How to add http:// if it doesn't exist in the URL

Question

How can I add http:// to a URL if it doesn't already include a protocol (e.g. http://, https:// or ftp://)?

Example:

addhttp("google.com"); // http://google.com
addhttp("www.google.com"); // http://www.google.com
addhttp("google.com"); // http://google.com
addhttp("ftp://google.com"); // ftp://google.com
addhttp("https://google.com"); // https://google.com
addhttp("http://google.com"); // http://google.com
addhttp("rubbish"); // http://rubbish

If you had, `mozilla.org` alone, how would you know if it should be, `http`, `https` or `ftp`? — Anthony Forloney, May 04 '10 at 00:25
@Anthony: he says he wants to add "http://" if there's no other protocol. — nickf, May 04 '10 at 00:27
@Anthony But when the user types the url without http:// or anything, do you expect it to be ftp:// or something? — CodeOverload, May 04 '10 at 00:28

score 272 · Accepted Answer · answered May 04 '10 at 00:30

272

A modified version of @nickf code:

function addhttp($url) {
    if (!preg_match("~^(?:f|ht)tps?://~i", $url)) {
        $url = "http://" . $url;
    }
    return $url;
}

Recognizes ftp://, ftps://, http:// and https:// in a case insensitive way.

answered May 04 '10 at 00:30

Alix Axel

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Having compared addhttp and addscheme below, I've come to the conclusion that addscheme is better in terms of performance: `$url = "www.google.com"; $init = microtime(true); for( $i = 1; $i < 100000; $i++ ) { addScheme( $url ); } echo microtime(true) - $init; echo "
"; $init = microtime(true); for( $i = 1; $i < 100000; $i++ ) { addhttp( $url ); } echo microtime(true) - $init; ` – Luis Lobo Borobia May 13 '13 at 19:56
What if url begins with '//'? – holden321 Oct 25 '19 at 09:00

score 149 · Answer 2 · edited Jan 08 '14 at 22:12

149

At the time of writing, none of the answers used a built-in function for this:

function addScheme($url, $scheme = 'http://')
{
  return parse_url($url, PHP_URL_SCHEME) === null ?
    $scheme . $url : $url;
}

echo addScheme('google.com'); // "http://google.com"
echo addScheme('https://google.com'); // "https://google.com"

See also: parse_url()

edited Jan 08 '14 at 22:12

Dave Jarvis

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answered Feb 05 '13 at 06:29

Ja͢ck

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This should be the selected answer - why roll your own when the language has native support? Nice work. – Tom Auger Aug 19 '13 at 15:24
2

One improvement that could be made with this function is checking to see if the field has a value so it is not adding an http to an empty field. – Randy Johnson Sep 18 '15 at 04:15
1

This doesn't work with relative protocols. e.g. `echo addScheme('//google.com');` – Taylan Mar 03 '16 at 10:23
2

@Taylan Yeah, you would have to `ltrim($url, '/')` – Ja͢ck Mar 03 '16 at 10:25

score 51 · Answer 3 · edited Nov 06 '20 at 16:28

51

Simply check if there is a protocol (delineated by "://") and add "http://" if there isn't.

if (false === strpos($url, '://')) {
    $url = 'http://' . $url;
}

Note: This may be a simple and straightforward solution, but Jack's answer using parse_url is almost as simple and much more robust. You should probably use that one.

edited Nov 06 '20 at 16:28

Peter Mortensen

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answered May 04 '10 at 00:44

Brenton Alker

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score 4 · Answer 4 · edited Nov 06 '20 at 16:26

4

The best answer for this would be something like this:

function addhttp($url, $scheme="http://" )
{
  return $url = empty(parse_url($url)['scheme']) ? $scheme . ltrim($url, '/') : $url;
}

The protocol flexible, so the same function can be used with ftp, https, etc.

edited Nov 06 '20 at 16:26

Peter Mortensen

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answered Jul 29 '17 at 02:33

ThisDude

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score 1 · Answer 5 · edited Nov 06 '20 at 16:20

1

Scan the string for ://. If it does not have it, prepend http:// to the string... Everything else just use the string as is.

This will work unless you have a rubbish input string.

edited Nov 06 '20 at 16:20

Peter Mortensen

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answered May 04 '10 at 00:32

Rosdi Kasim

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i'de prefer a regex version :) – CodeOverload May 04 '10 at 00:34
3

Don't be too quick on regex. Regex tends to be hard to read and it could introduce another problem/bug once the problem grows. – Rosdi Kasim May 04 '10 at 00:49

score 0 · Answer 6 · edited Nov 06 '20 at 16:30

0

<?php
    if (!preg_match("/^(http|ftp):/", $_POST['url'])) {
        $_POST['url'] = 'http://'.$_POST['url'];
    }
    $url = $_POST['url'];
?>

This code will add http:// to the URL if it’s not there.

edited Nov 06 '20 at 16:30

Peter Mortensen

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answered Jan 17 '13 at 04:08

ayan

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score 0 · Answer 7 · edited Nov 06 '20 at 16:18

0

Try this. It is not watertight¹, but it might be good enough:

function addhttp($url) {
    if (!preg_match("@^[hf]tt?ps?://@", $url)) {
        $url = "http://" . $url;
    }
    return $url;
}

_{1. That is, prefixes like "fttps://" are treated as valid.}

edited Nov 06 '20 at 16:18

Peter Mortensen

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answered May 04 '10 at 00:25

nickf

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This would match (ergo return true and if would evaluate to false) weird combinations.. like htps, fttps, fttp, htp, I guess. – kamasheto May 04 '10 at 00:28

score 0 · Answer 8 · edited Nov 06 '20 at 16:19

0

nickf's solution modified:

function addhttp($url) {
    if (!preg_match("@^https?://@i", $url) && !preg_match("@^ftps?://@i", $url)) {
        $url = "http://" . $url;
    }
    return $url;
}

edited Nov 06 '20 at 16:19

Peter Mortensen

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answered May 04 '10 at 00:30

kamasheto

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I believe `ftps://` is also valid. – Alix Axel May 04 '10 at 00:31

How to add http:// if it doesn't exist in the URL

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