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

Schaumberger

If you had, mozilla.org alone, how would you know if it should be, http, https or ftp? – Ilene

@Anthony: he says he wants to add "http://" if there's no other protocol. – Breezeway

@Anthony But when the user types the url without http:// or anything, do you expect it to be ftp:// or something? – Schaumberger

Answer 1

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.

Phony

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 "<BR>"; $init = microtime(true); for( $i = 1; $i < 100000; $i++ ) { addhttp( $url ); } echo microtime(true) - $init; – Downcome

What if url begins with '//'? – Ovovitellin

Answer 2

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()

Radiobroadcast

This should be the selected answer - why roll your own when the language has native support? Nice work. – Ultra

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. – Kurbash

This doesn't work with relative protocols. e.g. echo addScheme('//google.com'); – Loleta

@Loleta Yeah, you would have to ltrim($url, '/') – Parthenope

Answer 3

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.

Fussbudget

Answer 4

The best answer for this would be something like this:

function addScheme($url, $scheme="http://" )
{
  return $url = empty(parse_url($url)['scheme']) ? $scheme . ltrim($url, '/') : $url;
}
// Test below
$url = 'google.com';
echo addScheme($url,"ftp://"); // "https://google.com"
echo addScheme('google.com'); // "http://google.com"
echo addScheme('https://google.com'); // "https://google.com"

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

Tory

Answer 5

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.

Radiology

i'de prefer a regex version :) – Schaumberger

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. – Radiology

Answer 6

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.}

Breezeway

This would match (ergo return true and if would evaluate to false) weird combinations.. like htps, fttps, fttp, htp, I guess. – Berwick

Answer 7

nickf's solution modified:

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

Berwick

I believe ftps:// is also valid. – Phony

Answer 8

<?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.

Darrendarrey