Hello world

internal/linkhandler/install_linux.go

@@ -0,0 +1,108 @@
+package linkhandler
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+// On Linux a desktop entry claims the x-scheme-handler/lazysecrets type,
+// and xdg-open passes links to it as %u.
+
+const desktopFile = "lazysecrets-links.desktop"
+
+// AppPath is where the desktop entry is installed.
+func AppPath() (string, error) {
+	dir := os.Getenv("XDG_DATA_HOME")
+	if dir == "" {
+		home, err := os.UserHomeDir()
+		if err != nil {
+			return "", err
+		}
+		dir = filepath.Join(home, ".local", "share")
+	}
+	return filepath.Join(dir, "applications", desktopFile), nil
+}
+
+// Install registers launch (lazysecrets launch and its flags, the link
+// appended) as the handler for lazysecrets:// links, with env set.
+func Install(launch []string, env []string) (string, error) {
+	path, err := AppPath()
+	if err != nil {
+		return "", err
+	}
+	argv := append(append([]string{"env"}, env...), launch...)
+	entry := fmt.Sprintf(`[Desktop Entry]
+Type=Application
+Name=Lazysecrets Links
+Comment=Opens lazysecrets:// links in lazysecrets
+Exec=%s %%u
+MimeType=x-scheme-handler/lazysecrets;
+NoDisplay=true
+Terminal=false
+%s=%s
+`, desktopExec(argv), exeKey, launch[0])
+	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
+		return "", err
+	}
+	if err := os.WriteFile(path, []byte(entry), 0o644); err != nil {
+		return "", err
+	}
+	if out, err := exec.Command("xdg-mime", "default", desktopFile, "x-scheme-handler/lazysecrets").CombinedOutput(); err != nil {
+		return "", fmt.Errorf("xdg-mime: %v: %s", err, strings.TrimSpace(string(out)))
+	}
+	_ = exec.Command("update-desktop-database", filepath.Dir(path)).Run() // optional
+	return path, nil
+}
+
+// desktopExec quotes args for a desktop entry's Exec key.
+func desktopExec(args []string) string {
+	q := make([]string, len(args))
+	for i, a := range args {
+		a = strings.NewReplacer(`\`, `\\`, `"`, `\"`, "`", "\\`", "$", `\$`, "%", "%%").Replace(a)
+		q[i] = `"` + a + `"`
+	}
+	return strings.Join(q, " ")
+}
+
+// exeKey records, in the desktop entry, the lazysecrets it runs.
+const exeKey = "X-Lazysecrets-Executable"
+
+// Check reports why lazysecrets:// links don't open lazysecrets, or "" if
+// they do (as far as can be told without opening one).
+func Check() string {
+	path, err := AppPath()
+	if err != nil {
+		return ""
+	}
+	b, err := os.ReadFile(path)
+	if err != nil {
+		return "lazysecrets:// links don't open lazysecrets yet"
+	}
+	if out, err := exec.Command("xdg-mime", "query", "default", "x-scheme-handler/lazysecrets").Output(); err == nil &&
+		strings.TrimSpace(string(out)) != desktopFile {
+		return "lazysecrets:// links open " + strings.TrimSpace(string(out)) + ", not lazysecrets"
+	}
+	for _, l := range strings.Split(string(b), "\n") {
+		if exe, ok := strings.CutPrefix(l, exeKey+"="); ok {
+			if _, err := os.Stat(exe); err != nil {
+				return "lazysecrets:// links run " + exe + ", which no longer exists"
+			}
+		}
+	}
+	return ""
+}
+
+// Uninstall removes the desktop entry.
+func Uninstall() (string, error) {
+	path, err := AppPath()
+	if err != nil {
+		return "", err
+	}
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		return "", fmt.Errorf("not installed (%s doesn't exist)", path)
+	}
+	return path, os.Remove(path)
+}