PHP: Is String a valid URL?

Yes, you can just use the function filter_var() to validate a URL. Let us look at a small example:

$url = "https://www.askingbox.com";

if (filter_var($url, FILTER_VALIDATE_URL)) {
    echo("$url is a valid URL");
} else {
    echo("$url is not a valid URL");
}

First, you have to pass your string to the function and as a second parameter, you have to pass the constant FILTER_VALIDATE_URL to ensure that the function is checking for a URL.

Optionally, you can also use one of the following flags as a third parameter.

• FILTER_FLAG_PATH_REQUIRED: Requires the URL to contain a path part, for example www.example.com/example/
• FILTER_FLAG_QUERY_REQUIRED: Requires the URL to contain a query string, for example "example.com?id=100&action=2"
• FILTER_FLAG_SCHEME_REQUIRED: URL must be RFC compliant, for example http://example (by default)
• FILTER_FLAG_HOST_REQUIRED: URL must include host name, for example http://www.example.com (by default)

In order to check whether a URL is containing a path, for example you can call "if (filter_var($url, FILTER_VALIDATE_URL, FILTER_FLAG_PATH_REQUIRED))".

The flags FILTER_FLAG_SCHEME_REQUIRED and FILTER_FLAG_HOST_REQUIRED are activated by default so that you do not have to specify them.
2015-06-17 at 18:30