<?php
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class sensitive
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{
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private static $instance = null;
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/**
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* 替换符号
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* @var string
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*/
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private static $replaceSymbol = "*";
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/**
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* 敏感词树
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* @var array
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*/
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private static $sensitiveWordTree = [];
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private function __construct(){}
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/**
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* 获取实例
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*/
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public static function getInstance()
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{
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if (!(self::$instance instanceof Sensitive)) {
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return self::$instance = new self;
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}
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return self::$instance;
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}
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/**
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* @desc 添加敏感词，组成树结构。
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* @param $file_path:敏感词库文件路径
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*/
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public static function addSensitiveWords($file_path)
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{
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$file_path = (string)$file_path;
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foreach (self::readFile($file_path) as $words) {
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$len = mb_strlen($words);
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$treeArr = &self::$sensitiveWordTree;
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for ($i = 0; $i < $len; $i++) {
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$word = mb_substr($words, $i, 1);
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//敏感词树结尾记录状态为false；
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$treeArr = &$treeArr[$word];
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if(!isset($treeArr)){
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$treeArr = false;
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}
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}
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}
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}
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/**
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* 执行过滤
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* @param string $txt
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* @return string
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*/
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public static function execFilter($txt)
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{
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$txt = (string)$txt;
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$wordList = self::searchWords($txt);
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if(empty($wordList)){
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return $txt;
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}else{
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return strtr($txt,$wordList);
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}
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}
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/**
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* 搜索敏感词
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* @param string $txt
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* @return array
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*/
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private static function searchWords($txt)
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{
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$txt = (string)$txt;
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$txtLength = mb_strlen($txt);
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$wordList = array();
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for($i = 0; $i < $txtLength; $i++){
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//检查字符是否存在敏感词树内,传入检查文本、搜索开始位置、文本长度
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$len = self::checkWordTree($txt,$i,$txtLength);
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//存在敏感词，进行字符替换。
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if($len > 0){
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//搜索出来的敏感词
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$word = mb_substr($txt,$i,$len);
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$wordList[$word] = str_repeat(self::$replaceSymbol,$len);
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}
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}
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return $wordList;
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}
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/**
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* 检查敏感词树是否合法
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* @param string $txt 检查文本
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* @param int $index 搜索文本位置索引
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* @param int $txtLength 文本长度
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* @return int 返回不合法字符个数
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*/
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private static function checkWordTree($txt, $index, $txtLength)
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{
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$txt = (string)$txt;
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$index = (int)$index;
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$txtLength = (int)$txtLength;
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$treeArr = &self::$sensitiveWordTree;
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$wordLength = 0;//敏感字符个数
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$flag = false;
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for($i = $index; $i < $txtLength; $i++){
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$txtWord = mb_substr($txt,$i,1); //截取需要检测的文本，和词库进行比对
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//如果搜索字不存在词库中直接停止循环。
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if(!isset($treeArr[$txtWord])) break;
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if($treeArr[$txtWord] !== false){//检测还未到底
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$treeArr = &$treeArr[$txtWord]; //继续搜索下一层tree
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}else{
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$flag = true;
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}
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$wordLength++;
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}
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//没有检测到敏感词，初始化字符长度
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$flag ?: $wordLength = 0;
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return $wordLength;
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}
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/**
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* 读取文件内容
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* @param string $file_path
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* @return Generator
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*/
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private static function readFile($file_path)
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{
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$file_path = (string)$file_path;
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$handle = fopen($file_path, 'r');
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while (!feof($handle)) {
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yield trim(fgets($handle));
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}
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fclose($handle);
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}
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private function __clone()
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{
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throw new \Exception("clone instance failed!");
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}
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private function __wakeup()
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{
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throw new \Exception("unserialize instance failed!");
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}
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}
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?>
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