feat(gopher): add resume and metadata support

BACKLOG.md

@@ -29,7 +29,7 @@ certificate pinning and metadata debugging to all TLS protocols.
   downloads; `--resume` support.  Currently Gemini has `Features: []` —
   it doesn't advertise resume, and the download loop doesn't save
   progress.
-- [ ] **Gopher resume & metadata** — same as Gemini.  Gopher `typeHTML`
+- [x] **Gopher resume & metadata** — same as Gemini.  Gopher `typeHTML`
   and `typeTextFile` responses should save `.goget.meta` for resume.
 
 ### 🟢 Medium Priority

CHANGELOG.md

@@ -39,6 +39,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **Gemini resume & metadata** — Gemini downloads now persist `.goget.meta`
   sidecar on interrupt and delete it on successful completion. `--resume`
   continues interrupted Gemini transfers from the saved byte offset.
+- **Gopher resume & metadata** — Gopher `typeHTML` and `typeTextFile`
+  responses now persist `.goget.meta` sidecar on interrupt and delete it on
+  successful completion. `--resume` continues interrupted Gopher text
+  transfers, skipping already-written output bytes (post-transform length
+  because Gopher line metadata is stripped before writing).
 
 **Security**
 

internal/protocol/gopher/gopher.go

@@ -9,10 +9,13 @@ import (
 	"fmt"
 	"io"
 	"net"
+	"os"
+	"path/filepath"
 	"strings"
 	"time"
 
 	"codeberg.org/petrbalvin/goget/internal/core"
+	"codeberg.org/petrbalvin/goget/internal/output"
 	"codeberg.org/petrbalvin/goget/internal/protocol"
 )
 
@@ -43,7 +46,7 @@ func NewProtocol() *Protocol {
 			Name:        "GOPHER",
 			Scheme:      "gopher",
 			DefaultPort: 70,
-			Features:    []string{},
+			Features:    []string{"resume"},
 		}),
 	}
 }
@@ -72,6 +75,14 @@ func (p *Protocol) Download(ctx context.Context, req *core.DownloadRequest) (*co
 	defer conn.Close()
 	conn.SetDeadline(time.Now().Add(30 * time.Second))
 
+	// Close the connection when the context is cancelled so any
+	// blocking Read returns immediately instead of waiting for the
+	// 30-second deadline.
+	go func() {
+		<-ctx.Done()
+		conn.Close()
+	}()
+
 	// Send selector + CRLF
 	if _, err := fmt.Fprintf(conn, "%s\r\n", selector); err != nil {
 		return nil, core.NewNetworkError("failed to send gopher selector", err, core.SafeURL(req.URL))
@@ -138,20 +149,81 @@ func isTextGopherType(t byte) bool {
 }
 
 // downloadText handles text responses where each line has a type prefix.
+// Supports resume for typeHTML and typeTextFile responses: when interrupted,
+// writes a `.goget.meta` sidecar; on resume with valid metadata, skips
+// already-written output bytes by length. Gopher does not expose
+// Content-Length, so the resume metadata records only the bytes
+// actually delivered to the writer.
 func (p *Protocol) downloadText(ctx context.Context, reader *bufio.Reader, req *core.DownloadRequest, startTime time.Time, firstType byte) (*core.DownloadResult, error) {
 	var writer io.Writer
-	if req.Writer != nil {
-		writer = req.Writer
-	} else {
-		writer = io.Discard
+	var file *os.File
+	resumed := false
+	var startOffset int64
+
+	// Set up output destination. When req.Output is set and no external
+	// Writer was provided, we open the file directly. This covers both
+	// fresh downloads (create) and resume (append). When req.Writer is
+	// set (caller manages the file), we use it as-is.
+	if req.Output != "" && req.Output != "-" {
+		if req.Resume {
+			canResume, resumeMeta, rerr := output.CanResume(req.Output, req.URL.String())
+			if rerr != nil {
+				if req.Verbose {
+					fmt.Fprintf(os.Stderr, "[gopher] Resume check failed: %v\n", rerr)
+				}
+				output.CleanupResumeFiles(req.Output)
+			} else if canResume && resumeMeta != nil {
+				file, rerr = os.OpenFile(req.Output, os.O_APPEND|os.O_WRONLY, 0644)
+				if rerr != nil {
+					return nil, core.NewFileError("failed to open file for resume", rerr)
+				}
+				defer file.Close()
+				writer = file
+				startOffset = resumeMeta.Downloaded
+				resumed = true
+				if req.Verbose {
+					fmt.Fprintf(os.Stderr, "[gopher] Resuming from byte %d\n", startOffset)
+				}
+			}
+		}
+		if writer == nil && req.Writer == nil {
+			// Fresh download — create the output file.
+			dir := filepath.Dir(req.Output)
+			if dir != "" && dir != "." {
+				if err := os.MkdirAll(dir, 0755); err != nil {
+					return nil, core.NewFileError("failed to create output directory", err)
+				}
+			}
+			var ferr error
+			file, ferr = os.Create(req.Output)
+			if ferr != nil {
+				return nil, core.NewFileError("failed to create output file", ferr)
+			}
+			defer file.Close()
+			writer = file
+		}
+	}
+	if writer == nil {
+		if req.Writer != nil {
+			writer = req.Writer
+		} else {
+			writer = io.Discard
+		}
 	}
 
-	var totalRead int64
+	// bytesWritten tracks output payload actually delivered to the writer
+	// (after the per-line metadata strip). On resume we skip ahead by
+	// startOffset bytes of this post-transform stream so the file on
+	// disk ends up as the concatenation of the previous run and the
+	// new one — same convention as Gemini.
+	var bytesWritten int64
+	var skipped int64
 	lineCount := 0
 
 	for {
 		select {
 		case <-ctx.Done():
+			saveGopherResume(req, bytesWritten)
 			return nil, ctx.Err()
 		default:
 		}
@@ -161,6 +233,7 @@ func (p *Protocol) downloadText(ctx context.Context, reader *bufio.Reader, req *
 			if err == io.EOF {
 				break
 			}
+			saveGopherResume(req, bytesWritten)
 			return nil, core.NewNetworkError("failed to read gopher line", err, core.SafeURL(req.URL))
 		}
 
@@ -172,12 +245,8 @@ func (p *Protocol) downloadText(ctx context.Context, reader *bufio.Reader, req *
 		// Strip item-type prefix if present (first char = type, second char is usually tab/space)
 		displayLine := line
 		if len(line) > 1 && line[1] != '.' {
-			// Full menu line: type + display string + tab + selector + tab + host + tab + port
-			if true {
-				// For text downloads, strip the type and metadata, show only display string + \n
-				clean := stripGopherMeta(line)
-				displayLine = clean + "\n"
-			}
+			clean := stripGopherMeta(line)
+			displayLine = clean + "\n"
 		}
 
 		// For informational lines (type i), don't strip anything — just pass through
@@ -185,34 +254,75 @@ func (p *Protocol) downloadText(ctx context.Context, reader *bufio.Reader, req *
 			displayLine = line
 		}
 
-		n, err := writer.Write([]byte(displayLine))
-		if err != nil {
-			return nil, core.NewFileError("failed to write gopher text", err)
+		// On resume, drop the first startOffset bytes of the
+		// post-transform output so the file appends cleanly.
+		payload := []byte(displayLine)
+		if skipped < startOffset {
+			remain := startOffset - skipped
+			if int64(len(payload)) <= remain {
+				skipped += int64(len(payload))
+				payload = nil
+			} else {
+				skipped += remain
+				payload = payload[remain:]
+			}
+		}
+
+		if len(payload) > 0 {
+			n, werr := writer.Write(payload)
+			if werr != nil {
+				saveGopherResume(req, bytesWritten)
+				return nil, core.NewFileError("failed to write gopher text", werr)
+			}
+			bytesWritten += int64(n)
 		}
-		totalRead += int64(n)
 		lineCount++
 
 		if req.ProgressCallback != nil {
-			speed := float64(totalRead) / time.Since(startTime).Seconds()
-			req.ProgressCallback(totalRead, -1, speed)
+			speed := float64(bytesWritten) / time.Since(startTime).Seconds()
+			req.ProgressCallback(bytesWritten, -1, speed)
 		}
 	}
 
+	// Download complete — remove resume metadata sidecar.
+	if req.Output != "" && req.Output != "-" {
+		output.DeleteResumeMetadata(req.Output)
+	}
+
 	duration := time.Since(startTime)
-	speed := float64(totalRead) / duration.Seconds()
+	speed := float64(0)
+	if duration.Seconds() > 0 {
+		speed = float64(bytesWritten) / duration.Seconds()
+	}
 
 	return &core.DownloadResult{
-		BytesDownloaded: totalRead,
-		TotalSize:       totalRead,
+		BytesDownloaded: bytesWritten,
+		TotalSize:       bytesWritten,
 		Duration:        duration,
 		Protocol:        "GOPHER",
 		IPVersion:       4,
 		Speed:           speed,
 		OutputPath:      req.Output,
 		ContentType:     gopherContentType(firstType),
+		Resumed:         resumed,
 	}, nil
 }
 
+// saveGopherResume persists partial Gopher text download progress to the
+// standard `.goget.meta` sidecar. No-op for stdout writes, nil requests,
+// or zero-byte transfers. Gopher does not expose Content-Length, so the
+// total field stays 0; the resume offset is taken from the number of
+// bytes already delivered to the writer.
+func saveGopherResume(req *core.DownloadRequest, downloaded int64) {
+	if req == nil || req.Output == "" || req.Output == "-" || downloaded <= 0 {
+		return
+	}
+	meta := output.NewResumeMetadata(req.URL.String(), "", "", downloaded, 0)
+	if err := meta.Save(req.Output); err != nil && req.Verbose {
+		fmt.Fprintf(os.Stderr, "[gopher] Warning: failed to save resume metadata: %v\n", err)
+	}
+}
+
 // gopherContentType returns the MIME content type for a gopher item type.
 func gopherContentType(t byte) string {
 	switch t {

internal/protocol/gopher/gopher_test.go

@@ -8,11 +8,14 @@ import (
 	"context"
 	"net"
 	"net/url"
+	"os"
 	"strconv"
 	"strings"
 	"testing"
+	"time"
 
 	"codeberg.org/petrbalvin/goget/internal/core"
+	"codeberg.org/petrbalvin/goget/internal/output"
 )
 
 func TestFormatGopherMenu(t *testing.T) {
@@ -108,3 +111,309 @@ func TestGopherDownloadMock(t *testing.T) {
 		t.Errorf("output missing text: %q", buf.String())
 	}
 }
+
+// TestGopherResumeSaveMetadata verifies that interrupting a Gopher text
+// download persists a .goget.meta sidecar describing the partial state.
+func TestGopherResumeSaveMetadata(t *testing.T) {
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer listener.Close()
+	port := listener.Addr().(*net.TCPAddr).Port
+
+	go func() {
+		conn, _ := listener.Accept()
+		if conn == nil {
+			return
+		}
+		defer conn.Close()
+		reader := bufio.NewReader(conn)
+		reader.ReadString('\n')
+		// Send the first display line, sleep so the client has a chance
+		// to land in the read loop and receive the cancellation, then
+		// send the second line and the terminator.
+		conn.Write([]byte("hFirst\t/first\thost\t70\r\n"))
+		time.Sleep(150 * time.Millisecond)
+		conn.Write([]byte("hSecond\t/second\thost\t70\r\n"))
+		conn.Write([]byte(".\r\n"))
+	}()
+
+	tmp := t.TempDir()
+	outPath := tmp + "/page.html"
+
+	proto := NewProtocol()
+	u, _ := url.Parse("gopher://127.0.0.1:" + strconv.Itoa(port) + "/page")
+
+	ctx, cancel := context.WithCancel(context.Background())
+	errCh := make(chan error, 1)
+	go func() {
+		_, dlErr := proto.Download(ctx, &core.DownloadRequest{
+			URL:    u,
+			Output: outPath,
+		})
+		errCh <- dlErr
+	}()
+
+	// Cancel mid-download. The slow server keeps the connection open
+	// long enough for the cancellation to fire between reads.
+	time.Sleep(50 * time.Millisecond)
+	cancel()
+
+	dlErr := <-errCh
+	if dlErr == nil {
+		t.Fatal("expected error from cancelled context")
+	}
+
+	metaPath := outPath + output.ResumeMetaFileSuffix
+	if _, statErr := os.Stat(metaPath); statErr != nil {
+		t.Fatalf("expected .goget.meta sidecar to exist: %v", statErr)
+	}
+
+	meta, metaErr := output.LoadResumeMetadata(outPath)
+	if metaErr != nil {
+		t.Fatalf("LoadResumeMetadata: %v", metaErr)
+	}
+	if meta == nil {
+		t.Fatal("expected resume metadata, got nil")
+	}
+	if meta.Downloaded <= 0 {
+		t.Errorf("Downloaded = %d, want > 0", meta.Downloaded)
+	}
+	if meta.URL != u.String() {
+		t.Errorf("URL = %q, want %q", meta.URL, u.String())
+	}
+	// Gopher does not expose Content-Length, so Total stays 0.
+	if meta.Total != 0 {
+		t.Errorf("Total = %d, want 0", meta.Total)
+	}
+	// Sanity-check: the saved Downloaded should match what's on disk.
+	info, statErr := os.Stat(outPath)
+	if statErr != nil {
+		t.Fatalf("partial file missing: %v", statErr)
+	}
+	if info.Size() != meta.Downloaded {
+		t.Errorf("file size = %d, metadata.Downloaded = %d (must match)",
+			info.Size(), meta.Downloaded)
+	}
+}
+
+// TestGopherResumeDownload verifies end-to-end resume: an interrupted
+// download completes on the second attempt with --resume=true, and the
+// metadata sidecar is removed after the successful completion.
+func TestGopherResumeDownload(t *testing.T) {
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer listener.Close()
+	port := listener.Addr().(*net.TCPAddr).Port
+
+	cancelReady := make(chan struct{})
+	connReady := make(chan struct{})
+	go func() {
+		for i := 0; i < 2; i++ {
+			conn, lerr := listener.Accept()
+			if lerr != nil {
+				return
+			}
+			r := bufio.NewReader(conn)
+			r.ReadString('\n')
+			if i == 0 {
+				// First attempt: send the first line, then wait
+				// for the client to cancel before closing.
+				conn.Write([]byte("0Line one\t/foo\thost\t70\r\n"))
+				<-cancelReady
+				conn.Close()
+				connReady <- struct{}{}
+			} else {
+				// Second attempt: send the full body.
+				conn.Write([]byte("0Line one\t/foo\thost\t70\r\n"))
+				conn.Write([]byte("0Line two\t/bar\thost\t70\r\n"))
+				conn.Write([]byte(".\r\n"))
+				conn.Close()
+			}
+		}
+	}()
+
+	tmp := t.TempDir()
+	outPath := tmp + "/resume.txt"
+
+	proto := NewProtocol()
+	u, _ := url.Parse("gopher://127.0.0.1:" + strconv.Itoa(port) + "/foo")
+
+	// First attempt: send only the first line, then cancel.
+	ctx1, cancel1 := context.WithCancel(context.Background())
+	errCh := make(chan error, 1)
+	go func() {
+		_, dlErr := proto.Download(ctx1, &core.DownloadRequest{
+			URL:    u,
+			Output: outPath,
+		})
+		errCh <- dlErr
+	}()
+	time.Sleep(100 * time.Millisecond)
+	cancel1()
+	cancelReady <- struct{}{}
+	<-connReady
+	dlErr := <-errCh
+	if dlErr == nil {
+		t.Fatal("expected error from cancelled context")
+	}
+
+	// Sanity-check: partial file + metadata sidecar present.
+	info, statErr := os.Stat(outPath)
+	if statErr != nil {
+		t.Fatalf("partial file missing: %v", statErr)
+	}
+	if info.Size() == 0 {
+		t.Fatal("partial file is empty")
+	}
+	meta, metaErr := output.LoadResumeMetadata(outPath)
+	if metaErr != nil || meta == nil {
+		t.Fatalf("expected resume metadata: err=%v meta=%v", metaErr, meta)
+	}
+
+	// Second attempt: resume should pick up where we left off.
+	result, resErr := proto.Download(context.Background(), &core.DownloadRequest{
+		URL:    u,
+		Output: outPath,
+		Resume: true,
+	})
+	if resErr != nil {
+		t.Fatalf("resume download failed: %v", resErr)
+	}
+	if !result.Resumed {
+		t.Error("expected Resumed=true")
+	}
+
+	// The file should contain the full body, with the resume logic
+	// skipping already-written bytes via the post-transform offset.
+	data, readErr := os.ReadFile(outPath)
+	if readErr != nil {
+		t.Fatalf("read output: %v", readErr)
+	}
+	want := "Line one\nLine two\n"
+	if string(data) != want {
+		t.Errorf("file content = %q, want %q", string(data), want)
+	}
+
+	// Metadata sidecar should be deleted after a successful completion.
+	if output.FileExists(outPath + output.ResumeMetaFileSuffix) {
+		t.Error("expected .goget.meta to be deleted after successful resume")
+	}
+}
+
+// TestSaveGopherResumeMetadata exercises the helper directly.
+func TestSaveGopherResumeMetadata(t *testing.T) {
+	tmp := t.TempDir()
+	out := tmp + "/file.txt"
+
+	u, err := url.Parse("gopher://example.com/foo.txt")
+	if err != nil {
+		t.Fatalf("parse URL: %v", err)
+	}
+	req := &core.DownloadRequest{
+		URL:    u,
+		Output: out,
+	}
+
+	saveGopherResume(req, 4096)
+
+	meta, err := output.LoadResumeMetadata(out)
+	if err != nil {
+		t.Fatalf("LoadResumeMetadata: %v", err)
+	}
+	if meta == nil {
+		t.Fatal("expected resume metadata, got nil")
+	}
+	if meta.Downloaded != 4096 {
+		t.Errorf("Downloaded = %d, want 4096", meta.Downloaded)
+	}
+	if meta.URL != "gopher://example.com/foo.txt" {
+		t.Errorf("URL = %q, want %q", meta.URL, "gopher://example.com/foo.txt")
+	}
+	if meta.Total != 0 {
+		t.Errorf("Total = %d, want 0", meta.Total)
+	}
+}
+
+// TestSaveGopherResumeNoop verifies that the helper is a no-op for
+// stdout writes, empty output paths, zero-byte transfers, and nil
+// requests.
+func TestSaveGopherResumeNoop(t *testing.T) {
+	u, _ := url.Parse("gopher://example.com/")
+
+	t.Run("stdout", func(t *testing.T) {
+		saveGopherResume(&core.DownloadRequest{URL: u, Output: "-"}, 100)
+	})
+
+	t.Run("empty output", func(t *testing.T) {
+		saveGopherResume(&core.DownloadRequest{URL: u, Output: ""}, 100)
+	})
+
+	t.Run("zero bytes", func(t *testing.T) {
+		tmp := t.TempDir()
+		saveGopherResume(&core.DownloadRequest{URL: u, Output: tmp + "/f"}, 0)
+		if output.FileExists(tmp + "/f" + output.ResumeMetaFileSuffix) {
+			t.Error("metadata created for zero-byte transfer")
+		}
+	})
+
+	t.Run("nil request", func(t *testing.T) {
+		saveGopherResume(nil, 100)
+	})
+}
+
+// TestGopherResumeStaleMetadata exercises the path where the .goget.meta
+// sidecar exists but the partial file doesn't (or has been truncated),
+// forcing the resume code to clean up and start fresh.
+func TestGopherResumeStaleMetadata(t *testing.T) {
+	tmp := t.TempDir()
+	outPath := tmp + "/stale.txt"
+
+	// Pre-create an orphan .goget.meta for a URL we will not use.
+	orphanMeta := output.NewResumeMetadata("gopher://other.example/foo", "", "", 1234, 0)
+	if err := orphanMeta.Save(outPath); err != nil {
+		t.Fatalf("seed meta: %v", err)
+	}
+	// Do not pre-create the partial file; CanResume requires file size
+	// to match metadata Downloaded.
+
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer listener.Close()
+	port := listener.Addr().(*net.TCPAddr).Port
+
+	go func() {
+		conn, _ := listener.Accept()
+		if conn == nil {
+			return
+		}
+		defer conn.Close()
+		r := bufio.NewReader(conn)
+		r.ReadString('\n')
+		conn.Write([]byte("0Fresh\t/fresh\thost\t70\r\n.\r\n"))
+	}()
+
+	proto := NewProtocol()
+	u, _ := url.Parse("gopher://127.0.0.1:" + strconv.Itoa(port) + "/fresh")
+
+	res, err := proto.Download(context.Background(), &core.DownloadRequest{
+		URL:    u,
+		Output: outPath,
+		Resume: true,
+	})
+	if err != nil {
+		t.Fatalf("download: %v", err)
+	}
+	if res.Resumed {
+		t.Error("expected Resumed=false after stale-metadata cleanup")
+	}
+	data, _ := os.ReadFile(outPath)
+	if string(data) != "Fresh\n" {
+		t.Errorf("content = %q, want %q", string(data), "Fresh\n")
+	}
+}