Add automatic connection multiplexing

examples/MultipleConnections/MultipleConnections.ino

@@ -0,0 +1,79 @@
+/**
+ * This example shows how to use the connection management features of the ArduinoCellular library
+ * to maintain multiple HTTP and HTTPS clients.
+ * This is useful if e.g. you want to use ArduinoIoTCloud or other services that require
+ * a dedicated client while making custom HTTP requests to other servers.
+ *
+ * Instructions:
+ * 1. Insert a SIM card with or without PIN code in the Arduino Pro 4G Module.
+ * 2. Provide sufficient power to the Arduino Pro 4G Module. Ideally, use a 5V power supply
+ *   with a current rating of at least 2A and connect it to the VIN and GND pins.
+ * 3. Specify the APN, login, and password for your cellular network provider.
+ * 4. Upload the sketch to the connected Arduino board.
+ * 5. Open the serial monitor to view the output.
+ * 
+ * Initial author: Sebastian Romero
+*/
+
+#include <Arduino.h>
+#include "ArduinoCellular.h"
+#include <ArduinoHttpClient.h>
+
+#define SECRET_PINNUMBER ""
+#define SECRET_GPRS_LOGIN ""
+#define SECRET_GPRS_APN "gprs.swisscom.ch"
+#define SECRET_GPRS_PASSWORD ""
+
+constexpr int  SSL_PORT = 443;
+
+ArduinoCellular cellular = ArduinoCellular();
+
+void getResource(HttpClient &client, const char *resource) {
+    Serial.println("Making GET request...");
+    client.get(resource);
+    int statusCode = client.responseStatusCode();   
+
+    if (statusCode < 0) {
+        Serial.print("Error Response Code: ");
+        Serial.println(statusCode);
+        return;
+    }
+    Serial.print("Response: ");
+    Serial.println(client.responseBody()); 
+}
+
+
+void setup(){
+    Serial.begin(115200);
+    while (!Serial);
+
+    cellular.begin();
+
+    if(String(SECRET_PINNUMBER).length() > 0 && !cellular.unlockSIM(SECRET_PINNUMBER)){
+        Serial.println("Failed to unlock SIM card.");
+        while(true); // Stop here
+    }
+
+    Serial.println("Connecting...");
+    if(!cellular.connect(SECRET_GPRS_APN, SECRET_GPRS_LOGIN, SECRET_GPRS_PASSWORD)){
+        Serial.println("Failed to connect to the network.");
+        while(true); // Stop here
+    }
+    Serial.println("Connected!");
+
+    HttpClient client1 = cellular.getHTTPSClient("vsh.pp.ua", SSL_PORT);
+    HttpClient client2 = cellular.getHTTPSClient("wttr.in", SSL_PORT);
+    Serial.print("Managed client count: ");
+    Serial.println(cellular.getManagedClientCount());
+
+    getResource(client1, "/TinyGSM/logo.txt");
+    getResource(client2, "/?format=3");
+    client1.stop();
+    client2.stop();
+    cellular.cleanup(); // Clean up connections after use
+
+    Serial.print("Managed client count: ");
+    Serial.println(cellular.getManagedClientCount());
+}
+
+void loop(){}

src/ArduinoCellular.cpp

@@ -1,22 +1,27 @@
 
 
 #include "ArduinoCellular.h"
+
 #if defined(ARDUINO_ARCH_MBED)
   #include "Watchdog.h"
 #endif
 
 unsigned long ArduinoCellular::getTime() {
     int year, month, day, hour, minute, second;
     float tz;
-    modem.getNetworkTime(&year, &month, &day, &hour, &minute, &second, &tz);
+    Modem.getNetworkTime(&year, &month, &day, &hour, &minute, &second, &tz);
     return Time(year, month, day, hour, minute, second).getUNIXTimestamp();
 }
 
 ArduinoCellular::ArduinoCellular() {
 }
 
+ArduinoCellular::~ArduinoCellular() {
+    cleanup();
+}
+
 void ArduinoCellular::begin() {
-    modem.init();
+    Modem.init();
 
     String modemInfo = this ->sendATCommand("I");
     if(modemInfo.indexOf("EC200A") > 0){
@@ -28,15 +33,15 @@ void ArduinoCellular::begin() {
     }
 
     // Set GSM module to text mode
-    modem.sendAT("+CMGF=1");
-    modem.waitResponse();
+    Modem.sendAT("+CMGF=1");
+    Modem.waitResponse();
 
-    modem.sendAT(GF("+CSCS=\"GSM\""));
-    modem.waitResponse();
+    Modem.sendAT(GF("+CSCS=\"GSM\""));
+    Modem.waitResponse();
 
     // Send intrerupt when SMS has been received
-    modem.sendAT("+CNMI=2,1,0,0,0");
-    modem.waitResponse();
+    Modem.sendAT("+CNMI=2,1,0,0,0");
+    Modem.waitResponse();
 
 #if defined(ARDUINO_CELLULAR_BEARSSL)
     ArduinoBearSSL.onGetTime(ArduinoCellular::getTime);
@@ -103,7 +108,7 @@ Geolocation ArduinoCellular::getGPSLocation(unsigned long timeout){
         unsigned long startTime = millis();
 
         while((latitude == 0.00000 || longitude == 0.00000) && (millis() - startTime < timeout)) {
-            modem.getGPS(&latitude, &longitude);
+            Modem.getGPS(&latitude, &longitude);
             delay(1000);
         }
 
@@ -122,7 +127,7 @@ Geolocation ArduinoCellular::getGPSLocation(unsigned long timeout){
 
 Time ArduinoCellular::getGPSTime(){
     int year, month, day, hour, minute, second;
-    modem.getGPSTime(&year, &month, &day, &hour, &minute, &second);
+    Modem.getGPSTime(&year, &month, &day, &hour, &minute, &second);
     return Time(year, month, day, hour, minute, second);
 }
 
@@ -134,22 +139,22 @@ Time ArduinoCellular::getCellularTime(){
     int minute = 0;
     int second = 0;
     float tz;
-    if (modem.NTPServerSync() == 0) {
-      modem.getNetworkTime(&year, &month, &day, &hour, &minute, &second, &tz);
+    if (Modem.NTPServerSync() == 0) {
+      Modem.getNetworkTime(&year, &month, &day, &hour, &minute, &second, &tz);
     }
     return Time(year, month, day, hour, minute, second);
 }
 
 
 void ArduinoCellular::sendSMS(String number, String message){
-    modem.sendAT("+CMGF=1"); 
-    modem.waitResponse(1000);
-    modem.sendAT(GF("+CMGS=\""), number, GF("\""));
-    if (modem.waitResponse(GF(">")) != 1) { }
-    modem.stream->print(message);  // Actually send the message
-    modem.stream->write(static_cast<char>(0x1A));  // Terminate the message
-    modem.stream->flush();
-    auto response = modem.waitResponse(10000L);
+    Modem.sendAT("+CMGF=1"); 
+    Modem.waitResponse(1000);
+    Modem.sendAT(GF("+CMGS=\""), number, GF("\""));
+    if (Modem.waitResponse(GF(">")) != 1) { }
+    Modem.stream->print(message);  // Actually send the message
+    Modem.stream->write(static_cast<char>(0x1A));  // Terminate the message
+    Modem.stream->flush();
+    auto response = Modem.waitResponse(10000L);
 
     if(this->debugStream != nullptr){
         this->debugStream->println("Response: " + String(response));
@@ -158,40 +163,60 @@ void ArduinoCellular::sendSMS(String number, String message){
 
 
 IPAddress ArduinoCellular::getIPAddress(){
-    return modem.localIP();
+    return Modem.localIP();
 }
 
 int ArduinoCellular::getSignalQuality(){
-    return modem.getSignalQuality();
+    return Modem.getSignalQuality();
 }
 
 TinyGsmClient ArduinoCellular::getNetworkClient(){
-    return TinyGsmClient(modem);
+    return ManagedTinyGsmClient(Modem);
 }
 
 HttpClient ArduinoCellular::getHTTPClient(const char * server, const int port){
-    return HttpClient(* new TinyGsmClient(modem), server, port);
+    return HttpClient(* new ManagedTinyGsmClient(Modem), server, port);
 }
 
 #if defined(ARDUINO_CELLULAR_BEARSSL)
 HttpClient ArduinoCellular::getHTTPSClient(const char * server, const int port){
-    return HttpClient(* new BearSSLClient(* new TinyGsmClient(modem)), server, port);
+    auto gsmClient = std::make_unique<ManagedTinyGsmClient>(Modem);
+    auto sslClient = std::make_unique<BearSSLClient>(*gsmClient);
+    auto& sslRef = *sslClient;
+
+    managedGsmClients.push_back(std::move(gsmClient));
+    managedSslClients.push_back(std::move(sslClient));
+    return HttpClient(sslRef, server, port);
 }
 
 BearSSLClient ArduinoCellular::getSecureNetworkClient(){
-    return BearSSLClient(* new TinyGsmClient(modem));
+    return BearSSLClient(* new ManagedTinyGsmClient(Modem));
 }
 #endif
 
+void ArduinoCellular::cleanup() {
+    /*
+    It's necessary to to manage the lifetime of the clients created by the library
+    because the HttpClient and also BearSSLClient classes expect callers to manage the lifetime of the clients.
+    For convenience, the library provides factory functions that allocate these objects on behalf of the caller.
+     */
+    managedSslClients.clear();  // Destroys BearSSLClient instances
+    managedGsmClients.clear();  // Destroys ManagedTinyGsmClient instances
+}
+
+size_t ArduinoCellular::getManagedClientCount() const {
+    return managedSslClients.size();
+}
+
 bool ArduinoCellular::isConnectedToOperator(){
-    return modem.isNetworkConnected();
+    return Modem.isNetworkConnected();
 }
 
 bool ArduinoCellular::connectToGPRS(const char * apn, const char * gprsUser, const char * gprsPass){
     if(this->debugStream != nullptr){
         this->debugStream->println("Connecting to 4G network...");
     }
-    while(!modem.gprsConnect(apn, gprsUser, gprsPass)) {
+    while(!Modem.gprsConnect(apn, gprsUser, gprsPass)) {
         if(this->debugStream != nullptr){
             this->debugStream->print(".");
         }
@@ -201,11 +226,11 @@ bool ArduinoCellular::connectToGPRS(const char * apn, const char * gprsUser, con
 }
 
 bool ArduinoCellular::isConnectedToInternet(){
-    return modem.isGprsConnected();
+    return Modem.isGprsConnected();
 }
 
 SimStatus ArduinoCellular::getSimStatus(){
-    int simStatus = modem.getSimStatus();
+    int simStatus = Modem.getSimStatus();
     if(this->debugStream != nullptr){
         this->debugStream->println("SIM Status: " + String(simStatus));
     }
@@ -224,12 +249,12 @@ SimStatus ArduinoCellular::getSimStatus(){
 }
 
 bool ArduinoCellular::unlockSIM(String pin){
-    int simStatus = modem.getSimStatus();
+    int simStatus = Modem.getSimStatus();
     if(simStatus == SIM_LOCKED) {
         if(this->debugStream != nullptr){
             this->debugStream->println("Unlocking SIM...");
         }
-        return modem.simUnlock(pin.c_str());
+        return Modem.simUnlock(pin.c_str());
     }
     else if(simStatus == SIM_ERROR || simStatus == SIM_ANTITHEFT_LOCKED) {
         return false;
@@ -242,7 +267,7 @@ bool ArduinoCellular::awaitNetworkRegistration(bool waitForever){
     if(this->debugStream != nullptr){
         this->debugStream->println("Waiting for network registration...");
     }
-    while (!modem.waitForNetwork(waitForNetworkTimeout)) {
+    while (!Modem.waitForNetwork(waitForNetworkTimeout)) {
 
         if(!waitForever) {
             return false;
@@ -283,13 +308,13 @@ bool ArduinoCellular::enableGPS(bool assisted){
         return false;
     }
 
-    return modem.enableGPS();
+    return Modem.enableGPS();
 }
 
 String ArduinoCellular::sendATCommand(const char * command, unsigned long timeout){
     String response;
-    modem.sendAT(command); 
-    modem.waitResponse(timeout, response);
+    Modem.sendAT(command); 
+    Modem.waitResponse(timeout, response);
     return response;
 }
 
@@ -401,7 +426,7 @@ std::vector<SMS> parseSMSData(const String& data) {
 }
 
 String ArduinoCellular::sendUSSDCommand(const char * command){
-    return modem.sendUSSD(command);
+    return Modem.sendUSSD(command);
 }
 
 std::vector<SMS> ArduinoCellular::getReadSMS(){