我试图编写一个脚本来执行以下操作：
- 从文件或数据库中读取内容
- 从内容中提取所有锚标签
- 扫描所有链接并保留允许的链接，例如指向社交网络、搜索引擎或权威域的链接，并删除其余链接，同时保留其内容（锚文本）。
示例内容：
<p><a rel="nofollow" href="http://www.test.com/tyest">test1</a></p>
<p><a href="http://google.com">google</a></p>
<p><a title="This is just a check" href="http://www.check.com">check</a></p>
<p><a rel="nofollow" href="http://www.ip.com">http://www.ip.com</a></p>
允许的域：
google.com
msn.com
ip.com
期望的输出：
<p>test1</p>
<p><a href="http://google.com">google</a></p>
<p>check</p>
<p><a rel="nofollow" href="http://www.ip.com">http://www.ip.com</a></p>
限制：
- 锚标签将不遵循任何特定规则，并且可以包含或不包含 rel、title、description 属性和任何顺序。
- 锚文本本身也可以是一个链接，例如： http: //google.com，即使链接不被允许，也应该保留。
我做了功课并尝试编写一个简单的裸级脚本来使用不同的正则表达式以及在线提供的帮助来开始初始工作，但没有成功。这是我的代码：
// sample input
$comment = '<p><a rel="nofollow" href="http://www.1google.com/tyest">test with no http</a></p>
<p><a rel="nofollow" href="http://google.com">just a domain name</a></p>
<p><a rel="nofollow" href="http://www.g1gle.com">check</a></p>
<p><a rel="nofollow" href="http://www.ip.com">http://www.ip.com</a></p>
<p><a rel="nofollow" href="http://osamashabrez.com">http://testx.osamashabrez.com</a></p>
<p><a rel="nofollow" href="http://www.subchalega.com">http://www.subchalega.com</a></p>
<p><a rel="nofollow" href="http://www.letscheck.com">http://www.letscheck.com</a></p>
<p><a rel="nofollow" href="http://www.google.com/osama/here/">http://www.google.com</a></p>
<p><a rel="nofollow" description="testing" title="google" href="http://www.google.com/last/">laaaaaaaa</a></p><h1>Header one</h1>
<p><a rel="nofollow" href="http://domain1.com">http://testx.osamashabrez.com</a></p>';
// add http to the domain name if not already present
function addhttp($url) {
if (!preg_match('~^(?:f|ht)tps?://~i', $url)) {
$url = 'http://' . $url;
}
return $url;
}
// removed deep links to match with the allowed URLS
function removeDeepLinks($url) {
$pos = strrpos ( $url, '.com' );
if ( $pos !== false )
return substr( $url, 6, $pos-2 );
return $url;
}
// allowed domains fetched from the db
$domains = "http://osamashabrez.com\rhttp://google.com\rwordpress.org\rabc.com";
$domains = preg_split( "~\r~", $domains, -1, PREG_SPLIT_NO_EMPTY );
// adding http if not already present
// will be done one when data will be inserted
foreach ( $domains as $key => $domain ) { $domains[$key] = addhttp($domain); }
// remove this and sky will fall on your head :D
sort( $domains );
print_r ( $domains );
// regex to extract href="xyz.com" link as we can not use any other option
// due to the uncertainity of data passed to this script
$regex = '/(href=".*?")/is';
if ($c=preg_match_all ($regex, $comment, $matches)) {
$matches = $matches[1];
foreach ( $matches as $key => $url ) {
// remove deep links for matching
$matches[$key] = removeDeepLinks($url);
}
print_r($matches);
foreach( $matches as $key => $url ) {
// if domain is not allowed
if ( !array_search( $url, $domains ) ) {
// find position of URL
$pos_url = strrpos( $comment, $url );
// fint the starting position of anchor tag
$pos_a_start = strrpos(substr($comment, 0, $pos_url), '<a ');
// fint the end
$pos_a_end = strpos($comment, '</a>',$pos_url);
// extract the whole anchor tag
$anchor_tag = substr($comment, $pos_a_start, $pos_a_end - $pos_a_start + 4);
echo "URL:\t" .$url . "\r";
echo "Anchor Tag:\t{$anchor_tag}\r";
echo "POS START :: END:\t{$pos_a_start}::{$pos_a_end}\r";
// something weired goes where commenting this line works but only the opening
// tags are removed from the text
// the code does work with some data inputs and does not work with a few others
$comment = substr($comment, 0, $pos_a_end) . substr($comment, $pos_a_end+4);
// removing opening tags
$opening_tag = substr( $anchor_tag, 0, strpos($anchor_tag, '>') +1 );
$comment = str_replace($opening_tag, '', $comment);
}
}
}
echo $comment;
上面的代码正在处理一些数据输入和其他中断，我想获得一些帮助，工作代码示例或对我提供的代码的审查。还要提及是否有更好的方法来完成工作。任何帮助将不胜感激。
谢谢