captive portal support for AccessPoint

CivicTechTO · Mar 8, 2024 · e119ff6 · e119ff6
1 parent 7fda1e6
commit e119ff6
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Showing 3 changed files with 73 additions and 40 deletions.
diff --git a/noisemeter-device/access-point.cpp b/noisemeter-device/access-point.cpp
@@ -16,10 +16,9 @@
     "</body>" \
     "</html>"
 
-// The ESP32's IP address within its access point will be "4.3.2.1".
-// Once connected to the access point, open up 4.3.2.1 in a browser to get
-// to the credentials form.
-const IPAddress AccessPoint::IP (4, 3, 2, 1);
+constexpr int DNSPort = 53;
+
+const IPAddress AccessPoint::IP (8, 8, 4, 4);
 const IPAddress AccessPoint::Netmask (255, 255, 255, 0);
 
 // Main webpage HTML with form to collect WiFi credentials.
@@ -42,37 +41,72 @@ const char *AccessPoint::htmlSubmit =
     "<p>Connecting...</p>"
     HTML_FOOTER;
 
-void AccessPoint::begin()
+[[noreturn]]
+void AccessPoint::run()
 {
     WiFi.mode(WIFI_AP);
     WiFi.softAPConfig(IP, IP, Netmask);
     WiFi.softAP(SSID, Passkey);
 
-    // GET request means user wants to see the form.
-    // POST request means user has submitted data through the form.
-    server.on("/", HTTP_GET,
-        [this] { server.send_P(200, PSTR("text/html"), htmlSetup); });
-    server.on("/", HTTP_POST,
-        [this] {
-            server.client().setNoDelay(true);
-            server.send_P(200, PSTR("text/html"), htmlSubmit);
-            if (funcOnCredentialsReceived)
-                funcOnCredentialsReceived(server);
-        });
+    dns.start(DNSPort, "*", IP);
+
+    server.addHandler(this);
     server.begin();
 
     SERIAL.println("Running setup access point.");
+
+    while (1) {
+        dns.processNextRequest();
+        server.handleClient();
+        delay(10);
+    }
 }
 
-[[noreturn]]
-void AccessPoint::run()
+bool AccessPoint::canHandle(HTTPMethod, String)
 {
-    while (1)
-        server.handleClient();
+    return true;
 }
 
-void AccessPoint::onCredentialsReceived(void (*func)(WebServer&))
+bool AccessPoint::handle(WebServer& server, HTTPMethod method, String uri)
 {
-    funcOnCredentialsReceived = func;
+    if (method == HTTP_POST) {
+        if (uri == "/") {
+            server.client().setNoDelay(true);
+            server.send_P(200, PSTR("text/html"), htmlSubmit);
+            if (onCredentialsReceived)
+                onCredentialsReceived(server);
+        } else {
+            server.sendHeader("Location", "http://8.8.4.4/");
+            server.send(301);
+        }
+    } else if (method == HTTP_GET) {
+        // Redirects taken from https://github.com/CDFER/Captive-Portal-ESP32
+
+        if (uri == "/") {
+            server.send_P(200, PSTR("text/html"), htmlSetup);
+        } else if (uri == "/connecttest.txt") {
+            // windows 11 captive portal workaround
+            server.sendHeader("Location", "http://logout.net");
+            server.send(301);
+        } else if (uri == "/wpad.dat") {
+            // Honestly don't understand what this is but a 404 stops win 10
+            // keep calling this repeatedly and panicking the esp32 :)
+            server.send(404);
+        } else if (uri == "/success.txt") {
+            // firefox captive portal call home
+            server.send(200);
+        } else if (uri == "/favicon.ico") {
+            // return 404 to webpage icon
+            server.send(404);
+        } else {
+            server.sendHeader("Location", "http://8.8.4.4/");
+            server.send(301);
+        }
+    } else {
+        server.sendHeader("Location", "http://8.8.4.4/");
+        server.send(301);
+    }
+
+    return true;
 }
 
diff --git a/noisemeter-device/access-point.h b/noisemeter-device/access-point.h
@@ -1,30 +1,32 @@
 #ifndef ACCESS_POINT_H
 #define ACCESS_POINT_H
 
+#include <DNSServer.h>
 #include <WebServer.h>
 
-class AccessPoint
+class AccessPoint : public RequestHandler
 {
     static constexpr auto SSID = "Noise meter";
     static constexpr auto Passkey = "noisemeter";
-    // IP address set in access-point.cpp
 
 public:
-    AccessPoint():
-        server(80), funcOnCredentialsReceived(nullptr) {}
+    // Begins hosting a WiFi access point with the credentials form as a
+    // captive portal.
+    AccessPoint(void (*func)(WebServer&)):
+        server(80),
+        onCredentialsReceived(func) {}
 
-    // Configure the WiFi radio to be an access point.
-    void begin();
-
-    // Enter main loop for executing the access point and web server.
+    // Enters an infinite loop to handle the access point and web server.
     [[noreturn]] void run();
 
-    // Set handler for reception of WiFi credentials.
-    void onCredentialsReceived(void (*func)(WebServer&));
+    // RequestHandler implementation for web server functionality.
+    bool canHandle(HTTPMethod, String) override;
+    bool handle(WebServer&, HTTPMethod, String) override;
 
 private:
+    DNSServer dns;
     WebServer server;
-    void (*funcOnCredentialsReceived)(WebServer&);
+    void (*onCredentialsReceived)(WebServer&);
 
     static const IPAddress IP;
     static const IPAddress Netmask;

diff --git a/noisemeter-device/noisemeter-device.ino b/noisemeter-device/noisemeter-device.ino
@@ -160,16 +160,13 @@ void setup() {
 #ifndef UPLOAD_DISABLED
   // Run the access point if it is requested or if there are no valid credentials.
   bool resetPressed = !digitalRead(PIN_BUTTON);
-  if (resetPressed || !Creds.valid()) {
-    AccessPoint ap;
+  if (resetPressed || !Creds.valid() || Creds.get(Storage::Entry::SSID).isEmpty()) {
+    AccessPoint ap (saveNetworkCreds);
 
-    SERIAL.println("Erasing stored credentials...");
+    SERIAL.print("Erasing stored credentials...");
     Creds.clear();
-    SERIAL.print("Stored Credentials after erasing: ");
-    SERIAL.println(Creds);
+    SERIAL.println(" done.");
 
-    ap.onCredentialsReceived(saveNetworkCreds);
-    ap.begin();
     ap.run(); // does not return
   }