Add QR code output to quick tunnels

cmd/cloudflared/tunnel/quick_tunnel.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/google/uuid"
 	"github.com/pkg/errors"
+	"rsc.io/qr"
 
 	"github.com/cloudflare/cloudflared/cmd/cloudflared/cliutil"
 	"github.com/cloudflare/cloudflared/cmd/cloudflared/flags"
@@ -19,6 +20,10 @@ import (
 
 const httpTimeout = 15 * time.Second
 
+// qrQuietZoneModules is the number of empty modules added around the rendered
+// QR code. Four modules is the minimum quiet zone required by the QR spec.
+const qrQuietZoneModules = 4
+
 const disclaimer = "Thank you for trying Cloudflare Tunnel. Doing so, without a Cloudflare account, is a quick way to experiment and try it out. However, be aware that these account-less Tunnels have no uptime guarantee, are subject to the Cloudflare Online Services Terms of Use (https://www.cloudflare.com/website-terms/), and Cloudflare reserves the right to investigate your use of Tunnels for violations of such terms. If you intend to use Tunnels in production you should use a pre-created named tunnel by following: https://developers.cloudflare.com/cloudflare-one/connections/connect-apps"
 
 const (
@@ -116,15 +121,21 @@ func RunQuickTunnel(sc *subcommandContext) error {
 		TunnelID:     tunnelID,
 	}
 
-	url := data.Result.Hostname
-	if !strings.HasPrefix(url, "https://") {
-		url = "https://" + url
-	}
+	cliutil.LogTable(sc.log, quickTunnelURLDisplayLines(data.Result.Hostname))
 
-	cliutil.LogTable(sc.log, []string{
-		"Your quick Tunnel has been created! Visit it at (it may take some time to be reachable):",
-		url,
-	})
+	quickTunnelQRLines, err := quickTunnelQRCodeLines(data.Result.Hostname)
+	if err != nil {
+		sc.log.Warn().Err(err).Msg("Failed to generate quick Tunnel QR code")
+	} else {
+		// Filter out the all-white quiet-zone rows so the terminal output
+		// stays compact while the QR code itself remains scannable.
+		for _, line := range quickTunnelQRLines {
+			if line != "" {
+				sc.log.Info().Msg(line)
+			}
+		}
+		sc.log.Info().Msg("")
+	}
 
 	if !sc.c.IsSet(flags.Protocol) {
 		_ = sc.c.Set(flags.Protocol, "quic")
@@ -141,6 +152,72 @@ func RunQuickTunnel(sc *subcommandContext) error {
 	)
 }
 
+func quickTunnelURLDisplayLines(hostname string) []string {
+	return []string{
+		"Your quick Tunnel has been created! Visit it at (it may take some time to be reachable):",
+		normalizeQuickTunnelURL(hostname),
+	}
+}
+
+func quickTunnelQRCodeLines(hostname string) ([]string, error) {
+	url := normalizeQuickTunnelURL(hostname)
+	code, err := qr.Encode(url, qr.L)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to create quick Tunnel QR code")
+	}
+
+	return renderHalfBlockQRCode(code, qrQuietZoneModules), nil
+}
+
+func renderHalfBlockQRCode(code *qr.Code, quietZone int) []string {
+	minX, minY, maxX, maxY := code.Size, code.Size, 0, 0
+	for y := 0; y < code.Size; y++ {
+		for x := 0; x < code.Size; x++ {
+			if code.Black(x, y) {
+				minX = min(minX, x)
+				minY = min(minY, y)
+				maxX = max(maxX, x)
+				maxY = max(maxY, y)
+			}
+		}
+	}
+
+	minX -= quietZone
+	minY -= quietZone
+	maxX += quietZone
+	maxY += quietZone
+
+	lines := make([]string, 0, ((maxY-minY)+2)/2)
+	lineWidth := maxX - minX + 1
+	for y := minY; y <= maxY; y += 2 {
+		var line strings.Builder
+		line.Grow(lineWidth)
+		for x := minX; x <= maxX; x++ {
+			top := code.Black(x, y)
+			bottom := y+1 <= maxY && code.Black(x, y+1)
+			switch {
+			case top && bottom:
+				line.WriteRune('█')
+			case top:
+				line.WriteRune('▀')
+			case bottom:
+				line.WriteRune('▄')
+			default:
+				line.WriteRune(' ')
+			}
+		}
+		lines = append(lines, line.String())
+	}
+	return lines
+}
+
+func normalizeQuickTunnelURL(hostname string) string {
+	if strings.HasPrefix(hostname, "https://") {
+		return hostname
+	}
+	return "https://" + hostname
+}
+
 type QuickTunnelResponse struct {
 	Success bool
 	Result  QuickTunnel

cmd/cloudflared/tunnel/quick_tunnel_test.go

@@ -2,12 +2,115 @@ package tunnel
 
 import (
 	"encoding/json"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"rsc.io/qr"
 )
 
+func TestQuickTunnelURLDisplayLinesNormalizeURL(t *testing.T) {
+	t.Parallel()
+
+	lines := quickTunnelURLDisplayLines("example.trycloudflare.com")
+
+	require.Len(t, lines, 2)
+	assert.Equal(t, "Your quick Tunnel has been created! Visit it at (it may take some time to be reachable):", lines[0])
+	assert.Equal(t, "https://example.trycloudflare.com", lines[1])
+}
+
+func TestQuickTunnelURLDisplayLinesPreserveHTTPSURL(t *testing.T) {
+	t.Parallel()
+
+	lines := quickTunnelURLDisplayLines("https://example.trycloudflare.com")
+
+	require.Len(t, lines, 2)
+	assert.Equal(t, "https://example.trycloudflare.com", lines[1])
+}
+
+func TestQuickTunnelQRCodeLinesUseCompactTerminalBlocks(t *testing.T) {
+	t.Parallel()
+
+	lines, err := quickTunnelQRCodeLines("example.trycloudflare.com")
+
+	require.NoError(t, err)
+	require.NotEmpty(t, lines)
+	qrOutput := strings.Join(lines, "\n")
+	assert.Contains(t, qrOutput, "▀")
+	assert.Contains(t, qrOutput, "▄")
+	assert.NotContains(t, qrOutput, "https://example.trycloudflare.com")
+}
+
+func TestQuickTunnelQRCodeLinesKeepScanQuietZone(t *testing.T) {
+	t.Parallel()
+
+	lines, err := quickTunnelQRCodeLines("example.trycloudflare.com")
+
+	require.NoError(t, err)
+	require.Greater(t, len(lines), 4)
+	assert.Empty(t, strings.TrimSpace(lines[0]))
+	assert.Empty(t, strings.TrimSpace(lines[1]))
+	assert.Empty(t, strings.TrimSpace(lines[len(lines)-2]))
+	assert.Empty(t, strings.TrimSpace(lines[len(lines)-1]))
+	assert.NotEmpty(t, strings.TrimSpace(lines[2]))
+	for _, line := range lines[2 : len(lines)-2] {
+		assert.True(t, strings.HasPrefix(line, "    "))
+	}
+}
+
+func TestQuickTunnelQRCodeLinesReturnsErrorForURLTooLong(t *testing.T) {
+	t.Parallel()
+
+	// A URL longer than the largest QR version can encode.
+	longURL := strings.Repeat("a", 10000)
+
+	_, err := quickTunnelQRCodeLines(longURL)
+
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "failed to create quick Tunnel QR code")
+}
+
+func TestRenderHalfBlockQRCodeMatchesSourceBitmap(t *testing.T) {
+	t.Parallel()
+
+	url := "https://example.trycloudflare.com"
+	code, err := qr.Encode(url, qr.L)
+	require.NoError(t, err)
+
+	quietZone := 2
+	lines := renderHalfBlockQRCode(code, quietZone)
+	require.NotEmpty(t, lines)
+
+	// Reconstruct a per-module bitmap from the half-block terminal output
+	// and compare it to the original QR code.
+	for row, line := range lines {
+		yTop := row*2 - quietZone
+		yBottom := yTop + 1
+		col := 0
+		for _, r := range line {
+			x := col - quietZone
+			switch r {
+			case '█':
+				assert.True(t, code.Black(x, yTop), "expected black at (%d,%d)", x, yTop)
+				assert.True(t, code.Black(x, yBottom), "expected black at (%d,%d)", x, yBottom)
+			case '▀':
+				assert.True(t, code.Black(x, yTop), "expected black at (%d,%d)", x, yTop)
+				assert.False(t, code.Black(x, yBottom), "expected white at (%d,%d)", x, yBottom)
+			case '▄':
+				assert.False(t, code.Black(x, yTop), "expected white at (%d,%d)", x, yTop)
+				assert.True(t, code.Black(x, yBottom), "expected black at (%d,%d)", x, yBottom)
+			case ' ':
+				assert.False(t, code.Black(x, yTop), "expected white at (%d,%d)", x, yTop)
+				assert.False(t, code.Black(x, yBottom), "expected white at (%d,%d)", x, yBottom)
+			default:
+				t.Fatalf("unexpected rune %q at row %d col %d", r, row, col)
+			}
+			col++
+		}
+	}
+}
+
 func TestBuildQuickTunnelRequestBody_PublicMode(t *testing.T) {
 	t.Parallel()
 

go.mod

@@ -45,6 +45,7 @@ require (
 	gopkg.in/natefinch/lumberjack.v2 v2.0.0
 	gopkg.in/yaml.v3 v3.0.1
 	nhooyr.io/websocket v1.8.7
+	rsc.io/qr v0.2.0
 	zombiezen.com/go/capnproto2 v2.18.0+incompatible
 )
 

go.sum

@@ -298,5 +298,7 @@ gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 nhooyr.io/websocket v1.8.7 h1:usjR2uOr/zjjkVMy0lW+PPohFok7PCow5sDjLgX4P4g=
 nhooyr.io/websocket v1.8.7/go.mod h1:B70DZP8IakI65RVQ51MsWP/8jndNma26DVA/nFSCgW0=
+rsc.io/qr v0.2.0 h1:6vBLea5/NRMVTz8V66gipeLycZMl/+UlFmk8DvqQ6WY=
+rsc.io/qr v0.2.0/go.mod h1:IF+uZjkb9fqyeF/4tlBoynqmQxUoPfWEKh921coOuXs=
 zombiezen.com/go/capnproto2 v2.18.0+incompatible h1:mwfXZniffG5mXokQGHUJWGnqIBggoPfT/CEwon9Yess=
 zombiezen.com/go/capnproto2 v2.18.0+incompatible/go.mod h1:XO5Pr2SbXgqZwn0m0Ru54QBqpOf4K5AYBO+8LAOBQEQ=