How Can I Extract a YouTube Video ID from a URL?

Extracting Video IDs from YouTube URLs

When working with YouTube video URLs in your code, it's often necessary to extract the video ID for identification or processing. While the YouTube API doesn't directly offer a function to do this, you can use a simple technique to parse the URL and retrieve the ID.

Parsing the URL with Regular Expressions

One common approach is to use regular expressions to match and extract the video ID from the URL. Here's an example PHP function that uses this technique:

<code class="php">function youtube_id_from_url($url) {
    $pattern = '/^# Match any youtube URL
        (?:https?://)?  # Optional scheme. Either http or https
        (?:www\.)?      # Optional www subdomain
        (?:             # Group host alternatives
          youtu\.be/    # Either youtu.be,
        | youtube\.com  # or youtube.com
          (?:           # Group path alternatives
            /embed/     # Either /embed/
          | /v/         # or /v/
          | /watch\?v=  # or /watch\?v=
          )             # End path alternatives.
        )               # End host alternatives.
        ([\w-]{10,12})  # Allow 10-12 for 11 char youtube id.
        $/x';
    $result = preg_match($pattern, $url, $matches);
    if ($result) {
        return $matches[1];
    }
    return false;
}</code>

This function takes the YouTube URL as input and matches it against a regular expression that captures the video ID. The pattern ensures that it matches valid YouTube URLs of different formats.

Example Usage

To use this function, you can provide a YouTube URL and retrieve the extracted video ID:

<code class="php">echo youtube_id_from_url('http://youtu.be/NLqAF9hrVbY'); # NLqAF9hrVbY</code>

Alternative Approach: YouTube Oembed Service

While not directly related to the API, YouTube also provides an oembed service that offers more meta-information about a YouTube URL. However, the video ID is not directly accessible through this service.

By using the oembed service, you can obtain information such as the title, author, thumbnail, and more. This can be useful for validating the YouTube URL or extracting other relevant details.

<code class="php">$url = 'http://youtu.be/NLqAF9hrVbY';
var_dump(json_decode(file_get_contents(sprintf('http://www.youtube.com/oembed?url=%s&format=json', urlencode($url)))));</code>

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