ESP32_HTTP_POST.ino

/*
  Guide from xe-non to P-Use
*/

#include <WiFi.h>
#include <HTTPClient.h>

const char *ssid = "REPLACE_WITH_YOUR_SSID";
const char *password = "REPLACE_WITH_YOUR_PASSWORD";

//Your Domain name with URL path or IP address with path
const char *serverName = "https://mern-01.now.sh/api/books";

// the following variables are unsigned longs because the time, measured in
// milliseconds, will quickly become a bigger number than can be stored in an int.
unsigned long lastTime = 0;
// Timer set to 10 minutes (600000)
//unsigned long timerDelay = 600000;
// Set timer to 5 seconds (5000)
unsigned long timerDelay = 5000;

void setup()
{
  Serial.begin(115200);

  WiFi.begin(ssid, password);
  Serial.println("Connecting");
  while (WiFi.status() != WL_CONNECTED)
  {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.print("Connected to WiFi network with IP Address: ");
  Serial.println(WiFi.localIP());

  Serial.println("Timer set to 5 seconds (timerDelay variable), it will take 5 seconds before publishing the first reading.");
}

void loop()
{
  //Send an HTTP POST request every 10 minutes
  if ((millis() - lastTime) > timerDelay)
  {
    //Check WiFi connection status
    if (WiFi.status() == WL_CONNECTED)
    {
      HTTPClient http;

      // Your Domain name with URL path or IP address with path
      http.begin(serverName);

      // Specify content-type header
      http.addHeader("Content-Type", "application/json");
      // Data to send with HTTP POST
      int httpResponseCode = http.POST("
      {
        \"title\":\"Pumal's Book\",
        \"isbn\":\"08-07-2020\",
        \"author\":\"Sithum Online\"
      }
    ");

    Serial.print("HTTP Response code: ");
    Serial.println(httpResponseCode);

    // Free resources
    http.end();
    }
    else
    {
      Serial.println("WiFi Disconnected");
    }
    lastTime = millis();
  }
}