server.go

package common

import (
	"crypto/tls"
	"log"
	"net"
	"net/http"
	"time"
)

type Server struct {
	*http.Server

	stop chan chan error
}

func NewServer(srv *http.Server) *Server {
	return &Server{Server: srv, stop: make(chan chan error)}
}

func (s *Server) Close() error {
	for {
		errChan := make(chan error)
		select {
		case s.stop <- errChan:
			if err := <-errChan; err != nil {
				return err
			}
		default:
			close(s.stop)
			return nil
		}
	}
}

/*
 Struct tcpKeepAliveListener and its methods, as well as methods
 ListenAndServe and ListenAndServeTLS were originally copied from
 the original Go source and subsequently modified.  The origin source
 was provided under the following license terms:

Copyright (c) 2012 The Go Authors. All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

   * Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
   * Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
   * Neither the name of Google Inc. nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

// ListenAndServe listens on the TCP network address srv.Addr and then
// calls Serve to handle requests on incoming connections.  If
// srv.Addr is blank, ":http" is used.
func (srv *Server) ListenAndServe() error {
	addr := srv.Addr
	if addr == "" {
		addr = ":http"
	}
	ln, err := net.Listen("tcp", addr)
	if err != nil {
		return err
	}

	log.Print("Server listening at ", addr)
	go func() {
		select {
		case done := <-srv.stop:
			log.Print("Closing listener at ", addr)
			done <- ln.Close()
		}
	}()

	go srv.Serve(tcpKeepAliveListener{ln.(*net.TCPListener)})

	return nil
}

// ListenAndServeTLS listens on the TCP network address srv.Addr and
// then calls Serve to handle requests on incoming TLS connections.
//
// Filenames containing a certificate and matching private key for
// the server must be provided. If the certificate is signed by a
// certificate authority, the certFile should be the concatenation
// of the server's certificate followed by the CA's certificate.
//
// If srv.Addr is blank, ":https" is used.
func (srv *Server) ListenAndServeTLS(certFile, keyFile string) error {
	addr := srv.Addr
	if addr == "" {
		addr = ":https"
	}
	config := &tls.Config{}
	if srv.TLSConfig != nil {
		*config = *srv.TLSConfig
	}
	if config.NextProtos == nil {
		config.NextProtos = []string{"http/1.1"}
	}

	var err error
	config.Certificates = make([]tls.Certificate, 1)
	config.Certificates[0], err = tls.LoadX509KeyPair(certFile, keyFile)
	if err != nil {
		return err
	}

	ln, err := net.Listen("tcp", addr)
	if err != nil {
		return err
	}
	log.Print("Server listening at ", addr)

	tlsListener := tls.NewListener(tcpKeepAliveListener{ln.(*net.TCPListener)}, config)

	go func() {
		select {
		case done := <-srv.stop:
			log.Print("Closing listener at ", addr)
			done <- tlsListener.Close()
		}
	}()

	go srv.Serve(tlsListener)

	return nil
}

// tcpKeepAliveListener sets TCP keep-alive timeouts on accepted
// connections. It's used by ListenAndServe and ListenAndServeTLS so
// dead TCP connections (e.g. closing laptop mid-download) eventually
// go away.
type tcpKeepAliveListener struct {
	*net.TCPListener
}

func (ln tcpKeepAliveListener) Accept() (c net.Conn, err error) {
	tc, err := ln.AcceptTCP()
	if err != nil {
		return
	}
	tc.SetKeepAlive(true)
	tc.SetKeepAlivePeriod(3 * time.Minute)
	return tc, nil
}