Axum

cargo add resend-rs
cargo add tokio -F macros,rt-multi-thread

use std::sync::Arc;

use axum::{extract::State, http::StatusCode, routing::get, Router};
use resend_rs::types::CreateEmailBaseOptions;
use resend_rs::{Resend, Result};

// Cloning the Resend client is fine and cheap as the internal HTTP client is
// not cloned.
#[derive(Clone)]
struct AppState {
  resend: Resend,
}

#[tokio::main]
async fn main() {
  let shared_state = Arc::new(AppState {
    resend: Resend::new("re_123456789"),
  });

  // build our application with a single route
  let app = Router::new()
    .route("/", get(endpoint))
    // provide the state so the router can access it
    .with_state(shared_state);

  // run our app with hyper, listening globally on port 3000
  let listener = tokio::net::TcpListener::bind("0.0.0.0:3000").await.unwrap();
  axum::serve(listener, app).await.unwrap();
}

async fn endpoint(State(state): State<Arc<AppState>>) -> Result<String, StatusCode> {
  let from = "Acme <onboarding@resend.dev>";
  let to = ["delivered@resend.dev"];
  let subject = "Hello World";

  let email = CreateEmailBaseOptions::new(from, to, subject)
    .with_html("<strong>It works!</strong>");

  // access the state via the `State` extractor and handle the error
  match state.resend.emails.send(email).await {
    Ok(email) => Ok(email.id.to_string()),
    Err(_) => Err(StatusCode::INTERNAL_SERVER_ERROR),
  }
}