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package gemini
import (
"bufio"
"crypto/tls"
"fmt"
"io"
"net"
"strings"
)
// Request contains the data of the client request
type Request struct {
URL string
}
// Handler is the interface a struct need to implement to be able to handle Gemini requests
type Handler interface {
Handle(r Request) Response
}
// ListenAndServe create a TCP server on the specified address and pass
// new connections to the given handler.
// Each request is handled in a separate goroutine.
func ListenAndServe(addr, certFile, keyFile string, handler Handler) error {
if addr == "" {
addr = "127.0.0.1:1965"
}
listener, err := listen(addr, certFile, keyFile)
if err != nil {
return err
}
err = serve(listener, handler)
if err != nil {
return err
}
err = listener.Close()
if err != nil {
return fmt.Errorf("failed to close the listener: %v", err)
}
return nil
}
func listen(addr, certFile, keyFile string) (net.Listener, error) {
cer, err := tls.LoadX509KeyPair(certFile, keyFile)
if err != nil {
return nil, fmt.Errorf("failed to load certificates: %v", err)
}
config := &tls.Config{Certificates: []tls.Certificate{cer}}
ln, err := tls.Listen("tcp", addr, config)
if err != nil {
return nil, fmt.Errorf("failed to listen: %v", err)
}
return ln, nil
}
func serve(listener net.Listener, handler Handler) error {
for {
conn, err := listener.Accept()
if err != nil {
continue
}
go handleConnection(conn, handler)
}
}
func handleConnection(conn io.ReadWriteCloser, handler Handler) {
defer conn.Close()
requestURL, err := getRequestURL(conn)
if err != nil {
return
}
request := Request{requestURL}
response := handler.Handle(request)
if response.Body != nil {
defer response.Body.Close()
}
err = writeResponse(conn, response)
if err != nil {
return
}
}
func getRequestURL(conn io.Reader) (string, error) {
scanner := bufio.NewScanner(conn)
if ok := scanner.Scan(); !ok {
return "", scanner.Err()
}
rawURL := scanner.Text()
if strings.Contains(rawURL, "://") {
return rawURL, nil
}
return fmt.Sprintf("gemini://%s", rawURL), nil
}
func writeResponse(conn io.Writer, response Response) error {
_, err := fmt.Fprintf(conn, "%d %s\r\n", response.Status, response.Meta)
if err != nil {
return fmt.Errorf("failed to write header line to the client: %v", err)
}
if response.Body == nil {
return nil
}
_, err = io.Copy(conn, response.Body)
if err != nil {
return fmt.Errorf("failed to write the response body to the client: %v", err)
}
return nil
}
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