Update: 2020-05-21

Esp8266 Admin als Arduino Tab.

Die Spiffs.ino ist zum ausführen der Admin.ino erforderlich.

Admin.ino

// ****************************************************************
// Sketch Esp8266 Admin Modular(Tab)
// created: Jens Fleischer, 2018-05-09
// last mod: Jens Fleischer, 2019-04-16
// For more information visit: https://fipsok.de
// ****************************************************************
// Hardware: Esp8266
// Software: Esp8266 Arduino Core 2.4.2 / 2.5.0 / 2.5.2
// Geprüft: von 1MB bis 16MB Flash
// Getestet auf: Nodemcu, Wemos D1 Mini Pro, Sonoff Switch, Sonoff Dual
/******************************************************************
  Copyright (c) 2018 Jens Fleischer. All rights reserved.

  This file is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.
  This file is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.
*******************************************************************/
// Diese Version von Admin sollte als Tab eingebunden werden.
// #include <FS.h> #include <ESP8266WebServer.h> müssen im Haupttab aufgerufen werden
// Die Funktionalität des ESP8266 Webservers ist erforderlich.
// Die Spiffs.ino muss im ESP8266 Webserver enthalten sein
// Funktion "admin();" muss im setup() nach spiffs() aber vor dem Verbindungsaufbau aufgerufen werden.
// Die Funktion "runtime();" muss mindestens zweimal innerhalb 49 Tage aufgerufen werden.
// Entweder durch den Client(Webseite) oder zur Sicherheit im "loop();"
/**************************************************************************************/

const char* const PROGMEM flashChipMode[] = {"QIO", "QOUT", "DIO", "DOUT", "Unbekannt"};

void admin() {                          // Funktionsaufruf "admin();" muss im Setup eingebunden werden
  File file = SPIFFS.open("/config.json", "r");
  if (file) {
    String newhostname = file.readStringUntil('\n');
    if (newhostname != "") {
      WiFi.hostname(newhostname.substring(1, newhostname.length() - 1));
      file.close();
      ArduinoOTA.setHostname(WiFi.hostname().c_str());
    }
  }
  server.on("/admin/renew", handlerenew);
  server.on("/admin/once", handleonce);
  server.on("/reconnect", []() {
    server.send(204, "", "");
    WiFi.reconnect();
  });
  server.on("/restart", []() {
    server.send(204, "", "");
    //speichern();      //Wenn Werte vor dem Neustart gespeichert werden sollen
    ESP.restart();
  });
}

//Es kann entweder die Spannung am ADC-Pin oder die Modulversorgungsspannung (VCC) ausgegeben werden.

void handlerenew() {    // Um die am ADC-Pin anliegende externe Spannung zu lesen, verwende analogRead (A0)
  server.send(200, "application/json", "[\"" + runtime() + "\",\"" + WiFi.RSSI() + "\",\"" + analogRead(A0) + "\"]");     // Json als Array
}
/*
  ADC_MODE(ADC_VCC);
  void handlerenew() {   // Zum Lesen der Modulversorgungsspannung (VCC), verwende ESP.getVcc()
  server.send(200, "application/json", "[\"" + runtime() + "\",\"" + WiFi.RSSI() + "\",\"" + ESP.getVcc() + "\"]");     // Json als Array
  }
*/
void handleonce() {
  if (server.arg(0) != "") {
    WiFi.hostname(server.arg(0));
    File f = SPIFFS.open("/config.json", "w");                    // Datei zum schreiben öffnen
    f.printf("\"%s\"\n", WiFi.hostname().c_str());
    f.close();
  }
  char *pos = strrchr((__FILE__), strstr (__FILE__, "\\") ? '\\' : '/');  *pos = '\0';
  String temp = "{\"File\":\"" + String(__FILE__).substring(String(__FILE__).lastIndexOf (strstr (__FILE__, "\\") ? '\\' : '/') + 1, String(__FILE__).length()) +
                "\", \"Build\":\"" +  String(__DATE__) + " " + String(__TIME__) + "\", \"SketchSize\":\"" + formatBytes(ESP.getSketchSize()) +
                "\", \"SketchSpace\":\"" + formatBytes(ESP.getFreeSketchSpace()) + "\", \"LocalIP\":\"" +  WiFi.localIP().toString() +
                "\", \"Hostname\":\"" + WiFi.hostname() + "\", \"SSID\":\"" + WiFi.SSID() + "\", \"GatewayIP\":\"" +  WiFi.gatewayIP().toString() +
                "\", \"Channel\":\"" +  WiFi.channel() + "\", \"MacAddress\":\"" +  WiFi.macAddress() + "\", \"SubnetMask\":\"" +  WiFi.subnetMask().toString() +
                "\", \"BSSID\":\"" +  WiFi.BSSIDstr() + "\", \"ClientIP\":\"" + server.client().remoteIP().toString() + "\", \"DnsIP\":\"" + WiFi.dnsIP().toString() +
                "\", \"ResetReason\":\"" + ESP.getResetReason() + "\", \"CpuFreqMHz\":\"" + F_CPU / 1000000 + "\", \"FreeHeap\":\"" + formatBytes(ESP.getFreeHeap()) +
                "\", \"ChipSize\":\"" +  formatBytes(ESP.getFlashChipSize()) + "\", \"ChipSpeed\":\"" + ESP.getFlashChipSpeed() / 1000000 +
                "\", \"ChipMode\":\"" + flashChipMode[ESP.getFlashChipMode()] + "\", \"IdeVersion\":\"" + ARDUINO +
                "\", \"CoreVersion\":\"" + ESP.getCoreVersion() + "\", \"SdkVersion\":\"" + ESP.getSdkVersion()+ "\"}";
  server.send(200, "application/json", temp);     // Json als Objekt
}

String runtime() {
  static uint8_t rolloverCounter = 0;
  static uint32_t letzteMillis = 0;
  uint32_t aktuelleMillis = millis();
  if (aktuelleMillis < letzteMillis) {       // prüft Millis Überlauf
    rolloverCounter++;
  }
  letzteMillis = aktuelleMillis;
  uint32_t sek = (0xFFFFFFFF / 1000 ) * rolloverCounter + (aktuelleMillis / 1000);
  char buf[20];
  snprintf(buf, sizeof(buf), sek < 86400 || sek > 172800 ? "%d Tage %02d:%02d:%02d" : "%d Tag %02d:%02d:%02d", sek / 86400, sek / 3600 % 24, sek / 60 % 60, sek % 60);
  return buf;
}

Die Funktion "runtime();" muss mindestens zweimal innerhalb 49 Tage aufgerufen werden.
Entweder durch den Client(Webseite) oder besser im loop().

Beispiel:

*************** Aufruf runtime() ******************

void loop() {
 ......
 .........
  if (millis() < 0x2FFF || millis() > 0xFFFFF0FF) {
    runtime();
  }
 ......
}

Das Webinterface zum Esp8266 Admin Tab.

admin.html

<!DOCTYPE HTML> <!-- For more information visit: https://fipsok.de -->
<html lang="de">
   <head>
      <meta charset="UTF-8">
      <meta name="viewport" content="width=device-width, initial-scale=1">
      <link rel="stylesheet" href="style.css">
      <title>ESP8266 Admin</title>
      <script>
        window.addEventListener('load', () => {
		  renew(),once();
		  let output = document.querySelector('#note');
		  let button = document.querySelectorAll('button');
		  let span = document.querySelectorAll('#right span'); 
          button[0].addEventListener('click', () => {
            window.location = '/spiffs.html';
          });
          button[1].addEventListener('click', () => {
            window.location = '/';
          });
          button[2].addEventListener('click', check.bind(this, document.querySelector('input')));
		  button[3].addEventListener('click', re.bind(this, 'reconnect'));
		  button[4].addEventListener('click', () => {
            if (confirm('Bist du sicher!')) re('restart');
          });
          function once(arg1,arg2) {
            fetch('/admin/once', {
              method: 'POST',
              body: arg1
            }).then( (resp) => {
              return resp.json();
            }).then( (obj) => {
              output.innerHTML = '';
              output.classList.remove('note');
              document.querySelector('form').reset();
              if (arg1 == undefined) myIv = setInterval(renew, 1000);
              if (arg2 == 'reconnect') re(arg2);
			  span[3].innerHTML = obj['File'];
              span[4].innerHTML = obj['Build'];
              span[5].innerHTML = obj['SketchSize'];
              span[6].innerHTML = obj['SketchSpace'];
              span[7].innerHTML = obj['LocalIP'];		  
			  span[8].innerHTML = obj['Hostname'];
              span[9].innerHTML = obj['SSID'];
              span[10].innerHTML = obj['GatewayIP'];
              span[11].innerHTML = obj['Channel'];
              span[12].innerHTML = obj['MacAddress'];
              span[13].innerHTML = obj['SubnetMask'];
              span[14].innerHTML = obj['BSSID'];
              span[15].innerHTML = obj['ClientIP'];
              span[16].innerHTML = obj['DnsIP'];
              span[17].innerHTML = obj['ResetReason'];
              span[18].innerHTML = obj['CpuFreqMHz'] + " MHz";
			  span[19].innerHTML = obj['FreeHeap'];
              span[20].innerHTML = obj['ChipSize'];
              span[21].innerHTML = obj['ChipSpeed'] + " MHz";
              span[22].innerHTML = obj['ChipMode'];
			  span[23].innerHTML = obj['IdeVersion'].replace(/(\d)(\d)(\d)(\d)/,obj['IdeVersion'][3]!=0 ? '$1.$3.$4' : '$1.$3.');
              span[24].innerHTML = obj['CoreVersion'].replace(/_/g,'.');
              span[25].innerHTML = obj['SdkVersion'];
            }).catch(function(err) {
              re();
            });   
          }
          function renew() {
            fetch('admin/renew').then( (resp) => {
              return resp.json();
            }).then( (array) => {
			  array.forEach((x, i) => {
                span[i].innerHTML = x
              });
            }); 
          }
          function check(inObj) {
            !inObj.checkValidity() ? (output.innerHTML = inObj.validationMessage, output.classList.add('note')) : (once(inObj.value, 'reconnect'));
          }
          function re(arg) {
            clearInterval(myIv);
            fetch(arg);
            output.classList.add('note');
            if (arg == 'restart') {
              output.innerHTML = 'Der Server wird neu gestartet. Die Daten werden in 15 Sekunden neu geladen.';
              setTimeout(once, 15000);
            } 
            else if (arg == 'reconnect'){
              output.innerHTML = 'Die WiFi Verbindung wird neu gestartet. Daten werden in 10 Sekunden neu geladen.';
              setTimeout(once, 10000);
            }
            else {
              output.innerHTML = 'Es ist ein Verbindungfehler aufgetreten. Es wird versucht neu zu verbinden.';
              setTimeout(once, 3000);
            }
          }
        });
      </script>
    </head>
    <body>
      <h1>ESP8266 Admin Page</h1>
      <main>
         <aside id="left">
            <span>Runtime ESP:</span>
            <span>WiFi RSSI:</span>
            <span>ADC/VCC:</span>
            <span>Sketch Name:</span>
            <span>Sketch Build:</span>
            <span>SketchSize:</span>
            <span>FreeSketchSpace:</span>
            <span>IPv4 Address:</span>
            <span>Hostname:</span>
            <span>Connected to:</span>
            <span>Gateway IP:</span>
            <span>Channel:</span>
            <span>MacAddress:</span>
            <span>SubnetMask:</span>
            <span>BSSID:</span>	  
            <span>Client IP:</span>
            <span>DnsIP:</span>
            <span>Reset Ground:</span>
            <span>CPU Freq:</span>
            <span>FreeHeap:</span>	   
            <span>FlashSize:</span>
            <span>FlashSpeed:</span>
            <span>FlashMode:</span>
			<span>Arduino IDE Version:</span>
            <span>Esp Core Version:</span>
            <span>SDK Version:</span>
         </aside>
         <aside id="right">
            <span>0</span>
            <div>
               <span></span>
               dBm
            </div>
            <span>0</span>
            <span>?</span>
            <span>0</span>
            <span>0</span>
			<span>0</span>
            <span>0</span>
            <span>?</span>
            <span>?</span>
            <span>0</span>
            <span>0</span>
            <span>0</span>
            <span>0</span>
            <span>0</span>
            <span>?</span>
            <span>0</span>
            <span>0</span>
            <span>0</span>
            <span>0</span>
			<span>0</span>
			<span>0</span>
            <span>0</span>
            <span>0</span>
			<span>0</span>
			<span>0</span>
         </aside>
      </main>
      <div>
         <button>Spiffs</button>
         <button>Startseite</button>
      </div>
      <div id="note"></div>
      <div>
         <form>
		   <input placeholder=" neuer Hostname" pattern="([A-Za-z0-9-]{1,32})" title="Es dürfen nur Buchstaben 
		   (a-z, A-Z), Ziffern (0-9) und Bindestriche (-) enthalten sein. Maximal 32 Zeichen" required>
           <button type="button">Name Senden</button>
         </form>
      </div>
      <div>
         <button>WiFi Reconnect</button>
         <button>ESP Restart</button>
      </div>
   </body>
</html>

Für die Darstellung ist die style.css analog Spiffs Verwaltung, erforderlich.

style.css

/* For more information visit:https://fipsok.de */
body {
	font-family: sans-serif;
	background-color: #87cefa;
	display: flex;
	flex-flow: column;
	align-items: center;
}
h1,h2 {
	color: #e1e1e1;
	text-shadow: 2px 2px 2px black;
}
li {
  background-color: #feb1e2;
  list-style-type: none;
  margin-bottom: 10px;
  padding: 2px 5px 1px 0;
  box-shadow: 5px 5px 5px rgba(0,0,0,0.7);
}
li a:first-child, li b:first-child {
  background-color: #8f05a5;
  font-weight: bold;
  color: white;
  text-decoration:none;
  padding: 2px 5px;
  text-shadow: 2px 2px 1px black;
}
input {
	height:35px;
	font-size:14px;
}
h1 + main {
  display: flex;
}  
aside {
  display: flex;
  flex-direction: column;
  padding: 0.2em;
}
#left {
  align-items:flex-end;
  text-shadow: 0.5px 0.5px 1px #757474;
}
.note {
	background-color: #fecdee;
	padding: 0.5em;
	margin-top: 1em;
	text-align: center;
	max-width: 320px;
	border-radius: 0.5em;
}
[type=submit] {
	height:40px; 
	font-size: 16px;
}
[value*=Format] {
	margin-top: 1em;
	box-shadow: 5px 5px 5px rgba(0,0,0,0.7);
}
button {
	height:40px;
	width:130px;
	background-color: #7bff97;
	font-size:16px;
	margin-top: 1em;
	box-shadow: 5px 5px 5px rgba(0,0,0,0.7);
}
form [title] {
	background-color: skyblue;
	font-size: 16px;
	width: 125px;
}