1 use tonic::{transport::Server, Request, Response, Status}; 2 3 use hello_world::greeter_server::{Greeter, GreeterServer}; 4 use hello_world::{HelloReply, HelloRequest}; 5 6 pub mod hello_world { 7 tonic::include_proto!("helloworld"); 8 } 9 10 #[derive(Default)] 11 pub struct MyGreeter {} 12 13 #[tonic::async_trait] 14 impl Greeter for MyGreeter { 15 async fn say_hello( 16 &self, 17 request: Request<HelloRequest>, 18 ) -> Result<Response<HelloReply>, Status> { 19 let extension = request.extensions().get::<MyExtension>().unwrap(); 20 println!("extension data = {}", extension.some_piece_of_data); 21 22 let reply = hello_world::HelloReply { 23 message: format!("Hello {}!", request.into_inner().name), 24 }; 25 Ok(Response::new(reply)) 26 } 27 } 28 29 #[tokio::main] 30 async fn main() -> Result<(), Box<dyn std::error::Error>> { 31 let addr = "[::1]:50051".parse().unwrap(); 32 let greeter = MyGreeter::default(); 33 34 let svc = GreeterServer::with_interceptor(greeter, intercept); 35 36 println!("GreeterServer listening on {}", addr); 37 38 Server::builder().add_service(svc).serve(addr).await?; 39 40 Ok(()) 41 } 42 43 /// This function will get called on each inbound request, if a `Status` 44 /// is returned, it will cancel the request and return that status to the 45 /// client. 46 fn intercept(mut req: Request<()>) -> Result<Request<()>, Status> { 47 println!("Intercepting request: {:?}", req); 48 49 // Set an extension that can be retrieved by `say_hello` 50 req.extensions_mut().insert(MyExtension { 51 some_piece_of_data: "foo".to_string(), 52 }); 53 54 Ok(req) 55 } 56 57 struct MyExtension { 58 some_piece_of_data: String, 59 } 60