feat(callback): add config portal timeout callback for handle config portal timeout (#1497)

WiFiManager.cpp

@@ -786,6 +786,12 @@ boolean  WiFiManager::startConfigPortal(char const *apName, char const *apPasswo
       #endif
       shutdownConfigPortal();
       result = abort ? portalAbortResult : portalTimeoutResult; // false, false
+      if (_configportaltimeoutcallback != NULL) {
+        #ifdef WM_DEBUG_LEVEL
+        DEBUG_WM(DEBUG_VERBOSE,F("[CB] config portal timeout callback"));
+        #endif
+        _configportaltimeoutcallback();  // @CALLBACK
+      }
       break;
     }
 
@@ -830,6 +836,12 @@ boolean WiFiManager::process(){
         #endif
         webPortalActive = false;
         shutdownConfigPortal();
+        if (_configportaltimeoutcallback != NULL) {
+          #ifdef WM_DEBUG_LEVEL
+          DEBUG_WM(DEBUG_VERBOSE,F("[CB] config portal timeout callback"));
+          #endif
+          _configportaltimeoutcallback();  // @CALLBACK
+        }
         return false;
       }
 
@@ -2788,6 +2800,15 @@ void WiFiManager::setPreOtaUpdateCallback( std::function<void()> func ) {
   _preotaupdatecallback = func;
 }
 
+/**
+ * setConfigPortalTimeoutCallback, set a callback to config portal is timeout
+ * @access public
+ * @param {[type]} void (*func)(void)
+ */
+void WiFiManager::setConfigPortalTimeoutCallback( std::function<void()> func ) {
+  _configportaltimeoutcallback = func;
+}
+
 /**
  * set custom head html
  * custom element will be added to head, eg. new meta,style,script tag etc.

WiFiManager.h

@@ -276,6 +276,9 @@ class WiFiManager
     //called just before doing OTA update
     void          setPreOtaUpdateCallback( std::function<void()> func );
 
+    //called when config portal is timeout
+    void          setConfigPortalTimeoutCallback( std::function<void()> func );
+
     //sets timeout before AP,webserver loop ends and exits even if there has been no setup.
     //useful for devices that failed to connect at some point and got stuck in a webserver loop
     //in seconds setConfigPortalTimeout is a new name for setTimeout, ! not used if setConfigPortalBlocking
@@ -771,6 +774,7 @@ class WiFiManager
     std::function<void()> _saveparamscallback;
     std::function<void()> _resetcallback;
     std::function<void()> _preotaupdatecallback;
+    std::function<void()> _configportaltimeoutcallback;
 
     template <class T>
     auto optionalIPFromString(T *obj, const char *s) -> decltype(  obj->fromString(s)  ) {