Zend Framework学习之Zend_Filter_StripTags

Strip Tags HTML字符过滤器与Zend_Filter_HtmlEntities过滤器不同，
后者只是将“<”、“>”符号进行转换。而Zend_Filter_StripTags过滤器则是直接过滤掉“<>”符号所包含的内容。 

案例：

<?php
require_once 'Zend/Filter/StripTags.php';
$filter = new Zend_Filter_StripTags();
$temp1 = "<img src = './1.png' width='100px'>";
$temp2 = "<button>aaa</button>";
$temp3 = "<h1>Welcome to Bei Jing</h1>";

echo "内容:".$temp1."<p>经过过滤为：";
echo $filter->filter($temp1);
echo "<p>";

echo "内容:".$temp2."<p>经过过滤为：";
echo $filter->filter($temp2);
echo "<p>";

echo "内容:".$temp3."<p>经过过滤为：";
echo $filter->filter($temp3);
echo "<p>";

结果：

Zend源码分析：

public function filter($value)
    {
        $value = (string) $value;

        // Strip HTML comments first
        while (strpos($value, '<!--') !== false) {
            $pos   = strrpos($value, '<!--');
            $start = substr($value, 0, $pos);
            $value = substr($value, $pos);

            // If there is no comment closing tag, strip whole text
            if (!preg_match('/--\s*>/s', $value)) {
                $value = '';
            } else {
                $value = preg_replace('/<(?:!(?:--[\s\S]*?--\s*)?(>))/s', '',  $value);
            }

            $value = $start . $value;
        }

        // Initialize accumulator for filtered data
        $dataFiltered = '';
        // Parse the input data iteratively as regular pre-tag text followed by a
        // tag; either may be empty strings
        preg_match_all('/([^<]*)(<?[^>]*>?)/', (string) $value, $matches);

        // Iterate over each set of matches
        foreach ($matches[1] as $index => $preTag) {
            // If the pre-tag text is non-empty, strip any ">" characters from it
            if (strlen($preTag)) {
                $preTag = str_replace('>', '', $preTag);
            }
            // If a tag exists in this match, then filter the tag
            $tag = $matches[2][$index];
            if (strlen($tag)) {
                $tagFiltered = $this->_filterTag($tag);
            } else {
                $tagFiltered = '';
            }
            // Add the filtered pre-tag text and filtered tag to the data buffer
            $dataFiltered .= $preTag . $tagFiltered;
        }

        // Return the filtered data
        return $dataFiltered;
    }

我表示看不打懂。。。哈哈哈~