Send push notification from ESP32 using Pushbullet

esp32_pushbullet.ino

#include <WiFiClientSecure.h>
#include <string.h>

WiFiClientSecure client;

/**************************/
//WiFi config
/**************************/
const char* ssid     = "XXXXXXXXXXXXX";   // your network SSID (name of wifi network)
const char* password = "XXXXXXXXXXXXX";   // your network password

/**************************/
//Pushbullet config
/**************************/
const char* accessToken="XXXXXXXXXXXXXXXXXX";  // your pushbullet access token
const char* pushTitle="test";
const char* pushMsg="hoge";

// DSTRootCAX3.crt
const char* test_root_ca= \
  "-----BEGIN CERTIFICATE-----\n" \
  "MIIDSjCCAjKgAwIBAgIQRK+wgNajJ7qJMDmGLvhAazANBgkqhkiG9w0BAQUFADA/\n" \
  "MSQwIgYDVQQKExtEaWdpdGFsIFNpZ25hdHVyZSBUcnVzdCBDby4xFzAVBgNVBAMT\n" \
  "DkRTVCBSb290IENBIFgzMB4XDTAwMDkzMDIxMTIxOVoXDTIxMDkzMDE0MDExNVow\n" \
  "PzEkMCIGA1UEChMbRGlnaXRhbCBTaWduYXR1cmUgVHJ1c3QgQ28uMRcwFQYDVQQD\n" \
  "Ew5EU1QgUm9vdCBDQSBYMzCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEB\n" \
  "AN+v6ZdQCINXtMxiZfaQguzH0yxrMMpb7NnDfcdAwRgUi+DoM3ZJKuM/IUmTrE4O\n" \
  "rz5Iy2Xu/NMhD2XSKtkyj4zl93ewEnu1lcCJo6m67XMuegwGMoOifooUMM0RoOEq\n" \
  "OLl5CjH9UL2AZd+3UWODyOKIYepLYYHsUmu5ouJLGiifSKOeDNoJjj4XLh7dIN9b\n" \
  "xiqKqy69cK3FCxolkHRyxXtqqzTWMIn/5WgTe1QLyNau7Fqckh49ZLOMxt+/yUFw\n" \
  "7BZy1SbsOFU5Q9D8/RhcQPGX69Wam40dutolucbY38EVAjqr2m7xPi71XAicPNaD\n" \
  "aeQQmxkqtilX4+U9m5/wAl0CAwEAAaNCMEAwDwYDVR0TAQH/BAUwAwEB/zAOBgNV\n" \
  "HQ8BAf8EBAMCAQYwHQYDVR0OBBYEFMSnsaR7LHH62+FLkHX/xBVghYkQMA0GCSqG\n" \
  "SIb3DQEBBQUAA4IBAQCjGiybFwBcqR7uKGY3Or+Dxz9LwwmglSBd49lZRNI+DT69\n" \
  "ikugdB/OEIKcdBodfpga3csTS7MgROSR6cz8faXbauX+5v3gTt23ADq1cEmv8uXr\n" \
  "AvHRAosZy5Q6XkjEGB5YGV8eAlrwDPGxrancWYaLbumR9YbK+rlmM6pZW87ipxZz\n" \
  "R8srzJmwN0jP41ZL9c8PDHIyh8bwRLtTcm1D9SZImlJnt1ir/md2cXjbDaJWFBM5\n" \
  "JDGFoqgCWjBH4d1QB7wCCZAA62RjYJsWvIjJEubSfZGL+T0yjWW06XyxV3bqxbYo\n" \
  "Ob8VZRzI9neWagqNdwvYkQsEjgfbKbYK7p2CNTUQ\n" \
  "-----END CERTIFICATE-----\n";
const char*  server = "api.pushbullet.com";  // Server URL

void setup() {
  //Initialize serial and wait for port to open:
  Serial.begin(115200);
  delay(100);

  Serial.print("Attempting to connect to SSID: ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);

  // attempt to connect to Wifi network:
  while (WiFi.status() != WL_CONNECTED) {
    Serial.print(".");
    // wait 1 second for re-trying
    delay(1000);
  }

  Serial.print("Connected to ");
  Serial.println(ssid);

  client.setCACert(test_root_ca);

  Serial.println("\nStarting connection to server...");
  if (!client.connect(server, 443))
  {
    Serial.println("Connection failed!");
  }
  else
  {
    Serial.println("Connected to server!");

    //HTTP REQUEST
    client.println("POST /v2/pushes HTTP/1.0");

    //HTTP HEADER
    client.println("Host: api.pushbullet.com");
    client.println("Content-Type: application/json");
    client.println("Connection: close");
    client.print("Access-Token:");
    client.println(accessToken);
    client.print("Content-Length: ");
    client.println(41+strlen(pushTitle)+strlen(pushMsg));
    client.println();

    //HTTP BODY
    client.print("{\"type\": \"note\", \"title\": \"");
    client.print(pushTitle);
    client.print("\", \"body\": \"");
    client.print(pushMsg);
    client.println("\"}");
    
    while (client.connected()) {
      String line = client.readStringUntil('\n');
      if (line == "\r") {
        Serial.println("headers received");
        break;
      }
    }
    // if there are incoming bytes available
    // from the server, read them and print them:
    while (client.available())
    {
      char c = client.read();
      Serial.write(c);
    }

    client.stop();
  }
}

void loop() {
  // do nothing
}