PHP form filtering: sensitive word filtering and replacement

PHP form filtering: sensitive word filtering and replacement

In the process of developing web applications, we often need to filter and clean the data submitted by users to Protect the security of the website and the privacy of the users. Among them, filtering and replacing sensitive words is a very important task. This article will introduce how to use PHP to filter and replace sensitive words, and provide corresponding code examples.

1. Principle of sensitive word filtering and replacement

Sensitive word filtering and replacement refers to detecting the sensitive words contained in the data submitted by the user and replacing them with Specify characters or words. The principle can be divided into two steps:

Step 1: Build a sensitive vocabulary. A sensitive vocabulary library is a collection of sensitive words that are defined in advance by the website administrator or developer. Sensitive lexicon can be stored in a database or in the form of a file.

Step 2: Match sensitive words and replace them. Match the data submitted by the user with the sensitive word library, and if the match is successful, replace the sensitive word with the specified character or word.

2. Building a sensitive vocabulary library

Building a sensitive vocabulary library is the first step in filtering and replacing sensitive words. The following is an example of a simple sensitive vocabulary, including some common sensitive words:

$sensitiveWords = array(
    '敏感词1',
    '敏感词2',
    '敏感词3',
    // 其他敏感词...
);

Please modify the sensitive vocabulary to the sensitive words you need based on the actual situation.

3. Match sensitive words and replace

Next, we need to write a function that loops through the sensitive word library and uses PHP’s string replacement function str_replace() Replace sensitive words with specified characters or words.

The following is an example of a simple sensitive word filtering and replacement function:

function filterSensitiveWords($data, $sensitiveWords, $replaceWord = '*') {
    foreach ($sensitiveWords as $word) {
        $data = str_replace($word, $replaceWord, $data);
    }
    
    return $data;
}

This function accepts three parameters: $data represents the data to be filtered, $sensitiveWords represents the sensitive vocabulary, $ replaceWord represents the replaced character or word, and the default is an asterisk (*). This function will replace the sensitive word contained in $data with $replaceWord and return the replacement result.

4. Usage Example

The following is a usage example that demonstrates how to use the above function to filter user-submitted form data:

$sensitiveWords = array(
    '敏感词1',
    '敏感词2',
    '敏感词3',
    // 其他敏感词...
);

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $data = $_POST['data']; // 假设表单中有一个名为data的字段
    $filteredData = filterSensitiveWords($data, $sensitiveWords);
    
    // 输出过滤后的结果
    echo '过滤后的结果：' . $filteredData;
}

In the above example, We first define the sensitive vocabulary $sensitiveWords. Then, by determining whether the request method is POST, obtain the data submitted by the user and assign it to $data. Then, call the filterSensitiveWords() function to filter $data, and assign the filtered result to $filteredData. Finally, we output the filtered results.

5. Summary

This article introduces how to use PHP to implement sensitive word filtering and replacement, and provides corresponding code examples. By adding sensitive word filtering and replacement functions during website development, we can effectively protect user privacy and website security. I hope this article can help you filter and replace sensitive words during the development process.

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