[captive_portal] Allow web_server access while captive portal is active

esphome/components/captive_portal/captive_portal.cpp

@@ -43,7 +43,11 @@ void CaptivePortal::handle_config(AsyncWebServerRequest *request) {
                    scan.get_with_auth());
 #endif
   }
+#ifdef USE_WEBSERVER
+  stream->print(ESPHOME_F("],\"web_server\":true}"));
+#else
   stream->print(ESPHOME_F("]}"));
+#endif
   request->send(stream);
 }
 void CaptivePortal::handle_wifisave(AsyncWebServerRequest *request) {
@@ -71,7 +75,8 @@ void CaptivePortal::setup() {
 void CaptivePortal::start() {
   this->base_->init();
   if (!this->initialized_) {
-    this->base_->add_handler(this);
+    // Use fallback position so web_server handlers are checked first
+    this->base_->add_handler(this, web_server_base::HandlerPosition::FALLBACK);
   }
 
   network::IPAddress ip = wifi::global_wifi_component->wifi_soft_ap_ip();

esphome/components/captive_portal/captive_portal.h

@@ -46,9 +46,10 @@ class CaptivePortal : public AsyncWebHandler, public Component {
   }
 
   bool canHandle(AsyncWebServerRequest *request) const override {
-    // Handle all GET requests when captive portal is active
+    // Handle all GET requests when captive portal is active.
     // This allows us to respond with the portal page for any URL,
-    // triggering OS captive portal detection
+    // triggering OS captive portal detection.
+    // We use add_fallback_handler() so web_server handlers are checked first.
     return this->active_ && request->method() == HTTP_GET;
   }
 

esphome/components/web_server/web_server.cpp

@@ -28,6 +28,10 @@
 #include "esphome/components/climate/climate.h"
 #endif
 
+#ifdef USE_CAPTIVE_PORTAL
+#include "esphome/components/captive_portal/captive_portal.h"
+#endif
+
 #ifdef USE_WEBSERVER_LOCAL
 #if USE_WEBSERVER_VERSION == 2
 #include "server_index_v2.h"
@@ -1957,9 +1961,19 @@ bool WebServer::canHandle(AsyncWebServerRequest *request) const {
   const auto &url = request->url();
   const auto method = request->method();
 
-  // Static URL checks
+  // Handle root URL
+  if (url == ESPHOME_F("/")) {
+#ifdef USE_CAPTIVE_PORTAL
+    // When captive portal is active, only handle "/" if ?web_server param is present
+    if (captive_portal::global_captive_portal != nullptr && captive_portal::global_captive_portal->is_active()) {
+      return request->hasParam(ESPHOME_F("web_server"));
+    }
+#endif
+    return true;
+  }
+
+  // Other static URL checks
   static const char *const STATIC_URLS[] = {
-    "/",
 #if !defined(USE_ESP32) && defined(USE_ARDUINO)
     "/events",
 #endif

esphome/components/web_server_base/web_server_base.cpp

@@ -11,15 +11,18 @@ static const char *const TAG = "web_server_base";
 
 WebServerBase *global_web_server_base = nullptr;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
 
-void WebServerBase::add_handler(AsyncWebHandler *handler) {
-  // remove all handlers
-
+void WebServerBase::add_handler(AsyncWebHandler *handler, HandlerPosition position) {
 #ifdef USE_WEBSERVER_AUTH
-  if (!credentials_.username.empty()) {
+  if (position != HandlerPosition::FALLBACK && !credentials_.username.empty()) {
     handler = new internal::AuthMiddlewareHandler(handler, &credentials_);
   }
 #endif
-  this->handlers_.push_back(handler);
+  if (position == HandlerPosition::FALLBACK) {
+    this->handlers_.push_back(handler);
+  } else {
+    this->handlers_.insert(this->handlers_.begin() + this->fallback_start_, handler);
+    this->fallback_start_++;
+  }
   if (this->server_ != nullptr) {
     this->server_->addHandler(handler);
   }

esphome/components/web_server_base/web_server_base.h

@@ -91,6 +91,11 @@ class AuthMiddlewareHandler : public MiddlewareHandler {
 
 }  // namespace internal
 
+enum class HandlerPosition : uint8_t {
+  NORMAL,   ///< Before fallback handlers (default)
+  FALLBACK  ///< After normal handlers (catch-all)
+};
+
 class WebServerBase : public Component {
  public:
   void init() {
@@ -122,7 +127,7 @@ class WebServerBase : public Component {
   void set_auth_password(std::string auth_password) { credentials_.password = std::move(auth_password); }
 #endif
 
-  void add_handler(AsyncWebHandler *handler);
+  void add_handler(AsyncWebHandler *handler, HandlerPosition position = HandlerPosition::NORMAL);
 
   void set_port(uint16_t port) { port_ = port; }
   uint16_t get_port() const { return port_; }
@@ -132,6 +137,7 @@ class WebServerBase : public Component {
   uint16_t port_{80};
   std::unique_ptr<AsyncWebServer> server_{nullptr};
   std::vector<AsyncWebHandler *> handlers_;
+  size_t fallback_start_{0};  ///< Index where fallback handlers begin
 #ifdef USE_WEBSERVER_AUTH
   internal::Credentials credentials_;
 #endif