Arduino client-server post request

[monbes]

Hello everyone,
I am testing a custom API using ESP8266 to send and fetch data from it. Everything looks okay in the code but I always received Bad request error. Here is the code:

#include <ESP8266WiFi.h>

const char* ssid = "iottollgate";
const char* password = "iot2017/2018";

const char* host = "https://transformer-monitoring.herokuapp.com";
const char* path = "POST /api?c=20&l=55&t=87&v=78&n=1 HTTP/1.1\r\nHost: https://transformer-monitoring.herokuapp.com\r\n\r\n";

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

  Serial.printf("Connecting to %s ", ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED)
  {
    delay(500);
    Serial.print(".");
  }
  Serial.println(" connected");
}


void loop()
{
  WiFiClient client;

  Serial.printf("\n[Connecting to %s ... ", host);
  if (client.connect(host, 80))
  {
    Serial.println("connected]");

    Serial.println("[Sending a request]");
    client.print(String(path));
    Serial.println("Path:"+String(path));
    
    Serial.println("[Response:]");
    while (client.connected())
    {
      if (client.available())
      {
        String line = client.readStringUntil('\n');
        Serial.println(line);
      }
    }
    client.stop();
    Serial.println("\n[Disconnected]");
  }
  else
  {
    Serial.println("connection failed!]");
    client.stop();
  }
  delay(5000);
}

[J-M-L]

host should be transformer-monitoring.herokuapp.com

https is the protocol and I don't think you can issue a secure http request (over TLS) that way. You would need to either use website's fingerprint, or to use client.setInsecure()

[monbes]

https in the host is the cause of the problem as you pointed out. I removed it and the request was successful. This actually gave me serious headache for days and in fact, I destroyed an ESP32 dev kit in the process.

Thanks very much for this priceless help.

[J-M-L]

OK if that works it means your server is not HTTPS but just HTTP