Don't show Hotspot config on devices without wifi.

src/HotspotManager.cpp

@@ -33,6 +33,7 @@
 
 using namespace pipedal;
 using namespace dbus::networkmanager;
+namespace fs = std::filesystem;
 
 namespace pipedal::impl
 {
@@ -1032,3 +1033,33 @@ std::vector<std::string> HotspotManagerImpl::GetKnownWifiNetworks()
     std::lock_guard lock(knownWifiNetworksMutex); // pushed off the service thread.
     return this->knownWifiNetworks;
 }
+
+
+static bool is_wireless_sysfs(const std::string& ifname) {
+    return fs::exists("/sys/class/net/" + ifname + "/wireless");
+}
+
+static std::vector<std::string> get_wireless_interfaces_sysfs() {
+    std::vector<std::string> wireless_interfaces;
+    const std::string net_path = "/sys/class/net";
+
+    try {
+        for (const auto& entry : fs::directory_iterator(net_path)) {
+            std::string ifname = entry.path().filename();
+            if (is_wireless_sysfs(ifname)) {
+                wireless_interfaces.push_back(ifname);
+            }
+        }
+    } catch (const fs::filesystem_error& e) {
+        std::cerr << "Error accessing " << net_path << ": " << e.what() << std::endl;
+    }
+
+    return wireless_interfaces;
+}
+
+bool HotspotManager::HasWifiDevice()
+{
+    // use procfs to decide this, as NetworkManager may not be available yet.
+
+    return !(get_wireless_interfaces_sysfs().empty());
+}

src/HotspotManager.hpp

@@ -38,6 +38,8 @@ namespace pipedal {
         
         using ptr = std::unique_ptr<HotspotManager>;
 
+        static bool HasWifiDevice();
+
         static ptr Create();
 
         virtual ~HotspotManager() noexcept { }

src/WebServerConfig.cpp

@@ -33,6 +33,7 @@
 #include "TemporaryFile.hpp"
 #include "PresetBundle.hpp"
 #include "json.hpp"
+#include "HotspotManager.hpp"
 
 #define OLD_PRESET_EXTENSION ".piPreset"
 #define PRESET_EXTENSION ".piPreset"
@@ -701,6 +702,7 @@ public:
           << ", \"socket_server_address\": \"" << webSocketAddress
           << "\", \"ui_plugins\": [ ], \"max_upload_size\": " << maxUploadSize
           << ", \"enable_auto_update\": " << (ENABLE_AUTO_UPDATE ? " true" : "false")
+          << ", \"has_wifi_device\": " << (HotspotManager::HasWifiDevice() ? " true": "false")
           << " }";
 
         return s.str();