actix-web/guide/src/qs_3_5.md

Server

HttpServer type is responsible for serving http requests. HttpServer accept application factory as a parameter, Application factory must have Send + Sync boundaries. More about that in multi-threading section. To bind to specific socket address bind() must be used. This method could be called multiple times. To start http server one of the start methods could be used. start() method start simple server, start_tls() or start_ssl() starts ssl server. HttpServer is an actix actor, it has to be initialized within properly configured actix system:

# extern crate actix;
# extern crate actix_web;
use actix::*;
use actix_web::*;

fn main() {
    let sys = actix::System::new("guide");

    HttpServer::new(
        || Application::new()
            .resource("/", |r| r.h(httpcodes::HTTPOk)))
        .bind("127.0.0.1:59080").unwrap()
        .start();

#     actix::Arbiter::system().send(actix::msgs::SystemExit(0));
    let _ = sys.run();
}

It is possible to start server in separate thread with spawn() method. In that case server spawns new thread and create new actix system in it. To stop this server send StopServer message.

Http server is implemented as an actix actor. It is possible to communicate with server via messaging system. All start methods like start(), start_ssl(), etc returns address of the started http server. Actix http server accept several messages:

• PauseServer - Pause accepting incoming connections
• ResumeServer - Resume accepting incoming connections
• StopServer - Stop incoming connection processing, stop all workers and exit

# extern crate futures;
# extern crate actix;
# extern crate actix_web;
# use futures::Future;
use actix_web::*;
use std::thread;
use std::sync::mpsc;

fn main() {
    let (tx, rx) = mpsc::channel();
    
    thread::spawn(move || {
        let sys = actix::System::new("http-server");
        let addr = HttpServer::new(
            || Application::new()
                .resource("/", |r| r.h(httpcodes::HTTPOk)))
            .bind("127.0.0.1:0").expect("Can not bind to 127.0.0.1:0")
            .shutdown_timeout(60)    // <- Set shutdown timeout to 60 seconds
            .start();
        let _ = tx.send(addr);
        let _ = sys.run();
    });

    let addr = rx.recv().unwrap();
    let _ = addr.call_fut(
         server::StopServer{graceful:true}).wait(); // <- Send `StopServer` message to server.
}

Multi-threading

Http server automatically starts number of http workers, by default this number is equal to number of logical cpu in the system. This number could be overridden with HttpServer::threads() method.

# extern crate actix_web;
# extern crate tokio_core;
# use tokio_core::net::TcpStream;
# use std::net::SocketAddr;
use actix_web::*;

fn main() {
    HttpServer::<TcpStream, SocketAddr, _, _>::new(
        || Application::new()
            .resource("/", |r| r.h(httpcodes::HTTPOk)))
        .threads(4); // <- Start 4 workers
}

Server create separate application instance for each created worker. Application state is not shared between threads, to share state Arc could be used. Application state does not need to be Send and Sync but application factory must be Send + Sync.

SSL

There are two tls and alpn features for ssl server. tls feature is for native-tls integration and alpn is for openssl.

[dependencies]
actix-web = { git = "https://github.com/actix/actix-web", features=["alpn"] }

use std::fs::File;
use actix_web::*;

fn main() {
    let mut file = File::open("identity.pfx").unwrap();
    let mut pkcs12 = vec![];
    file.read_to_end(&mut pkcs12).unwrap();
    let pkcs12 = Pkcs12::from_der(&pkcs12).unwrap().parse("12345").unwrap();

    HttpServer::new(
        || Application::new()
            .resource("/index.html", |r| r.f(index)))
        .bind("127.0.0.1:8080").unwrap()
        .serve_ssl(pkcs12).unwrap();
}

Note on HTTP/2.0 protocol over tls without prior knowledge, it requires tls alpn. At the moment only openssl has alpn support.

Please check example for full example.

Keep-Alive

Actix can wait for requests on a keep-alive connection. Keep alive connection behavior is defined by server settings.

• Some(75) - enable 75 sec keep alive timer according request and response settings.
• Some(0) - disable keep alive.
• None - Use SO_KEEPALIVE socket option.

# extern crate actix_web;
# extern crate tokio_core;
# use tokio_core::net::TcpStream;
# use std::net::SocketAddr;
use actix_web::*;

fn main() {
    HttpServer::<TcpStream, SocketAddr, _, _>::new(||
        Application::new()
            .resource("/", |r| r.h(httpcodes::HTTPOk)))
        .keep_alive(None); // <- Use `SO_KEEPALIVE` socket option.
}

If first option is selected then keep alive state calculated based on response's connection-type. By default HttpResponse::connection_type is not defined in that case keep alive defined by request's http version. Keep alive is off for HTTP/1.0 and is on for HTTP/1.1 and "HTTP/2.0".

Connection type could be change with HttpResponseBuilder::connection_type() method.

# extern crate actix_web;
# use actix_web::httpcodes::*;
use actix_web::*;

fn index(req: HttpRequest) -> HttpResponse {
    HTTPOk.build()
        .connection_type(headers::ConnectionType::Close) // <- Close connection
        .force_close()                                   // <- Alternative method
        .finish().unwrap()
}
# fn main() {}

Graceful shutdown

Actix http server support graceful shutdown. After receiving a stop signal, workers have specific amount of time to finish serving requests. Workers still alive after the timeout are force dropped. By default shutdown timeout sets to 30 seconds. You can change this parameter with HttpServer::shutdown_timeout() method.

You can send stop message to server with server address and specify if you what graceful shutdown or not. start() methods return address of the server.

Http server handles several OS signals. CTRL-C is available on all OSs, other signals are available on unix systems.

• SIGINT - Force shutdown workers
• SIGTERM - Graceful shutdown workers
• SIGQUIT - Force shutdown workers

It is possible to disable signals handling with HttpServer::disable_signals() method.