adding rel=“nofollow” while saving data
Question
I have my application to allow users to write comments on my website. Its working fine. I also have tool to insert their weblinks in it. I feel good with contents with their own weblinks.
Now i want to add rel="nofollow" to every links on content that they have been written.
I would like to add rel="nofollow" using php ie while saving data.
So what's a simple method to add rel="nofollow" or updated rel="someother" with rel="someother nofollow" using php
a nice example will be much efficient
3 answers
solution1
18 ACCPTED 2011-05-01 12:14:55
Regexs really aren't the best tool for dealing with HTML, especially when PHP has a pretty good HTML parser built in.
This code will handle adding nofollow if the rel attribute is already populated.
$dom = new DOMDocument;
$dom->loadHTML($str);
$anchors = $dom->getElementsByTagName('a');
foreach($anchors as $anchor) {
$rel = array();
if ($anchor->hasAttribute('rel') AND ($relAtt = $anchor->getAttribute('rel')) !== '') {
$rel = preg_split('/\s+/', trim($relAtt));
}
if (in_array('nofollow', $rel)) {
continue;
}
$rel[] = 'nofollow';
$anchor->setAttribute('rel', implode(' ', $rel));
}
var_dump($dom->saveHTML());
CodePad .
The resulting HTML is in $dom->saveHTML() . Except it will wrap it with html , body elements, etc, so use this to extract just the HTML you entered...
$html = '';
foreach($dom->getElementsByTagName('body')->item(0)->childNodes as $element) {
$html .= $dom->saveXML($element, LIBXML_NOEMPTYTAG);
}
echo $html;
If you have >= PHP 5.3, replace saveXML() with saveHTML() and drop the second argument.
Example
This HTML...
<a href="">hello</a>
<a href="" rel="">hello</a>
<a href="" rel="hello there">hello</a>
<a href="" rel="nofollow">hello</a>
...is converted into...
<a href="" rel="nofollow">hello</a>
<a href="" rel="nofollow">hello</a>
<a href="" rel="hello there nofollow">hello</a>
<a href="" rel="nofollow">hello</a>
solution2
2 2011-05-27 09:36:49
Good Alex. If it is in the form of a function it is more useful. So I made it below:
function add_no_follow($str){
$dom = new DOMDocument;
$dom->loadHTML($str);
$anchors = $dom->getElementsByTagName('a');
foreach($anchors as $anchor) {
$rel = array();
if ($anchor->hasAttribute('rel') AND ($relAtt = $anchor->getAttribute('rel')) !== '') {
$rel = preg_split('/\s+/', trim($relAtt));
}
if (in_array('nofollow', $rel)) {
continue;
}
$rel[] = 'nofollow';
$anchor->setAttribute('rel', implode(' ', $rel));
}
$dom->saveHTML();
$html = '';
foreach($dom->getElementsByTagName('body')->item(0)->childNodes as $element) {
$html .= $dom->saveXML($element, LIBXML_NOEMPTYTAG);
}
return $html;
}
Use as follows:
$str = "Some content with link Some content ... "; $str = add_no_follow($str);
solution3
0 2016-01-15 10:47:50
I've copied Alex's answer and made it into a function that makes links nofollow and open in a new tab/window (and added UTF-8 support). I'm not sure if this is the best way to do this, but it works (constructive input is welcome):
function nofollow_new_window($str)
{
$dom = new DOMDocument;
$dom->loadHTML($str);
$anchors = $dom->getElementsByTagName('a');
foreach($anchors as $anchor)
{
$rel = array();
if ($anchor->hasAttribute('rel') AND ($relAtt = $anchor->getAttribute('rel')) !== '') {
$rel = preg_split('/\s+/', trim($relAtt));
}
if (in_array('nofollow', $rel)) {
continue;
}
$rel[] = 'nofollow';
$anchor->setAttribute('rel', implode(' ', $rel));
$target = array();
if ($anchor->hasAttribute('target') AND ($relAtt = $anchor->getAttribute('target')) !== '') {
$target = preg_split('/\s+/', trim($relAtt));
}
if (in_array('_blank', $target)) {
continue;
}
$target[] = '_blank';
$anchor->setAttribute('target', implode(' ', $target));
}
$str = utf8_decode($dom->saveHTML($dom->documentElement));
return $str;
}
Simply use the function like this:
$str = '<html><head></head><body>fdsafffffdfsfdffff dfsdaff flkklfd aldsfklffdssfdfds <a href="http://www.google.com">Google</a></body></html>';
$str = nofollow_new_window($str);
echo $str;
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