来自 URL 的 Youtube 视频 ID - Swift3

Question

基本上我有一个 Youtube URL 作为字符串，我想从那个 URL 中提取视频 ID。我在 objective c 中找到了一些代码，如下所示：

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];
}

当我将此代码转换为 swift3 时：

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)
}

给出错误为：

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

谁能帮我解决这个错误，或者谁能解释一下如何从 Swift 中的 url 获取视频 ID 3.

提前致谢

Answer 1

我有一种使用 URLComponents 的不同方法。如果 url 中的 'v' 参数存在，那么您只需 select 即可。

func getYoutubeId(youtubeUrl: String) -> String? {
    return URLComponents(string: youtubeUrl)?.queryItems?.first(where: { [=10=].name == "v" })?.value
}

然后像这样传入 Youtube url：

print (getYoutubeId(youtubeUrl: "https://www.youtube.com/watch?v=Y7ojcTR78qE&spfreload=9"))

Answer 2

您的第一个问题是您没有在表达式中转义 ?。 ? 是保留字符，如果你想在你的表达式中使用它，你必须用 \ 转义，因为 \ 也用于转义 " 字符你必须转义 ? 带有双反斜杠，例如 \?。因此根据以上信息，以下代码正确提取了 videoId

let youtubeURL = "https://www.youtube.com/watch?v=uH8o-JTHJdM"
let regex = try! NSRegularExpression(pattern: "\?.*v=([^&]+)", options: .caseInsensitive)
let match = regex.firstMatch(in: youtubeURL, options: [], range: NSRange(location: 0, length: youtubeURL.characters.count))
if let videoIDRange = match?.rangeAt(1) {
    let substringForFirstMatch = (youtubeURL as NSString).substring(with: videoIDRange)
} else {
    //NO video URL
}

Answer 3

这是从任何 YouTube url 中提取 YouTube 视频 ID 的代码： (Swift)

func extractYoutubeId(fromLink link: String) -> String {
        let regexString: String = "((?<=(v|V)/)|(?<=be/)|(?<=(\?|\&)v=)|(?<=embed/))([\w-]++)"
        let regExp = try? NSRegularExpression(pattern: regexString, options: .caseInsensitive)
        let array: [Any] = (regExp?.matches(in: link, options: [], range: NSRange(location: 0, length: (link.characters.count ))))!
        if array.count > 0 {
            let result: NSTextCheckingResult? = array.first as? NSTextCheckingResult
            return (link as NSString).substring(with: (result?.range)!)
        }

        return ""
    }

Answer 4

更安全版本（没有强制展开!）：

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)
    }
}

示例：

"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"

致谢：

Answer 5

ASwift4版本使用优雅flatMap:

func extractYouTubeId(from url: String) -> String? {
    let typePattern = "(?:(?:\.be\/|embed\/|v\/|\?v=|\&v=|\/videos\/)|(?:[\w+]+#\w\/\w(?:\/[\w]+)?\/\w\/))([\w-_]+)"
    let regex = try? NSRegularExpression(pattern: typePattern, options: .caseInsensitive)
    return regex
        .flatMap { [=10=].firstMatch(in: url, range: NSMakeRange(0, url.count)) }
        .flatMap { Range([=10=].range(at: 1), in: url) }
        .map { String(url[[=10=]]) }
}

此方法使用正则表达式检测大多数可能的 YouTube URL 格式（.be/*、/embed/、/v/ - 您可以找到完整列表 here).

Answer 6

要从 Youtube Url 获取视频 ID，请使用代码 # Swift4 :

var videoId = ""

    if youtubeLink.lowercased().contains("youtu.be"){
            linkString = youtubeLink
            if let range = linkString.range(of: "be/"){
                videoId = youtubeLink[range.upperBound...].trimmingCharacters(in: .whitespaces)
            }
        }
        else if youtubeLink.lowercased().contains("youtube.com"){
            linkString = youtubeLink
            if let range = linkString.range(of: "?v="){
                videoId = youtubeLink[range.upperBound...].trimmingCharacters(in: .whitespaces)
            }
        }

希望对您有所帮助！ :)

Answer 7

Youtube 的一些示例 url:

let urls: [String] = [
    "www.youtube-nocookie.com/embed/up_lNV-yoK4?rel=0",
    "http://www.youtube.com/watch?v=peFZbP64dsU",
    "http://www.youtube.com/watch?v=cKZDdG9FTKY&feature=channel",
    "http://youtube.com/v/dQw4w9WgXcQ?feature=youtube_gdata_player",
    "http://youtube.com/?v=dQw4w9WgXcQ&feature=youtube_gdata_player",
    "http://youtu.be/6dwqZw0j_jY",
    "http://youtu.be/dQw4w9WgXcQ?feature=youtube_gdata_playe",
    "http://youtube.com/vi/dQw4w9WgXcQ?feature=youtube_gdata_player",
    "http://youtube.com/?vi=dQw4w9WgXcQ&feature=youtube_gdata_player",
    "http://youtube.com/watch?vi=dQw4w9WgXcQ&feature=youtube_gdata_player",
    "http://www.youtube.com/user/Scobleizer#p/u/1/1p3vcRhsYGo?rel=0",
    "http://www.youtube.com/user/SilkRoadTheatre#p/a/u/2/6dwqZw0j_jY",
    "1p3vcRhsY02"
]

我的扩展基于解决方案：

private extension String {
    var youtubeID: String? {
        let pattern = "((?<=(v|V|vi)/)|(?<=be/)|(?<=(\?|\&)v=)|(?<=vi=)|(?<=/u/[0-9_]/)|(?<=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 count == 11 ? self : nil
        }

        let id = (self as NSString).substring(with: result.range)
        return id.count == 11 ? id : nil
    }
}

Answer 8

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)")
}

结果：

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

来自 URL 的 Youtube 视频 ID - Swift3

Youtube Video Id from URL - Swift3

regex

swift

swift3

nsregularexpression