frb can extend its capabilities so that both Android and iOS can also benefit from it.

[fzyzcjy]

Hmm I see. Some brainstorms:

• Is it possible to use both frb (for flutter) and uniffi (for android/ios)? Since frb usually needs very minimal (if not zero) configuration and adaptation, usually the frb side can be generated automatically, and you may only need to spend some time handling uniffi's requirements.
• Is it possible to call android/ios --> flutter --> rust? (the former via flutter's official Pigeon, the latter via frb) This will have lower performance, but if the overhead is negligible (e.g. this is not called a huge number of times) then I guess this is OK.