Merge pull request #613 from rusq/i511-2

adjust max QR code size

Author: rusq

auth/auth_ui/huh.go

@@ -26,11 +26,21 @@ import (
 
 	"github.com/charmbracelet/bubbles/key"
 	"github.com/charmbracelet/huh"
+	"github.com/rusq/osenv/v2"
 	"github.com/rusq/slackauth"
 
 	"github.com/rusq/slackdump/v4/internal/structures"
 )
 
+const (
+	defQRCodeSz = 9000      // default limit for encoded image size, seen values 6174, 8462
+	maxQRCodeSz = 1<<16 - 1 // maximum allowed QR code image size.
+	imgPrefix   = "data:image/png;base64,"
+)
+
+// limQRCodeSz is the size of the input field for QR Code image.
+var limQRCodeSz = osenv.Value("QR_CODE_SIZE", defQRCodeSz)
+
 // Huh is the Auth UI that uses the huh library to provide a terminal UI.
 type Huh struct{}
 
@@ -250,21 +260,17 @@ func valSixDigits(s string) error {
 	return nil
 }
 
-const (
-	maxEncImgSz = 7000
-	imgPrefix   = "data:image/png;base64,"
-)
-
 func (*Huh) RequestQR(ctx context.Context, _ io.Writer) (string, error) {
 	const description = `In logged in Slack Client or Web:
   1. click the username in the upper left corner;
   2. choose 'Sign in on mobile';
   3. right-click the QR code image;
   4. choose Copy Image.`
+
 	var imageData string
 	q := huh.NewForm(huh.NewGroup(
 		huh.NewText().
-			CharLimit(maxEncImgSz).
+			CharLimit(qrCharLimit()).
 			Value(&imageData).
 			Validate(func(s string) error {
 				if !strings.HasPrefix(s, imgPrefix) {
@@ -281,3 +287,12 @@ func (*Huh) RequestQR(ctx context.Context, _ io.Writer) (string, error) {
 	}
 	return imageData, nil
 }
+
+// qrCharLimit returns the effective character limit for the QR code input
+// field.
+func qrCharLimit() int {
+	if defQRCodeSz <= limQRCodeSz && limQRCodeSz <= maxQRCodeSz {
+		return limQRCodeSz
+	}
+	return defQRCodeSz
+}

auth/auth_ui/huh_test.go

@@ -15,7 +15,9 @@
 
 package auth_ui
 
-import "testing"
+import (
+	"testing"
+)
 
 func Test_valSixDigits(t *testing.T) {
 	type args struct {
@@ -60,3 +62,27 @@ func Test_valSixDigits(t *testing.T) {
 		})
 	}
 }
+
+func Test_qrCharLimit(t *testing.T) {
+	tests := []struct {
+		name    string
+		limQRsz int
+		want    int
+	}{
+		{"zero", 0, defQRCodeSz},
+		{"default", defQRCodeSz, defQRCodeSz},
+		{"between allowed values", (maxQRCodeSz - defQRCodeSz) / 2, (maxQRCodeSz - defQRCodeSz) / 2},
+		{"over maximum", maxQRCodeSz + 1, defQRCodeSz},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var old = limQRCodeSz
+			limQRCodeSz = tt.limQRsz
+			t.Cleanup(func() { limQRCodeSz = old })
+
+			if got := qrCharLimit(); got != tt.want {
+				t.Errorf("qrCharLimit() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

slackdump.1

@@ -394,6 +394,13 @@ for more details.
 .It Ev NOCOLOR
 .BOOL
 disables colorful log messages.
+.It Ev QR_CODE_SIZE
+Sets the maximum length, in characters, of the pasted QR Code image data
+(the
+.Ql data:image/png;base64,...
+string) used for "Sign in on Mobile".  The default limit is 9000 characters;
+values outside the supported range (up to a maximum of 65535 characters) are
+ignored and the default is used.
 .It Ev SLACK_COOKIE
 Contains Slack cookie (for token+cookie-based authentication).  See
 .Sx Authentication