add check if wrong youtube link is given

Question

I have a function that converts youtube links to embed format

But if I specify a link in the wrong format, or instead of a link in plain text, I get an error

$youtube_id is undefined

public function getYoutubeEmbedUrl()
    {
        $shortUrlRegex = '/youtu.be\/([a-zA-Z0-9_-]+)\??/i';
        $longUrlRegex = '/youtube.com\/((?:embed)|(?:watch))((?:\?v\=)|(?:\/))([a-zA-Z0-9_-]+)/i';
    
        if (preg_match($longUrlRegex, $this->video_link, $matches)) {
            $youtube_id = $matches[count($matches) - 1];
        }
    
        if (preg_match($shortUrlRegex, $this->video_link, $matches)) {
            $youtube_id = $matches[count($matches) - 1];
        }
        
        return 'https://www.youtube.com/embed/' . $youtube_id ;
   }

I am trying to add validation to the function but I am getting the same error

if (!$youtube_id) {
  return null;
}

Does this answer your question? [Reference - What does this error mean in PHP?](https://stackoverflow.com/questions/12769982/reference-what-does-this-error-mean-in-php) — Nico Haase, Mar 21 '23 at 11:57

score 2 · Accepted Answer · answered Mar 21 '23 at 11:54

2

If the provided input doesn't match the regular expressions, you can just add an else and handle the invalid input there. For example, if you want to return null:

if (preg_match($longUrlRegex, $this->video_link, $matches)) {
    $youtube_id = $matches[count($matches) - 1];
} else if (preg_match($shortUrlRegex, $this->video_link, $matches)) {
    $youtube_id = $matches[count($matches) - 1];
} else {
    return null;
}

Note that the two existing if blocks are now chained with an else if so they're mutually exclusive, so now all three potential conditions are covered.

answered Mar 21 '23 at 11:54

David

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I tried to do this, but if I have one link normal, and the other is not, then no output at all. And null should be returned only for the one with the wrong link – broken heart Mar 21 '23 at 11:58
let's say I have a foreach where there are several such $item->getYoutubeEmbedUrl() elements, and if there is at least one crooked link, then null will apply to all – broken heart Mar 21 '23 at 11:59
@brokenheart: Please clarify the problem. What exactly do you mean by "all" in this case? The only input given in the code shown is the single value `$this->video_link`. In this suggested change, all the code does is check that input against two different regular expressions (which your original code already did) and add a default case to `return null` if neither expression matches (which is what you were attempting to do). What exactly isn't working? – David Mar 21 '23 at 12:02
everything, figured it out, it works, thanks for the answer – broken heart Mar 21 '23 at 12:04

add check if wrong youtube link is given

1 Answers1