Best way to check if a URL is valid

php

Question

I want to use PHP to check, if string stored in $myoutput variable contains a valid link syntax or is it just a normal text. The function or solution, that I'm looking for, should recognize all links formats including the ones with GET parameters.

A solution, suggested on many sites, to actually query string (using CURL or file_get_contents() function) is not possible in my case and I would like to avoid it.

I thought about regular expressions or another solution.

1
127
7/30/2015 9:48:55 AM

Accepted Answer

You can use a native Filter Validator

filter_var($url, FILTER_VALIDATE_URL);

Validates value as URL (according to » http://www.faqs.org/rfcs/rfc2396), optionally with required components. Beware a valid URL may not specify the HTTP protocol http:// so further validation may be required to determine the URL uses an expected protocol, e.g. ssh:// or mailto:. Note that the function will only find ASCII URLs to be valid; internationalized domain names (containing non-ASCII characters) will fail.

Example:

if (filter_var($url, FILTER_VALIDATE_URL) === FALSE) {
    die('Not a valid URL');
}
267
8/15/2017 6:27:15 AM

Here is the best tutorial I found over there:

http://www.w3schools.com/php/filter_validate_url.asp

<?php
$url = "http://www.qbaki.com";

// Remove all illegal characters from a url
$url = filter_var($url, FILTER_SANITIZE_URL);

// Validate url
if (filter_var($url, FILTER_VALIDATE_URL) !== false) {
echo("$url is a valid URL");
} else {
echo("$url is not a valid URL");
}
?>

Possible flags:

FILTER_FLAG_SCHEME_REQUIRED - URL must be RFC compliant (like http://example)
FILTER_FLAG_HOST_REQUIRED - URL must include host name (like http://www.example.com)
FILTER_FLAG_PATH_REQUIRED - URL must have a path after the domain name (like www.example.com/example1/)
FILTER_FLAG_QUERY_REQUIRED - URL must have a query string (like "example.php?name=Peter&age=37")

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