Add simple WiFiMulti support (#771)

Takes a list of APs, finds the one with highest RSSI, and tries to connect.

Author: earlephilhower

libraries/WiFi/examples/WiFiClient/WiFiClient.ino

@@ -16,6 +16,8 @@ const char* password = STAPSK;
 const char* host = "djxmmx.net";
 const uint16_t port = 17;
 
+WiFiMulti multi;
+
 void setup() {
   Serial.begin(115200);
 
@@ -26,11 +28,12 @@ void setup() {
   Serial.print("Connecting to ");
   Serial.println(ssid);
 
-  WiFi.begin(ssid, password);
+  multi.addAP(ssid, password);
 
-  while (WiFi.status() != WL_CONNECTED) {
-    delay(500);
-    Serial.print(".");
+  if (multi.run() != WL_CONNECTED) {
+    Serial.println("Unable to connect to network, rebooting in 10 seconds...");
+    delay(10000);
+    rp2040.reboot();
   }
 
   Serial.println("");

libraries/WiFi/keywords.txt

@@ -13,6 +13,7 @@ WiFiClient	KEYWORD1
 WiFiSSLClient	KEYWORD1
 WiFiServer	KEYWORD1
 WiFiUDP	KEYWORD1
+WiFiMulti	KEYWORD1
 NTP	KEYWORD1
 
 
@@ -48,6 +49,7 @@ parsePacket	KEYWORD2
 remoteIP	KEYWORD2
 remotePort	KEYWORD2
 mode	KEYWORD2
+addAP	KEYWORD2
 
 beginAP	KEYWORD2
 beginEnterprise	KEYWORD2

libraries/WiFi/src/WiFi.h

@@ -12,4 +12,6 @@
 #include "WiFiServerSecure.h"
 #include "WiFiUdp.h"
 
+#include "WiFiMulti.h"
+
 #include "WiFiNTP.h"

libraries/WiFi/src/WiFiClient.h

@@ -23,7 +23,6 @@
 #pragma once
 
 #include <memory>
-#include "WiFi.h"
 #include "Print.h"
 #include "Client.h"
 #include "IPAddress.h"

libraries/WiFi/src/WiFiMulti.cpp

@@ -0,0 +1,90 @@
+/*
+    WiFiMulti.cpp - Choose best RSSI and connect
+    Copyright (c) 2022 Earle F. Philhower, III
+
+    This library 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 library 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.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+    Modified by Ivan Grokhotkov, January 2015 - esp8266 support
+*/
+
+#include "WiFi.h"
+#include <string.h>
+#include <algorithm>
+
+WiFiMulti::WiFiMulti() {
+}
+
+WiFiMulti::~WiFiMulti() {
+    while (!_list.empty()) {
+        struct _AP ap = _list.front();
+        _list.pop_front();
+        free(ap.ssid);
+        free(ap.pass);
+    }
+}
+
+bool WiFiMulti::addAP(const char *ssid, const char *pass) {
+    struct _AP ap;
+    ap.ssid = strdup(ssid);
+    if (!ap.ssid) {
+        return false;
+    }
+    if (pass) {
+        ap.pass = strdup(pass);
+        if (!ap.pass) {
+            free(ap.ssid);
+            return false;
+        }
+    } else {
+        ap.pass = nullptr;
+    }
+    _list.push_front(ap);
+    return true;
+}
+
+uint8_t WiFiMulti::run(uint32_t to) {
+    int cnt = WiFi.scanNetworks();
+    if (!cnt) {
+        return WL_DISCONNECTED;
+    }
+
+    // Find the highest RSSI network in our list.  Probably more efficient searches, but the list
+    // of APs will have < 5 in > 99% of the cases so it's a don't care.
+    int maxRSSID = -999;
+    std::list<struct _AP>::iterator hit;
+    bool found = false;
+    for (int i = 0; i < cnt; i++) {
+        if (WiFi.RSSI(i) > maxRSSID) {
+            for (auto j = _list.begin(); j != _list.end(); j++) {
+                if (!strcmp(j->ssid, WiFi.SSID(i))) {
+                    hit = j;
+                    maxRSSID = WiFi.RSSI(i);
+                    found = true;
+                }
+            }
+        }
+    }
+    if (!found) {
+        return WL_DISCONNECTED;
+    }
+
+    // Connect!
+    uint32_t start = millis();
+    WiFi.begin(hit->ssid, hit->pass);
+    while (!WiFi.connected() && (millis() - start < to)) {
+        delay(5);
+    }
+    return WiFi.status();
+}

libraries/WiFi/src/WiFiMulti.h

@@ -0,0 +1,43 @@
+/*
+    WiFiMulti.h - Choose best RSSI and connect
+    Copyright (c) 2022 Earle F. Philhower, III
+
+    This library 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 library 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.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+    Modified by Ivan Grokhotkov, January 2015 - esp8266 support
+*/
+
+#pragma once
+
+#include <list>
+#include <stdint.h>
+#include "wl_definitions.h"
+
+class WiFiMulti {
+public:
+    WiFiMulti();
+    ~WiFiMulti();
+
+    bool addAP(const char *ssid, const char *pass = NULL);
+
+    uint8_t run(uint32_t to = 5000);
+
+private:
+    struct _AP {
+        char *ssid;
+        char *pass;
+    };
+    std::list<struct _AP> _list;
+};