How to implement sensitive word filtering in laravel

Laravel is a popular PHP framework that provides many powerful features, such as routing, ORM, form validation, and more. In practical applications, many websites need to filter the content input by users for sensitive words to ensure the civility and health of the website. This article will introduce how to use Laravel to implement sensitive word filtering function.

1. Principle of sensitive word filtering

Sensitive word filtering refers to detecting sensitive words in text content and replacing or marking them to achieve the purpose of blocking sensitive words. There are many ways to implement sensitive word filtering, the most commonly used of which is to use regular expressions to match sensitive words. Regular expressions are a powerful text matching tool that can be used to match large amounts of text simply by defining the pattern to be matched.

2. Implementing sensitive word filtering in Laravel

In Laravel, middleware can be used to implement sensitive word filtering. Middleware is a concept in Laravel framework that can perform some logical operations before or after a route or controller. The following are the specific steps to implement sensitive word filtering:

1. Create middleware

First, you need to create a middleware to filter sensitive words. You can use the following command to create it:

php artisan make:middleware SensitiveWordsFilter

This command will create a middleware file named SensitiveWordsFilter in the app/Http/Middleware directory. In this file, you need to define a handle method for processing requests and responses. The following is a sample code:

<?php

namespace App\Http\Middleware;

use Closure;

class SensitiveWordsFilter
{
    public function handle($request, Closure $next)
    {
        //敏感词过滤代码
        //...
        
        return $next($request);
    }
}

2. Write sensitive word filtering code

In the handle method, you need to write the code for sensitive word filtering. Specifically, you can use PHP's regular expression function preg_replace to replace sensitive words. The following is a sample code:

$content = $request->input('content');

$words = ['敏感词1', '敏感词2', '敏感词3'];

$pattern = '/('.implode('|', $words).')/i';

$content = preg_replace($pattern, "***", $content);

$request->merge(['content' => $content]);

In the above code, $content is the content input by the user, $words is the array of sensitive words that need to be replaced, $pattern is the regular expression pattern, use the implode function to convert the array of sensitive words It is the "or" condition in the regular expression. Finally, use the preg_replace function to replace the matching sensitive words with asterisks. It should be noted that in order to avoid the impact of sensitive word filtering on other functions, you need to use the $request->merge method to update the replaced content back to the request.

3. Register middleware

Finally, you need to register the SensitiveWordsFilter middleware in the route or controller so that it can be used where sensitive word filtering is required. You can add a record in the $routeMiddleware array, as follows:

protected $routeMiddleware = [
    //其它中间件
    'sensitive' => \App\Http\Middleware\SensitiveWordsFilter::class,
];

In the route or controller, you can use the middleware method to register the SensitiveWordsFilter middleware to the specified route or method, as follows:

Route::get('/article', 'ArticleController@show')->middleware('sensitive');

In this way, when accessing the /article route, the SensitiveWordsFilter middleware will be automatically called to filter sensitive words.

3. Summary

Sensitive word filtering is an important means to ensure the health of the website. Using the middleware function provided by the Laravel framework, you can easily implement sensitive word filtering. In practical applications, adjustments need to be made based on the actual situation of the website, such as updating sensitive vocabulary lists, limiting the number of substitutions, recording filtering information, etc.

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