Youtube complete Java Regex

Question

I need to parse several pages to get all of their Youtube IDs.

I found many regular expressions on the web, but : the Java ones are not complete (they either give me garbage in addition to the IDs, or they miss some IDs).

The one that I found that seems to be complete is hosted here. But it is written in JavaScript and PHP. Unfortunately I couldn't translate them into JAVA.

Can somebody help me rewrite this PHP regex or the following JavaScript one in Java?

'~
    https?://         # Required scheme. Either http or https.
    (?:[0-9A-Z-]+\.)? # Optional subdomain.
    (?:               # Group host alternatives.
      youtu\.be/      # Either youtu.be,
    | youtube\.com    # or youtube.com followed by
      \S*             # Allow anything up to VIDEO_ID,
      [^\w\-\s]       # but char before ID is non-ID char.
    )                 # End host alternatives.
    ([\w\-]{11})      # $1: VIDEO_ID is exactly 11 chars.
    (?=[^\w\-]|$)     # Assert next char is non-ID or EOS.
    (?!               # Assert URL is not pre-linked.
      [?=&+%\w]*      # Allow URL (query) remainder.
      (?:             # Group pre-linked alternatives.
        [\'"][^<>]*>  # Either inside a start tag,
      | </a>          # or inside <a> element text contents.
      )               # End recognized pre-linked alts.
    )                 # End negative lookahead assertion.
    [?=&+%\w]*        # Consume any URL (query) remainder.
    ~ix'

/https?:\/\/(?:[0-9A-Z-]+\.)?(?:youtu\.be\/|youtube\.com\S*[^\w\-\s])([\w\-]{11})(?=[^\w\-]|$)(?![?=&+%\w]*(?:['"][^<>]*>|<\/a>))[?=&+%\w]*/ig;

Answer 1

First of all you need to insert and extra backslash \ foreach backslash in the old regex, else java thinks you escapes some other special characters in the string, which you are not doing.

https?:\\/\\/(?:[0-9A-Z-]+\\.)?(?:youtu\\.be\\/|youtube\\.com\\S*[^\\w\\-\\s])([\\w\\-]{11})(?=[^\\w\\-]|$)(?![?=&+%\\w]*(?:['\"][^<>]*>|<\\/a>))[?=&+%\\w]*

Next when you compile your pattern you need to add the CASE_INSENSITIVE flag. Here's an example:

String pattern = "https?:\\/\\/(?:[0-9A-Z-]+\\.)?(?:youtu\\.be\\/|youtube\\.com\\S*[^\\w\\-\\s])([\\w\\-]{11})(?=[^\\w\\-]|$)(?![?=&+%\\w]*(?:['\"][^<>]*>|<\\/a>))[?=&+%\\w]*";

Pattern compiledPattern = Pattern.compile(pattern, Pattern.CASE_INSENSITIVE);
Matcher matcher = compiledPattern.matcher(link);
while(matcher.find()) {
    System.out.println(matcher.group());
}

Answer 2

Marcus above has a good regex, but i found that it doesn't recognize youtube links that have "www" but not "http(s)" in them for example www.youtube....

i have an update:

^(?:https?:\\/\\/)?(?:[0-9A-Z-]+\\.)?(?:youtu\\.be\\/|youtube\\.com\\S*[^\\w\\-\\s])([\\w\\-]{11})(?=[^\\w\\-]|$)(?![?=&+%\\w]*(?:['\"][^<>]*>|<\\/a>))[?=&+%\\w]*

it's the same except for the start