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I was wondering how I could check a string broken into an array against a preg_match to see if it started with www. I already have one that check for http://www. 

function isValidURL($url) { return preg_match('|^http(s)?://[a-z0-9-]+(.[a-z0-9-]+)*(:[0-9]+)?(/.*)?$|i', $url); } $stringToArray = explode(" ",$_POST['text']); foreach($stringToArray as $key=>$val){ $urlvalid = isValidURL($val); if($urlvalid){ $_SESSION["messages"][] = "NO URLS ALLOWED!"; header("Location: http://www.domain.com/post/id/".$_POST['postID']); exit(); } }

Thanks! Stefan

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    Can you show some code you have tried based on the one that does work? More people here will help you solve a problem you're working on that give you the answer. Just getting a requirement and producing an answer is what I get paid to do. Commented May 4, 2010 at 1:33
  • added in the working code so far Commented May 4, 2010 at 1:39

5 Answers 5

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You want something like:

%^((https?://)|(www\.))([a-z0-9-].?)+(:[0-9]+)?(/.*)?$%i

this is using the | to match either http:// or www at the beginning. I changed the delimiter to % to avoid clashing with the |

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this is not true... the second group is (www\.) which requires a . after www.. also, i tested the regexp against 'wwwtumblr.com' here: solmetra.com/scripts/regex/index.php and it did not pass. however, this will match something like www.tumblrcom. the biggest error is probably the unescaped . in the third group. these days i usually do ([a-z0-9-]\.)+([a-z0-9-]) to match the subdomains and the tld.
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John Gruber of Daring Fireball has posted a very comprehensive regex for all types of URLs that may be of interest. You can find it here:

http://daringfireball.net/2010/07/improved_regex_for_matching_urls

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How looks the actual code? I have string $str = "Blaa lorem ipsum domain-name.studio blaa blaa another.com blaa blaa"; and I want to get output: Yes it contains one or more domains: domain-name.studio another.com Thanks if you have time to help!
I tried: $found_url = ""; if(preg_match("~^$regex$~i", $description, $m)) $found_url = $m; if(preg_match("~^$regex$~i", $description, $m)) $found_url .= $m; But got error: PHP Parse error: syntax error, unexpected ','
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I explode the string at first as the url might be half way through it e.g. hello how are you www.google.com

Explode the string and use a foreach statement.

Eg:

$string = "hello how are you www.google.com"; $string = explode(" ", $string); foreach ($string as $word){ if ( (strpos($word, "http://") === 0) || (strpos($word, "www.") === 0) ){ // Code you want to excute if string is a link } }

Note you have to use the === operator because strpos can return, will return a 0 which will appear to be false.

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How would you extract the link only?
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I used this below which allows you to detect url's anywhere in a string. For my particular application it's a contact form to combat spam so no url's are allowed. Works very well.

Link to resource: https://css-tricks.com/snippets/php/find-urls-in-text-make-links/

My implementation;

<?php // Validate message if(isset($_POST['message']) && $_POST['message'] == 'Include your order number here if relevant...') { $messageError = "Required"; } else { $message = test_input($_POST["message"]); } if (strlen($message) > 1000) { $messageError = "1000 chars max"; } $reg_exUrl = "/(http|https|ftp|ftps)\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(\/\S*)?/"; if (preg_match($reg_exUrl, $message)) { $messageError = "Url's not allowed"; } // Validate data function test_input($data) { $data = trim($data); $data = stripslashes($data); $data = htmlspecialchars($data); return $data; } ?>
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Limiting TLD from 2 upto 3 characters is really poor, see: iana.org/domains/root/db
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Try implode($myarray, '').strstr("www.")==0. That implodes your array into one string, then checks whether www. is at the beginning of the string (index 0).

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I explode the string at first as the url might be half way through it e.g. hello how are you www.google.com

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