POST request not working

Question

I'm following a guide on storing sensor data to MySQL:

Guide

My POST request isn't getting any results to my server. For now, I'm only storing temperature.

Here is my code for saving data:

void sendData(double input) {
 String data = "sensorid=3000000&temp=" + doubleToString(input, 2) + "&hum=1.2";
 
 if (client.connect("192.168.1.50", 80)) {
 client.println("POST /arduino/add.php HTTP/1.1");
 client.println("Host: 192.168.1.50");
 // client.println("User-Agent: Arduino/1.0");
 // client.println("Connection: close");
 client.println("Content-Type: application/x-www-form-urlencoded");
 client.print("Content-Length: ");
 client.print(data.length());
 client.println();
 client.print(data);
 Serial.println("Sent data: " + data);
 }
 
 if (client.connected()) {
 client.stop(); 
 }
 delay(300000);
}

I've commented out two headers since it did not give any other results. My Serial.println gives: Sent data: sensorid=3000000&temp=24.00&hum=1.2, which means that the Arduino is connected to the given IP-adress and that my request data is as I want. They are also working perfectly when I'm testing with Requestmaker, so I'm pretty sure my error comes from the way I'm doing the request here.

Do you have any idea how I can solve or debug this?

• Edgar Bonet: There needs to be an empty line between the headers and the body of the request. Therefore you have to println() (not print()) the end of the last header.
• aaa: Try to use print() with '\n' at the end (only a newline, not carriage return. xportSendTextNoLine("C192.168.200.136/80\n"); sprintf(request,"GET /debug.php?dat=%u HTTP/1.0\n\n",value); xportSendTextNoLine(request); <-- This worked for me. But you'll have to change it a bit to arduino code.
• mvcharcos: did you solve this problem. I am having exactly the same issue and came to the same conclusion: the error comes from the way I am doing the request from the arduino.
• Ruben Ravnå: yes, the first comment was the solution to my problem. End with println instead of print. Could not mark it as answer since it was only a comment.

Answer 1

Answered by Edgar Bonet

There needs to be an empty line between the headers and the body of the request. Therefore you have to println() (not print()) the end of the last header.