feat(veans): add browser launcher helpers for OAuth flow

veans/internal/auth/browser.go

@@ -0,0 +1,48 @@
+// Vikunja is a to-do list application to facilitate your life.
+// Copyright 2018-present Vikunja and contributors. All rights reserved.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package auth
+
+// osOpen launches the OS's default browser at the given URL. The file is
+// kept platform-neutral by delegating to "xdg-open" — the same approach
+// most Go CLIs take. macOS, Linux and BSD all ship it (or a compat alias);
+// on Windows the ./browser_windows.go shim takes precedence via build tag.
+
+import (
+	"context"
+	"os/exec"
+	"runtime"
+	"time"
+)
+
+func osOpen(ctx context.Context, url string) error {
+	// Cap the launch attempt so a misbehaving xdg-open shim can't block
+	// the OAuth flow indefinitely. The browser process itself runs
+	// independently of this child and survives the timeout.
+	cctx, cancel := context.WithTimeout(ctx, 5*time.Second)
+	defer cancel()
+
+	var cmd *exec.Cmd
+	switch runtime.GOOS {
+	case "darwin":
+		cmd = exec.CommandContext(cctx, "open", url)
+	case "windows":
+		cmd = exec.CommandContext(cctx, "rundll32", "url.dll,FileProtocolHandler", url)
+	default:
+		cmd = exec.CommandContext(cctx, "xdg-open", url)
+	}
+	return cmd.Start()
+}