Add http:// prefix to URL when missing

Question

Hello I have a very simple code

<a href="'.$aProfileInfo['Website'].'" target="_self">
    <div class="callButton">Website</div>
</a>

The problem is that if the user does not enter http:// the link will then point to my website and not to the external website as it should.

How do I check in PHP if the user has not entered http:// and automatically add it when it is not there?

Also, _please_ make sure that you are escaping user input before inserting it into html. See [htmlspecialchars()](http://php.net/manual/en/function.htmlspecialchars.php). — Wilbur Vandrsmith, Jun 05 '11 at 01:23
You can simplify David's answer to work on one line (so you can put it inline with your HTML). See: http://stackoverflow.com/a/24482058/1101095 — Nate, Jun 30 '14 at 02:00
@Nate actually, you can simplify it even further than that. Also the regular expression way can be a one-liner as well. See: http://stackoverflow.com/a/31549463/1572938 — Evan Kennedy, Jul 21 '15 at 21:22
This might be a duplicate of http://stackoverflow.com/questions/2762061/how-to-add-http-if-its-not-exists-in-the-url — Adam, May 16 '16 at 12:13

score 54 · Answer 1 · edited Dec 10 '12 at 07:09

54

I think you'd better use the built in function parse_url() which returns an associative array with its components

something like this will work for you:

 if  ( $ret = parse_url($url) ) {

      if ( !isset($ret["scheme"]) )
       {
       $url = "http://{$url}";
       }
}

edited Dec 10 '12 at 07:09

Akhil Jain

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answered Jul 15 '11 at 10:03

David

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This is the proper way! – sk8terboi87 ツ Apr 19 '14 at 14:58
The regex answer is cool, but I agree that this is the proper way to do it. – Nate Jun 30 '14 at 01:50
Will fail if user input is something like: **foo:bar@foobar/p?arg=val#a** « foo » will be interpreted as the scheme. – Marcky Dec 22 '14 at 22:38
You could simply concatenate `//` instead of `http` to use current page's scheme (http / https). – Jose Philip Raja Sep 13 '16 at 08:54
I guess this will force the same protocol of the site is coming from, so if your site is under https:// all link will became https:// and they may not has an https:// url – al404IT Jul 06 '17 at 08:30
I killed my regex answer. This is the better answer. It will maintain the scheme if it is there and if not it will assume and prefix the url with `http://`. +1 – Robert Groves Dec 30 '17 at 19:31

score 33 · Answer 2 · edited Oct 13 '22 at 00:31

33

I personally use this, which is partially taken from the php docs

$scheme = parse_url($link, PHP_URL_SCHEME);
if (empty($scheme))
    $link = 'https://' . ltrim($link, '/');

edited Oct 13 '22 at 00:31

Bram Hammer

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answered Nov 18 '15 at 10:11

Satbir Kira

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This should definitely be the first answer. Perfect! – slothstronaut Jul 25 '18 at 21:10
With HTTPS being the new standard this should be updated to https – Mav2287 Sep 05 '21 at 00:30

score 19 · Accepted Answer · answered Jun 05 '11 at 01:18

19

A simple solution which may not work in all cases (i.e. 'https://'):

if (strpos($aProfileInfo['Website'],'http://') === false){
    $aProfileInfo['Website'] = 'http://'.$aProfileInfo['Website'];
}

answered Jun 05 '11 at 01:18

Christopher Armstrong

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1

Doesn't `strpos` require haystack first, needle second? – Kevin Ji Jun 05 '11 at 01:21

Evan Kennedy · Answer 4 · 2015-07-21T21:18:30.090

There are two ways of tackling this problem: url parsing and regular expressions.

Some will say url parsing is right, but regular expressions work just as well in this case. I like being able to have simple one-liners for things like this especially because this would be a common occurrence in template files where you may need a one-liner inside an echo statement to maintain readability.

Regular Expressions

We can do this in a single function call with preg_replace.

preg_replace('/^(?!https?:\/\/)/', 'http://', $aProfileInfo['Website'])

This uses a negative lookahead at the beginning of the string that looks for http:// or https://. If either are found, the replace doesn't happen. If they aren't found, it replaces the beginning of the string (0 characters) with http:// essentially prepending this to the string without modifying it.

In context:

<a href="'. preg_replace('/^(?!https?:\/\/)/', 'http://', $aProfileInfo['Website']).'" target="_self">
    <div class="callButton">Website</div>
</a>

URL Parsing

(parse_url($aProfileInfo['Website'], PHP_URL_SCHEME) ? '' : 'http://') . $aProfileInfo['Website']

What this does is find out if a scheme is present on the link throught parse_url($aProfileInfo['Website'], PHP_URL_SCHEME). Then using a ternary operator, it will either output '' if there was one found or 'http://' if one wasn't found. Then it appends the link onto that.

In context:

<a href="'.((parse_url($aProfileInfo['Website'], PHP_URL_SCHEME) ? '' : 'http://') . $aProfileInfo['Website']).'" target="_self">
    <div class="callButton">Website</div>
</a>

Your regex is smart that it preserves `https://` however it doesn't work with relative urls such as `//www.example.com`. It also appends `http://` onto `ftp://` or other protocols. Try this instead: `preg_replace('/^\/\/|^(?!https?:)(?!ftps?:)/', 'http://', $src)` (note: you can remove the check for ftp if you dont need it) — dhaupin, May 13 '16 at 16:05

score 3 · Answer 5 · answered Jun 05 '11 at 01:20

You could use strpos:

// Trim trailing whitespace
$aProfileInfo['Website'] = trim($aProfileInfo['Website']);

// Test if the string begins with "http://"
if (strpos($aProfileInfo['Website'], 'http://') !== 0) {
  $aProfileInfo['Website'] = 'http://' . $aProfileInfo['Website'];
}

score 1 · Answer 6 · edited Jul 01 '15 at 14:34

1

You also may take into account that "http(s)" must be at the beginning of the url:

if (preg_match('/^https?:\/\//', $aProfileInfo['Website']) === 0) {
    $aProfileInfo['Website'] = 'http://'.$aProfileInfo['Website'];
}

edited Jul 01 '15 at 14:34

NDY

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answered Jul 01 '15 at 14:06

ggonzal

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score 1 · Answer 7 · answered Jun 05 '11 at 01:25

You can use this function as a general if nothing from the array is found in the string append something to it.

function httpify($link, $append = 'http://', $allowed = array('http://', 'https://')){

  $found = false;
  foreach($allowed as $protocol)
    if(strpos($link, $protocol) !== 0)
      $found = true;

  if($found)
    return $link;
  return $append.$link;
}

score 0 · Answer 8 · answered Jan 02 '14 at 13:51

0

Here is another example with string subtraction:

$changeLink = $myRow->site_url;
  if(substr($changeLink, 0, 7) != 'http://') {
     $changeLink = 'http://' . $changeLink;  
}

// ....

echo "<a href=\"" . $changeLink . "\" target=\"_blank\"></a>";

answered Jan 02 '14 at 13:51

Porta Shqipe

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score 0 · Answer 9 · edited May 23 '17 at 11:54

0

I believe David's answer is the proper way to do this, but it can be simplified like this:

parse_url($aProfileInfo['Website'], PHP_URL_SCHEME)==''?'http://'.$aProfileInfo['Website']:$aProfileInfo['Website']

edited May 23 '17 at 11:54

Community

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answered Jun 30 '14 at 01:59

Nate

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score 0 · Answer 10 · answered Jun 05 '11 at 01:21

0

Something like this?

if (!strpos($aProfileInfo['Website'], 'http://')) {
    $aProfileInfo['Website'] = 'http://' . $aProfileInfo['Website'];
}

answered Jun 05 '11 at 01:21

gpresland

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Add http:// prefix to URL when missing

10 Answers10

Regular Expressions

URL Parsing

Linked

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