airquality.ino

#include <ArduinoJson.h>
#include <WiFiClientSecure.h>

#define LOG_LOCAL_LEVEL ESP_LOG_VERBOSE
#include "esp_log.h"



// WiFi network name and password:
const char * networkName = "YOUR NETWORK SSID HERE";
const char * networkPswd = "YOUR PASSWORD HERE";

// Internet domain to request from:
//const char * hostDomain = "opendata.bristol.gov.uk";
const char * hostDomain = "www.howsmyssl.com";
const int hostPort = 443;

const char* test_root_ca= \
     "-----BEGIN CERTIFICATE-----\n" \
     "MIIEkjCCA3qgAwIBAgIQCgFBQgAAAVOFc2oLheynCDANBgkqhkiG9w0BAQsFADA/\n" \
     "MSQwIgYDVQQKExtEaWdpdGFsIFNpZ25hdHVyZSBUcnVzdCBDby4xFzAVBgNVBAMT\n" \
     "DkRTVCBSb290IENBIFgzMB4XDTE2MDMxNzE2NDA0NloXDTIxMDMxNzE2NDA0Nlow\n" \
     "SjELMAkGA1UEBhMCVVMxFjAUBgNVBAoTDUxldCdzIEVuY3J5cHQxIzAhBgNVBAMT\n" \
     "GkxldCdzIEVuY3J5cHQgQXV0aG9yaXR5IFgzMIIBIjANBgkqhkiG9w0BAQEFAAOC\n" \
     "AQ8AMIIBCgKCAQEAnNMM8FrlLke3cl03g7NoYzDq1zUmGSXhvb418XCSL7e4S0EF\n" \
     "q6meNQhY7LEqxGiHC6PjdeTm86dicbp5gWAf15Gan/PQeGdxyGkOlZHP/uaZ6WA8\n" \
     "SMx+yk13EiSdRxta67nsHjcAHJyse6cF6s5K671B5TaYucv9bTyWaN8jKkKQDIZ0\n" \
     "Z8h/pZq4UmEUEz9l6YKHy9v6Dlb2honzhT+Xhq+w3Brvaw2VFn3EK6BlspkENnWA\n" \
     "a6xK8xuQSXgvopZPKiAlKQTGdMDQMc2PMTiVFrqoM7hD8bEfwzB/onkxEz0tNvjj\n" \
     "/PIzark5McWvxI0NHWQWM6r6hCm21AvA2H3DkwIDAQABo4IBfTCCAXkwEgYDVR0T\n" \
     "AQH/BAgwBgEB/wIBADAOBgNVHQ8BAf8EBAMCAYYwfwYIKwYBBQUHAQEEczBxMDIG\n" \
     "CCsGAQUFBzABhiZodHRwOi8vaXNyZy50cnVzdGlkLm9jc3AuaWRlbnRydXN0LmNv\n" \
     "bTA7BggrBgEFBQcwAoYvaHR0cDovL2FwcHMuaWRlbnRydXN0LmNvbS9yb290cy9k\n" \
     "c3Ryb290Y2F4My5wN2MwHwYDVR0jBBgwFoAUxKexpHsscfrb4UuQdf/EFWCFiRAw\n" \
     "VAYDVR0gBE0wSzAIBgZngQwBAgEwPwYLKwYBBAGC3xMBAQEwMDAuBggrBgEFBQcC\n" \
     "ARYiaHR0cDovL2Nwcy5yb290LXgxLmxldHNlbmNyeXB0Lm9yZzA8BgNVHR8ENTAz\n" \
     "MDGgL6AthitodHRwOi8vY3JsLmlkZW50cnVzdC5jb20vRFNUUk9PVENBWDNDUkwu\n" \
     "Y3JsMB0GA1UdDgQWBBSoSmpjBH3duubRObemRWXv86jsoTANBgkqhkiG9w0BAQsF\n" \
     "AAOCAQEA3TPXEfNjWDjdGBX7CVW+dla5cEilaUcne8IkCJLxWh9KEik3JHRRHGJo\n" \
     "uM2VcGfl96S8TihRzZvoroed6ti6WqEBmtzw3Wodatg+VyOeph4EYpr/1wXKtx8/\n" \
     "wApIvJSwtmVi4MFU5aMqrSDE6ea73Mj2tcMyo5jMd6jmeWUHK8so/joWUoHOUgwu\n" \
     "X4Po1QYz+3dszkDqMp4fklxBwXRsW10KXzPMTZ+sOPAveyxindmjkW8lGy+QsRlG\n" \
     "PfZ+G6Z6h7mjem0Y+iWlkYcV4PIWL1iwBi8saCbGS5jN2p8M+X+Q7UNKEkROb3N6\n" \
     "KOqkqm57TH2H3eDJAkSnh6/DNFu0Qg==\n" \
     "-----END CERTIFICATE-----\n";
     

void setup()
{

  // Initilize hardware:
  Serial.begin(115200);
    // Connect to the WiFi network (see function below loop)
  connectToWiFi(networkName, networkPswd);
}


void loop()
{
    requestURL(hostDomain, hostPort); // Connect to server
    delay(100000);
}

void connectToWiFi(const char * ssid, const char * pwd)
{
  printLine();
  Serial.println("Connecting to WiFi network: " + String(ssid));

  WiFi.begin(ssid, pwd);

  while (WiFi.status() != WL_CONNECTED) 
  {
    Serial.print(".");
  }

  Serial.println();
  Serial.println("WiFi connected!");
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
}

void requestURL(const char * host, uint8_t port)
{
 // printLine();
  Serial.println("Connecting to domain: " + String(host));


  WiFiClientSecure client;
  client.setCACert(test_root_ca);
  
  if (!client.connect(host, port))
  {
    Serial.println("Connection failed!");
      char err_buf[100];
      if (client.lastError(err_buf, 100) < 0) {
          Serial.println(err_buf);
      } else {
          Serial.println("Connection error");
      }
  }
  Serial.println("Connected!");
  printLine();

    Serial.print("heap: ");
  Serial.println(ESP.getFreeHeap());

  // This will send the request to the server
  client.print((String)"GET /api/records/1.0/search/?dataset=air-quality-data-continuous&rows=1&sort=date_time&facet=date_time&facet=location&facet=current&refine.location=AURN+St+Pauls HTTP/1.1\r\n" +
               "Host: " + String(host) + "\r\n" +
               "Connection: close\r\n\r\n");
  unsigned long timeout = millis();
  while (client.available() == 0) 
  {
    if (millis() - timeout > 5000) 
    {
      Serial.println(">>> Client Timeout !");
      client.stop();
      return;
    }
  }
  Serial.println("here!");

   String line = ""; 
 while (client.available()) { 
   line = client.readStringUntil('\r');
   Serial.println(line);
   if (line.indexOf('{')>=0) {
   Serial.println("parsingValues"); 
   DynamicJsonDocument json_doc(6000);
   DeserializationError json_error = deserializeJson(json_doc, line);
   if (json_error) { 
     Serial.println("parseing failed");
     Serial.println(json_error.c_str());
   } 
   else {

   Serial.println("Nox");
   String nox=json_doc["records"][0]["fields"]["nox"];
   Serial.println(nox);

// Extract the data here
  

   }
   }
 }
}

void printLine()
{
  Serial.println();
  for (int i=0; i<30; i++)
    Serial.print("-");
  Serial.println();
}