restsend client sdk

RestSend is a secure instant messaging system, with the server written in Go:

• Unit test coverage is over 80%
• Supports millions of concurrent connections on a single machine and supports cluster deployment
• High-reliability protocol design, supporting reliable message transmission
• Based on synchronous protocol design
• Complete OpenAPI and Webhook support, the server supports various forms of extensions:
• Avatar generation
• Highly extensible account and permission system, no need to migrate existing user systems
• Flow control and content detection
• SDK is written in Rust, providing SDK implementations for Android, iOS, and WASM, capable of rendering 100,000 sessions on a single machine
• Code can be managed with go module and can be directly embedded into existing Go projects

For testing, you can visit the online demo or contact me at: [email protected]

The RestSend client SDK is written in Rust, providing SDK implementations for Android and iOS. It requires a Rust version of at least 1.85.0. If the version is lower, please update Rust using rustup update. Check the Rust version:

mpi@mpis-Mac-mini restsend-sdk % rustc --version
rustc 1.85.0 (4d91de4e4 2025-02-17)

Code Dependencies and Environment Preparation

• Requires rust 1.72.0 (5680fa18f 2023-08-23) or higher, and setting up rsproxy.cn to speed up compilation

• For iOS, prepare the development environment (for M1/M2):

    ```shell
    rustup target add aarch64-apple-ios aarch64-apple-ios-sim x86_64-apple-darwin
    ```
  

• For Android, prepare the development environment: Install NDK and set the NDK_HOME environment variable to point to the NDK installation directory.

  1. Download NDK from NDK download page - wget "https://dl.google.com/android/repository/android-ndk-r25c-linux.zip?hl=en" - Extract the NDK directory and modify the .profile file to add the environment variable:

     export NDK_HOME=/home/xxx/ndk/android-ndk-r25c

  2. Add Android toolchain to cargo

     cargo install cargo-ndk
     rustup target add aarch64-linux-android x86_64-linux-android

Compile for iOS

Tested only on M2 machines, please use an M2 machine for compilation.

• Development test version: Simulator

    ```ruby
    # Add to Podfile in Xcode project
    pod 'restsendSdk', :path => '../restsend-rs'
    ```
  

  1. compile the Rust library

     cargo build --target aarch64-apple-ios-sim
     # For x86 Mac machines
     cargo build  --target x86_64-apple-darwin 

  2. Compile the Swift binding code

     cargo run --bin bindgen -- --language swift

• Release version:

  cargo build --release --target aarch64-apple-ios-sim --target aarch64-apple-ios --target x86_64-apple-darwin
  
  cargo run --release --bin bindgen -- --language swift

  To release the official pod version:

   cargo run --release --bin bindgen -- --language swift -p true

Compile for Wasm

It is recommended to use Node version 20 or above.

First, manually download the wasm-opt tool from binaryen and place it in the PATH. Download from: https://github.com/WebAssembly/binaryen/releases/ After extraction, place wasm-opt in the PATH, for example, in the /usr/local/bin directory.

 cargo install wasm-pack wasm-bindgen-cli
 cd crates/restsend-wasm
 npm install --force
 
 # For Linux/WSL, install dependencies first
 # npx playwright install-deps
 
 npx playwright install webkit
 npm run build

Compile for Android

Tested only on M2 machines, currently only supports ARM simulators, x86_64 simulators are pending. First, configure the NDK directory to point to the NDK, for example, if downloaded to ~/ndk directory:

export NDK_HOME=$HOME/ndk
cargo ndk -t arm64-v8a build --release
cargo run --release --bin bindgen -- --language kotlin 
cargo ndk -t arm64-v8a -o ./jniLibs build --release

cd android-sdk
# test
# gradle connectedAndroidTest

gradle assembleRelease

# for Publish aar
gradle buildAndDeploy

How to Test

• For cargo development phase testing, test on PC:

  cargo test

• Rust version demo requires a GUI environment, such as Windows/Mac to run

  cargo run -p demo

Android Configuration

• In app/build.gradle, add JNA support using AAR to automatically compile the required .so files

    ```gradle
    dependencies {
            implementation 'net.java.dev.jna:jna:5.16.0@aar'
            ....
    }
    ```
  

• In AndroidManifest.xml, add storage and network permissions

    ```xml
            <uses-permission android:name="android.permission.INTERNET"></uses-permission>
            <application ...>
    ```