1 files changed, 118 insertions, 0 deletions
diff --git a/server.go b/server.go
new file mode 100644
index 0000000..ff7df80
--- /dev/null
+++ b/server.go
@@ -0,0 +1,118 @@
+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)
+	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)
+	}
+
+	_, 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
+}