import Foundation import HTMLEntities // Given a track, attempts to fetch the lyrics from lyricswiki class LyricsEngine { // URL of the API endpoint to use private let apiURL = "https://lyrics.wikia.com/api.php?action=lyrics&func=getSong&fmt=realjson" // Method used to call the API private let apiMethod = "GET" // Regular expxression used to find the lyrics in the lyricswiki HTML private let lyricsMatcher = "class='lyricbox'>(.+) Void in lyrics = lyricsResult requestFinished = true asyncLock.signal() }) while !requestFinished { asyncLock.wait() } asyncLock.unlock() } } } return lyrics } // Initializes with a track init(withTrack targetTrack: Track) { track = targetTrack } // Fetch the lyrics URL from the API, triggers the request to fetch the // lyrics page private func fetchLyricsFromAPI(withURL url: URL, completionHandler: @escaping (String?) -> Void) { var apiRequest = URLRequest(url: url) apiRequest.httpMethod = "GET" let task = URLSession.shared.dataTask(with: apiRequest, completionHandler: {data, _, _ -> Void in // If the response is parseable JSON, and has a url, we'll look for // the lyrics in there if let data = data { if let jsonResponse = try? JSONSerialization.jsonObject(with: data) { if let jsonResponse = jsonResponse as? [String: Any] { if let lyricsUrlString = jsonResponse["url"] as? String { if let lyricsUrl = URL(string: lyricsUrlString) { // At this point we have a valid wiki url self.fetchLyricsFromPage(withURL: lyricsUrl, completionHandler: completionHandler) return } } } } } completionHandler(nil) }) task.resume() } // Fetch the lyrics from the page and send it to the parser private func fetchLyricsFromPage(withURL url: URL, completionHandler: @escaping (String?) -> Void) { var pageRequest = URLRequest(url: url) pageRequest.httpMethod = "GET" let task = URLSession.shared.dataTask(with: pageRequest, completionHandler: {data, _, _ -> Void in // If the response is parseable JSON, and has a url, we'll look for // the lyrics in there if let data = data { if let htmlBody = String(data: data, encoding: String.Encoding.utf8) { self.parseHtmlBody(htmlBody, completionHandler: completionHandler) return } } completionHandler(nil) }) task.resume() } // Parses the wiki to find the lyrics, decodes the lyrics object private func parseHtmlBody(_ body: String, completionHandler: @escaping (String?) -> Void) { // Look for the lyrics lightbox if let regex = try? NSRegularExpression(pattern: lyricsMatcher) { let matches = regex.matches(in: body, range: NSRange(location: 0, length: body.characters.count)) for match in matches { let nsBody = body as NSString let range = match.rangeAt(1) let encodedLyrics = nsBody.substring(with: range) let decodedLyrics = decodeLyrics(encodedLyrics) completionHandler(decodedLyrics) return } } completionHandler(nil) } // Escapes the HTML entities private func decodeLyrics(_ lyrics: String) -> String { let unescapedLyrics = lyrics.htmlUnescape() return unescapedLyrics.replacingOccurrences(of: "
", with: "\n") } }