BluetoothSerial add discover and connect with channel number example

Author: ferbar

libraries/BluetoothSerial/examples/DiscoverConnect/.skip.esp32c3

@@ -0,0 +1,110 @@
+/**
+ * Bluetooth Classic Example
+ * Scan for devices - asyncronously, print device as soon as found
+ * query devices for SPP - SDP profile
+ * connect to first device offering a SPP connection
+ * 
+ * Example python server:
+ * source: https://gist.github.com/ukBaz/217875c83c2535d22a16ba38fc8f2a91
+ *
+ * Tested with Raspberry Pi onboard Wifi/BT, USB BT 4.0 dongles, USB BT 1.1 dongles, 
+ * 202202: does NOT work with USB BT 2.0 dongles when esp32 aduino lib is compiled with SSP support!
+ *         see https://github.com/espressif/esp-idf/issues/8394
+ *         
+ * use ESP_SPP_SEC_ENCRYPT|ESP_SPP_SEC_AUTHENTICATE in connect() if remote side requests 'RequireAuthentication': dbus.Boolean(True),
+ * use ESP_SPP_SEC_NONE or ESP_SPP_SEC_ENCRYPT|ESP_SPP_SEC_AUTHENTICATE in connect() if remote side has Authentication: False
+ */
+
+#include <map>
+#include <BluetoothSerial.h>
+
+#if !defined(CONFIG_BT_ENABLED) || !defined(CONFIG_BLUEDROID_ENABLED)
+#error Bluetooth is not enabled! Please run `make menuconfig` to and enable it
+#endif
+
+BluetoothSerial SerialBT;
+
+
+#define BT_DISCOVER_TIME  10000
+esp_spp_sec_t sec_mask=ESP_SPP_SEC_NONE; // or ESP_SPP_SEC_ENCRYPT|ESP_SPP_SEC_AUTHENTICATE to request pincode confirmation
+esp_spp_role_t role=ESP_SPP_ROLE_SLAVE; // or ESP_SPP_ROLE_MASTER
+
+// std::map<BTAddress, BTAdvertisedDeviceSet> btDeviceList;
+
+void setup() {
+  Serial.begin(115200);
+  if(! SerialBT.begin("ESP32test", true) ) {
+    Serial.println("========== serialBT failed!");
+    abort();
+  }
+  // SerialBT.setPin("1234"); // doesn't seem to change anything
+  // SerialBT.enableSSP(); // doesn't seem to change anything
+
+
+  Serial.println("Starting discoverAsync...");
+  BTScanResults* btDeviceList = SerialBT.getScanResults();  // maybe accessing from different threads!
+  if (SerialBT.discoverAsync([](BTAdvertisedDevice* pDevice) {
+      // BTAdvertisedDeviceSet*set = reinterpret_cast<BTAdvertisedDeviceSet*>(pDevice);
+      // btDeviceList[pDevice->getAddress()] = * set;
+      Serial.printf(">>>>>>>>>>>Found a new device asynchronously: %s\n", pDevice->toString().c_str());
+    } )
+    ) {
+    delay(BT_DISCOVER_TIME);
+    Serial.print("Stopping discoverAsync... ");
+    SerialBT.discoverAsyncStop();
+    Serial.println("discoverAsync stopped");
+    delay(5000);
+    if(btDeviceList->getCount() > 0) {
+      BTAddress addr;
+      int channel=0;
+      Serial.println("Found devices:");
+      for (int i=0; i < btDeviceList->getCount(); i++) {
+        BTAdvertisedDevice *device=btDeviceList->getDevice(i);
+        Serial.printf(" ----- %s  %s %d\n", device->getAddress().toString().c_str(), device->getName().c_str(), device->getRSSI());
+        std::map<int,std::string> channels=SerialBT.getChannels(device->getAddress());
+        Serial.printf("scanned for services, found %d\n", channels.size());
+        for(auto const &entry : channels) {
+          Serial.printf("     channel %d (%s)\n", entry.first, entry.second.c_str());
+        }
+        if(channels.size() > 0) {
+          addr = device->getAddress();
+          channel=channels.begin()->first;
+        }
+      }
+      if(addr) {
+        Serial.printf("connecting to %s - %d\n", addr.toString().c_str(), channel);
+        SerialBT.connect(addr, channel, sec_mask, role);
+      }
+    } else {
+      Serial.println("Didn't find any devices");
+    }
+  } else {
+    Serial.println("Error on discoverAsync f.e. not workin after a \"connect\"");
+  }
+}
+
+
+String sendData="Hi from esp32!\n";
+
+void loop() {
+  if(! SerialBT.isClosed() && SerialBT.connected()) {
+    if( SerialBT.write((const uint8_t*) sendData.c_str(),sendData.length()) != sendData.length()) {
+      Serial.println("tx: error");
+    } else {
+      Serial.printf("tx: %s",sendData.c_str());
+    }
+    if(SerialBT.available()) {
+      Serial.print("rx: ");
+      while(SerialBT.available()) {
+        int c=SerialBT.read();
+        if(c >= 0) {
+          Serial.print((char) c);
+        }
+      }
+      Serial.println();
+    }
+  } else {
+    Serial.println("not connected");
+  }
+  delay(1000);
+}