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server.go
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server.go
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package eventghostnetwork
import (
"bufio"
"context"
"io"
"log"
"net"
"strings"
)
// you can give multiple passwords to differentiate between multiple computers
func RunServer(ctx context.Context, passwords []string, events eventListener) error {
tcpListener, err := net.Listen("tcp", ":3762")
if err != nil {
return err
}
handleOneClient := func(conn net.Conn) {
if err := serverHandleClient(passwords, events, conn); err != nil {
log.Printf("serverHandleClient: %v", err)
}
}
go func() {
<-ctx.Done()
if err := tcpListener.Close(); err != nil {
log.Printf("error closing tcpListener: %v", err)
}
}()
for {
conn, err := tcpListener.Accept()
if err != nil {
select {
case <-ctx.Done():
return nil // error was expected, since we got cancelled
default:
return err // probably cannot Accept() anymore
}
}
go handleOneClient(conn)
}
}
func serverHandleClient(passwords []string, listener eventListener, conn net.Conn) error {
client := newLineScanner(conn)
state := newServerStateMachine(passwords, listener)
for client.Scan() {
// bufio.ScanLines() removes trailing \r\n and \n, but not \n\r which EventGhost
// network sender sends on magic knock, and because of that we will get a leading
// \r on the next message
inputStripped := strings.TrimLeft(client.Text(), "\r")
response := state.process(inputStripped)
if response != "" {
if _, err := conn.Write([]byte(response + "\n")); err != nil {
return err
}
}
if state.state == serverStateDisconnected {
if err := conn.Close(); err != nil {
return err
}
return nil
}
}
if err := client.Err(); err != nil {
return err
}
return nil
}
func newLineScanner(r io.Reader) *bufio.Scanner {
ls := bufio.NewScanner(r)
ls.Split(bufio.ScanLines)
return ls
}