httplistener.go

// httplistener is a simplified version of camlistore.org/pkg/webserver
package httplistener

import (
	"crypto/rand"
	"crypto/tls"
	"fmt"
	"github.com/bradfitz/runsit/listen"
	"net"
	"time"
)

type Listener struct {
	net.Listener
	TLSCertFile,
	TLSKeyFile string
}

func Listen(addr string) (error, net.Listener) {
	return new(Listener).Listen(addr)
}

func ListenTLS(addr, certFile, keyFile string) (error, net.Listener) {
	l := &Listener{TLSCertFile: certFile, TLSKeyFile: keyFile}
	return l.Listen(addr)
}

func (l *Listener) Listen(addr string) (error, net.Listener) {
	if l.Listener != nil {
		return nil, l.Listener
	}

	var err error
	l.Listener, err = listen.Listen(addr)
	if err != nil {
		return fmt.Errorf("Failed to listen on %s: %v", addr, err), nil
	}

	if l.TLSCertFile != "" && l.TLSKeyFile != "" {
		config := &tls.Config{
			Rand:       rand.Reader,
			Time:       time.Now,
			NextProtos: []string{"http/1.1"},
		}
		config.Certificates = make([]tls.Certificate, 1)
		config.Certificates[0], err = tls.LoadX509KeyPair(l.TLSCertFile, l.TLSKeyFile)
		if err != nil {
			return fmt.Errorf("Failed to load TLS cert: %v", err), nil
		}
		l.Listener = tls.NewListener(l.Listener, config)
	}

	return nil, l.Listener
}

func (l *Listener) ListenURL() string {
	scheme := "http"
	if l.TLSCertFile != "" && l.TLSKeyFile != "" {
		scheme = "https"
	}
	if l.Listener != nil {
		if taddr, ok := l.Listener.Addr().(*net.TCPAddr); ok {
			if taddr.IP.IsUnspecified() {
				return fmt.Sprintf("%s://localhost:%d", scheme, taddr.Port)
			}
			return fmt.Sprintf("%s://%s", scheme, l.Listener.Addr())
		}
	}
	return ""
}