How to receive post array parameters in php

When using PHP to develop web applications, receiving POST array parameters is a very basic skill. This article will introduce how to receive POST array parameters in PHP to help readers better process and display form data.

1. What are POST array parameters

POST is an HTTP request method, which is used to submit data to the server, generally used for form submission. When a user fills in form information on the website, each data item contained in the form will be converted into a key-value pair, such as "username" => "Zhang San", "password" => 123456.

When the user submits the form, these key-value pairs will be encapsulated in a POST array and passed to the backend server. In the background PHP script, we need to extract this data from the POST array for subsequent processing.

2. Use $_POST to collect POST array parameters

In PHP, we can use the $_POST global array to collect POST array parameters. $_POST is a predefined variable provided by PHP, which is used to save the data passed by the POST method. It is an associative array, where the key name is the name attribute value of the control in the form, and the key value is the data entered by the user.

The following is a simple example showing how to receive POST array parameters through $_POST:

<form action="process.php" method="POST">
    用户名：<input type="text" name="username"><br>
    密码：<input type="password" name="password"><br>
    <input type="submit" name="submit" value="提交">
</form>

<?php
if (isset($_POST['submit'])) {
    $username = $_POST['username'];
    $password = $_POST['password'];
    
    echo "您输入的用户名是：" . $username . "<br>";
    echo "您输入的密码是：" . $password . "<br>";
}
?>

In the above example, we first submit the form information to process.php through the form element in the file. When the user clicks the submit button, we will check whether there is an element with the 'name' attribute of 'submit' in the $_POST array. If it exists, it means that the user has submitted the form, and we can get the user-submitted form from the $_POST array. data.

Specifically, we use $_POST['username'] and $_POST['password'] to get the user name and password in the form, and print them out on the page. Among them, the isset() function is used to check whether the submit element exists. If it exists, it means that the user submitted the form.

It is worth noting that the data obtained through $_POST is presented in the form of a string, so we need to perform type conversion when necessary.

3. Security issues of POST array parameters

When using POST arrays, we need to pay attention to some security issues. Since the data in the POST array comes from user input, there may be malicious data attacks, such as SQL injection, cross-site scripting and other issues. Therefore, we should pay attention to the following points when receiving POST array parameters:

1. Verify whether the value entered by the user is legal. For example, when we receive an email address, we should verify whether it conforms to the format of the email address to avoid users passing some invalid data.

2. Filter and process the received values. For example, we should HTML escape the received string to prevent users from passing malicious data in the form of HTML code.

3. Do not pass the value in $_POST directly into SQL query statements or other sensitive operations. Parameterized queries and other methods should be used to prevent SQL injection attacks from occurring.

4. Summary

In the PHP development process, receiving POST array parameters is a very basic skill. This article introduces how to receive POST array parameters through the $_POST global array, and pays attention to the security issues of POST array parameters. Readers can flexibly use this knowledge in actual development to improve the development efficiency and security of Web applications.

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