Youtube Video Id from URL - Swift3

Question

Basically I have a Youtube URL as string, I want to extract the video Id from that URL. I found some code in objective c that is as below:

NSError *error = NULL;
NSRegularExpression *regex = 
[NSRegularExpression regularExpressionWithPattern:@"?.*v=([^&]+)"
                                          options:NSRegularExpressionCaseInsensitive
                                            error:&error];
NSTextCheckingResult *match = [regex firstMatchInString:youtubeURL
                                                options:0
                                                  range:NSMakeRange(0, [youtubeURL length])];
if (match) {
    NSRange videoIDRange = [match rangeAtIndex:1];
    NSString *substringForFirstMatch = [youtubeURL substringWithRange:videoIDRange];
}

When I am converting this code to swift3 that is:

var error: Error? = nil
var regex = try! NSRegularExpression(pattern: "?.*v=([^&]+)", options: .caseInsensitive)
var match = regex!.firstMatch(in: youtubeURL, options: [], range: NSRange(location: 0, length: youtubeURL.length))!
if match {
    var videoIDRange = match.rangeAt(1)
    var substringForFirstMatch = (youtubeURL as NSString).substring(with: videoIDRange)
}

Gives error as:

fatal error: 'try!' expression unexpectedly raised an error: Error Domain=NSCocoaErrorDomain Code=2048 "The value “?.*v=([^&]+)” is invalid."

Can anybody help me about this error or anybody explain how to get video id from url in Swift 3.

Thanks in advance

Answer 1

Safer version (without force unwrapping !):

extension String {
    var youtubeID: String? {
        let pattern = "((?<=(v|V)/)|(?<=be/)|(?<=(\\?|\\&)v=)|(?<=embed/))([\\w-]++)"

        let regex = try? NSRegularExpression(pattern: pattern, options: .caseInsensitive)
        let range = NSRange(location: 0, length: count)

        guard let result = regex?.firstMatch(in: self, range: range) else {
            return nil
        }

        return (self as NSString).substring(with: result.range)
    }
}

Examples:

"https://www.youtube.com/watch?v=C0DPdy98e4c".youtubeID // "C0DPdy98e4c"
"https://youtube.com/watch?v=C0DPdy98e4c".youtubeID // "C0DPdy98e4c"
"www.youtube.com/watch?v=C0DPdy98e4c".youtubeID // "C0DPdy98e4c"
"youtube.com/watch?v=C0DPdy98e4c".youtubeID // "C0DPdy98e4c"

"https://youtu.be/C0DPdy98e4c".youtubeID // "C0DPdy98e4c"
"youtu.be/C0DPdy98e4c".youtubeID // "C0DPdy98e4c"

Credits: Usman Nisar's answer

Answer 2

Swift 5

var youtubeURLs = [
    "http://www.youtube.com/watch?v=-wtIMTCHWuI",
    "http://www.youtube.com/v/-wtIMTCHWuI?version=3&autohide=1",
    "http://youtu.be/-wtIMTCHWuI",
    "http://www.youtube.com/oembed?url=http%3A//www.youtube.com/watch?v%3D-wtIMTCHWuI&format=json",
    "https://youtu.be/uJ2PZaO1N5E",
    "https://www.youtube.com/embed/M7lc1UVf-VE",
    "http://www.youtube.com/attribution_link?a=JdfC0C9V6ZI&u=%2Fwatch%3Fv%3DEhxJLojIE_o%26feature%3Dshare",
    "https://www.youtube.com/attribution_link?a=8g8kPrPIi-ecwIsS&u=/watch%3Fv%3DyZv2daTWRZU%26feature%3Dem-uploademail"
]

func getVideoID(from urlString: String) -> String? {
    guard let url = urlString.removingPercentEncoding else { return nil }
    do {
        let regex = try NSRegularExpression.init(pattern: "((?<=(v|V)/)|(?<=be/)|(?<=(\\?|\\&)v=)|(?<=embed/))([\\w-]++)", options: .caseInsensitive)
        let range = NSRange(location: 0, length: url.count)
        if let matchRange = regex.firstMatch(in: url, options: .reportCompletion, range: range)?.range {
            let matchLength = (matchRange.lowerBound + matchRange.length) - 1
            if range.contains(matchRange.lowerBound) &&
                range.contains(matchLength) {
                let start = url.index(url.startIndex, offsetBy: matchRange.lowerBound)
                let end = url.index(url.startIndex, offsetBy: matchLength)
                return String(url[start...end])
            }
        }
    } catch {
        print(error.localizedDescription)
    }
    return nil
}

for url in youtubeURLs {
    print("Video id: \(getVideoID(from: url) ?? "NA") for url: \(url)")
}

Result:

Video id: -wtIMTCHWuI for url: http://www.youtube.com/watch?v=-wtIMTCHWuI
Video id: -wtIMTCHWuI for url: http://www.youtube.com/v/-wtIMTCHWuI?version=3&autohide=1
Video id: -wtIMTCHWuI for url: http://youtu.be/-wtIMTCHWuI
Video id: -wtIMTCHWuI for url: http://www.youtube.com/oembed?url=http%3A//www.youtube.com/watch?v%3D-wtIMTCHWuI&format=json
Video id: uJ2PZaO1N5E for url: https://youtu.be/uJ2PZaO1N5E
Video id: M7lc1UVf-VE for url: https://www.youtube.com/embed/M7lc1UVf-VE
Video id: EhxJLojIE_o for url: http://www.youtube.com/attribution_link?a=JdfC0C9V6ZI&u=%2Fwatch%3Fv%3DEhxJLojIE_o%26feature%3Dshare
Video id: yZv2daTWRZU for url: https://www.youtube.com/attribution_link?a=8g8kPrPIi-ecwIsS&u=/watch%3Fv%3DyZv2daTWRZU%26feature%3Dem-uploademail