How to append to all urls in a string?

Question

How should I go about appending to the end of all urls in string of html that is about to be sent out as as email? I want to add the google analytics campaign tracking to it like this:
?utm_source=email&utm_medium=email&utm_campaign=product_notify

99% of the pages will not end in '.html' and some urls might already have things like ?sr=1 at the end of them.

Answer 1

<?php
$add = array(
 'utm_source'=>'email',
 'utm_medium'=>'email'
 'utm_campaign'=>'product_notify');
$doc = new DOMDocument();
$doc->loadHTML('your html');
foreach($doc->getElementsByTagName('a') as $link){
    $url = parse_url($link->getAttribute('href'));
    $gets = isset($url['query']) ? array_merge(parse_str($url['query'])) : $add;
    $newstring = '';
    if(isset($url['scheme'])) $newstring .= $url['scheme'].'://';
    if(isset($url['host']))   $newstring .= $url['host'];
    if(isset($url['port']))   $newstring .= ':'.$url['port'];
    if(isset($url['path']))   $newstring .= $url['path'];
    $newstring .= '?'.http_build_query($gets);
    if(isset($url['fragment']))   $newstring .= '#'.$url['fragment'];
    $link->setAttribute('href',$newstring);
 }
 $html - $doc->saveHTML();
 ?>

Answer 2

Here is mine solution, simple question but quite complex solution working all over URL types with

$campaign = (object)['utm_source' => 'email', 'utm_medium' => 'email', 'utm_campaign' => 'abc'];
$host = 'www.me.com';

$html = preg_replace_callback(
        '#(<a.*?href=["\']?)(?<href>https?://[^\s"\']+)(["\']?.*?>.*?</a>)#si', function ($matches) use ($campaign, $host) {
    $url = parse_url($matches['href']);
    // if (isset($url['host']) && $url['host'] !== $host) return $matches[0];
    parse_str(isset($url['query']) ? $url['query'] : '', $query);
    $query = array_merge(
        $query, array_filter(
                  [
                      'utm_source' => $campaign->utm_source,
                      'utm_medium' => $campaign->utm_medium,
                      'utm_term' => $campaign->utm_term,
                      'utm_content' => $campaign->utm_content,
                      'utm_campaign' => $campaign->utm_campaign,
                  ]
              )
    );
    return $matches[1] . // anchor part before url
    (isset($url['scheme']) ? $url['scheme'] . '://' : '') .
    (isset($url['user']) ? $url['user'] : '') .
    (isset($url['pass']) ? (isset($url['user']) ? ':' : '') . $url['pass'] : '') .
    (isset($url['user']) || isset($url['pass']) ? '@' : '').
    (isset($url['host']) ? $url['host'] : '') .
    (isset($url['port']) ? ':' . $url['port'] : '') .
    (isset($url['path']) ? $url['path'] : '') .
    '?' . http_build_query($query) .
    (isset($url['fragment']) ? '#' . $url['fragment'] : '') .
    $matches[3]; // anchor part after URL
}, $html
);

Last part (concat URL) can be also replaced with http_build_url() but you will need HTTP extension enabled.

Code was tested on follow URLs:

<a href="http://www.me.com">Lorem</a>
<a href="http://www.me.com/">ipsum</a>
<a href="http://www.me.com/#section-2">dolor</a>
<a href="http://www.me.com/path-to-somewhere/file.php">sit</a>
<a href="http://www.me.com/?">amet</a>
<a href="http://www.me.com/?foo=bar">consectetur</a>
<a href="http://www.me.com/?foo=bar&bar=foo">consectetur</a>
<a href="http://www.NOTME.com?utm_source=XXX&utm_medium=XXX&utm_campaign=XXX">existing utm params</a>
<a href="http://user:password@www.me.com/?foo=bar#section-3">elit</a>
<a href="http://user:@www.me.com/?foo=bar#section-3">elit</a>
<a href="http://user@www.me.com?foo=bar#section-3">elit</a>

with following results:

<a href="http://www.me.com?utm_source=email&utm_medium=email&utm_campaign=abc">Lorem</a>
<a href="http://www.me.com/?utm_source=email&utm_medium=email&utm_campaign=abc">ipsum</a>
<a href="http://www.me.com/?utm_source=email&utm_medium=email&utm_campaign=abc#section-2">dolor</a>
<a href="http://www.me.com/path-to-somewhere/file.php?utm_source=email&utm_medium=email&utm_campaign=abc">sit</a>
<a href="http://www.me.com/?utm_source=email&utm_medium=email&utm_campaign=abc">amet</a>
<a href="http://www.me.com/?foo=bar&utm_source=email&utm_medium=email&utm_campaign=abc">consectetur</a>
<a href="http://www.me.com/?foo=bar&bar=foo&utm_source=email&utm_medium=email&utm_campaign=abc">consectetur</a>
<a href="http://www.NOTME.com?utm_source=email&utm_medium=email&utm_campaign=abc">existing utm params</a>
<a href="http://user:password@www.me.com/?foo=bar&utm_source=email&utm_medium=email&utm_campaign=abc#section-3">elit</a>
<a href="http://user:@www.me.com/?foo=bar&utm_source=email&utm_medium=email&utm_campaign=abc#section-3">elit</a>
<a href="http://user@www.me.com?foo=bar&utm_source=email&utm_medium=email&utm_campaign=abc#section-3">elit</a>

As you can notice, my code works for all links in HTML (not just me.com) if you want filter hostname uncomment line right after parse_url().

Answer 3

Update to @ircmaxell's answer, regex now matches even when there are attributes on the before href & code simplification.

/**
 * @param string $body
 * @param string $campaign
 * @param string $medium
 * @return mixed
 */
protected function add_analytics_tracking_to_urls($body, $campaign, $medium = 'email') {
    return preg_replace_callback('#(<a.*?href=")([^"]*)("[^>]*?>)#i', function($match) use ($campaign, $medium) {
        $url = $match[2];
        if (strpos($url, '?') === false) {
            $url .= '?';
        } else {
            $url .= '&';
        }
        $url .= 'utm_source=' . $medium . '&utm_medium=' . $medium . '&utm_campaign=' . urlencode($campaign);
        return $match[1] . $url . $match[3];
    }, $body);
}

Answer 4

My solution I've built & tested last night:

I match only the links which DO NOT already have "utm_" like query parameters, but includes links with "utm_" as a part of the path: before query params or substring of another param name like "xutm_".

For this I've used a combination of positive and negative RegEx lookahead assertions (http://php.net/manual/en/regexp.reference.assertions.php)

I have also allowed tags to have other attributes before and after href

$pattern = '/<a[^>]*href="(?=(.(?!(\?|&)utm_))*?>)[^"]*/i';

Which matches all links which do NOT have '?utm_' nor '&utm_' in href tag

Then I use a class callback function solution in order to be able pass the query parameters to be appended (as extra parameters to the callback)

class link_params{
  private $parameters;    

  function __construct($params){
    $this->parameters = $params;
  }

  function callback($matches){
    return $matches[0] . (preg_match('/\\?[^"]/', $matches[0]) ? '&' : '?') . http_build_query($this->parameters);
  }
}

Prepare query parameters that I want to add to links:

$params_to_add = array(
    'utm_source' => 'newsletter-sep13',
    'utm_medium' => 'email',
    'utm_campaign' => 'product-X'
);

$callback_helper = new link_params($params_to_add);

In the end I apply the preg_replace_callback function like this:

$html = preg_replace_callback($pattern, array($callback_helper, 'callback'), $html);

Answer 5

Well... You could do something like this:

function AppendCampaignToString($string) {
    $regex = '#(<a href=")([^"]*)("[^>]*?>)#i';
    return preg_replace_callback($regex, '_appendCampaignToString', $string);
}
function _AppendCampaignToString($match) {
    $url = $match[2];
    if (strpos($url, '?') === false) {
        $url .= '?';
    }
    $url .= '&utm_source=email&utm_medium=email&utm_campaign=product_notify';
    return $match[1].$url.$match[3];
}

That should automatically find all the links on the page (even external ones, so be careful). The ? check just makes sure that we append a query string on to it...

Edit: Fixed issue in the regex that didn't work as intended.

Answer 6

You can use the following snippet, to append your google analytics GET parameters to the existing parameters of the current script URI.

function getQuery() {

 $url = parse_url($_SERVER['REQUEST_URI']);

 return $url['query'].'&utm_source=email&utm_medium=email&utm_campaign=product_notify';
}