server: Disallow ServeConn usage after Shutdown

This reverts commit 48c67bcead.

doc.go

@@ -9,7 +9,7 @@ Client is a Gemini client.
 	if err != nil {
 		// handle error
 	}
-	defer resp.Close()
+	defer resp.Body.Close()
 	// ...
 
 Server is a Gemini server.

examples/client.go

@@ -103,9 +103,9 @@ func do(req *gemini.Request, via []*gemini.Request) (*gemini.Response, error) {
 		return resp, err
 	}
 
-	switch resp.Status().Class() {
+	switch resp.Status.Class() {
 	case gemini.StatusInput:
-		input, ok := getInput(resp.Meta(), resp.Status() == gemini.StatusSensitiveInput)
+		input, ok := getInput(resp.Meta, resp.Status == gemini.StatusSensitiveInput)
 		if !ok {
 			break
 		}
@@ -119,7 +119,7 @@ func do(req *gemini.Request, via []*gemini.Request) (*gemini.Response, error) {
 			return resp, errors.New("too many redirects")
 		}
 
-		target, err := url.Parse(resp.Meta())
+		target, err := url.Parse(resp.Meta)
 		if err != nil {
 			return resp, err
 		}
@@ -153,11 +153,11 @@ func main() {
 		fmt.Println(err)
 		os.Exit(1)
 	}
-	defer resp.Close()
+	defer resp.Body.Close()
 
 	// Handle response
-	if resp.Status().Class() == gemini.StatusSuccess {
-		_, err := io.Copy(os.Stdout, resp)
+	if resp.Status.Class() == gemini.StatusSuccess {
+		_, err := io.Copy(os.Stdout, resp.Body)
 		if err != nil {
 			log.Fatal(err)
 		}

examples/server.go

@@ -102,7 +102,3 @@ func (w *logResponseWriter) WriteHeader(status gemini.Status, meta string) {
 func (w *logResponseWriter) Flush() error {
 	return nil
 }
-
-func (w *logResponseWriter) Close() error {
-	return nil
-}

fs.go

@@ -1,3 +1,5 @@
+// +build go1.16
+
 package gemini
 
 import (
@@ -13,12 +15,6 @@ import (
 	"strings"
 )
 
-func init() {
-	// Add Gemini mime types
-	mime.AddExtensionType(".gmi", "text/gemini")
-	mime.AddExtensionType(".gemini", "text/gemini")
-}
-
 // FileServer returns a handler that serves Gemini requests with the contents
 // of the provided file system.
 //

gemini.go

@@ -2,8 +2,15 @@ package gemini
 
 import (
 	"errors"
+	"mime"
 )
 
+func init() {
+	// Add Gemini mime types
+	mime.AddExtensionType(".gmi", "text/gemini")
+	mime.AddExtensionType(".gemini", "text/gemini")
+}
+
 var crlf = []byte("\r\n")
 
 // Errors.

go.mod

@@ -1,5 +1,5 @@
 module git.sr.ht/~adnano/go-gemini
 
-go 1.16
+go 1.15
 
 require golang.org/x/net v0.0.0-20210119194325-5f4716e94777

handler.go

@@ -14,11 +14,10 @@ import (
 // ServeGemini should write the response header and data to the ResponseWriter
 // and then return. Returning signals that the request is finished; it is not
 // valid to use the ResponseWriter after or concurrently with the completion
-// of the ServeGemini call. Handlers may also call ResponseWriter.Close to
-// manually close the connection.
+// of the ServeGemini call.
 //
-// The provided context is canceled when the client's connection is closed,
-// when ResponseWriter.Close is called, or when the ServeGemini method returns.
+// The provided context is canceled when the client's connection is closed
+// or the ServeGemini method returns.
 //
 // Handlers should not modify the provided Request.
 type Handler interface {
@@ -100,7 +99,7 @@ func (t *timeoutHandler) ServeGemini(ctx context.Context, w ResponseWriter, r *R
 
 	buf := &bytes.Buffer{}
 	tw := &timeoutWriter{
-		wc: &contextWriter{
+		wr: &contextWriter{
 			ctx:    ctx,
 			cancel: cancel,
 			done:   ctx.Done(),
@@ -124,7 +123,7 @@ func (t *timeoutHandler) ServeGemini(ctx context.Context, w ResponseWriter, r *R
 }
 
 type timeoutWriter struct {
-	wc          io.WriteCloser
+	wr          io.Writer
 	status      Status
 	meta        string
 	mediatype   string
@@ -139,7 +138,7 @@ func (w *timeoutWriter) Write(b []byte) (int, error) {
 	if !w.wroteHeader {
 		w.WriteHeader(StatusSuccess, w.mediatype)
 	}
-	return w.wc.Write(b)
+	return w.wr.Write(b)
 }
 
 func (w *timeoutWriter) WriteHeader(status Status, meta string) {
@@ -154,7 +153,3 @@ func (w *timeoutWriter) WriteHeader(status Status, meta string) {
 func (w *timeoutWriter) Flush() error {
 	return nil
 }
-
-func (w *timeoutWriter) Close() error {
-	return w.wc.Close()
-}

response.go

@@ -15,24 +15,29 @@ const defaultMediaType = "text/gemini; charset=utf-8"
 //
 // The Client returns Responses from servers once the response
 // header has been received. The response body is streamed on demand
-// as the response is read. If the network connection fails or the server
-// terminates the response, Read calls return an error.
-//
-// It is the caller's responsibility to close the response.
+// as the Body field is read.
 type Response struct {
-	status Status
-	meta   string
-	body   io.ReadCloser
-	conn   net.Conn
-}
+	// Status is the response status code.
+	Status Status
 
-// NewResponse returns a new response with the provided status, meta, and body.
-func NewResponse(status Status, meta string, body io.ReadCloser) *Response {
-	return &Response{
-		status: status,
-		meta:   meta,
-		body:   body,
-	}
+	// Meta returns the response meta.
+	// For successful responses, the meta should contain the media type of the response.
+	// For failure responses, the meta should contain a short description of the failure.
+	Meta string
+
+	// Body represents the response body.
+	//
+	// The response body is streamed on demand as the Body field
+	// is read. If the network connection fails or the server
+	// terminates the response, Body.Read calls return an error.
+	//
+	// The Gemini client guarantees that Body is always
+	// non-nil, even on responses without a body or responses with
+	// a zero-length body. It is the caller's responsibility to
+	// close Body.
+	Body io.ReadCloser
+
+	conn net.Conn
 }
 
 // ReadResponse reads a Gemini response from the provided io.ReadCloser.
@@ -49,7 +54,7 @@ func ReadResponse(r io.ReadCloser) (*Response, error) {
 	if err != nil {
 		return nil, ErrInvalidResponse
 	}
-	resp.status = Status(status)
+	resp.Status = Status(status)
 
 	// Read one space
 	if b, err := br.ReadByte(); err != nil {
@@ -69,11 +74,11 @@ func ReadResponse(r io.ReadCloser) (*Response, error) {
 	if len(meta) > 1024 {
 		return nil, ErrInvalidResponse
 	}
-	if resp.status.Class() == StatusSuccess && meta == "" {
+	if resp.Status.Class() == StatusSuccess && meta == "" {
 		// Use default media type
 		meta = defaultMediaType
 	}
-	resp.meta = meta
+	resp.Meta = meta
 
 	// Read terminating newline
 	if b, err := br.ReadByte(); err != nil {
@@ -82,38 +87,15 @@ func ReadResponse(r io.ReadCloser) (*Response, error) {
 		return nil, ErrInvalidResponse
 	}
 
-	if resp.status.Class() == StatusSuccess {
-		resp.body = newBufReadCloser(br, r)
+	if resp.Status.Class() == StatusSuccess {
+		resp.Body = newBufReadCloser(br, r)
 	} else {
-		resp.body = nopReadCloser{}
+		resp.Body = nopReadCloser{}
 		r.Close()
 	}
 	return resp, nil
 }
 
-// Status returns the response status code.
-func (r *Response) Status() Status {
-	return r.status
-}
-
-// Meta returns the response meta.
-// For successful responses, the meta should contain the media type of the response.
-// For failure responses, the meta should contain a short description of the failure.
-func (r *Response) Meta() string {
-	return r.meta
-}
-
-// Read reads data from the response body.
-// The response body is streamed on demand as Read is called.
-func (r *Response) Read(p []byte) (n int, err error) {
-	return r.body.Read(p)
-}
-
-// Close closes the response body.
-func (r *Response) Close() error {
-	return r.body.Close()
-}
-
 // Conn returns the network connection on which the response was received.
 func (r *Response) Conn() net.Conn {
 	return r.conn
@@ -165,10 +147,6 @@ type ResponseWriter interface {
 
 	// Flush sends any buffered data to the client.
 	Flush() error
-
-	// Close closes the connection.
-	// Any blocked Write operations will be unblocked and return errors.
-	Close() error
 }
 
 type responseWriter struct {
@@ -179,10 +157,9 @@ type responseWriter struct {
 	bodyAllowed bool
 }
 
-func newResponseWriter(w io.WriteCloser) *responseWriter {
+func newResponseWriter(w io.Writer) *responseWriter {
 	return &responseWriter{
 		bw: bufio.NewWriter(w),
-		cl: w,
 	}
 }
 
@@ -228,7 +205,3 @@ func (w *responseWriter) Flush() error {
 	// Write errors from WriteHeader will be returned here.
 	return w.bw.Flush()
 }
-
-func (w *responseWriter) Close() error {
-	return w.cl.Close()
-}

response_test.go

@@ -91,13 +91,13 @@ func TestReadWriteResponse(t *testing.T) {
 			// No response
 			continue
 		}
-		if resp.status != test.Status {
-			t.Errorf("expected status = %d, got %d", test.Status, resp.status)
+		if resp.Status != test.Status {
+			t.Errorf("expected status = %d, got %d", test.Status, resp.Status)
 		}
-		if resp.meta != test.Meta {
-			t.Errorf("expected meta = %s, got %s", test.Meta, resp.meta)
+		if resp.Meta != test.Meta {
+			t.Errorf("expected meta = %s, got %s", test.Meta, resp.Meta)
 		}
-		b, _ := ioutil.ReadAll(resp.body)
+		b, _ := ioutil.ReadAll(resp.Body)
 		body := string(b)
 		if body != test.Body {
 			t.Errorf("expected body = %#v, got %#v", test.Body, body)

server.go

@@ -282,14 +282,17 @@ func (srv *Server) serve(ctx context.Context, l net.Listener) error {
 			return err
 		}
 		tempDelay = 0
-		go srv.ServeConn(ctx, rw)
+		go srv.serveConn(ctx, rw, false)
 	}
 }
 
-func (srv *Server) trackConn(conn *net.Conn, cancel context.CancelFunc) bool {
+func (srv *Server) trackConn(conn *net.Conn, cancel context.CancelFunc, external bool) bool {
 	srv.mu.Lock()
 	defer srv.mu.Unlock()
-	if srv.closed && !srv.shutdown {
+	// Reject the connection under the following conditions:
+	// - Shutdown or Close has been called and conn is external (from ServeConn)
+	// - Close (not Shutdown) has been called and conn is internal (from Serve)
+	if srv.closed && (external || !srv.shutdown) {
 		return false
 	}
 	if srv.conns == nil {
@@ -309,15 +312,17 @@ func (srv *Server) deleteConn(conn *net.Conn) {
 // It closes the connection when the response has been completed.
 // If the provided context expires before the response has completed,
 // ServeConn closes the connection and returns the context's error.
-//
-// Note that ServeConn can be used during a Shutdown.
 func (srv *Server) ServeConn(ctx context.Context, conn net.Conn) error {
+	return srv.serveConn(ctx, conn, true)
+}
+
+func (srv *Server) serveConn(ctx context.Context, conn net.Conn, external bool) error {
 	defer conn.Close()
 
 	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 
-	if !srv.trackConn(&conn, cancel) {
+	if !srv.trackConn(&conn, cancel, external) {
 		return context.Canceled
 	}
 	defer srv.tryCloseDone()
@@ -332,7 +337,7 @@ func (srv *Server) ServeConn(ctx context.Context, conn net.Conn) error {
 
 	errch := make(chan error, 1)
 	go func() {
-		errch <- srv.serveConn(ctx, conn)
+		errch <- srv.goServeConn(ctx, conn)
 	}()
 
 	select {
@@ -343,7 +348,7 @@ func (srv *Server) ServeConn(ctx context.Context, conn net.Conn) error {
 	}
 }
 
-func (srv *Server) serveConn(ctx context.Context, conn net.Conn) error {
+func (srv *Server) goServeConn(ctx context.Context, conn net.Conn) error {
 	ctx, cancel := context.WithCancel(ctx)
 	done := ctx.Done()
 	cw := &contextWriter{