在保留格式且不破坏HTML的情况下使用PHP substr（）和strip_tags（）

Question

我有各种HTML字符串可以切成100个字符（已剥离内容的内容，而不是原始内容），而不剥离标签且不破坏HTML。

原始HTML字符串 （288个字符）：

$content = "<div>With a <span class='spanClass'>span over here</span> and a
<div class='divClass'>nested div over <div class='nestedDivClass'>there</div>
</div> and a lot of other nested <strong><em>texts</em> and tags in the air
<span>everywhere</span>, it's a HTML taggy kind of day.</strong></div>";

标准修剪： 修剪至100个字符和HTML中断，剥离的内容约40个字符：

$content = substr($content, 0, 100)."..."; /* output:
<div>With a <span class='spanClass'>span over here</span> and a
<div class='divClass'>nested div ove... */

剥离的HTML： 输出正确的字符数，但显然失去了格式设置：

$content = substr(strip_tags($content)), 0, 100)."..."; /* output:
With a span over here and a nested div over there and a lot of other nested
texts and tags in the ai... */

局部解决方案： 使用HTML Tidy或Purifier关闭标签可输出干净的HTML，但100个字符的HTML不会显示内容。

$content = substr($content, 0, 100)."...";
$tidy = new tidy; $tidy->parseString($content); $tidy->cleanRepair(); /* output:
<div>With a <span class='spanClass'>span over here</span> and a
<div class='divClass'>nested div ove</div></div>... */

挑战： 要输出干净的HTML和 n个 字符（不包括HTML元素的字符数）：

$content = cutHTML($content, 100); /* output:
<div>With a <span class='spanClass'>span over here</span> and a
<div class='divClass'>nested div over <div class='nestedDivClass'>there</div>
</div> and a lot of other nested <strong><em>texts</em> and tags in the
ai</strong></div>...";

Answer 1

并不令人惊讶，但可以。

function html_cut($text, $max_length)
{
    $tags   = array();
    $result = "";

    $is_open   = false;
    $grab_open = false;
    $is_close  = false;
    $in_double_quotes = false;
    $in_single_quotes = false;
    $tag = "";

    $i = 0;
    $stripped = 0;

    $stripped_text = strip_tags($text);

    while ($i < strlen($text) && $stripped < strlen($stripped_text) && $stripped < $max_length)
    {
        $symbol  = $text{$i};
        $result .= $symbol;

        switch ($symbol)
        {
           case '<':
                $is_open   = true;
                $grab_open = true;
                break;

           case '"':
               if ($in_double_quotes)
                   $in_double_quotes = false;
               else
                   $in_double_quotes = true;

            break;

            case "'":
              if ($in_single_quotes)
                  $in_single_quotes = false;
              else
                  $in_single_quotes = true;

            break;

            case '/':
                if ($is_open && !$in_double_quotes && !$in_single_quotes)
                {
                    $is_close  = true;
                    $is_open   = false;
                    $grab_open = false;
                }

                break;

            case ' ':
                if ($is_open)
                    $grab_open = false;
                else
                    $stripped++;

                break;

            case '>':
                if ($is_open)
                {
                    $is_open   = false;
                    $grab_open = false;
                    array_push($tags, $tag);
                    $tag = "";
                }
                else if ($is_close)
                {
                    $is_close = false;
                    array_pop($tags);
                    $tag = "";
                }

                break;

            default:
                if ($grab_open || $is_close)
                    $tag .= $symbol;

                if (!$is_open && !$is_close)
                    $stripped++;
        }

        $i++;
    }

    while ($tags)
        $result .= "</".array_pop($tags).">";

    return $result;
}

用法示例：

$content = html_cut($content, 100);