How to log specific user executed queries - php

Question

I am wanting to keep a table log history of executed MySQLI queries and log the specific user who executed a query and date & time the query was executed - on any (all) of my PHP pages.
What is the best way and simplest way to achieve this?
PHP
session_start();
if(!isset($_SESSION["username"])){
header("Location: login.php");
exit(); }
$connection = mysqli_connect("****", "****", "****", "****");
if (!$connection) {
die("Database connection failed: " . mysqli_connect_error());
}
if(isset($_POST['update'])) {
$accountNo = $_GET['ID'];
$firstname = $_POST['firstname'];
$surname = $_POST['surname'];
$dob = $_POST['dob'];
$email = $_POST['email'];
$phone = $_POST['phone'];
$address = $_POST['address'];
$town = $_POST['town'];
$postcode = $_POST['postcode'];
Recommendation from a SO user:
However, there are errors with this suggestion ...many.
$query = "UPDATE usertable set firstname = '".$firstname."', surname='".$surname."', dob='".$dob."', email='".$email."', phone='".$phone."', address='".$address."', town='".$town."', postcode='".$postcode."' where accountNo='".$accountNo."'";
$log_action = mysqli_query($connection,$query);
$result = mysqli_query($connection,$query);
if($result) {
define("LOG_FILE", "https://www.*******.com/logfile.txt");
function log_action($action, $data) {
$time = date('Y-m-d h:i:s');
$user = isset($_SESSION['username']) ? $_SESSION['username'] : '';
$message = "$time\tuser=$user\taction=$action\tdata=$data\n";
file_put_contents(LOG_FILE, $message, FILE_APPEND);
}

Answer 1

Write a wrapper library that logs all the mysqli calls that you want to record, e.g.
function my_mysqli_query($link, $query, $resultmode = MYSQLI_STORE_RESULT) {
log_action('mysqli_query', $query);
return mysqli_query($link, $query, $resultmode);
}
function my_mysqli_prepare($link, $query) {
log_action('mysqli_prepare', $query);
return mysqli_prepare($link, $query);
}
...
define("LOG_FILE", "/path/to/logfile.txt");
function log_action($action, $data) {
$time = date('Y-m-d h:i:s');
$user = isset($_SESSION['username']) ? $_SESSION['username'] : '';
message = "$time\tuser=$user\taction=$action\tdata=$data\n";
file_put_contents(LOG_FILE, $message, FILE_APPEND);
}
I've written it to log to a file. You could log to a database table instead, it's just more code in log_action().
Then do a global replace in all your other scripts, replacing mysqli_query with my_mysqli_query, mysqli_prepare with my_mysqli_prepare, and so on. So your code would look like:
if(isset($_POST['update'])) {
$accountNo = $_GET['ID'];
$firstname = $_POST['firstname'];
$surname = $_POST['surname'];
$dob = $_POST['dob'];
$email = $_POST['email'];
$phone = $_POST['phone'];
$address = $_POST['address'];
$town = $_POST['town'];
$postcode = $_POST['postcode'];
$query = "UPDATE usertable set firstname = '".$firstname."', surname='".$surname."', dob='".$dob."', email='".$email."', phone='".$phone."', address='".$address."', town='".$town."', postcode='".$postcode."' where accountNo='".$accountNo."'";
$result = my_mysqli_query($connection,$query);
if ($result) {
echo "Update successful";
}
}