php-自动换行/剪切HTML字符串中的文本
作者：互联网
在这里,我想做的是：我有一个包含HTML标签的字符串,并且我想使用除HTML标签之外的自动换行功能将其剪切.
我被卡住了：
public function textWrap($string, $width)
{
$dom = new DOMDocument();
$dom->loadHTML($string);
foreach ($dom->getElementsByTagName('*') as $elem)
{
foreach ($elem->childNodes as $node)
{
if ($node->nodeType === XML_TEXT_NODE)
{
$text = trim($node->nodeValue);
$length = mb_strlen($text);
$width -= $length;
if($width <= 0)
{
// Here, I would like to delete all next nodes
// and cut the current nodeValue and finally return the string
}
}
}
}
}
我不确定目前是否以正确的方式进行操作.我希望这很清楚…
编辑：
这里举个例子.我有这句话
<p>
<span class="Underline"><span class="Bold">Test to be cut</span></span>
</p><p>Some text</p>
假设我想在第6个字符处剪切它,我想返回以下内容：
<p>
<span class="Underline"><span class="Bold">Test to</span></span>
</p>
解决方法:
正如我在评论中所写,您首先需要找到要进行剪切的文本偏移量.
首先,我设置一个包含HTML片段的DOMDocument,然后选择在DOM中表示它的正文：
$htmlFragment = <<<HTML
<p>
<span class="Underline"><span class="Bold">Test to be cut</span></span>
</p><p>Some text </p>
HTML;
$dom = new DOMDocument();
$dom->loadHTML($htmlFragment);
$parent = $dom->getElementsByTagName('body')->item(0);
if (!$parent)
{
throw new Exception('Parent element not found.');
}
然后,我使用TextRange类找到需要剪切的地方,并使用TextRange实际进行剪切,并找到应该成为片段最后一个节点的DOMNode：
$range = new TextRange($parent);
// find position where to cut the HTML textual represenation
// by looking for a word or the at least matching whitespace
// with a regular expression.
$width = 17;
$pattern = sprintf('~^.{0,%d}(?<=\S)(?=\s)|^.{0,%1$d}(?=\s)~su', $width);
$r = preg_match($pattern, $range, $matches);
if (FALSE === $r)
{
throw new Exception('Wordcut regex failed.');
}
if (!$r)
{
throw new Exception(sprintf('Text "%s" is not cut-able (should not happen).', $range));
}
此正则表达式查找在$range可用的文本表示形式中剪切内容的偏移量.正则表达式模式为inspired by another answer,对其进行了更详细的讨论,并进行了略微修改以适应此答案的需求.
// chop-off the textnodes to make a cut in DOM possible
$range->split($matches[0]);
$nodes = $range->getNodes();
$cutPosition = end($nodes);
由于可能没有什么要剪裁的(例如,主体将变空),我需要处理这种特殊情况.否则,如注释中所述,需要删除以下所有节点：
// obtain list of elements to remove with xpath
if (FALSE === $cutPosition)
{
// if there is no node, delete all parent children
$cutPosition = $parent;
$xpath = 'child::node()';
}
else
{
$xpath = 'following::node()';
}
其余的很简单：查询xpath,删除节点并输出结果：
// execute xpath
$xp = new DOMXPath($dom);
$remove = $xp->query($xpath, $cutPosition);
if (!$remove)
{
throw new Exception('XPath query failed to obtain elements to remove');
}
// remove nodes
foreach($remove as $node)
{
$node->parentNode->removeChild($node);
}
// inner HTML (PHP >= 5.3.6)
foreach($parent->childNodes as $node)
{
echo $dom->saveHTML($node);
}
完整的代码示例为available on viper codepad incl. TextRange类.键盘有一个错误,因此结果不正确(相关：XPath query result order).实际输出如下：
<p>
<span class="Underline"><span class="Bold">Test to</span></span></p>
因此,请确保您具有当前的libxml版本(通常是这种情况),并且最后的foreach输出使用了PHP函数saveHTML,该函数自PHP 5.3.6起就可以使用该参数.如果您没有该PHP版本,请采用How to get the xml content of a node as a string?中概述的替代方法或类似问题.
当您仔细查看我的示例代码时,您可能会注意到剪切长度非常大($width = 17;).那是因为文本前面有很多空白字符.可以通过使正则表达式在其前面删除任意数量的空格和/或通过首先修剪TextRange来进行调整.第二个选项确实需要更多功能,我写了一些快速的东西,可以在创建初始范围后使用：
...
$range = new TextRange($parent);
$trimmer = new TextRangeTrimmer($range);
$trimmer->trim();
...
这样可以删除HTML片段内左右两侧不必要的空格. TextRangeTrimmer代码如下：
class TextRangeTrimmer
{
/**
* @var TextRange
*/
private $range;
/**
* @var array
*/
private $charlist;
public function __construct(TextRange $range, Array $charlist = NULL)
{
$this->range = $range;
$this->setCharlist($charlist);
}
/**
* @param array $charlist list of UTF-8 encoded characters
* @throws InvalidArgumentException
*/
public function setCharlist(Array $charlist = NULL)
{
if (NULL === $charlist)
$charlist = str_split(" \t\n\r\0\x0B")
;
$list = array();
foreach($charlist as $char)
{
if (!is_string($char))
{
throw new InvalidArgumentException('Not an Array of strings.');
}
if (strlen($char))
{
$list[] = $char;
}
}
$this->charlist = array_flip($list);
}
/**
* @return array characters
*/
public function getCharlist()
{
return array_keys($this->charlist);
}
public function trim()
{
if (!$this->charlist) return;
$this->ltrim();
$this->rtrim();
}
/**
* number of consecutive charcters of $charlist from $start to $direction
*
* @param array $charlist
* @param int $start offset
* @param int $direction 1: forward, -1: backward
* @throws InvalidArgumentException
*/
private function lengthOfCharacterSequence(Array $charlist, $start, $direction = 1)
{
$start = (int) $start;
$direction = max(-1, min(1, $direction));
if (!$direction) throw new InvalidArgumentException('Direction must be 1 or -1.');
$count = 0;
for(;$char = $this->range->getCharacter($start), $char !== ''; $start += $direction, $count++)
if (!isset($charlist[$char])) break;
return $count;
}
public function ltrim()
{
$count = $this->lengthOfCharacterSequence($this->charlist, 0);
if ($count)
{
$remainder = $this->range->split($count);
foreach($this->range->getNodes() as $textNode)
{
$textNode->parentNode->removeChild($textNode);
}
$this->range->setNodes($remainder->getNodes());
}
}
public function rtrim()
{
$count = $this->lengthOfCharacterSequence($this->charlist, -1, -1);
if ($count)
{
$chop = $this->range->split(-$count);
foreach($chop->getNodes() as $textNode)
{
$textNode->parentNode->removeChild($textNode);
}
}
}
}
希望这会有所帮助.
标签：word-wrap,html-parsing,html,php 来源： https://codeday.me/bug/20191202/2084944.html