新增DFA算法过滤敏感词

2020-06-17 23:02:52 +08:00 · 2020-06-17 23:02:52 +08:00 · 4fc4577be3
commit 4fc4577be3
parent dec79f2b28
1 changed files with 140 additions and 0 deletions
--- a/extend/catcher/library/Trie.php
+++ b/extend/catcher/library/Trie.php
@ -1 +1,141 @@
 <?php
+namespace catcher\library;
+
+use catcher\CatchCacheKeys;
+use think\facade\Cache;
+
+class Trie
+{
+    protected  $tree = [];
+
+    protected $end = 'end';
+
+    protected $sensitiveWord = '';
+
+    protected $sensitiveWords = [];
+
+    /**
+     * add
+     *
+     * @time 2020年06月17日
+     * @param string $word
+     * @return $this
+     */
+    public function add(string $word)
+    {
+        $words = mb_str_split($word);
+
+        $array = [];
+
+        $len = count($words);
+
+        $end = true;
+        while ($len > 0) {
+             if ($end) {
+                 $array[] = [
+                     $words[$len - 1] => ['end' => true],
+                 ];
+             } else {
+                $latest = array_pop($array);
+                $array[] = [
+                    $words[$len-1] => $latest,
+                ];
+             }
+             $end = false;
+             $len--;
+        }
+
+        $this->tree = array_merge_recursive($this->tree, array_pop($array));
+
+        return $this;
+    }
+
+    /**
+     * 获取
+     *
+     * @time 2020年06月17日
+     * @throws \Psr\SimpleCache\InvalidArgumentException
+     * @return array|bool
+     */
+    public function getTries()
+    {
+        if (!empty($this->tree)) {
+            return $this->tree;
+        }
+
+        return Cache::store('redis')->get(CatchCacheKeys::TRIE_TREE);
+    }
+
+    /**
+     * 获取敏感词
+     *
+     * @time 2020年06月17日
+     * @param array $trieTree
+     * @param string $content
+     * @param bool $all
+     * @return array|string
+     */
+    public function getSensitiveWords(array $trieTree, string $content, $all = true)
+    {
+        $words = mb_str_split($content);
+        $len = count($words);
+        for ($start = 0; $start < $len; $start++) {
+            // 未搜索到
+            if (!isset($trieTree[$words[$start]]))  {
+                continue;
+            }
+            $node = $trieTree[$words[$start]];
+            $this->sensitiveWord = $words[$start];
+            for ($i = $start+1; $i< $len; $i++) {
+                $node = $node[$words[$i]] ?? null;
+                $this->sensitiveWord .= $words[$i];
+                if (isset($node['end'])) {
+                    if ($all) {
+                        $this->sensitiveWords[] = $this->sensitiveWord;
+                        $this->sensitiveWord = '';
+                    } else {
+                       break 2;
+                    }
+                }
+                if (!$node) {
+                    $this->sensitiveWord = '';
+                    $start = $i-1;
+                    break;
+                }
+            }
+        }
+
+        return $all ? $this->sensitiveWords : $this->sensitiveWord;
+    }
+
+    /**
+     * replace
+     *
+     * @time 2020年06月17日
+     * @param $tree
+     * @param string $content
+     * @return string|string[]
+     */
+    public function replace($tree, string $content)
+    {
+        $sensitiveWords = $this->getSensitiveWords($tree, $content);
+
+        $replace = [];
+
+        foreach ($sensitiveWords as $word) {
+            $replace[] = str_repeat('*', mb_strlen($word));
+        }
+
+        return str_replace($sensitiveWords, $replace, $content);
+    }
+
+    /**
+     * cache
+     *
+     * @time 2020年06月17日
+     */
+    public function cached()
+    {
+        Cache::store('redis')->set(CatchCacheKeys::TRIE_TREE, $this->tree);
+    }
+}