ESP32 POST request error 400 using WiFiClientSecure protocol

Using Arduino Programming Questions
1

Hello community,

This is my first post, I am a new user of this IoT world so please I ask you understanding if I make little mistakes.

I am trying to program an ESP32 to upload some sensor readings to an online web server via WiFiClientSecure, with no success. I get to connect with the server but somehow, something is wrong with my request. Due to privacy, I will change my domains name for mydomain.com. My server is equipped with SSL certificates (connection seems to go OK). On the server side I have a .php recieving the data

String post_link = "https://www.mycomain.com/post-data.php";
String host = "mydomain.com";

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

        // Prepare the data to be uploaded:
        String data_upload = "api_key=" + apiKeyValue + "&value1=" + String(value1)
                           + "&value2=" + String(value2) + "&value3=" + String(value3);
        String request = "POST " + String(post_link) + "HTTP/1.1\r\n" +
                         "Host: " + String(host) + "\r\n" +
                         "Content-Type: application/x-www-form-urlencoded\r\n" +
                         "Content-Length: " + String(data_upload.length()) + "\r\n" +
                         "\r\n" + data_upload;
        // Send HTTPS POST request
        client.print(request);

      }
      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();
      Serial.println("Connection closed");

This is what I get as response:

18:37:54.871 -> Starting connection to server...
18:37:56.112 -> Connected to server!
18:37:56.144 -> headers received
18:37:56.144 -> <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
18:37:56.144 -> <html><head>
18:37:56.144 -> <title>400 Bad Request</title>
18:37:56.144 -> </head><body>
18:37:56.144 -> <h1>Bad Request</h1>
18:37:56.144 -> <p>Your browser sent a request that this server could not understand.<br />
18:37:56.144 -> </p>
18:37:56.144 -> <p>Additionally, a 400 Bad Request
18:37:56.144 -> error was encountered while trying to use an ErrorDocument to handle the request.</p>
18:37:56.144 -> </body></html>
18:37:56.180 -> Connection closed

Does someone know whay I can't realize a successful data sending to the server?
I would appreciate your help.
Thanks in advance.

2

quick search of the HTTP status code shows that this is a client error,

instead of this,

try this,

"POST " + String(post_link) + " HTTP/1.1\r\n" +

noticed the added space in front of the HTTP version!

3

Yep, completely right. Didn't realize about that detail that kept me crazy for a longish while.

Now it worked!!

Thank you very much.

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4

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