rust_in_flutter 1.1.0

Easily integrate Rust to make your Flutter app blazingly fast!

🆎 Rust-In-Flutter

Easily integrate Rust to make your Flutter app blazingly fast!

This high-level wrapper package simplifies Rust integration for your Flutter app without the need for code generation or native tooling. Designed with ease of use, future scalability, and exceptional performance in mind, it handles all the complicated aspects behind the scenes. Simply add this package to your Flutter project and you're ready to write Rust!

Benefits

• Rust integration with the ability to use an arbitrary number of library crates
• Async RESTful API with easy request from Dart and response from Rust without blocking
• Streaming from Rust to Dart
• Restarting Rust logic on Dart's hot restart
• No memory copy when sending native data
• No complicated code generation during development
• No messing with sensitive build files such as CMake, Gradle, Podfile, etc.

Platform Support

All the challenging build settings are automatically handled by this package. Note that the files in your Flutter project are not affected.

• ✅ Linux: Tested and supported
• ✅ Android: Tested and supported
• ✅ Windows: Tested and supported
• ✅ macOS: Tested and supported
• ✅ iOS: Tested and supported
• ⏸️ Web: Not now but considered

If you have any suggestions or want to report a bug, please leave it as an issue or a pull request. We will try to respond as quickly as possible.

Why Use Rust?

While Dart is an amazing object-oriented modern language, its performance sometimes does not meet the requirements because it's non-native garbage-collected language. That's where Rust comes into play. Rust's performance is known to be roughly about 2~40 times faster than Dart, not to mention the ability to utilize multiple threads.

👜 Installing Components

Basic Steps

First, add this package to your Flutter project.

flutter pub add rust_in_flutter

Then install Rust toolchain. Refer to the official Rust docs.

Finally, check that your system is ready for compiling. Flutter might want you to install additional components. You can repeat this commands to verify your system status after each installation step. If there are no issues in the output, you are good to go!

rustc --version
flutter doctor

Extra Steps

If you intend to compile your code for Linux, Windows, macOS, or iOS, you won't need to take any additional steps.

For Android, install Android NDK version 23.1.7779620.

Using extra build targets with Rust can sometimes present various issues. If you encounter any problems, feel free to visit the discussions page and open a Q&A thread for assistance.

👜 Applying Template

Simply run this in the command-line from the Flutter project folder.

dart run rust_in_flutter:apply_template

Once you've run the command, there will be some new folders and files that will be your starter Rust template.

    my_flutter_project/
    ├── android/
    ├── ios/
    ├── lib/
    ├── linux/
+   ├── native/
+   │   ├── hub/
+   │   ├── sample_crate/
+   │   └── README.md
    ├── web/
    ├── windows/
*   ├── .gitignore
+   ├── Cargo.toml
*   ├── pubspec.yaml
    └── ...

Entry point of your Rust logic is the hub library crate. You might want to remove sample_crate in production.

Please keep in mind:

• Do NOT change the name of the hub crate or the native folder. Compilation presets expect the entry library crate to be located at ./native/hub.
• Do NOT modify the bridge module inside ./native/hub/src.
• You CAN name crates other than hub as you want.

Now by heading over to ./native/hub/src/lib.rs, you can start writing Rust!

🧱 Tips

When requesting from Dart, you should specify the operation and address. This way of communication follows the definition of RESTful API.

import 'package:rust_in_flutter/rust_in_flutter.dart';
import 'package:msgpack_dart/msgpack_dart.dart';

void someFunction() async {
    var rustRequest = RustRequest(
      address: 'basicCategory.counterNumber',
      operation: Operation.Read,
      bytes: serialize(
        {
          'letter': 'Hello from Dart!',
          'before_number': 888,
          'dummy_one': 1,
          'dummy_two': 2,
          'dummy_three': [3, 4, 5]
        },
      ),
    );

    var rustResponse = await requestToRust(rustRequest);
    var message = deserialize(rustResponse.bytes) as Map;
    var innerValue = message['after_number'] as int;
}

Upon receiving requests from Rust, you should first classify them by address.

pub async fn handle_request(request_unique: RustRequestUnique) {
    let rust_request = request_unique.request;
    let interaction_id = request_unique.id;

    let layered: Vec<&str> = rust_request.address.split('.').collect();
    let rust_response = if layered.is_empty() {
        RustResponse::default()
    } else if layered[0] == "basicCategory" {
        if layered.len() == 1 {
            RustResponse::default()
        } else if layered[1] == "counterNumber" {
            sample_functions::calculate_something(rust_request).await
        } else {
            RustResponse::default()
        }
    } else {
        RustResponse::default()
    };

    let response_unique = RustResponseUnique {
        id: interaction_id,
        response: rust_response,
    };
    respond_to_dart(response_unique);
}

Handling requests in Rust is as follows. Endpoint message schema is defined here because it will be different by address and operation type.

pub async fn calculate_something(rust_request: RustRequest) -> RustResponse {
    match rust_request.operation {
        Operation::Create => RustResponse::default(),
        Operation::Read => {
            #[allow(dead_code)]
            #[derive(Deserialize)]
            struct RustRequestSchema {
                letter: String,
                before_number: i32,
                dummy_one: i32,
                dummy_two: i32,
                dummy_three: Vec<i32>,
            }
            let slice = rust_request.bytes.as_slice();
            let received: RustRequestSchema = from_slice(slice).unwrap();
            println!("{:?}", received.letter);

            let before_value = received.before_number;
            let after_value = sample_crate::add_seven(before_value);

            #[derive(Serialize)]
            struct RustResponseSchema {
                after_number: i32,
                dummy_one: i32,
                dummy_two: i32,
                dummy_three: Vec<i32>,
            }
            RustResponse {
                successful: true,
                bytes: to_vec_named(&RustResponseSchema {
                    after_number: after_value,
                    dummy_one: 1,
                    dummy_two: 2,
                    dummy_three: vec![3, 4, 5],
                })
                .unwrap(),
            }
        }
        Operation::Update => RustResponse::default(),
        Operation::Delete => RustResponse::default(),
    }
}

You can extend this RESTful API pattern and create hundreds and thousands of endpoints as you need. If you have a web background, this system might look familiar. More comments and details are included in the actual code inside the Rust template.

Ideally, Flutter would deal with the cross-platform user interface while Rust handles the business logic. The front-end and back-end can be completely separated, meaning that Dart and Rust codes are detachable from each other. These two worlds communicate through channels and streams.

Use MessagePack for serializing messages sent between Dart and Rust as provided by the Rust template unless you have other reasons not to do so. For those who aren't familiar, MessagePack is a nested binary structure similar to JSON, but much faster and more efficient.

Data being sent between Dart and Rust are basically bytes arrays, represented as Uint8List in Dart and Vec<u8> in Rust. Though using MessagePack serialization is recommended, you can send any kind of bytes data as you wish, such as a high-resolution image or some kind of file data.

☕ Support Us

😉 If you are benefiting from the features of Rust-In-Flutter and find it helpful, why not consider supporting this project? Your generous donations contribute to the maintenance and development of Rust-In-Flutter, ensuring its continuous improvement and growth.

If you feel like so, please consider buying us a coffee.