Data filtering and validation in PHP7: How to ensure the correctness and security of data?

Data filtering and validation in PHP7: How to ensure the correctness and security of data?

Overview:
With the development of the Internet, data processing and transmission have become a very important part of website development. However, due to untrustworthy user input and the existence of malicious attacks, it is crucial to ensure that the data we process is correct and secure. PHP7 provides some powerful tools and functions to help us complete this task. This article will introduce how to use PHP7's data filtering and verification functions to ensure the correctness and security of data.

1. Data filtering:
   Data filtering refers to processing the data input by the user, removing some invalid content or converting it into a valid format. PHP7 provides two functions, filter_var() and filter_input(), for data filtering. The following is a sample code:

$username = $_POST['username'];
$filterUsername = filter_var($username, FILTER_SANITIZE_STRING);
if ($username !== $filterUsername) {
    echo "用户名格式不正确！";
}

In the above sample code, we use the filter_var() function to use the FILTER_SANITIZE_STRING filter to filter the user name entered by the user, removing all HTML tags and special characters All removed. Then, we compare the filtered results with the original username. If they are not equal, it means that the entered username is not in the correct format.

2. Data validation:
   Data validation refers to checking the data entered by the user to ensure that it meets specific requirements. PHP7 provides two functions, filter_var() and filter_input() for data validation. The following is a sample code:

$email = $_POST['email'];
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
    echo "请输入正确的电子邮箱地址！";
}

In the above sample code, we use the filter_var() function to use the FILTER_VALIDATE_EMAIL filter to verify the email address entered by the user to determine whether it conforms to the format of the email address. . If it does not match, the email address entered is incorrect.

3. XSS attack prevention:
   XSS (Cross-Site Scripting) attack refers to an attack method in which hackers steal user information by injecting malicious scripts on websites. In order to prevent XSS attacks, we can use the htmlspecialchars() function in PHP7 to escape the content entered by the user to ensure that it will not be parsed and executed as an HTML tag.

$content = $_POST['content'];
$filteredContent = htmlspecialchars($content, ENT_QUOTES, 'UTF-8');

In the above example code, we use the htmlspecialchars() function to escape the content entered by the user and convert the special characters into HTML entities, so that even if the input contains HTML tags, It will also be displayed as normal text.

4. SQL injection prevention:
   SQL injection refers to an attack method in which hackers obtain or tamper with data in the database by constructing malicious SQL statements. In order to prevent SQL injection attacks, we can use the mysqli_real_escape_string() function in PHP7 to escape the content entered by the user to ensure that it will not be executed as part of the SQL statement.

$username = $_POST['username'];
$filteredUsername = mysqli_real_escape_string($conn, $username);

In the above sample code, we use the mysqli_real_escape_string() function to escape the user name entered by the user and escape the special characters in it to ensure that it will not be treated as SQL Part of the statement is executed.

Summary:
By using the data filtering and verification functions in PHP7, we can effectively ensure the correctness and security of the data. When processing user input, we should always remain vigilant and use appropriate methods to filter and verify user-entered data to prevent problems caused by malicious attacks and data errors. I hope the introduction in this article will be helpful for you to understand and use the data filtering and validation functions of PHP7.

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