Use preg_match() and replace to converting URL to anchor tag in text

Question

I currently have the following code to add an a href to user-submitted plain text where HTTPS:// is found. The problem is that this obviously changes all links in the text to the same name/location. How can I do this process seperately for every instance of HTTPS:// in the text?

//Example variables (usually from MySQL)
$moreOrig = "https://duckduckgo.com is better than https://google.com";
// The Regular Expression filter
$testUrl = "/(http|https|ftp|ftps)\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(\/\S*)?/";

if (preg_match($testUrl, $moreOrig, $url)) {
//split into parts if user has a /something to clean url
    $parts = explode ("/", $url[0]);

    //glue
    list($first, $second, $third) = $parts;

    //output
    $shortUrl = implode ("/", array($third));

    $more = nl2br(preg_replace($testUrl, "<a href='" . $url[0] . "' rel = 'nofollow'>" . $shortUrl . "</a>", $moreOrig));
  }

Output, desired vs actual ( assume input variable = "https://duckduckgo.com?q=Duck+Duck+Go is better than https://google.com?q=Duck+Duck+Go")

Desired:
<a href = "https://duckduckgo.com?q=Duck+Duck+Go">duckduckgo.com</a> is better than <a href = "https://google.com?q=Duck+Duck+Go">google.com.</a>
<br>
Actual:
<a href = "https://duckduckgo.com?q=Duck+Duck+Go">duckduckgo.com</a> is better than <a href = "https://google.com?q=Duck+Duck+Go">google.com.</a>

Possible duplicate of PHP: How can I make preg_match match only the first occurrence? — Shardj
– Shardj, Commented Nov 1, 2018 at 15:42
@GeorgeAppleton I think my question is different because I want to replace all occurances, not just the first. — John S
– John S, Commented Nov 1, 2018 at 15:44
You can just put it in a loop, if you want to replace all occurrences how is that different to what you're doing now though? A desired input and output would be helpful I think — Shardj
– Shardj, Commented Nov 1, 2018 at 15:45
You can easily capture the link in the regex and use $1 to put it back in where you use $url[0] now. However, to manipulate it to get a short url, you would probably need preg_replace_callback(). — jeroen
– jeroen, Commented Nov 1, 2018 at 15:47

ChunkyBarsEater · Accepted Answer · 2018-11-02 12:20:44Z

4

<?php declare(strict_types = 1);

$input = "
xxx
https://duckduckgo.com/url/foo
xxx
https://bing.com
xxx
https://google.com/
xxx
";

$result = preg_replace_callback(
    "@
        (?:http|ftp|https)://
        (?:
            (?P<domain>\S+?) (?:/\S+)|
            (?P<domain_only>\S+)
        )
    @sx",
    function($a){
        $link = "<a href='" . $a[0] . "'>";
        $link .= $a["domain"] !== "" ? $a["domain"] : $a["domain_only"];
        $link .= "</a>";
        return $link;
    },
    $input
);

echo $result;

edited Nov 2, 2018 at 12:20

answered Nov 1, 2018 at 16:24

ChunkyBarsEater

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9 Comments

Barmar Over a year ago

The capture group around the whole pattern doesn't seem necessary.

Barmar Over a year ago

Actually, there's no need for the callback. Just use replace with $0 and $2 in the replacement.

ChunkyBarsEater Over a year ago

Right. Thanks!!

Toto Over a year ago

\b inside a character class means "backspace". Your negated character class will be better written as \S that means not a space (any kind of)

ChunkyBarsEater Over a year ago

TIL. Thanks for the hint.

|

Smuuf · Accepted Answer · 2018-11-01 16:27:18Z

0

You can do this easily with preg_replace_callback.

<?php

//Example variables (usually from MySQL)
$string = "https://duckduckgo.com is better than https://google.com";

// The Regular Expression filter
$pattern = "/(http|https|ftp|ftps)\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(\/\S*)?/";

$result = preg_replace_callback($pattern, function($match) {
    $url = $match[0];
    return sprintf('<a href="%1$s">%1$s</a>', $url);
}, $string);

// Result:
// "<a href="https://duckduckgo.com">https://duckduckgo.com</a> is better than <a href="https://google.com">https://google.com</a>"

answered Nov 1, 2018 at 16:27

Smuuf

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Comments

Mohammad · Accepted Answer · 2018-11-01 16:43:49Z

0

You does not need to use preg_match(), explode() and implode(). Just use preg_replace(). You need to use a group match for whole of url to replacing it by <a></a>

$testUrl = "@((https?|ftps?)://([\w\-.]+\.[a-zA-Z]{2,3})(/\S*)?)@";
$newStr = preg_replace($testUrl, "<a href='$1'>$3</a>", $moreOrig);

Check result in demo

edited Nov 1, 2018 at 16:43

answered Nov 1, 2018 at 16:29

Mohammad

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