1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
use std::{
    any::Any,
    cmp, fmt, io,
    marker::PhantomData,
    net,
    sync::{Arc, Mutex},
    time::Duration,
};

use actix_http::{body::MessageBody, Extensions, HttpService, KeepAlive, Request, Response};
use actix_server::{Server, ServerBuilder};
use actix_service::{
    map_config, IntoServiceFactory, Service, ServiceFactory, ServiceFactoryExt as _,
};

#[cfg(feature = "openssl")]
use actix_tls::accept::openssl::reexports::{AlpnError, SslAcceptor, SslAcceptorBuilder};
#[cfg(feature = "rustls")]
use actix_tls::accept::rustls::reexports::ServerConfig as RustlsServerConfig;

#[cfg(any(feature = "openssl", feature = "rustls"))]
use actix_http::TlsAcceptorConfig;

use crate::{config::AppConfig, Error};

struct Socket {
    scheme: &'static str,
    addr: net::SocketAddr,
}

struct Config {
    host: Option<String>,
    keep_alive: KeepAlive,
    client_request_timeout: Duration,
    client_disconnect_timeout: Duration,
    #[cfg(any(feature = "openssl", feature = "rustls"))]
    tls_handshake_timeout: Option<Duration>,
}

/// An HTTP Server.
///
/// Create new HTTP server with application factory.
///
/// # HTTP/2
/// Currently, HTTP/2 is only supported when using TLS (HTTPS). See `bind_rustls` or `bind_openssl`.
///
/// # Examples
/// ```no_run
/// use actix_web::{web, App, HttpResponse, HttpServer};
///
/// #[actix_web::main]
/// async fn main() -> std::io::Result<()> {
///     HttpServer::new(|| {
///         App::new()
///             .service(web::resource("/").to(|| async { "hello world" }))
///     })
///     .bind(("127.0.0.1", 8080))?
///     .run()
///     .await
/// }
/// ```
pub struct HttpServer<F, I, S, B>
where
    F: Fn() -> I + Send + Clone + 'static,
    I: IntoServiceFactory<S, Request>,
    S: ServiceFactory<Request, Config = AppConfig>,
    S::Error: Into<Error>,
    S::InitError: fmt::Debug,
    S::Response: Into<Response<B>>,
    B: MessageBody,
{
    pub(super) factory: F,
    config: Arc<Mutex<Config>>,
    backlog: u32,
    sockets: Vec<Socket>,
    builder: ServerBuilder,
    #[allow(clippy::type_complexity)]
    on_connect_fn: Option<Arc<dyn Fn(&dyn Any, &mut Extensions) + Send + Sync>>,
    _phantom: PhantomData<(S, B)>,
}

impl<F, I, S, B> HttpServer<F, I, S, B>
where
    F: Fn() -> I + Send + Clone + 'static,
    I: IntoServiceFactory<S, Request>,

    S: ServiceFactory<Request, Config = AppConfig> + 'static,
    S::Error: Into<Error> + 'static,
    S::InitError: fmt::Debug,
    S::Response: Into<Response<B>> + 'static,
    <S::Service as Service<Request>>::Future: 'static,
    S::Service: 'static,

    B: MessageBody + 'static,
{
    /// Create new HTTP server with application factory
    pub fn new(factory: F) -> Self {
        HttpServer {
            factory,
            config: Arc::new(Mutex::new(Config {
                host: None,
                keep_alive: KeepAlive::default(),
                client_request_timeout: Duration::from_secs(5),
                client_disconnect_timeout: Duration::from_secs(1),
                #[cfg(any(feature = "rustls", feature = "openssl"))]
                tls_handshake_timeout: None,
            })),
            backlog: 1024,
            sockets: Vec::new(),
            builder: ServerBuilder::default(),
            on_connect_fn: None,
            _phantom: PhantomData,
        }
    }

    /// Sets number of workers to start (per bind address).
    ///
    /// By default, the number of available physical CPUs is used as the worker count.
    pub fn workers(mut self, num: usize) -> Self {
        self.builder = self.builder.workers(num);
        self
    }

    /// Sets server keep-alive preference.
    ///
    /// By default keep-alive is set to 5 seconds.
    pub fn keep_alive<T: Into<KeepAlive>>(self, val: T) -> Self {
        self.config.lock().unwrap().keep_alive = val.into();
        self
    }

    /// Sets the maximum number of pending connections.
    ///
    /// This refers to the number of clients that can be waiting to be served. Exceeding this number
    /// results in the client getting an error when attempting to connect. It should only affect
    /// servers under significant load.
    ///
    /// Generally set in the 64–2048 range. Default value is 2048.
    ///
    /// This method will have no effect if called after a `bind()`.
    pub fn backlog(mut self, backlog: u32) -> Self {
        self.backlog = backlog;
        self.builder = self.builder.backlog(backlog);
        self
    }

    /// Sets the per-worker maximum number of concurrent connections.
    ///
    /// All socket listeners will stop accepting connections when this limit is reached for
    /// each worker.
    ///
    /// By default max connections is set to a 25k.
    pub fn max_connections(mut self, num: usize) -> Self {
        self.builder = self.builder.max_concurrent_connections(num);
        self
    }

    /// Sets the per-worker maximum concurrent TLS connection limit.
    ///
    /// All listeners will stop accepting connections when this limit is reached. It can be used to
    /// limit the global TLS CPU usage.
    ///
    /// By default max connections is set to a 256.
    #[allow(unused_variables)]
    pub fn max_connection_rate(self, num: usize) -> Self {
        #[cfg(any(feature = "rustls", feature = "openssl"))]
        actix_tls::accept::max_concurrent_tls_connect(num);
        self
    }

    /// Sets max number of threads for each worker's blocking task thread pool.
    ///
    /// One thread pool is set up **per worker**; not shared across workers.
    ///
    /// By default set to 512 divided by the number of workers.
    pub fn worker_max_blocking_threads(mut self, num: usize) -> Self {
        self.builder = self.builder.worker_max_blocking_threads(num);
        self
    }

    /// Sets server client timeout for first request.
    ///
    /// Defines a timeout for reading client request head. If a client does not transmit the entire
    /// set headers within this time, the request is terminated with a 408 (Request Timeout) error.
    ///
    /// To disable timeout set value to 0.
    ///
    /// By default client timeout is set to 5000 milliseconds.
    pub fn client_request_timeout(self, dur: Duration) -> Self {
        self.config.lock().unwrap().client_request_timeout = dur;
        self
    }

    #[doc(hidden)]
    #[deprecated(since = "4.0.0", note = "Renamed to `client_request_timeout`.")]
    pub fn client_timeout(self, dur: Duration) -> Self {
        self.client_request_timeout(dur)
    }

    /// Sets server connection shutdown timeout.
    ///
    /// Defines a timeout for connection shutdown. If a shutdown procedure does not complete within
    /// this time, the request is dropped.
    ///
    /// To disable timeout set value to 0.
    ///
    /// By default client timeout is set to 5000 milliseconds.
    pub fn client_disconnect_timeout(self, dur: Duration) -> Self {
        self.config.lock().unwrap().client_disconnect_timeout = dur;
        self
    }

    /// Sets TLS handshake timeout.
    ///
    /// Defines a timeout for TLS handshake. If the TLS handshake does not complete within this
    /// time, the connection is closed.
    ///
    /// By default handshake timeout is set to 3000 milliseconds.
    #[cfg(any(feature = "openssl", feature = "rustls"))]
    #[cfg_attr(docsrs, doc(cfg(any(feature = "openssl", feature = "rustls"))))]
    pub fn tls_handshake_timeout(self, dur: Duration) -> Self {
        self.config
            .lock()
            .unwrap()
            .tls_handshake_timeout
            .replace(dur);

        self
    }

    #[doc(hidden)]
    #[deprecated(since = "4.0.0", note = "Renamed to `client_disconnect_timeout`.")]
    pub fn client_shutdown(self, dur: u64) -> Self {
        self.client_disconnect_timeout(Duration::from_millis(dur))
    }

    /// Sets function that will be called once before each connection is handled.
    ///
    /// It will receive a `&std::any::Any`, which contains underlying connection type and an
    /// [Extensions] container so that connection data can be accessed in middleware and handlers.
    ///
    /// # Connection Types
    /// - `actix_tls::accept::openssl::TlsStream<actix_web::rt::net::TcpStream>` when using OpenSSL.
    /// - `actix_tls::accept::rustls::TlsStream<actix_web::rt::net::TcpStream>` when using Rustls.
    /// - `actix_web::rt::net::TcpStream` when no encryption is used.
    ///
    /// See the `on_connect` example for additional details.
    pub fn on_connect<CB>(self, f: CB) -> HttpServer<F, I, S, B>
    where
        CB: Fn(&dyn Any, &mut Extensions) + Send + Sync + 'static,
    {
        HttpServer {
            factory: self.factory,
            config: self.config,
            backlog: self.backlog,
            sockets: self.sockets,
            builder: self.builder,
            on_connect_fn: Some(Arc::new(f)),
            _phantom: PhantomData,
        }
    }

    /// Sets server host name.
    ///
    /// Host name is used by application router as a hostname for url generation. Check
    /// [`ConnectionInfo`](crate::dev::ConnectionInfo::host()) docs for more info.
    ///
    /// By default, hostname is set to "localhost".
    pub fn server_hostname<T: AsRef<str>>(self, val: T) -> Self {
        self.config.lock().unwrap().host = Some(val.as_ref().to_owned());
        self
    }

    /// Flags the `System` to exit after server shutdown.
    ///
    /// Does nothing when running under `#[tokio::main]` runtime.
    pub fn system_exit(mut self) -> Self {
        self.builder = self.builder.system_exit();
        self
    }

    /// Disables signal handling.
    pub fn disable_signals(mut self) -> Self {
        self.builder = self.builder.disable_signals();
        self
    }

    /// Sets timeout for graceful worker shutdown of workers.
    ///
    /// After receiving a stop signal, workers have this much time to finish serving requests.
    /// Workers still alive after the timeout are force dropped.
    ///
    /// By default shutdown timeout sets to 30 seconds.
    pub fn shutdown_timeout(mut self, sec: u64) -> Self {
        self.builder = self.builder.shutdown_timeout(sec);
        self
    }

    /// Returns addresses of bound sockets.
    pub fn addrs(&self) -> Vec<net::SocketAddr> {
        self.sockets.iter().map(|s| s.addr).collect()
    }

    /// Returns addresses of bound sockets and the scheme for it.
    ///
    /// This is useful when the server is bound from different sources with some sockets listening
    /// on HTTP and some listening on HTTPS and the user should be presented with an enumeration of
    /// which socket requires which protocol.
    pub fn addrs_with_scheme(&self) -> Vec<(net::SocketAddr, &str)> {
        self.sockets.iter().map(|s| (s.addr, s.scheme)).collect()
    }

    /// Resolves socket address(es) and binds server to created listener(s).
    ///
    /// # Hostname Resolution
    /// When `addr` includes a hostname, it is possible for this method to bind to both the IPv4 and
    /// IPv6 addresses that result from a DNS lookup. You can test this by passing `localhost:8080`
    /// and noting that the server binds to `127.0.0.1:8080` _and_ `[::1]:8080`. To bind additional
    /// addresses, call this method multiple times.
    ///
    /// Note that, if a DNS lookup is required, resolving hostnames is a blocking operation.
    ///
    /// # Typical Usage
    /// In general, use `127.0.0.1:<port>` when testing locally and `0.0.0.0:<port>` when deploying
    /// (with or without a reverse proxy or load balancer) so that the server is accessible.
    ///
    /// # Errors
    /// Returns an `io::Error` if:
    /// - `addrs` cannot be resolved into one or more socket addresses;
    /// - all the resolved socket addresses are already bound.
    ///
    /// # Example
    /// ```
    /// # use actix_web::{App, HttpServer};
    /// # fn inner() -> std::io::Result<()> {
    /// HttpServer::new(|| App::new())
    ///     .bind(("127.0.0.1", 8080))?
    ///     .bind("[::1]:9000")?
    /// # ; Ok(()) }
    /// ```
    pub fn bind<A: net::ToSocketAddrs>(mut self, addrs: A) -> io::Result<Self> {
        let sockets = self.bind2(addrs)?;

        for lst in sockets {
            self = self.listen(lst)?;
        }

        Ok(self)
    }

    fn bind2<A: net::ToSocketAddrs>(&self, addrs: A) -> io::Result<Vec<net::TcpListener>> {
        let mut err = None;
        let mut success = false;
        let mut sockets = Vec::new();

        for addr in addrs.to_socket_addrs()? {
            match create_tcp_listener(addr, self.backlog) {
                Ok(lst) => {
                    success = true;
                    sockets.push(lst);
                }
                Err(e) => err = Some(e),
            }
        }

        if success {
            Ok(sockets)
        } else if let Some(e) = err.take() {
            Err(e)
        } else {
            Err(io::Error::new(
                io::ErrorKind::Other,
                "Can not bind to address.",
            ))
        }
    }

    /// Resolves socket address(es) and binds server to created listener(s) for TLS connections
    /// using Rustls.
    ///
    /// See [`bind()`](Self::bind) for more details on `addrs` argument.
    ///
    /// ALPN protocols "h2" and "http/1.1" are added to any configured ones.
    #[cfg(feature = "rustls")]
    #[cfg_attr(docsrs, doc(cfg(feature = "rustls")))]
    pub fn bind_rustls<A: net::ToSocketAddrs>(
        mut self,
        addrs: A,
        config: RustlsServerConfig,
    ) -> io::Result<Self> {
        let sockets = self.bind2(addrs)?;
        for lst in sockets {
            self = self.listen_rustls_inner(lst, config.clone())?;
        }
        Ok(self)
    }

    /// Resolves socket address(es) and binds server to created listener(s) for TLS connections
    /// using OpenSSL.
    ///
    /// See [`bind()`](Self::bind) for more details on `addrs` argument.
    ///
    /// ALPN protocols "h2" and "http/1.1" are added to any configured ones.
    #[cfg(feature = "openssl")]
    #[cfg_attr(docsrs, doc(cfg(feature = "openssl")))]
    pub fn bind_openssl<A>(mut self, addrs: A, builder: SslAcceptorBuilder) -> io::Result<Self>
    where
        A: net::ToSocketAddrs,
    {
        let sockets = self.bind2(addrs)?;
        let acceptor = openssl_acceptor(builder)?;

        for lst in sockets {
            self = self.listen_openssl_inner(lst, acceptor.clone())?;
        }

        Ok(self)
    }

    /// Binds to existing listener for accepting incoming connection requests.
    ///
    /// No changes are made to `lst`'s configuration. Ensure it is configured properly before
    /// passing ownership to `listen()`.
    pub fn listen(mut self, lst: net::TcpListener) -> io::Result<Self> {
        let cfg = self.config.clone();
        let factory = self.factory.clone();
        let addr = lst.local_addr().unwrap();

        self.sockets.push(Socket {
            addr,
            scheme: "http",
        });

        let on_connect_fn = self.on_connect_fn.clone();

        self.builder =
            self.builder
                .listen(format!("actix-web-service-{}", addr), lst, move || {
                    let c = cfg.lock().unwrap();
                    let host = c.host.clone().unwrap_or_else(|| format!("{}", addr));

                    let mut svc = HttpService::build()
                        .keep_alive(c.keep_alive)
                        .client_request_timeout(c.client_request_timeout)
                        .client_disconnect_timeout(c.client_disconnect_timeout)
                        .local_addr(addr);

                    if let Some(handler) = on_connect_fn.clone() {
                        svc = svc.on_connect_ext(move |io: &_, ext: _| {
                            (handler)(io as &dyn Any, ext)
                        })
                    };

                    let fac = factory()
                        .into_factory()
                        .map_err(|err| err.into().error_response());

                    svc.finish(map_config(fac, move |_| {
                        AppConfig::new(false, host.clone(), addr)
                    }))
                    .tcp()
                })?;
        Ok(self)
    }

    /// Binds to existing listener for accepting incoming TLS connection requests using Rustls.
    ///
    /// See [`listen()`](Self::listen) for more details on the `lst` argument.
    ///
    /// ALPN protocols "h2" and "http/1.1" are added to any configured ones.
    #[cfg(feature = "rustls")]
    #[cfg_attr(docsrs, doc(cfg(feature = "rustls")))]
    pub fn listen_rustls(
        self,
        lst: net::TcpListener,
        config: RustlsServerConfig,
    ) -> io::Result<Self> {
        self.listen_rustls_inner(lst, config)
    }

    #[cfg(feature = "rustls")]
    fn listen_rustls_inner(
        mut self,
        lst: net::TcpListener,
        config: RustlsServerConfig,
    ) -> io::Result<Self> {
        let factory = self.factory.clone();
        let cfg = self.config.clone();
        let addr = lst.local_addr().unwrap();
        self.sockets.push(Socket {
            addr,
            scheme: "https",
        });

        let on_connect_fn = self.on_connect_fn.clone();

        self.builder =
            self.builder
                .listen(format!("actix-web-service-{}", addr), lst, move || {
                    let c = cfg.lock().unwrap();
                    let host = c.host.clone().unwrap_or_else(|| format!("{}", addr));

                    let svc = HttpService::build()
                        .keep_alive(c.keep_alive)
                        .client_request_timeout(c.client_request_timeout)
                        .client_disconnect_timeout(c.client_disconnect_timeout);

                    let svc = if let Some(handler) = on_connect_fn.clone() {
                        svc.on_connect_ext(move |io: &_, ext: _| (handler)(io as &dyn Any, ext))
                    } else {
                        svc
                    };

                    let fac = factory()
                        .into_factory()
                        .map_err(|err| err.into().error_response());

                    let acceptor_config = match c.tls_handshake_timeout {
                        Some(dur) => TlsAcceptorConfig::default().handshake_timeout(dur),
                        None => TlsAcceptorConfig::default(),
                    };

                    svc.finish(map_config(fac, move |_| {
                        AppConfig::new(true, host.clone(), addr)
                    }))
                    .rustls_with_config(config.clone(), acceptor_config)
                })?;

        Ok(self)
    }

    /// Binds to existing listener for accepting incoming TLS connection requests using OpenSSL.
    ///
    /// See [`listen()`](Self::listen) for more details on the `lst` argument.
    ///
    /// ALPN protocols "h2" and "http/1.1" are added to any configured ones.
    #[cfg(feature = "openssl")]
    #[cfg_attr(docsrs, doc(cfg(feature = "openssl")))]
    pub fn listen_openssl(
        self,
        lst: net::TcpListener,
        builder: SslAcceptorBuilder,
    ) -> io::Result<Self> {
        self.listen_openssl_inner(lst, openssl_acceptor(builder)?)
    }

    #[cfg(feature = "openssl")]
    fn listen_openssl_inner(
        mut self,
        lst: net::TcpListener,
        acceptor: SslAcceptor,
    ) -> io::Result<Self> {
        let factory = self.factory.clone();
        let cfg = self.config.clone();
        let addr = lst.local_addr().unwrap();
        self.sockets.push(Socket {
            addr,
            scheme: "https",
        });

        let on_connect_fn = self.on_connect_fn.clone();

        self.builder =
            self.builder
                .listen(format!("actix-web-service-{}", addr), lst, move || {
                    let c = cfg.lock().unwrap();
                    let host = c.host.clone().unwrap_or_else(|| format!("{}", addr));

                    let svc = HttpService::build()
                        .keep_alive(c.keep_alive)
                        .client_request_timeout(c.client_request_timeout)
                        .client_disconnect_timeout(c.client_disconnect_timeout)
                        .local_addr(addr);

                    let svc = if let Some(handler) = on_connect_fn.clone() {
                        svc.on_connect_ext(move |io: &_, ext: _| (handler)(io as &dyn Any, ext))
                    } else {
                        svc
                    };

                    let fac = factory()
                        .into_factory()
                        .map_err(|err| err.into().error_response());

                    // false positive lint (?)
                    #[allow(clippy::significant_drop_in_scrutinee)]
                    let acceptor_config = match c.tls_handshake_timeout {
                        Some(dur) => TlsAcceptorConfig::default().handshake_timeout(dur),
                        None => TlsAcceptorConfig::default(),
                    };

                    svc.finish(map_config(fac, move |_| {
                        AppConfig::new(true, host.clone(), addr)
                    }))
                    .openssl_with_config(acceptor.clone(), acceptor_config)
                })?;

        Ok(self)
    }

    /// Opens Unix Domain Socket (UDS) from `uds` path and binds server to created listener.
    #[cfg(unix)]
    pub fn bind_uds<A>(mut self, uds_path: A) -> io::Result<Self>
    where
        A: AsRef<std::path::Path>,
    {
        use actix_http::Protocol;
        use actix_rt::net::UnixStream;
        use actix_service::{fn_service, ServiceFactoryExt as _};

        let cfg = self.config.clone();
        let factory = self.factory.clone();
        let socket_addr =
            net::SocketAddr::new(net::IpAddr::V4(net::Ipv4Addr::new(127, 0, 0, 1)), 8080);

        self.sockets.push(Socket {
            scheme: "http",
            addr: socket_addr,
        });

        self.builder = self.builder.bind_uds(
            format!("actix-web-service-{:?}", uds_path.as_ref()),
            uds_path,
            move || {
                let c = cfg.lock().unwrap();
                let config = AppConfig::new(
                    false,
                    c.host.clone().unwrap_or_else(|| format!("{}", socket_addr)),
                    socket_addr,
                );

                let fac = factory()
                    .into_factory()
                    .map_err(|err| err.into().error_response());

                fn_service(|io: UnixStream| async { Ok((io, Protocol::Http1, None)) }).and_then(
                    HttpService::build()
                        .keep_alive(c.keep_alive)
                        .client_request_timeout(c.client_request_timeout)
                        .client_disconnect_timeout(c.client_disconnect_timeout)
                        .finish(map_config(fac, move |_| config.clone())),
                )
            },
        )?;

        Ok(self)
    }

    /// Binds to existing Unix Domain Socket (UDS) listener.
    #[cfg(unix)]
    pub fn listen_uds(mut self, lst: std::os::unix::net::UnixListener) -> io::Result<Self> {
        use actix_http::Protocol;
        use actix_rt::net::UnixStream;
        use actix_service::{fn_service, ServiceFactoryExt as _};

        let cfg = self.config.clone();
        let factory = self.factory.clone();
        let socket_addr =
            net::SocketAddr::new(net::IpAddr::V4(net::Ipv4Addr::new(127, 0, 0, 1)), 8080);
        self.sockets.push(Socket {
            scheme: "http",
            addr: socket_addr,
        });

        let addr = lst.local_addr()?;
        let name = format!("actix-web-service-{:?}", addr);
        let on_connect_fn = self.on_connect_fn.clone();

        self.builder = self.builder.listen_uds(name, lst, move || {
            let c = cfg.lock().unwrap();
            let config = AppConfig::new(
                false,
                c.host.clone().unwrap_or_else(|| format!("{}", socket_addr)),
                socket_addr,
            );

            fn_service(|io: UnixStream| async { Ok((io, Protocol::Http1, None)) }).and_then({
                let mut svc = HttpService::build()
                    .keep_alive(c.keep_alive)
                    .client_request_timeout(c.client_request_timeout)
                    .client_disconnect_timeout(c.client_disconnect_timeout);

                if let Some(handler) = on_connect_fn.clone() {
                    svc = svc
                        .on_connect_ext(move |io: &_, ext: _| (handler)(io as &dyn Any, ext));
                }

                let fac = factory()
                    .into_factory()
                    .map_err(|err| err.into().error_response());

                svc.finish(map_config(fac, move |_| config.clone()))
            })
        })?;
        Ok(self)
    }
}

impl<F, I, S, B> HttpServer<F, I, S, B>
where
    F: Fn() -> I + Send + Clone + 'static,
    I: IntoServiceFactory<S, Request>,
    S: ServiceFactory<Request, Config = AppConfig>,
    S::Error: Into<Error>,
    S::InitError: fmt::Debug,
    S::Response: Into<Response<B>>,
    S::Service: 'static,
    B: MessageBody,
{
    /// Start listening for incoming connections.
    ///
    /// # Workers
    /// This method starts a number of HTTP workers in separate threads. The number of workers in a
    /// set is defined by [`workers()`](Self::workers) or, by default, the number of the machine's
    /// physical cores. One worker set is created for each socket address to be bound. For example,
    /// if workers is set to 4, and there are 2 addresses to bind, then 8 worker threads will be
    /// spawned.
    ///
    /// # Panics
    /// This methods panics if no socket addresses were successfully bound or if no Tokio runtime
    /// is set up.
    pub fn run(self) -> Server {
        self.builder.run()
    }
}

fn create_tcp_listener(addr: net::SocketAddr, backlog: u32) -> io::Result<net::TcpListener> {
    use socket2::{Domain, Protocol, Socket, Type};
    let domain = Domain::for_address(addr);
    let socket = Socket::new(domain, Type::STREAM, Some(Protocol::TCP))?;
    socket.set_reuse_address(true)?;
    socket.bind(&addr.into())?;
    // clamp backlog to max u32 that fits in i32 range
    let backlog = cmp::min(backlog, i32::MAX as u32) as i32;
    socket.listen(backlog)?;
    Ok(net::TcpListener::from(socket))
}

/// Configure `SslAcceptorBuilder` with custom server flags.
#[cfg(feature = "openssl")]
fn openssl_acceptor(mut builder: SslAcceptorBuilder) -> io::Result<SslAcceptor> {
    builder.set_alpn_select_callback(|_, protocols| {
        const H2: &[u8] = b"\x02h2";
        const H11: &[u8] = b"\x08http/1.1";

        if protocols.windows(3).any(|window| window == H2) {
            Ok(b"h2")
        } else if protocols.windows(9).any(|window| window == H11) {
            Ok(b"http/1.1")
        } else {
            Err(AlpnError::NOACK)
        }
    });

    builder.set_alpn_protos(b"\x08http/1.1\x02h2")?;

    Ok(builder.build())
}