How Can I Ensure URLs Always Begin with a Protocol (http:// or https://)?

Adding HTTP Protocol to URLs

In web development, it's often desirable to ensure that a URL starts with a protocol (e.g. http:// or https://). This helps browsers interpret the URL correctly and load the appropriate content.

Solution

To add the "http://" protocol to a URL if it's missing, consider the following code:

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

This function handles different protocols such as "ftp://", "ftps://", "http://", and "https://" in a case-insensitive manner.

Examples

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

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