Captive Portal_ESP32.ino

#include <WiFi.h>
#include <WiFiClient.h> 
#include <WebServer.h>
#include <ESPmDNS.h>
#include <DNSServer.h>
#include <EEPROM.h>

#define GPIO_OUT_W1TS_REG (DR_REG_GPIO_BASE + 0x0008)
#define GPIO_OUT_W1TC_REG (DR_REG_GPIO_BASE + 0x000c)

static const byte WiFiPwdLen = 25;
static const byte APSTANameLen = 20;

struct WiFiEEPromData
  {
    bool APSTA = true; // Access Point or Sation Mode - true AP Mode
    bool PwDReq = false; // PasswordRequired
    bool CapPortal = true ; //CaptivePortal on in AP Mode
    char APSTAName[APSTANameLen]; // STATION /AP Point Name TO cONNECT, if definded   
    char WiFiPwd[WiFiPwdLen]; // WiFiPAssword, if definded    
    char ConfigValid[3]; //If Config is Vaild, Tag "TK" is required"
  };

/* hostname for mDNS. Should work at least on windows. Try http://esp8266.local */
const char *ESPHostname = "ESP32";

// DNS server
const byte DNS_PORT = 53;
DNSServer dnsServer;

//Conmmon Paramenters
bool SoftAccOK  = false;

// Web server
WebServer server(80);

/* Soft AP network parameters */
IPAddress apIP(172, 20, 0, 1);
IPAddress netMsk(255, 255, 255, 0);

unsigned long currentMillis = 0;
unsigned long startMillis;

/** Current WLAN status */
short status = WL_IDLE_STATUS;

WiFiEEPromData MyWiFiConfig;
String temp ="";


void setup() 
{
  REG_WRITE(GPIO_OUT_W1TS_REG, BIT(GPIO_NUM_16));     // Guru Meditation Error Remediation set
  delay(1);
  REG_WRITE(GPIO_OUT_W1TC_REG, BIT(GPIO_NUM_16));     // Guru Meditation Error Remediation clear
  bool ConnectSuccess = false;
  bool CreateSoftAPSucc  = false;
  bool CInitFSSystem  = false;
  bool CInitHTTPServer  = false;
  byte len; 
  Serial.begin(9600);
   while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB
  }
  Serial.println(F("Serial Interface initalized at 9600 Baud.")); 
  WiFi.setAutoReconnect (false);
  WiFi.persistent(false);
  WiFi.disconnect(); 
  WiFi.setHostname(ESPHostname); // Set the DHCP hostname assigned to ESP station.
  if (loadCredentials()) // Load WLAN credentials for WiFi Settings
  { 
     Serial.println(F("Valid Credentials found."));   
     if (MyWiFiConfig.APSTA == true)  // AP Mode
      { 
        Serial.println(F("Access Point Mode selected.")); 
        Serial.println(MyWiFiConfig.APSTA);
        len = strlen(MyWiFiConfig.APSTAName);
        MyWiFiConfig.APSTAName[len+1] = '\0'; 
        len = strlen(MyWiFiConfig.WiFiPwd);
        MyWiFiConfig.WiFiPwd[len+1] = '\0';  
        CreateSoftAPSucc = CreateWifiSoftAP();
      } else
      {
        Serial.println(F("Station Mode selected."));       
        len = strlen(MyWiFiConfig.APSTAName);
        MyWiFiConfig.APSTAName[len+1] = '\0'; 
        len = strlen(MyWiFiConfig.WiFiPwd);
        MyWiFiConfig.WiFiPwd[len+1] = '\0';
        len = ConnectWifiAP();     
        if ( len == 3 ) { ConnectSuccess = true; } else { ConnectSuccess = false; }     
      }
  } else
  { //Set default Config - Create AP
     Serial.println(F("NO Valid Credentials found.")); 
     SetDefaultWiFiConfig ();
     CreateSoftAPSucc = CreateWifiSoftAP(); 
     saveCredentials();
     delay(500);     
  }
  if ((ConnectSuccess or CreateSoftAPSucc))
    {         
      Serial.print (F("IP Address: "));
      if (CreateSoftAPSucc) { Serial.println(WiFi.softAPIP());}   
      if (ConnectSuccess) { Serial.println(WiFi.localIP());}
      InitalizeHTTPServer();     
    }
    else
    {
      Serial.setDebugOutput(true); //Debug Output for WLAN on Serial Interface.
      Serial.println(F("Error: Cannot connect to WLAN. Set DEFAULT Configuration."));
      SetDefaultWiFiConfig();
      CreateSoftAPSucc = CreateWifiSoftAP();
      InitalizeHTTPServer();  
      SetDefaultWiFiConfig();
      saveCredentials();   
    } 
}

void InitalizeHTTPServer() 
 {
  bool initok = false;
  /* Setup web pages: root, wifi config pages, SO captive portal detectors and not found. */
  server.on("/", handleRoot);
  server.on("/wifi", handleWifi);
  if (MyWiFiConfig.CapPortal) { server.on("/generate_204", handleRoot); } //Android captive portal. Maybe not needed. Might be handled by notFound handler.
  if (MyWiFiConfig.CapPortal) { server.on("/favicon.ico", handleRoot); }   //Another Android captive portal. Maybe not needed. Might be handled by notFound handler. Checked on Sony Handy
  if (MyWiFiConfig.CapPortal) { server.on("/fwlink", handleRoot); }  //Microsoft captive portal. Maybe not needed. Might be handled by notFound handler.
  //server.on("/generate_204", handleRoot);  //Android captive portal. Maybe not needed. Might be handled by notFound handler.
  //server.on("/favicon.ico", handleRoot);    //Another Android captive portal. Maybe not needed. Might be handled by notFound handler. Checked on Sony Handy
  //server.on("/fwlink", handleRoot);   //Microsoft captive portal. Maybe not needed. Might be handled by notFound handler. 
  server.onNotFound ( handleNotFound );
  // Speicherung Header-Elemente anfordern
  // server.collectHeaders(Headers, sizeof(Headers)/ sizeof(Headers[0]));
  server.begin(); // Web server start
 }

boolean CreateWifiSoftAP() 
{
  WiFi.disconnect();
  Serial.print(F("Initalize SoftAP "));
  if (MyWiFiConfig.PwDReq) 
    {
      SoftAccOK  =  WiFi.softAP(MyWiFiConfig.APSTAName, MyWiFiConfig.WiFiPwd); // Passwortlänge mindestens 8 Zeichen !
    } else
    {
      SoftAccOK  =  WiFi.softAP(MyWiFiConfig.APSTAName); // Access Point WITHOUT Password
      // Overload Function:; WiFi.softAP(ssid, password, channel, hidden)
    }
  delay(2000); // Without delay I've seen the IP address blank
  WiFi.softAPConfig(apIP, apIP, netMsk);
  if (SoftAccOK)
  {
  /* Setup the DNS server redirecting all the domains to the apIP */  
  dnsServer.setErrorReplyCode(DNSReplyCode::NoError);
  dnsServer.start(DNS_PORT, "*", apIP);
  Serial.println(F("successful."));
  // Serial.setDebugOutput(true); // Debug Output for WLAN on Serial Interface.
  } else
  {
  Serial.println(F("Soft AP Error."));
  Serial.println(MyWiFiConfig.APSTAName);
  Serial.println(MyWiFiConfig.WiFiPwd);
  }
  return SoftAccOK;
}

byte ConnectWifiAP() 
{
  Serial.println(F("Initalizing Wifi Client."));  
  byte connRes = 0;
  byte i = 0;
  WiFi.disconnect();
  WiFi.softAPdisconnect(true); // Function will set currently configured SSID and password of the soft-AP to null values. The parameter  is optional. If set to true it will switch the soft-AP mode off.
  delay(500);  
  WiFi.begin(MyWiFiConfig.APSTAName, MyWiFiConfig.WiFiPwd);
  connRes  = WiFi.waitForConnectResult();
  while (( connRes == 0 ) and (i != 10))  //if connRes == 0  "IDLE_STATUS - change Statius"
    { 
      connRes  = WiFi.waitForConnectResult();
      delay(2000);
      i++;
      Serial.print(F("."));
      // statement(s)
    }
  while (( connRes == 1 ) and (i != 10))  //if connRes == 1  NO_SSID_AVAILin - SSID cannot be reached
    { 
      connRes  = WiFi.waitForConnectResult();
      delay(2000);
      i++;
      Serial.print(F("."));
      // statement(s)
    }  
  if (connRes == 3 ) { 
                        WiFi.setAutoReconnect(true); // Set whether module will attempt to reconnect to an access point in case it is disconnected.
                        // Setup MDNS responder
                            if (!MDNS.begin(ESPHostname)) {
                                Serial.println(F("Error: MDNS"));
                                } else { MDNS.addService("http", "tcp", 80); }
                     }
  while (( connRes == 4 ) and (i != 10))  //if connRes == 4  Bad Password. Sometimes happens this with corrct PWD
    { 
      WiFi.begin(MyWiFiConfig.APSTAName, MyWiFiConfig.WiFiPwd); 
      connRes = WiFi.waitForConnectResult();
      delay(3000);
      i++;
      Serial.print(F("."));                 
    }
  if (connRes == 4 ) {  
                        Serial.println(F("STA Pwd Err"));                     
                        Serial.println(MyWiFiConfig.APSTAName);
                        Serial.println(MyWiFiConfig.WiFiPwd); 
                        WiFi.disconnect();
                      }
  // if (connRes == 6 ) { Serial.println("DISCONNECTED - Not in station mode"); }
  // WiFi.printDiag(Serial);
Serial.println("");
return connRes;
}

#define SD_BUFFER_PIXELS 20
/** Load WLAN credentials from EEPROM */
bool loadCredentials() 
{
 bool RetValue;
 EEPROM.begin(512);
 EEPROM.get(0, MyWiFiConfig);
 EEPROM.end();
 if (String(MyWiFiConfig.ConfigValid) = String("TK")) 
  {
    RetValue = true;
  } else
  {
    RetValue = false; // WLAN Settings not found.
  }
  return RetValue;
}

/** Store WLAN credentials to EEPROM */

bool saveCredentials() 
{
bool RetValue;
// Check logical Errors
RetValue = true;
if  (MyWiFiConfig.APSTA == true ) //AP Mode
  {
   if (MyWiFiConfig.PwDReq and (sizeof(String(MyWiFiConfig.WiFiPwd)) < 8))
    {    
      RetValue = false;  // Invalid Config
    }
   if (sizeof(String(MyWiFiConfig.APSTAName)) < 1)
    {
      RetValue = false;  // Invalid Config
    }
  } 
if (RetValue)
  {
  EEPROM.begin(512);
  for (int i = 0 ; i < sizeof(MyWiFiConfig) ; i++) 
     {
      EEPROM.write(i, 0);
     }
  strncpy( MyWiFiConfig.ConfigValid , "TK", sizeof(MyWiFiConfig.ConfigValid) );
  EEPROM.put(0, MyWiFiConfig);
  EEPROM.commit();
  EEPROM.end();
  }
  return RetValue;
}

void SetDefaultWiFiConfig()
{
   byte len;
   MyWiFiConfig.APSTA = true;
   MyWiFiConfig.PwDReq = true;  // default PW required
   MyWiFiConfig.CapPortal = true;
   strncpy( MyWiFiConfig.APSTAName, "ESP_Config", sizeof(MyWiFiConfig.APSTAName) );
   len = strlen(MyWiFiConfig.APSTAName);
   MyWiFiConfig.APSTAName[len+1] = '\0';   
   strncpy( MyWiFiConfig.WiFiPwd, "12345678", sizeof(MyWiFiConfig.WiFiPwd) );
   len = strlen(MyWiFiConfig.WiFiPwd);
   MyWiFiConfig.WiFiPwd[len+1] = '\0';  
   strncpy( MyWiFiConfig.ConfigValid, "TK", sizeof(MyWiFiConfig.ConfigValid) );
   len = strlen(MyWiFiConfig.ConfigValid);
   MyWiFiConfig.ConfigValid[len+1] = '\0'; 
   Serial.println(F("Reset WiFi Credentials.")); 
}

void handleRoot() {
//  Main Page:
 temp = "";
 byte PicCount = 0;
 byte ServArgs = 0;
  // HTML Header
  server.sendHeader("Cache-Control", "no-cache, no-store, must-revalidate");
  server.sendHeader("Pragma", "no-cache");
  server.sendHeader("Expires", "-1");
  server.setContentLength(CONTENT_LENGTH_UNKNOWN);
// HTML Content
  server.send ( 200, "text/html", temp );   // Speichersparen - Schon mal dem Cleint senden
  temp = "";
  temp += "<!DOCTYPE HTML><html lang='de'><head><meta charset='UTF-8'><meta name= viewport content='width=device-width, initial-scale=1.0,'>";
  server.sendContent(temp);
  temp = "";
  temp += "<style type='text/css'><!-- DIV.container { min-height: 10em; display: table-cell; vertical-align: middle }.button {height:35px; width:90px; font-size:16px}";
  server.sendContent(temp);
  temp = "";
  temp += "body {background-color: powderblue;}</style>";
  temp += "<head><title>Hauptseite</title></head>";
  temp += "<h2>Hauptseite</h2>";
  temp += "<body>";
  server.sendContent(temp);
  temp = ""; 
// Processing User Request
  temp = ""; 
  temp += "<table border=2 bgcolor = white width = 500 cellpadding =5 ><caption><p><h3>Systemlinks:</h2></p></caption>";
  temp += "<tr><th><br>";
  temp += "<a href='/wifi'>WIFI Einstellungen</a><br><br>";
  temp += "</th></tr></table><br><br>";
  temp += "<footer><p>Programmed and designed by: Tobias Kuch</p><p>Contact information: <a href='mailto:tobias.kuch@googlemail.com'>tobias.kuch@googlemail.com</a>.</p></footer>";
  temp += "</body></html>";
  server.sendContent(temp);
  temp = "";
  server.client().stop(); // Stop is needed because we sent no content length
}

void handleNotFound() { 
    if (captivePortal()) 
      { // If caprive portal redirect instead of displaying the error page.
        return;
      } 
    temp = ""; 
    // HTML Header
    server.sendHeader("Cache-Control", "no-cache, no-store, must-revalidate");
    server.sendHeader("Pragma", "no-cache");
    server.sendHeader("Expires", "-1");
    server.setContentLength(CONTENT_LENGTH_UNKNOWN);
    // HTML Content
    temp += "<!DOCTYPE HTML><html lang='de'><head><meta charset='UTF-8'><meta name= viewport content='width=device-width, initial-scale=1.0,'>";
    temp += "<style type='text/css'><!-- DIV.container { min-height: 10em; display: table-cell; vertical-align: middle }.button {height:35px; width:90px; font-size:16px}";
    temp += "body {background-color: powderblue;}</style>";
    temp += "<head><title>File not found</title></head>";
    temp += "<h2> 404 File Not Found</h2><br>";
    temp += "<h4>Debug Information:</h4><br>";
    temp += "<body>";
    temp += "URI: ";
    temp += server.uri();
    temp += "\nMethod: ";
    temp+= ( server.method() == HTTP_GET ) ? "GET" : "POST";
    temp += "<br>Arguments: ";
    temp += server.args();
    temp += "\n";
      for ( uint8_t i = 0; i < server.args(); i++ ) {
        temp += " " + server.argName ( i ) + ": " + server.arg ( i ) + "\n";
        }
    temp += "<br>Server Hostheader: "+ server.hostHeader();
    for ( uint8_t i = 0; i < server.headers(); i++ ) {
        temp += " " + server.headerName ( i ) + ": " + server.header ( i ) + "\n<br>";
        }  
    temp += "</table></form><br><br><table border=2 bgcolor = white width = 500 cellpadding =5 ><caption><p><h2>You may want to browse to:</h2></p></caption>";
    temp += "<tr><th>";
    temp += "<a href='/'>Main Page</a><br>";
    temp += "<a href='/wifi'>WIFI Settings</a><br>";
    temp += "</th></tr></table><br><br>";
    temp += "<footer><p>Programmed and designed by: Tobias Kuch</p><p>Contact information: <a href='mailto:tobias.kuch@googlemail.com'>tobias.kuch@googlemail.com</a>.</p></footer>";
    temp += "</body></html>";
    server.send ( 404, "", temp );
    server.client().stop(); // Stop is needed because we sent no content length
    temp = "";
    
}

/** Redirect to captive portal if we got a request for another domain. Return true in that case so the page handler do not try to handle the request again. */
boolean captivePortal() {
  if (!isIp(server.hostHeader()) && server.hostHeader() != (String(ESPHostname)+".local")) {
    // Serial.println("Request redirected to captive portal");  
    server.sendHeader("Location", String("http://") + toStringIp(server.client().localIP()), true);
    server.send ( 302, "text/plain", ""); // Empty content inhibits Content-length header so we have to close the socket ourselves.
    server.client().stop(); // Stop is needed because we sent no content length
    return true;
  }
  return false;
}
 
/** Wifi config page handler */
void handleWifi() 
 {
  //  Page: /wifi
  byte i;
  byte len ;
  temp = "";
  // Check for Site Parameters  
      if (server.hasArg("Reboot") )  // Reboot System 
       {
         temp = "Rebooting System in 5 Seconds..";
         server.send ( 200, "text/html", temp );
         delay(5000);
         server.client().stop();      
         WiFi.disconnect();
         delay(1000);      
       }

      if (server.hasArg("WiFiMode") and (server.arg("WiFiMode") == "1")  )  // STA Station Mode Connect to another WIFI Station  
       {
        startMillis = millis(); // Reset Time Up Counter to avoid Idle Mode whiole operating
        // Connect to existing STATION
        if ( sizeof(server.arg("WiFi_Network")) > 0  )
          {
            Serial.println("STA Mode");
            MyWiFiConfig.APSTA = false; // Access Point or Station Mode - false Station Mode
            temp = "";          
            for ( i = 0; i < APSTANameLen;i++) { MyWiFiConfig.APSTAName[i] =  0; }
            temp = server.arg("WiFi_Network");
            len =  temp.length();
            for ( i = 0; i < len;i++) 
            { 
                  MyWiFiConfig.APSTAName[i] =  temp[i];              
            }
            temp = "";

            for ( i = 0; i < WiFiPwdLen;i++)  { MyWiFiConfig.WiFiPwd[i] =  0; }          
            temp = server.arg("STAWLanPW");
            len =  temp.length();                     
            for ( i = 0; i < len;i++)  
              { 
                if (temp[i] > 32) //Steuerzeichen raus
                  {
                   MyWiFiConfig.WiFiPwd[i] =  temp[i];  
                  }  
              }
            temp = "WiFi Connect to AP: -"; 
            temp += MyWiFiConfig.APSTAName;
            temp += "-<br>WiFi PW: -"; 
            temp += MyWiFiConfig.WiFiPwd;
            temp += "-<br>";          
            temp += "Connecting to STA Mode in 2 Seconds..<br>";
            server.send ( 200, "text/html", temp ); 
            server.sendContent(temp);
            delay(2000);
            server.client().stop(); 
            server.stop();
            temp = "";
            WiFi.disconnect();
            WiFi.softAPdisconnect(true);
            delay(500);
           // ConnectWifiAP
           bool SaveOk = saveCredentials();          
            i = ConnectWifiAP();
            delay(700);
            if (i != 3) // 4: WL_CONNECT_FAILED - Password is incorrect 1: WL_NO_SSID_AVAILin - Configured SSID cannot be reached
              {
                 Serial.print(F("Cannot Connect to specified Network. Reason: "));
                 Serial.println(i);
                 server.client().stop();
                 delay(100);             
                 WiFi.setAutoReconnect (false);
                 delay(100);     
                 WiFi.disconnect();             
                 delay(1000);
                 SetDefaultWiFiConfig();
                 CreateWifiSoftAP();
                 return; 
              } else
              {
                 // Safe Config
                 bool SaveOk = saveCredentials();
                 InitalizeHTTPServer();
                 return;
              }
          }
       }
         
      if (server.hasArg("WiFiMode") and (server.arg("WiFiMode") == "2")  )  // Change AP Mode 
       {
        startMillis = millis(); // Reset Time Up Counter to avoid Idle Mode whiole operating
        // Configure Access Point
        temp = server.arg("APPointName");      
        len =  temp.length();
        temp =server.arg("APPW");
        if (server.hasArg("PasswordReq"))
            {      
              i =  temp.length();
            } else { i = 8; }
        
        if (  ( len > 1 ) and (server.arg("APPW") == server.arg("APPWRepeat")) and ( i > 7)          )
          {
            temp = "";
            Serial.println(F("APMode"));
            MyWiFiConfig.APSTA = true; // Access Point or Sation Mode - true AP Mode
                       
            if (server.hasArg("CaptivePortal"))
            {
              MyWiFiConfig.CapPortal = true ; //CaptivePortal on in AP Mode
            } else { MyWiFiConfig.CapPortal = false ; }
            
            if (server.hasArg("PasswordReq"))
            {
              MyWiFiConfig.PwDReq = true ; //Password Required in AP Mode
            } else { MyWiFiConfig.PwDReq = false ; }

            for ( i = 0; i < APSTANameLen;i++) { MyWiFiConfig.APSTAName[i] =  0; }
            temp = server.arg("APPointName");
            len =  temp.length();
            for ( i = 0; i < len;i++) { MyWiFiConfig.APSTAName[i] =  temp[i]; }
            MyWiFiConfig.APSTAName[len+1] = '\0';  
            temp = "";
            for ( i = 0; i < WiFiPwdLen;i++)  {  MyWiFiConfig.WiFiPwd[i] =  0; }          
            temp = server.arg("APPW");
            len =  temp.length();                     
            for ( i = 0; i < len;i++)  { MyWiFiConfig.WiFiPwd[i] =  temp[i];  }
            MyWiFiConfig.WiFiPwd[len+1] = '\0';  
            temp = "";         
            if (saveCredentials()) // Save AP ConfigCongfig  
              {
                        temp = "Daten des AP Modes erfolgreich gespeichert. Reboot notwendig.";
              } else  { temp = "Daten des AP Modes fehlerhaft.";  }
          } else if (server.arg("APPW") != server.arg("APPWRepeat"))
                {
                  temp = "";
                  temp = "WLAN Passwort nicht gleich. Abgebrochen.";
                } else
                {            
                  temp = "";
                  temp = "WLAN Passwort oder AP Name zu kurz. Abgebrochen.";
                }       
       }
  
  // HTML Header
  server.sendHeader("Cache-Control", "no-cache, no-store, must-revalidate");
  server.sendHeader("Pragma", "no-cache");
  server.sendHeader("Expires", "-1");
  server.setContentLength(CONTENT_LENGTH_UNKNOWN);
// HTML Content
  temp += "<!DOCTYPE HTML><html lang='de'><head><meta charset='UTF-8'><meta name= viewport content='width=device-width, initial-scale=1.0,'>";
  server.send ( 200, "text/html", temp ); 
  temp = ""; 
  temp += "<style type='text/css'><!-- DIV.container { min-height: 10em; display: table-cell; vertical-align: middle }.button {height:35px; width:90px; font-size:16px}";
  temp += "body {background-color: powderblue;}</style><head><title>Smartes Tuerschild - WiFi Settings</title></head>";
  server.sendContent(temp);
  temp = "";
  temp += "<h2>WiFi Einstellungen</h2><body><left>";
  temp += "<table border=2 bgcolor = white width = 500 ><td><h4>Current WiFi Settings: </h4>";
  if (server.client().localIP() == apIP) {
     temp += "Mode : Soft Access Point (AP)<br>";
     temp += "SSID : " + String (MyWiFiConfig.APSTAName) + "<br><br>";
  } else {
     temp += "Mode : Station (STA) <br>";
     temp += "SSID  :  "+ String (MyWiFiConfig.APSTAName) + "<br>";
     temp += "BSSID :  " + WiFi.BSSIDstr()+ "<br><br>";
  }
  temp += "</td></table><br>";
  server.sendContent(temp);
  temp = "";
  temp += "<form action='/wifi' method='post'>";
  temp += "<table border=2 bgcolor = white width = 500><tr><th><br>";
  if (MyWiFiConfig.APSTA == 1)
    {
      temp += "<input type='radio' value='1' name='WiFiMode' > WiFi Station Mode<br>";
    } else
    {
      temp += "<input type='radio' value='1' name='WiFiMode' checked > WiFi Station Mode<br>";
    }
  temp += "Available WiFi Networks:<table border=2 bgcolor = white ></tr></th><td>Number </td><td>SSID  </td><td>Encryption </td><td>WiFi Strength </td>";
  server.sendContent(temp);
  temp = "";
  WiFi.scanDelete();
  int n = WiFi.scanNetworks(false, false); //WiFi.scanNetworks(async, show_hidden)
  if (n > 0) {
    for (int i = 0; i < n; i++) {
    temp += "</tr></th>";
    String Nrb = String(i);
    temp += "<td>" + Nrb + "</td>";
    temp += "<td>" + WiFi.SSID(i) +"</td>";
   
    Nrb = GetEncryptionType(WiFi.encryptionType(i));
    temp += "<td>"+ Nrb + "</td>";
    temp += "<td>" + String(WiFi.RSSI(i)) + "</td>";   
    }
  } else {
    temp += "</tr></th>";
    temp += "<td>1 </td>";
    temp += "<td>No WLAN found</td>";
    temp += "<td> --- </td>";
    temp += "<td> --- </td>";
  }
  temp += "</table><table border=2 bgcolor = white ></tr></th><td>Connect to WiFi SSID: </td><td><select name='WiFi_Network' >";
if (n > 0) {
    for (int i = 0; i < n; i++) {
    temp += "<option value='" + WiFi.SSID(i) +"'>" + WiFi.SSID(i) +"</option>";      
    }
  } else {
    temp += "<option value='No_WiFi_Network'>No WiFiNetwork found !/option>";
  }
  server.sendContent(temp);
  temp = "";
  temp += "</select></td></tr></th></tr></th><td>WiFi Password: </td><td>";
  temp += "<input type='text' name='STAWLanPW' maxlength='40' size='40'>"; 
  temp += "</td></tr></th><br></th></tr></table></table><table border=2 bgcolor = white width = 500 ><tr><th><br>";
  server.sendContent(temp);
  temp = "";
  if (MyWiFiConfig.APSTA == true)
    {
      temp += "<input type='radio' name='WiFiMode' value='2' checked> WiFi Access Point Mode <br>";
    } else
    {
      temp += "<input type='radio' name='WiFiMode' value='2' > WiFi Access Point Mode <br>";
    }
  temp += "<table border=2 bgcolor = white ></tr></th> <td>WiFi Access Point Name: </td><td>";  
  server.sendContent(temp);
  temp = "";            
  if (MyWiFiConfig.APSTA == true)
    {
      temp += "<input type='text' name='APPointName' maxlength='"+String(APSTANameLen-1)+"' size='30' value='" + String(MyWiFiConfig.APSTAName) + "'></td>";
    } else
    {
      temp += "<input type='text' name='APPointName' maxlength='"+String(APSTANameLen-1)+"' size='30' ></td>";
    }
  server.sendContent(temp);
  temp = "";       
  if (MyWiFiConfig.APSTA == true)
    {
      temp += "</tr></th><td>WiFi Password: </td><td>";
      temp += "<input type='password' name='APPW' maxlength='"+String(WiFiPwdLen-1)+"' size='30' value='" + String(MyWiFiConfig.WiFiPwd) + "'> </td>";
      temp += "</tr></th><td>Repeat WiFi Password: </td>";
      temp += "<td><input type='password' name='APPWRepeat' maxlength='"+String(WiFiPwdLen-1)+"' size='30' value='" + String(MyWiFiConfig.WiFiPwd) + "'> </td>";
    } else
    {
      temp += "</tr></th><td>WiFi Password: </td><td>";
      temp += "<input type='password' name='APPW' maxlength='"+String(WiFiPwdLen-1)+"' size='30'> </td>";
      temp += "</tr></th><td>Repeat WiFi Password: </td>";
      temp += "<td><input type='password' name='APPWRepeat' maxlength='"+String(WiFiPwdLen-1)+"' size='30'> </td>";
    }
      temp += "</table>";
  server.sendContent(temp);
  temp = "";      
  if (MyWiFiConfig.PwDReq)
    {
      temp += "<input type='checkbox' name='PasswordReq' checked> Password for Login required. "; 
    } else
    {
      temp += "<input type='checkbox' name='PasswordReq' > Password for Login required. "; 
    }
  server.sendContent(temp);
  temp = "";  
  if (MyWiFiConfig.CapPortal)
    {
      temp += "<input type='checkbox' name='CaptivePortal' checked> Activate Captive Portal"; 
    } else
    {
      temp += "<input type='checkbox' name='CaptivePortal' > Activate Captive Portal"; 
    }
  server.sendContent(temp);
  temp = "";  
  temp += "<br></tr></th></table><br> <button type='submit' name='Settings' value='1' style='height: 50px; width: 140px' autofocus>Set WiFi Settings</button>";
  temp += "<button type='submit' name='Reboot' value='1' style='height: 50px; width: 200px' >Reboot System</button>";
  server.sendContent(temp);
  temp = "";
  temp += "<button type='reset' name='action' value='1' style='height: 50px; width: 100px' >Reset</button></form>";
  temp += "<table border=2 bgcolor = white width = 500 cellpadding =5 ><caption><p><h3>Systemlinks:</h2></p></caption><tr><th><br>";
  server.sendContent(temp);
  temp = "";
  temp += "<a href='/'>Main Page</a><br><br></th></tr></table><br><br>";
  temp += "<footer><p>Programmed and designed by: Tobias Kuch</p><p>Contact information: <a href='mailto:tobias.kuch@googlemail.com'>tobias.kuch@googlemail.com</a>.</p></footer>";
  temp += "</body></html>";  
  server.sendContent(temp);
  server.client().stop(); // Stop is needed because we sent no content length
  temp = "";
}


/** Is this an IP? */
boolean isIp(String str) {
  for (int i = 0; i < str.length(); i++) {
    int c = str.charAt(i);
    if (c != '.' && (c < '0' || c > '9')) {
      return false;
    }
  }
  return true;
}

String GetEncryptionType(byte thisType) {
  String Output = "";
   // read the encryption type and print out the name:
   switch (thisType) {
     case 5:
       Output = "WEP";
       return Output;
       break;
     case 2:
       Output = "WPA";
       return Output;
       break;
     case 4:
       Output = "WPA2";
       return Output;
       break;
     case 7:
       Output = "None";
       return Output;
       break;
     case 8:
       Output = "Auto";
       return Output;
      break;
   }
}

/** IP to String? */
String toStringIp(IPAddress ip) {
  String res = "";
  for (int i = 0; i < 3; i++) {
    res += String((ip >> (8 * i)) & 0xFF) + ".";
  }
  res += String(((ip >> 8 * 3)) & 0xFF);
  return res;
}

String formatBytes(size_t bytes) {            // lesbare Anzeige der Speichergrößen
   if (bytes < 1024) {
     return String(bytes) + " Byte";
   } else if (bytes < (1024 * 1024)) {
     return String(bytes / 1024.0) + " KB";
   } else if (bytes < (1024 * 1024 * 1024)) {
     return String(bytes / 1024.0 / 1024.0) + " MB";
   }
 }

void loop() 
 {  
  if (SoftAccOK)
  {
    dnsServer.processNextRequest(); //DNS
  }
  //HTTP
  server.handleClient();  
  }