I have a simple commenting system where people can submit hyperlinks inside the plain text field. When I display these records back from the database and into the web page, what RegExp in PHP can I use to convert these links into HTML-type anchor links?

I do开发者_StackOverflow社区n't want the algorithm to do this with any other kind of link, just http and https.

Here is another solution, This will catch all http/https/www and convert to clickable links.

$url = '~(?:(https?)://([^\s<]+)|(www\.[^\s<]+?\.[^\s<]+))(?<![\.,:])~i'; 
$string = preg_replace($url, '<a href="$0" target="_blank" title="$0">$0</a>', $string);
echo $string;

Alternatively for just catching http/https then use the code below.

$url = '/(http|https|ftp|ftps)\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(\/\S*)?/';   
$string= preg_replace($url, '<a href="$0" target="_blank" title="$0">$0</a>', $string);
echo $string;

EDIT: The script below will catch all URL types and convert them to clickable links.

$url = '@(http)?(s)?(://)?(([a-zA-Z])([-\w]+\.)+([^\s\.]+[^\s]*)+[^,.\s])@';
$string = preg_replace($url, '<a href="http$2://$4" target="_blank" title="$0">$0</a>', $string);
echo $string;

The new update, If you're having the string strip the (s) then use the below code block, Thanks to @AndrewEllis for pointing this out.

$url = '@(http(s)?)?(://)?(([a-zA-Z])([-\w]+\.)+([^\s\.]+[^\s]*)+[^,.\s])@';
$string = preg_replace($url, '<a href="http$2://$4" target="_blank" title="$0">$0</a>', $string);
echo $string;

Here's a very simple solution for the URL not displaying correctly.

$email = '<a href="mailto:email@email.com">email@email.com</a>';
$string = $email;
echo $string;

It is a very simple fix but you will have to modify it for your own purpose.

I've provided multiple answers as some servers are set up differently, so one answer may work for some but not for others, but I hope the answer(s) work for you and if not then let me know, and hopefully, I can come up with another solution.

There are multiple scripts as some PHP files require different scripts also some servers are set up differently, Plus each has different requirements, Some want just HTTP/S, some want WWW and some want FTP/S, Each one will work depending on how the users own scripts are set up, I provided some text with each one with what they do.

Well, Volomike's answer is much closer. And to push it a bit further, here's what I did for it to disregard the trailing period at the end of the hyperlinks. I also considered URI fragments.

public static function makeClickableLinks($s) {
  return preg_replace('@(https?://([-\w\.]+[-\w])+(:\d+)?(/([\w/_\.#-]*(\?\S+)?[^\.\s])?)?)@', '<a href="$1" target="_blank">$1</a>', $s);
}

Refer http://zenverse.net/php-function-to-auto-convert-url-into-hyperlink/. This is how wordpress solve it

function _make_url_clickable_cb($matches) {
    $ret = '';
    $url = $matches[2];

    if ( empty($url) )
        return $matches[0];
    // removed trailing [.,;:] from URL
    if ( in_array(substr($url, -1), array('.', ',', ';', ':')) === true ) {
        $ret = substr($url, -1);
        $url = substr($url, 0, strlen($url)-1);
    }
    return $matches[1] . "<a href=\"$url\" rel=\"nofollow\">$url</a>" . $ret;
}

function _make_web_ftp_clickable_cb($matches) {
    $ret = '';
    $dest = $matches[2];
    $dest = 'http://' . $dest;

    if ( empty($dest) )
        return $matches[0];
    // removed trailing [,;:] from URL
    if ( in_array(substr($dest, -1), array('.', ',', ';', ':')) === true ) {
        $ret = substr($dest, -1);
        $dest = substr($dest, 0, strlen($dest)-1);
    }
    return $matches[1] . "<a href=\"$dest\" rel=\"nofollow\">$dest</a>" . $ret;
}

function _make_email_clickable_cb($matches) {
    $email = $matches[2] . '@' . $matches[3];
    return $matches[1] . "<a href=\"mailto:$email\">$email</a>";
}

function make_clickable($ret) {
    $ret = ' ' . $ret;
    // in testing, using arrays here was found to be faster
    $ret = preg_replace_callback('#([\s>])([\w]+?://[\w\\x80-\\xff\#$%&~/.\-;:=,?@\[\]+]*)#is', '_make_url_clickable_cb', $ret);
    $ret = preg_replace_callback('#([\s>])((www|ftp)\.[\w\\x80-\\xff\#$%&~/.\-;:=,?@\[\]+]*)#is', '_make_web_ftp_clickable_cb', $ret);
    $ret = preg_replace_callback('#([\s>])([.0-9a-z_+-]+)@(([0-9a-z-]+\.)+[0-9a-z]{2,})#i', '_make_email_clickable_cb', $ret);

    // this one is not in an array because we need it to run last, for cleanup of accidental links within links
    $ret = preg_replace("#(<a( [^>]+?>|>))<a [^>]+?>([^>]+?)</a></a>#i", "$1$3</a>", $ret);
    $ret = trim($ret);
    return $ret;
}

<?
function makeClickableLinks($text)
{

        $text = html_entity_decode($text);
        $text = " ".$text;
        $text = eregi_replace('(((f|ht){1}tp://)[-a-zA-Z0-9@:%_\+.~#?&//=]+)',
                '<a href="\\1" target=_blank>\\1</a>', $text);
        $text = eregi_replace('(((f|ht){1}tps://)[-a-zA-Z0-9@:%_\+.~#?&//=]+)',
                '<a href="\\1" target=_blank>\\1</a>', $text);
        $text = eregi_replace('([[:space:]()[{}])(www.[-a-zA-Z0-9@:%_\+.~#?&//=]+)',
        '\\1<a href="http://\\2" target=_blank>\\2</a>', $text);
        $text = eregi_replace('([_\.0-9a-z-]+@([0-9a-z][0-9a-z-]+\.)+[a-z]{2,3})',
        '<a href="mailto:\\1" target=_blank>\\1</a>', $text);
        return $text;
}

// Example Usage
echo makeClickableLinks("This is a test clickable link: http://www.websewak.com  You can also try using an email address like test@websewak.com");
?>

The most rated answer didn't do the job for me, following link was not replaced correctly:

http://www.fifa.com/worldcup/matches/round255951/match=300186487/index.html#nosticky

After some google searches and some tests, this is what I came up with:

public static function replaceLinks($s) {
    return preg_replace('@(https?://([-\w\.]+)+(:\d+)?(/([\w/_\.%-=#]*(\?\S+)?)?)?)@', '<a href="$1">$1</a>', $s);
}

I'm not an expert in regex, actually it quite confuses me :)

So feel free to comment and improve this solution.

Here is my code to format all the links inside text, including emails, urls with and without protocol.

public function formatLinksInText($text)
{
    //Catch all links with protocol      
    $reg = '/(http|https|ftp|ftps)\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,}(\/\S*)?/'; 
    $formatText = preg_replace($reg, '<a href="$0" style="font-weight: normal;" target="_blank" title="$0">$0</a>', $text);

    //Catch all links without protocol
    $reg2 = '/(?<=\s|\A)([0-9a-zA-Z\-\.]+\.[a-zA-Z0-9\/]{2,})(?=\s|$|\,|\.)/';
    $formatText = preg_replace($reg2, '<a href="//$0" style="font-weight: normal;" target="_blank" title="$0">$0</a>', $formatText);

    //Catch all emails
    $emailRegex = '/(\S+\@\S+\.\S+)\b/';
    $formatText = preg_replace($emailRegex, '<a href="mailto:$1" style="font-weight: normal;" target="_blank" title="$1">$1</a>', $formatText);
    $formatText = nl2br($formatText);
    return $formatText;
}

Please comment the url that doesn't work. I'll try to update the regex.

The answer from MkVal works but in the case we already have the anchor link, it will render the text in weird format.

Here is the solution which works for me in both cases:

$s = preg_replace ( 
    "/(?<!a href=\")(?<!src=\")((http|ftp)+(s)?:\/\/[^<>\s]+)/i",
    "<a href=\"\\0\" target=\"blank\">\\0</a>",
    $s
);

Try this one:

$s = preg_replace('/(?<!href="|">)(?<!src=\")((http|ftp)+(s)?:\/\/[^<>\s]+)/is', '<a href="\\1" target="_blank">\\1</a>', $s);

It skips the existing links (if we already have a href, it won't add a href inside of a href). Otherwise it will add the a href with blank target.

public static function makeClickableLinks($s) {
    return preg_replace('@(https?://([-\w\.]+)+(:\d+)?(/([\w/_\.-]*(\?\S+)?)?)?)@', '<a href="$1">$1</a>', $s);
}

<?php
/**
 * Turn all URLs in clickable links.
 * 
 * @param string $value
 * @param array  $protocols  http/https, ftp, mail, twitter
 * @param array  $attributes
 * @return string
 */
public function linkify($value, $protocols = array('http', 'mail'), array $attributes = array())
{
    // Link attributes
    $attr = '';
    foreach ($attributes as $key => $val) {
        $attr .= ' ' . $key . '="' . htmlentities($val) . '"';
    }
    
    $links = array();
    
    // Extract existing links and tags
    $value = preg_replace_callback('~(<a .*?>.*?</a>|<.*?>)~i', function ($match) use (&$links) { return '<' . array_push($links, $match[1]) . '>'; }, $value);
    
    // Extract text links for each protocol
    foreach ((array)$protocols as $protocol) {
        switch ($protocol) {
            case 'http':
            case 'https':   $value = preg_replace_callback('~(?:(https?)://([^\s<]+)|(www\.[^\s<]+?\.[^\s<]+))(?<![\.,:])~i', function ($match) use ($protocol, &$links, $attr) { if ($match[1]) $protocol = $match[1]; $link = $match[2] ?: $match[3]; return '<' . array_push($links, "<a $attr href=\"$protocol://$link\">$link</a>") . '>'; }, $value); break;
            case 'mail':    $value = preg_replace_callback('~([^\s<]+?@[^\s<]+?\.[^\s<]+)(?<![\.,:])~', function ($match) use (&$links, $attr) { return '<' . array_push($links, "<a $attr href=\"mailto:{$match[1]}\">{$match[1]}</a>") . '>'; }, $value); break;
            case 'twitter': $value = preg_replace_callback('~(?<!\w)[@#](\w++)~', function ($match) use (&$links, $attr) { return '<' . array_push($links, "<a $attr href=\"https://twitter.com/" . ($match[0][0] == '@' ? '' : 'search/%23') . $match[1]  . "\">{$match[0]}</a>") . '>'; }, $value); break;
            default:        $value = preg_replace_callback('~' . preg_quote($protocol, '~') . '://([^\s<]+?)(?<![\.,:])~i', function ($match) use ($protocol, &$links, $attr) { return '<' . array_push($links, "<a $attr href=\"$protocol://{$match[1]}\">{$match[1]}</a>") . '>'; }, $value); break;
        }
    }
    
    // Insert all link
    return preg_replace_callback('/<(\d+)>/', function ($match) use (&$links) { return $links[$match[1] - 1]; }, $value);
}

Not my code, I got it from here https://gist.github.com/jasny/2000705

I recommend not to do many things on fly like this. I prefer to use simple editor interface like the one used in stackoverflow. It is called Markdown.

I am using a function that originated from question2answer, it accepts plain text and even plain text links in html:

// $html holds the string
$htmlunlinkeds = array_reverse(preg_split('|<[Aa]\s+[^>]+>.*</[Aa]\s*>|', $html, -1, PREG_SPLIT_OFFSET_CAPTURE)); // start from end so we substitute correctly
foreach ($htmlunlinkeds as $htmlunlinked)
{ // and that we don't detect links inside HTML, e.g. <img src="http://...">
    $thishtmluntaggeds = array_reverse(preg_split('/<[^>]*>/', $htmlunlinked[0], -1, PREG_SPLIT_OFFSET_CAPTURE)); // again, start from end
    foreach ($thishtmluntaggeds as $thishtmluntagged)
    {
        $innerhtml = $thishtmluntagged[0];
        if(is_numeric(strpos($innerhtml, '://'))) 
        { // quick test first
            $newhtml = qa_html_convert_urls($innerhtml, qa_opt('links_in_new_window'));
            $html = substr_replace($html, $newhtml, $htmlunlinked[1]+$thishtmluntagged[1], strlen($innerhtml));
        }
    }
}   
echo $html;

function qa_html_convert_urls($html, $newwindow = false)
/*
    Return $html with any URLs converted into links (with nofollow and in a new window if $newwindow).
    Closing parentheses/brackets are removed from the link if they don't have a matching opening one. This avoids creating
    incorrect URLs from (http://www.question2answer.org) but allow URLs such as http://www.wikipedia.org/Computers_(Software)
*/
{
    $uc = 'a-z\x{00a1}-\x{ffff}';
    $url_regex = '#\b((?:https?|ftp)://(?:[0-9'.$uc.'][0-9'.$uc.'-]*\.)+['.$uc.']{2,}(?::\d{2,5})?(?:/(?:[^\s<>]*[^\s<>\.])?)?)#iu';

    // get matches and their positions
    if (preg_match_all($url_regex, $html, $matches, PREG_OFFSET_CAPTURE)) {
        $brackets = array(
            ')' => '(',
            '}' => '{',
            ']' => '[',
        );

        // loop backwards so we substitute correctly
        for ($i = count($matches[1])-1; $i >= 0; $i--) {
            $match = $matches[1][$i];
            $text_url = $match[0];
            $removed = '';
            $lastch = substr($text_url, -1);

            // exclude bracket from link if no matching bracket
            while (array_key_exists($lastch, $brackets)) {
                $open_char = $brackets[$lastch];
                $num_open = substr_count($text_url, $open_char);
                $num_close = substr_count($text_url, $lastch);

                if ($num_close == $num_open + 1) {
                    $text_url = substr($text_url, 0, -1);
                    $removed = $lastch . $removed;
                    $lastch = substr($text_url, -1);
                }
                else
                    break;
            }

            $target = $newwindow ? ' target="_blank"' : '';
            $replace = '<a href="' . $text_url . '" rel="nofollow"' . $target . '>' . $text_url . '</a>' . $removed;
            $html = substr_replace($html, $replace, $match[1], strlen($match[0]));
        }
    }

    return $html;
}

A bit much code due to accepting links that hold brackets and other characters, but probably it helps.

Finding Plain Text Links inside HTML

I really liked this answer - yet I needed a solution for possible plain text links that are inside very simple HTML text:

<p>I found a really cool site you might like:</p>
<p>www.stackoverflow.com</p>

This meant I needed the regex patterns to ignore the html chars < and >

Regex Adjustment

So I changed parts of the patterns to [^\s\>\<] instead of \S

• \S - not white-space; matches any char that is not white-space (tab, space, newline)
• [^] - a negated set; matches any char not in the set

My version of the function from this answer

I needed another format in addition to HTML so I separated out the regexes from their replacements to accommodate this.

I also added a way to return just the links/emails found into an array so I can save them as a relationship on my posts (great for making meta cards for them later ...and for analytics!).

UPDATE: Consecutive periods were matching

I was getting matches for text like there...it - So I wanted to ensure I didn't get any matches that included consecutive dots.

Note: To accomplish fixing this, I added an additional format string to undo matching them to avoid having to redo these otherwise reliable url regexes.

/***
 * based on this answer: https://stackoverflow.com/a/49689245/2100636
 *
 * @var $text String
 * @var $format String - html (<a href=""...), short ([link:https://somewhere]), other (https://somewhere)
 */
public function formatLinksInString(
    $string,
    $format = 'html', 
    $returnMatches = false
) {
    $formatProtocol = $format == 'html'
        ? '<a href="$0" target="_blank" title="$0">$0</a>'
        : ($format == 'short' || $returnMatches ? '[link:$0]' : '$0');

    $formatSansProtocol = $format == 'html'
        ? '<a href="//$0" target="_blank" title="$0">$0</a>'
        : ($format == 'short' || $returnMatches ? '[link://$0]' : '$0');

    $formatMailto = $format == 'html'
        ? '<a href="mailto:$1" target="_blank" title="$1">$1</a>'
        : ($format == 'short' || $returnMatches ? '[mailto:$1]' : '$1');

    $regProtocol = '/(http|https|ftp|ftps)\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,}(\/[^\<\>\s]*)?/';
    $regSansProtocol = '/(?<=\s|\A|\>)([0-9a-zA-Z\-\.]+\.[a-zA-Z0-9\/]{2,})(?=\s|$|\,|\<)/';
    $regEmail = '/([^\s\>\<]+\@[^\s\>\<]+\.[^\s\>\<]+)\b/';
    $consecutiveDotsRegex = $format == 'html'
        ? '/<a[^\>]+[\.]{2,}[^\>]*?>([^\<]*?)<\/a>/'
        : '/\[link:.*?\/\/([^\]]+[\.]{2,}[^\]]*?)\]/';

    // Protocol links
    $formatString = preg_replace($regProtocol, $formatProtocol, $string);
    // Sans Protocol Links
    $formatString = preg_replace($regSansProtocol, $formatSansProtocol, $formatString); // use formatString from above
    // Email - Mailto - Links
    $formatString = preg_replace($regEmail, $formatMailto, $formatString); // use formatString from above
    // Prevent consecutive periods from getting captured
    $formatString = preg_replace($consecutiveDotsRegex, '$1', $formatString);

    if ($returnMatches) {
        // Find all [x:link] patterns
        preg_match_all('/\[.*?:(.*?)\]/', $formatString, $matches);

        current($matches); // to move pointer onto groups
        return next($matches); // return the groups
    }

    return $formatString;
}

$string = 'example.com
www.example.com
http://example.com
https://example.com
http://www.example.com
https://www.example.com';

preg_match_all('#(\w*://|www\.)[a-z0-9]+(-+[a-z0-9]+)*(\.[a-z0-9]+(-+[a-z0-9]+)*)+(/([^\s()<>;]+\w)?/?)?#i', $string, $matches, PREG_OFFSET_CAPTURE | PREG_SET_ORDER);
foreach (array_reverse($matches) as $match) {
  $a = '<a href="'.(strpos($match[1][0], '/') ? '' : 'http://') . $match[0][0].'">' . $match[0][0] . '</a>';
  $string = substr_replace($string, $a, $match[0][1], strlen($match[0][0]));
}

echo $string;

Result:

example.com
<a href="http://www.example.com">www.example.com</a>
<a href="http://example.com">http://example.com</a>
<a href="https://example.com">https://example.com</a>
<a href="http://www.example.com">http://www.example.com</a>
<a href="https://www.example.com">https://www.example.com</a>

What I like in this solution is that it also converts www.example.com to http://www.example.com because <a href="www.example.com"></a> doesn't work (without http/https protocol it points to yourdomain.com/www.example.com).

If am right, what you want to do is turn ordinary text into http links. Here's what I think can help:

<?php

   $list = mysqli_query($con,"SELECT * FROM list WHERE name = 'table content'"); 
   while($row2 = mysqli_fetch_array($list)) {
echo "<a target='_blank' href='http://www." . $row2['content']. "'>" . $row2['content']. "</a>";

   }  
?>