AIDL Client
Finally, we can create a Rust client for our new service.
birthday_service/src/client.rs:
use com_example_birthdayservice::aidl::com::example::birthdayservice::IBirthdayService::IBirthdayService;
use com_example_birthdayservice::binder;
const SERVICE_IDENTIFIER: &str = "birthdayservice";
/// Call the birthday service.
fn main() -> Result<(), Box<dyn Error>> {
let name = std::env::args().nth(1).unwrap_or_else(|| String::from("Bob"));
let years = std::env::args()
.nth(2)
.and_then(|arg| arg.parse::<i32>().ok())
.unwrap_or(42);
binder::ProcessState::start_thread_pool();
let service = binder::get_interface::<dyn IBirthdayService>(SERVICE_IDENTIFIER)
.map_err(|_| "Failed to connect to BirthdayService")?;
// Call the service.
let msg = service.wishHappyBirthday(&name, years)?;
println!("{msg}");
}
birthday_service/Android.bp:
rust_binary {
name: "birthday_client",
crate_name: "birthday_client",
srcs: ["src/client.rs"],
rustlibs: [
"com.example.birthdayservice-rust",
"libbinder_rs",
],
prefer_rlib: true, // To avoid dynamic link error.
}
Notice that the client does not depend on libbirthdayservice
.
Build, push, and run the client on your device:
m birthday_client
adb push "$ANDROID_PRODUCT_OUT/system/bin/birthday_client" /data/local/tmp
adb shell /data/local/tmp/birthday_client Charlie 60
Happy Birthday Charlie, congratulations with the 60 years!
Strong<dyn IBirthdayService>
is the trait object representing the service that the client has connected to.Strong
is a custom smart pointer type for Binder. It handles both an in-process ref count for the service trait object, and the global Binder ref count that tracks how many processes have a reference to the object.- Note that the trait object that the client uses to talk to the service uses the exact same trait that the server implements. For a given Binder interface, there is a single Rust trait generated that both client and server use.
- Use the same service identifier used when registering the service. This should ideally be defined in a common crate that both the client and server can depend on.