Detecting a url using preg_match? without http:// in the string

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){
  $_SESSION["messages"][] = "开发者_JS百科NO URLS ALLOWED!";
  header("Location: http://www.domain.com/post/id/".$_POST['postID']);
     exit();
     }
     }

Thanks! Stefan

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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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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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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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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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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).