Strengthen your PHP: mysqli_prepare against SQL injections

Security is a fundamental pillar in web application development, and protecting your project from SQL injection attacks should be at the top of your priority list. PHP, being one of the most popular programming languages for developing web applications, offers tools to protect your databases from these malicious attacks. The function mysqli_prepare It is one of the most effective when creating secure SQL queries. In this article, I will guide you step by step so that you understand how to use this tool correctly and strengthen the security of your applications.

Understanding SQL injection

Before we dive into the code, it's crucial to have a solid understanding of what a SQL injection is. This is an attack technique in which the attacker inserts or "injects" a malicious SQL query through the client's input data into the application. If the application is not properly secured, this code can be executed by the database, resulting in unauthorized manipulation of the database and potentially access to sensitive data.

The mysqli_prepare function: Your shield against SQL injection

mysqli_prepare is a PHP function that allows you to prepare an SQL statement for execution. This preparation involves two stages: creating a prepared statement and binding the input variables (parameters) to the statement. Below I will show you how to use mysqli_prepare to create more secure applications.

Step 1: Connect to the database with mysqli

Before you can prepare a query, you need to establish a secure connection to your database. Here is an example of how to do it:

$host = 'localhost'; 1TP4YourUser = 'my_user'; $password = 'my_password'; $DatabaseName = 'my_database'; $mysqli = new mysqli($host, 1TP4YourUser, $password, $databaseName); if ($mysqli->connect_error) { die('Connection error: ' . $mysqli->connect_error); }

Step 2: Prepare the return

With the connection established, the next step is to prepare your query. Let's say you want to get information about a specific user in your database:

$preparedquery = $mysqli->prepare("SELECT * FROM users WHERE email = ?");

The interrogation ? is a marker that will represent the parameter that will be linked later.

Step 3: Bind parameters

After preparing the query, you must bind the PHP variables with the parameter markers in the SQL statement:

$email = '[email protected]'; $preparedquery->bind_param("s", $email);

The "s" means that the parameter $email is a string (string). If you were linking an integer, you would use "i", for a double "d", and for a blob "b".

Step 4: Execute the statement

With the parameters bound, you can now run the query:

$preparedquery->execute();

Step 5: Get the results

Finally, you need to get the data returned by the query:

$Result = $PreparedQuery-&gt;get_result(); while ($row = $result-&gt;fetch_assoc()) { echo $row[&#039;name&#039;] . &#039; - &#039; . $row[&#039;email&#039;] .&#039;<br>&#039;;
}

Step 6: Close the statement and connection

Don't forget to close the statement and connection once you're done with them:

$PreparedQuery->close(); $mysqli->close();

Advantages of using mysqli_prepare

Why go through this process instead of simply concatenating variables to your SQL query? The answer is security. Parameter markers prevent the application from taking input data as part of the SQL code, which decreases the risk of malicious queries being executed.

Good practices and additional recommendations

While mysqli_prepare is a powerful tool, the security of your application is further strengthened with additional practices such as:

• Input validation: Before passing the data to your prepared statement, make sure it meets the criteria you expect (for example, that the email is in a valid format).
• Correctly escape data: If you find yourself in a scenario where you cannot use a prepared statement, be sure to escape the data using mysqli_real_escape_string.
• Use prepared statements whenever possible: This is not only for SELECT, but also for INSERT, UPDATE and DELETE operations.

Conclusion

Addressing SQL injections is essential to maintaining the integrity of your applications and the trust of your users. Use mysqli_prepare PHP allows you to create secure queries and avoid being vulnerable to these attacks. Implement these practices into your development workflow and you will strengthen the security of your web projects.

For any additional queries or needs related to secure PHP application development or any other technical concerns, visit NelkoDev and I will be happy to assist you in your programming projects.