add /open endpoint: open files with EDITOR or xdg-open

main.go

@@ -191,6 +191,11 @@ func writeJSON(w http.ResponseWriter, status int, v any) {
 }
 
 func handler(w http.ResponseWriter, r *http.Request) {
+	if r.URL.Path == "/open" {
+		handleOpen(w, r)
+		return
+	}
+
 	fsys, err := dial()
 	if err != nil {
 		writeJSON(w, http.StatusBadGateway, map[string]string{"error": "9p connect: " + err.Error()})
@@ -424,6 +429,23 @@ func handleStat(w http.ResponseWriter, fsys *client.Fsys, p string) {
 	w.Header().Set("Content-Type", "application/json")
 }
 
+func handleOpen(w http.ResponseWriter, r *http.Request) {
+	p := r.URL.Query().Get("path")
+	if p == "" {
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "missing path"})
+		return
+	}
+	editor := os.Getenv("EDITOR")
+	if editor == "" {
+		editor = "xdg-open"
+	}
+	if err := exec.Command(editor, p).Start(); err != nil {
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]string{"opened": p})
+}
+
 func handlePut(w http.ResponseWriter, r *http.Request, fsys *client.Fsys, p string) {
 	body, err := io.ReadAll(r.Body)
 	if err != nil {