How can someone with limited knowledge of HTTP requests and PHP effectively troubleshoot issues with data transfer?

Issue: If there are issues with data transfer in HTTP requests using PHP, it could be due to incorrect handling of data formats or errors in the code that processes the incoming data. One way to troubleshoot this is to check the data being sent in the request and ensure that it matches the expected format. Additionally, checking for any error messages or logs generated during the data transfer process can help identify the problem. PHP Code Snippet:

// Check if data is being sent in the request
if ($_SERVER['REQUEST_METHOD'] == 'POST') {
    $data = file_get_contents('php://input');
    
    // Check if data is in JSON format
    $json_data = json_decode($data);
    
    if ($json_data) {
        // Process the JSON data
        // Code to handle the data transfer
    } else {
        // Handle data transfer error
        echo "Error: Data format is not JSON";
    }
} else {
    // Handle request method error
    echo "Error: Only POST requests are allowed";
}