Google文本语音转换API每个请求都有一个配额-5000个字符。因此，我们有一个HTML页面，该页面需要分成多个部分，并且不超过5000个字符，并且保留单词和html标签。
以下是输入HTML的示例（例如，经过简化）：
<div id="myID">
<span class="test">
Links in PHP are a means of accessing the contents of one variable under different names.
</span>
<span>
They are not like pointers in C and are not aliases for the symbol table.
</span>
</div>
<p>
In PHP, the name of a variable and its contents are different things, so one content can have different names.
</p>
假设我们将文本（仅文本）划分为70个字符的片段，同时保留了标记并且不破坏单词，结果得到：
第1部分
<div id="myID">
<span class="test">
Links in PHP are a means of accessing the contents of one variable under
</span>
</div>
第2部分
<div id="myID">
<span class="test">
different names.
</span>
<span>
They are not like pointers in C and are not aliases for the symbol table.
</span>
</div>
第3部分
<p>
In PHP, the name of a variable and its contents are different things, so one
</p>
第4部分
<p>
content can have different names.
</p>
长期以来，存在一个很好的解决方案：
/**
* Truncates text.
*
* Cuts a string to the length of $length and replaces the last characters
* with the ending if the text is longer than length.
*
* @param string $text String to truncate.
* @param integer $length Length of returned string, including ellipsis.
* @param string $ending Ending to be appended to the trimmed string.
* @param boolean $exact If true, $text will not be cut mid-word
* @param boolean $considerHtml If true, HTML tags would be handled correctly
* @return string Trimmed string.
*/
function str_truncate($text, $length = 100, $ending = '...', $exact = true, $considerHtml = false) {
if ($considerHtml) {
// if the plain text is shorter than the maximum length, return the whole text
if (strlen(preg_replace('/<.*?>/', '', $text)) <= $length) {
return $text;
}
// splits all html-tags to scanable lines
preg_match_all('/(<.+?>)?([^<>]*)/s', $text, $lines, PREG_SET_ORDER);
$total_length = strlen($ending);
$open_tags = array();
$truncate = '';
foreach ($lines as $line_matchings) {
// if there is any html-tag in this line, handle it and add it (uncounted) to the output
if (!empty($line_matchings[1])) {
// if it's an "empty element" with or without xhtml-conform closing slash (f.e. <br/>)
if (preg_match('/^<(\s*.+?\/\s*|\s*(img|br|input|hr|area|base|basefont|col|frame|isindex|link|meta|param)(\s.+?)?)>$/is', $line_matchings[1])) {
// do nothing
// if tag is a closing tag (f.e. </b>)
} else if (preg_match('/^<\s*\/([^\s]+?)\s*>$/s', $line_matchings[1], $tag_matchings)) {
// delete tag from $open_tags list
$pos = array_search($tag_matchings[1], $open_tags);
if ($pos !== false) {
unset($open_tags[$pos]);
}
// if tag is an opening tag (f.e. <b>)
} else if (preg_match('/^<\s*([^\s>!]+).*?>$/s', $line_matchings[1], $tag_matchings)) {
// add tag to the beginning of $open_tags list
array_unshift($open_tags, strtolower($tag_matchings[1]));
}
// add html-tag to $truncate'd text
$truncate .= $line_matchings[1];
}
// calculate the length of the plain text part of the line; handle entities as one character
$content_length = strlen(preg_replace('/&[0-9a-z]{2,8};|&#[0-9]{1,7};|&#x[0-9a-f]{1,6};/i', ' ', $line_matchings[2]));
if ($total_length+$content_length> $length) {
// the number of characters which are left
$left = $length - $total_length;
$entities_length = 0;
// search for html entities
if (preg_match_all('/&[0-9a-z]{2,8};|&#[0-9]{1,7};|&#x[0-9a-f]{1,6};/i', $line_matchings[2], $entities, PREG_OFFSET_CAPTURE)) {
// calculate the real length of all entities in the legal range
foreach ($entities[0] as $entity) {
if ($entity[1]+1-$entities_length <= $left) {
$left--;
$entities_length += strlen($entity[0]);
} else {
// no more characters left
break;
}
}
}
$truncate .= substr($line_matchings[2], 0, $left+$entities_length);
// maximum lenght is reached, so get off the loop
break;
} else {
$truncate .= $line_matchings[2];
$total_length += $content_length;
}
// if the maximum length is reached, get off the loop
if($total_length>= $length) {
break;
}
}
} else {
if (strlen($text) <= $length)
return $text;
else
$truncate = substr($text, 0, $length - strlen($ending));
}
// if the words shouldn't be cut in the middle...
if ($exact) {
// ...search the last occurance of a space...
$spacepos = strrpos($truncate, ' ');
if (isset($spacepos)) {
// ...and cut the text in this position
$truncate = substr($truncate, 0, $spacepos);
}
}
// add the defined ending to the text
$truncate .= $ending;
if($considerHtml) {
// close all unclosed html-tags
foreach ($open_tags as $tag)
$truncate .= '</' . $tag . '>';
}
return $truncate;
}
它的唯一缺点是我们只获得HTML的第一部分。如果不仅可以得到第一部分，而且可以得到结尾，那将是理想的选择。
任何线索挖掘，我将不胜感激。