How Can I Programmatically Add \'http://\' to URLs Missing a Protocol?

Adding "http://" to URLs Without Protocols

In instances where a URL does not specify a protocol such as "http://", "https://" or "ftp://", there may be a need to add "http://" to the URL. Here's how to accomplish this:

Function to Add "http://"

The following function can be utilized to add "http://" to URLs without protocols:

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

Example Usage

Invoking this function with the following URLs will yield the desired results:

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

Recognizing Various Protocols

This function recognizes the following protocols in a case-insensitive manner:

• http://
• https://
• ftp://
• ftps://

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