update docs and improve readability

README.md

@@ -11,7 +11,7 @@ server? Because it's educational and that's the spirit of the protocol.
 - directory listing support through the auto index flag
 - reloads ssl certs and reopens log files on SIGHUP, e.g. after Let's Encrypt renewal
 - response writer interceptor and middleware support
-- simple middleware for lru document cache
+- simple middleware for fifo document cache
 - concurrent request limiter
 - KISS, single file gemini implementation, handler func in main
 - modern tls ciphers (from [Mozilla's TLS ciphers recommendations](https://statics.tls.security.mozilla.org/server-side-tls-conf.json))
@@ -26,7 +26,7 @@ Currently only supported through the go toolchain, either check out the repot an
 go install github.com/n0x1m/gmifs
 ```
 
-### Dev & Tests
+### Development
 
 Test it locally by serving e.g. a `./public` directory on localhost with directory listing turned on
 
@@ -68,15 +68,15 @@ If debug logs are enabled, the certificate rotation will be confirmed.
 ### Supported flags
 
 ```
-Usage of ./gmifs:
+sage of ./gmifs:
   -addr string
         address to listen on, e.g. 127.0.0.1:1965 (default ":1965")
   -autocertvalidity int
-        valid days when using a gmifs auto provisioned self-signed certificate (default 1)
+        valid days when using a gmifs provisioned certificate (default 1)
   -autoindex
         enables auto indexing, directory listings
   -cache int
-        simple lru document cache for n items. Disabled when zero.
+        simple fifo document cache for n items. Disabled when zero.
   -cert string
         TLS chain of one or more certificates
   -debug

gemini/gemini.go

@@ -56,8 +56,8 @@ var (
 	ErrEmptyRequestURL = errors.New("gemini: empty request URL")
 	ErrInvalidPath     = errors.New("gemini: path error")
 	ErrInvalidHost     = errors.New("gemini: empty host")
-	ErrInvalidUtf8     = errors.New("empty request URL")
+	ErrInvalidUtf8     = errors.New("gemini: empty request URL")
-	ErrUnknownProtocol = fmt.Errorf("unknown protocol scheme")
+	ErrUnknownProtocol = fmt.Errorf("gemini: unknown protocol scheme")
 )
 
 type Request struct {
@@ -108,9 +108,10 @@ type Server struct {
 	MaxOpenConns int
 
 	// internal
-	listener net.Listener
+	listener       net.Listener
-	shutdown bool
+	shutdown       bool
-	closed   chan struct{}
+	closed         chan struct{}
+	sighupListener chan struct{}
 }
 
 func (s *Server) log(v string) {
@@ -134,18 +135,13 @@ func (s *Server) loadTLS() (err error) {
 	return err
 }
 
-func (s *Server) ListenAndServe() error {
+func (s *Server) reloadTLSConfigOnSighup() {
-	err := s.loadTLS()
-	if err != nil {
-		return err
-	}
-
 	hup := make(chan os.Signal, 1)
 	signal.Notify(hup, syscall.SIGHUP)
 
-	go func() {
+	for {
-		for {
+		select {
-			<-hup
+		case <-hup:
 
 			s.log("reloading certificate")
 			if s.listener != nil {
@@ -157,8 +153,21 @@ func (s *Server) ListenAndServe() error {
 
 				s.listener.Close()
 			}
+		case <-s.closed:
+			close(s.sighupListener)
+			return
 		}
-	}()
+	}
+}
+
+func (s *Server) ListenAndServe() error {
+	err := s.loadTLS()
+	if err != nil {
+		return err
+	}
+
+	s.sighupListener = make(chan struct{})
+	go s.reloadTLSConfigOnSighup()
 
 	// outer for loop, if listener closes we will restart it. This may be useful if we switch out
 	// TLSConfig.
@@ -166,6 +175,7 @@ func (s *Server) ListenAndServe() error {
 		s.closed = make(chan struct{})
 
 		var err error
+
 		s.listener, err = tls.Listen("tcp", s.Addr, s.TLSConfig)
 		if err != nil {
 			return fmt.Errorf("gemini server listen: %w", err)
@@ -218,8 +228,10 @@ func (s *Server) handleConnection(conn net.Conn, sem chan struct{}) {
 		conn.Close()
 		<-sem // release
 	}()
+
 	reqChan := make(chan request)
 	w := &writer{conn}
+
 	// push job for which we allocated a sem slot and wait
 	go requestChannel(conn, reqChan)
 	select {
@@ -229,6 +241,7 @@ func (s *Server) handleConnection(conn net.Conn, sem chan struct{}) {
 
 			return
 		}
+
 		ctx := context.Background()
 		r := &Request{
 			ctx:        ctx,
@@ -236,6 +249,7 @@ func (s *Server) handleConnection(conn net.Conn, sem chan struct{}) {
 			RequestURI: header.rawuri,
 			RemoteAddr: conn.RemoteAddr().String(),
 		}
+
 		s.Handler.ServeGemini(w, r)
 
 	case <-time.After(s.ReadTimeout):
@@ -283,10 +297,12 @@ type request struct {
 
 func requestChannel(c net.Conn, rsp chan request) {
 	req := &request{}
+
 	r, err := readHeader(c)
 	if r != nil {
 		req = r
 	}
+
 	req.err = err
 	rsp <- *req
 }
@@ -294,6 +310,7 @@ func requestChannel(c net.Conn, rsp chan request) {
 func readHeader(c net.Conn) (*request, error) {
 	req, err := bufio.NewReader(c).ReadString('\r')
 	if err != nil {
+		// not sure this is the right response
 		return nil, Error(StatusTemporaryFailure, ErrEmptyRequest)
 	}
 
@@ -315,19 +332,22 @@ func readHeader(c net.Conn) (*request, error) {
 	}
 
 	r.URL = parsedURL
+	return validateRequest(r)
+}
 
-	if parsedURL.Scheme != "" && parsedURL.Scheme != "gemini" {
+func validateRequest(r *request) (*request, error) {
+	if r.URL.Scheme != "" && r.URL.Scheme != "gemini" {
 		return r, Error(StatusProxyRequestRefused, ErrUnknownProtocol)
-	} else if parsedURL.Host == "" {
+	} else if r.URL.Host == "" {
 		return r, Error(StatusBadRequest, ErrInvalidHost)
 	}
 
-	if parsedURL.Path == "" {
+	if r.URL.Path == "" {
 		// This error is a redirect path.
-		return r, Error(StatusRedirectPermanent, errors.New("./"+parsedURL.Path))
+		return r, Error(StatusRedirectPermanent, errors.New("./"+r.URL.Path))
-	} else if cleaned := path.Clean(parsedURL.Path); cleaned != parsedURL.Path {
+	} else if cleaned := path.Clean(r.URL.Path); cleaned != r.URL.Path {
 		// check valid alternative if unclean for directories
-		if cleaned != strings.TrimRight(parsedURL.Path, "/") {
+		if cleaned != strings.TrimRight(r.URL.Path, "/") {
 			return r, Error(StatusBadRequest, ErrInvalidPath)
 		}
 	}
@@ -362,6 +382,8 @@ func (s *Server) Shutdown(ctx context.Context) error {
 			s.logf("error while closing listener %v", err)
 		}
 	}
+	// confirm sighup listener for cert reloading exited
+	<-s.sighupListener
 
 	return nil
 }
@@ -381,7 +403,6 @@ func (w *writer) WriteHeader(code int, message string) (int, error) {
 
 func (w *writer) Write(body []byte) (int, error) {
 	reader := bytes.NewReader(body)
-
 	n, err := io.Copy(w.w, reader)
 	return int(n), err
 }

gemini/interceptor.go

@@ -12,7 +12,7 @@ import (
 // Note that the body being written two times and the complete caching of the body in the memory.
 type Interceptor struct {
 	// ResponseWriter is the underlying response writer that is wrapped by Interceptor
-	w ResponseWriter
+	responseWriter ResponseWriter
 
 	// Interceptor is the underlying io.Writer that buffers the response body
 	Body bytes.Buffer
@@ -30,9 +30,10 @@ type Interceptor struct {
 }
 
 // NewInterceptor creates a new Interceptor by wrapping the given response writer.
-func NewInterceptor(w ResponseWriter) (m *Interceptor) {
+func NewInterceptor(responseWriter ResponseWriter) (m *Interceptor) {
 	m = &Interceptor{}
-	m.w = w
+	m.responseWriter = responseWriter
+
 	return
 }
 
@@ -66,10 +67,10 @@ func (m *Interceptor) Flush() {
 
 // FlushBody flushes to the underlying responsewriter.
 func (m *Interceptor) FlushBody() {
-	m.w.Write(m.Body.Bytes())
+	m.responseWriter.Write(m.Body.Bytes())
 }
 
 // FlushHeader writes the header to the underlying ResponseWriter.
 func (m *Interceptor) FlushHeader() {
-	m.w.WriteHeader(m.Code, m.Meta)
+	m.responseWriter.WriteHeader(m.Code, m.Meta)
 }

main.go

@@ -41,12 +41,12 @@ func main() {
 	flag.StringVar(&addr, "addr", defaultAddress, "address to listen on, e.g. 127.0.0.1:1965")
 	flag.IntVar(&maxconns, "max-conns", defaultMaxConns, "maximum number of concurrently open connections")
 	flag.IntVar(&timeout, "timeout", defaultTimeout, "connection timeout in seconds")
-	flag.IntVar(&cache, "cache", defaultCacheObjects, "simple lru document cache for n items. Disabled when zero.")
+	flag.IntVar(&cache, "cache", defaultCacheObjects, "simple fifo document cache for n items. Disabled when zero.")
 	flag.StringVar(&root, "root", defaultRootPath, "server root directory to serve from")
 	flag.StringVar(&host, "host", defaultHost, "hostname for sni and x509 CN when using temporary self-signed certs")
 	flag.StringVar(&crt, "cert", defaultCertPath, "TLS chain of one or more certificates")
 	flag.StringVar(&key, "key", defaultKeyPath, "TLS private key")
-	flag.IntVar(&autocertvalidity, "autocertvalidity", defaultAutoCertValidity, "valid days when using a gmifs auto provisioned self-signed certificate")
+	flag.IntVar(&autocertvalidity, "autocertvalidity", defaultAutoCertValidity, "valid days when using a gmifs provisioned certificate")
 	flag.StringVar(&logs, "logs", defaultLogsDir, "enables file based logging and specifies the directory")
 	flag.BoolVar(&debug, "debug", defaultDebugMode, "enable verbose logging of the gemini server")
 	flag.BoolVar(&autoindex, "autoindex", defaultAutoIndex, "enables auto indexing, directory listings")
@@ -54,6 +54,7 @@ func main() {
 
 	var err error
 	var flogger, dlogger *log.Logger
+
 	flogger, err = setupLogger(logs, "access.log")
 	if err != nil {
 		log.Fatal(err)

middleware/cache.go

@@ -26,6 +26,7 @@ func (c *cache) Read(key string) ([]byte, string, bool) {
 
 func (c *cache) housekeeping(key string) {
 	// we enter locked and can modify
+	// check if we need to free a slot.
 	if len(c.tracker) >= c.size {
 		overflow := c.index
 		expired := c.tracker[overflow]
@@ -33,9 +34,10 @@ func (c *cache) housekeeping(key string) {
 		delete(c.mimeTypes, expired)
 		delete(c.tracker, overflow)
 	}
+
 	c.tracker[c.index] = key
 	c.index++
-	c.index = c.index % (c.size)
+	c.index %= c.size
 }
 
 func (c *cache) Write(key string, mimeType string, doc []byte) {
@@ -43,6 +45,7 @@ func (c *cache) Write(key string, mimeType string, doc []byte) {
 	if c.size <= 0 {
 		return
 	}
+
 	c.Lock()
 	c.housekeeping(key)
 	c.documents[key] = doc
@@ -65,6 +68,7 @@ func (c *cache) middleware(next gemini.Handler) gemini.Handler {
 		if body, mimeType, hit := c.Read(key); hit {
 			w.WriteHeader(gemini.StatusSuccess, mimeType)
 			w.Write(body)
+
 			return
 		}
 
@@ -75,6 +79,7 @@ func (c *cache) middleware(next gemini.Handler) gemini.Handler {
 		if ri.HasHeader() && ri.Code == gemini.StatusSuccess {
 			c.Write(key, ri.Meta, ri.Body.Bytes())
 		}
+
 		ri.Flush()
 	}
 	return gemini.HandlerFunc(fn)