PHP implements html tag closure detection and processing

How does php implement html tag closure detection and processing? This article mainly introduces the method of detecting and repairing html tag closures in PHP, which can detect and complete the closing tags in html tags. I hope to be helpful.

The example in this article describes the method of detecting and repairing html tag closure in PHP. Share it with everyone for your reference. The details are as follows:

html tag closure detection and repair, it is a bit big, and it is not considered completely. Regular expressions are not used. It is suitable for html files that only have start tags and no end tags. Yes, there is an end tag. There is no start tag. The closing position of the label needs to be adjusted according to the needs

<?php
$str = &#39;
<p data="<li></li>">
  <img  src="/static/imghwm/default1.png"  data-src="http://www.baidu.com/123123.png"  class="lazy"  / alt="PHP implements html tag closure detection and processing" >
  <p2>
    <a>content</a>
  </p2>
    <ul>
      <li>
      </li>
    </ul>
    <p>
    content full
    </p>
    this is content</test1>
    this is content</test2>
    <test4 data="liujinjing"> This is cont
    <li></li>
    <test3 data="liujinjing"> This is content
<p3>
</p3>
</p4>
</p>
</p>
<p6 style="width:90px; "> this is content&#39;;
$str_len = strlen($str);
//记录起始标签
$pre_data = array();
//记录起始标签位置
$pre_pos = array();
$last_data = array();
$error_data = array();
$error_pos = array();
$i = 0;
//标记为 < 开始
$start_flag = false;
while( $i < $str_len ) {
  if($str[$i]=="<" && $str[$i+1]!=&#39;/&#39; && $str[$i+1]!=&#39;!&#39;) {
    $i++;
    $_tmp_str = &#39;&#39;;
    //标记为 < 开始
    $start_flag = true;
    //标记空白
    $space_flag = false;
    while($str[$i]!=">" && $str[$i]!="&#39;" && $str[$i]!=&#39;"&#39; && $str[$i] !=&#39;/&#39; && $i<$str_len){
      if($str[$i]==&#39; &#39;) {
        $space_flag = true;
      }
      if(!$space_flag) {
        $_tmp_str .= $str[$i];  
      }
      $i++;
    }
    $pre_data[] = $_tmp_str;
    $pre_pos[] = $i;
  } else if ($str[$i]=="<" && $str[$i+1]==&#39;/&#39;) {
    $i += 2;
    $_tmp_str = &#39;&#39;;
    while($str[$i]!=">" && $i<$str_len){
      $_tmp_str .= $str[$i];
      $i++;
    }
    $last_data[] = $_tmp_str;
    //查看开始标签的上一个值
    if(count($pre_data)>0) {
      $last_pre_node = getLastNode($pre_data, 1);
      if($last_pre_node == $_tmp_str) {
        //配对上, 删除对应位置的值
        array_pop($pre_data);
        array_pop($pre_pos);
        array_pop($last_data);
      } else {
      //没有配对上， 有两种情况
        //情况一： 只有闭合标签， 没有开始标签
        //情况二：只有开始标签， 没有闭合标签
        array_pop($last_data);
        $error_data[] = $_tmp_str;
        $error_pos[] = $i;
      }
    } else {
        array_pop($last_data);
        $error_data[] = $_tmp_str;
        $error_pos[] = $i;      
    }
  }else if ($str[$i]=="<" && $str[$i+1]=="!") {
    $i++;
    while($i<$str_len) {
      if($str[$i]=="-" && $str[$i+1]=="-" && $str[$i+2]==">") {
        $i++;
        break;
      } else {
        $i++;
      }
    }
    $i++;
  }else if($str[$i]==&#39;/&#39; && $str[$i+1]==&#39;>&#39;) {
    //跳过自动单个闭合标签
    if($start_flag) {
      array_pop($pre_data);
      array_pop($pre_pos);
      $i+=2;
    }
  }else if($str[$i]=="/" && $str[$i+1]=="*"){
    $i++;
    while($i<$str_len) {
      if($str[$i]=="*" && $str[$i+1]=="/") {
        $i++;
        break;
      } else {
        $i++;
    }
    $i++;
  }
  }else if($str[$i]=="&#39;"){
    $i++;
    while($str[$i]!="&#39;" && $i<$str_len) {
      $i++;
    }
    $i++;
  } else if($str[$i]==&#39;"&#39;){
    $i++;
    while($str[$i]!=&#39;"&#39; && $i<$str_len ) {
      $i++;
    }
    $i++;
  } else {
    $i++;
  }
}
//确定起始标签的位置
function confirm_pre_pos($str, $pre_pos){
  $str_len = strlen($str);
  $j=$pre_pos;
  while($j < $str_len) {
    if($str[$j] == &#39;"&#39;) {
      $j++;
      while ($j<$str_len) {
        if($str[$j]==&#39;"&#39;) {
          $j++;
          break;
        }
        $j++;
      }
    }
    else if($str[$j] == "&#39;") {
      $j++;
      while ($j<$str_len) {
        if($str[$j]=="&#39;") {
          $j++;
          break;
        }
        $j++;
      }
    }
    else if($str[$j]==">") {
      $j++;
      while ($j<$str_len) {
        if($str[$j]=="<") {
          //退回到原有内容位置
          $j--;
          break;
        }
        $j++;
      }
      break;
    } 
    else {
      $j++;
    }
  }
  return $j;
}
//确定起始标签的位置
function confirm_err_pos($str, $err_pos){
  $j=$err_pos;
  $j--;
  while($j > 0) {
    if($str[$j] == &#39;"&#39;) {
      $j--;
      while ($j<$str_len) {
        if($str[$j]==&#39;"&#39;) {
          $j--;
          break;
        }
        $j--;
      }
    }
    else if($str[$j] == "&#39;") {
      $j--;
      while ($j<$str_len) {
        if($str[$j]=="&#39;") {
          $j--;
          break;
        }
        $j--;
      }
    }
    else if($str[$j]==">") {
      $j++;
      break;
    } 
    else {
      $j--;
    }
  }
  return $j;
}
//获取数组的倒数第num个值
function getLastNode(array $arr, $num){
  $len = count($arr);
  if($len > $num) {
    return $arr[$len-$num];
  } else {
    return $arr[0];
  }
}
//整理数据， 主要是向后看， 进一步进行检查
function sort_data(&$pre_data, &$pre_pos, &$error_data, &$error_pos){
  $rem_key_array = array();
  $rem_i_array = array();
  //获取需要删除的值
  foreach($error_data as $key=>$value){
    $count = count($pre_data);
    for($i=($count-1) ; $i>=0; $i--) {
      if($pre_data[$i] == $value && !in_array($i, $rem_i_array)) {
        $rem_key_array[] = $key;
        $rem_i_array[] = $i;
        break;
      }
    }
  }
  //删除起始标签相应的值
  foreach($rem_key_array as $_item) {
    unset($error_pos[$_item]);
    unset($error_data[$_item]);
  }
  //删除结束标签相应的值
  foreach($rem_i_array as $_item) {
    unset($pre_data[$_item]);
    unset($pre_pos[$_item]);
  }
}
//整理数据， 闭合标签
function modify_data($str, $pre_data, $pre_pos, $error_data, $error_pos){
  $move_log = array();
  //只有闭合标签的数据
  foreach ($error_data as $key => $value) {
    // code...
    $_tmp_move_count = 0;
    foreach ($move_log as $pos_key => $move_value) {
      // code...
      if($error_pos[$key]>=$pos_key) {
        $_tmp_move_count += $move_value;
      }
    }
    $data = insert_data($str, $value, $error_pos[$key]+$_tmp_move_count, false);
    $str = $data[&#39;str&#39;];
    $move_log[$data[&#39;pos&#39;]] = $data[&#39;move_count&#39;];
  }
  //只有起始标签的数据
  foreach ($pre_data as $key => $value) {
    // code...
    $_tmp_move_count = 0;
    foreach ($move_log as $pos_key => $move_value) {
      // code...
      if($pre_pos[$key]>=$pos_key) {
        $_tmp_move_count += $move_value;
      }
    }
    $data = insert_data($str, $value, $pre_pos[$key]+$_tmp_move_count, true);
    $str = $data[&#39;str&#39;];
    $move_log[$data[&#39;pos&#39;]] = $data[&#39;move_count&#39;];
  }
  return $str;
}
//插入数据， $type 表示插入数据的方式
function insert_data($str, $insert_data, $pos, $type) {
  $len = strlen($str);
  //起始标签类型
  if($type==true) {
    $move_count = strlen($insert_data)+3;
    $pos = confirm_pre_pos($str, $pos);
    $pre_str = substr($str, 0, $pos);
    $end_str = substr($str, $pos);
    $mid_str = "</" . $insert_data . ">";
  //闭合标签类型
  } else {
    $pos = confirm_err_pos($str, $pos);
    $move_count = strlen($insert_data) + 2;
    $pre_str = substr($str, 0, $pos);
    $end_str = substr($str, $pos);
    $mid_str = "<" . $insert_data . ">";
  }
  $str = $pre_str.$mid_str.$end_str;
  return array(&#39;str&#39;=>$str, &#39;pos&#39;=>$pos, &#39;move_count&#39;=>$move_count);
}
sort_data($pre_data, $pre_pos, $error_data, $error_pos);
$new_str = modify_data($str, $pre_data, $pre_pos, $error_data, $error_pos);
echo $new_str;
// print_r($pre_data);
// print_r($pre_pos);
// print_r($error_data);
// print_r($error_pos);
// echo strlen($str);
// foreach($pre_pos as $value){
//   $value = confirm_pre_pos($str, $value);
//   for($i=$value-5; $i<=$value; $i++) {
//     echo $str[$i];
//   }
//   echo "\n";
// }
// foreach($error_pos as $value){
//   for($i=$value-5; $i<=$value; $i++) {
//     echo $str[$i];
//   }
//   echo "\n";
// }
?>

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