Why does the following not appear to open an SQL connection? - php

Question

I find that the folowing script hangs for some reason. It will load and PHP doesn't see any errors, but it will not process the data (noting that we are in a context where I have a seperate login database open.)
In process.php we have the following:
<? PHP
//Process the POST data in prepration to write to SQL database.
$_POST['chat_input'] = $input;
$time = date("Y-m-d H:i:s");
$ip = $_SERVER['REMOTE_ADDR'];
$name = $_SESSION['username'];
$servername = "localhost";
$username = "id3263427_chat_user";
$password = "Itudmenif1!Itudmenif1!";
$dbname = "id3263427_chat_user";
$id = "NULL";
// Create connection
$conn = mysqli_connect($servername, $username, $password, $dbname);
if($link === false){
die("ERROR: Could not connect. " . mysqli_connect_error());
}
$sql = 'INSERT INTO `chat` (`id`, `username`, `ip`, `timestamp`,
`message`) VALUES ('$id','$name', '$ip', '$time', '$input')';
if(mysqli_query($link, $sql)){
mysqli_close($conn);
header('Location: ../protected_page.php');
} else {
echo "ERROR: Could not able to execute $sql. " . mysqli_error($link);
}
?>
the html form passed to the script above is as follows:
<form action="/process.php" method="post" id="chat">
<b> Send A Message (500 Character Max):</b><br>
<textarea name="chat_input" form="chat" size="500"></textarea>
<input type="submit" value=submit>
</form>
Not sure what's going on with this.

Answer 1

You got the syntax error because you're closing the $sql string before $id with your '.
What is this about your $id variable? With your current code you will insert the String "NULL". If you want to set the sql value null you should use $id = null; or just don't insert any value.
If you want your database to set an id, also leave it blank.
$input = $_POST['chat_input'];
$id = null;
$conn = new mysqli($servername, $username, $password, $dbname);
if($conn->connect_error){
die("ERROR: Could not connect. " . $conn->connect_error);
}
First solution
If this isn't a production code, you could insert the variables directly into the statement, but you should use " instead of ' for your sql string, so you can insert variables and ' without closing the string.
$sql = "INSERT INTO chat (id, username, ip, timestamp, message) VALUES ('$id', '$name', '$ip', '$time', '$input')";
if($conn->query($sql) === true) {
$conn->close();
header('Location: ../protected_page.php');
} else {
echo "ERROR: Could not able to execute $sql. " .$conn->error;
$conn->close();
}
Second solution
A better approach would be a prepared statement.
$stmt = $conn->prepare('INSERT INTO chat (username, ip, timestamp, message) VALUES (?, ?, ?, ?)');
$stmt->bind_param("ssss", $username, $ip, $time, $input);
if($stmt->execute()) {
$stmt->close();
$conn->close();
header('Location: ../protected_page.php');
} else {
echo "ERROR: Could not able to execute $stmt. " . $conn->error;
$stmt->close();
$conn->close();
}
The "s" in bind_param() defines a string at the given position, if you want to insert an integer, use "i" instead.
e.g. bindParam("sis", $string, $integer, $string);