git.r.bdr.sh - rbdr/lyricli/blob - Sources/lyricli/lyrics_engine.swift

   1 import Foundation
   2 import SwiftSoup
   3
   4 // Given a track, attempts to fetch the lyrics from lyricswiki
   5 class LyricsEngine {
   6
   7     private let clientToken = <GENIUS_CLIENT_TOKEN>
   8
   9     // URL of the API endpoint to use
  10     private let apiURL = "https://api.genius.com/search"
  11
  12     // Method used to call the API
  13     private let apiMethod = "GET"
  14
  15     // The track we'll be looking for
  16     private let track: Track
  17
  18     // Fetches the lyrics and returns if found
  19     var lyrics: String? {
  20
  21         var lyrics: String?
  22
  23         // Encode the track artist and name and finish building the API call URL
  24
  25         if let artist = track.artist.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed) {
  26             if let name = track.name.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed) {
  27
  28                 if let url = URL(string: "\(apiURL)?access_token=\(clientToken)&q=\(artist)%20\(name)") {
  29
  30                     // We'll lock until the async call is finished
  31
  32                     var requestFinished = false
  33                     let asyncLock = NSCondition()
  34                     asyncLock.lock()
  35
  36                     // Call the API and unlock when you're done
  37
  38                     searchLyricsUsingAPI(withURL: url, completionHandler: {lyricsResult -> Void in
  39                         lyrics = lyricsResult
  40                         requestFinished = true
  41                         asyncLock.signal()
  42                     })
  43
  44                     while !requestFinished {
  45                         asyncLock.wait()
  46                     }
  47                     asyncLock.unlock()
  48                 }
  49             }
  50         }
  51
  52         return lyrics
  53     }
  54
  55     // Initializes with a track
  56     init(withTrack targetTrack: Track) {
  57
  58         track = targetTrack
  59     }
  60
  61     // Fetch the lyrics URL from the API, triggers the request to fetch the
  62     // lyrics page
  63     private func searchLyricsUsingAPI(withURL url: URL, completionHandler: @escaping (String?) -> Void) {
  64
  65         var apiRequest = URLRequest(url: url)
  66         apiRequest.httpMethod = "GET"
  67
  68         let task = URLSession.shared.dataTask(with: apiRequest, completionHandler: {data, _, _ -> Void in
  69
  70             // If the response is parseable JSON, and has a url, we'll look for
  71             // the lyrics in there
  72
  73             if let data = data {
  74                 if let jsonResponse = try? JSONSerialization.jsonObject(with: data) {
  75                     if let jsonResponse = jsonResponse as? [String: Any] {
  76                         if let response = jsonResponse["response"] as? [String:Any] {
  77                             if let hits = response["hits"] as? [Any] {
  78                                 if let firstHit = hits[0] as? [String: Any] {
  79                                     if let firstHitData = firstHit["result"] as? [String: Any] {
  80                                         if let lyricsUrlString = firstHitData["url"] as? String {
  81                                             if let lyricsUrl = URL(string: lyricsUrlString) {
  82
  83                                                 // At this point we have a valid wiki url
  84                                                 self.fetchLyricsFromPage(
  85                                                     withURL: lyricsUrl,
  86                                                     completionHandler: completionHandler
  87                                                 )
  88                                                 return
  89                                             }
  90                                         }
  91                                     }
  92                                 }
  93                             }
  94                         }
  95                     }
  96                 }
  97             }
  98
  99             completionHandler(nil)
 100         })
 101         task.resume()
 102     }
 103
 104     // Fetch the lyrics from the page and send it to the parser
 105     private func fetchLyricsFromPage(withURL url: URL, completionHandler: @escaping (String?) -> Void) {
 106
 107         var pageRequest = URLRequest(url: url)
 108         pageRequest.httpMethod = "GET"
 109
 110         let task = URLSession.shared.dataTask(with: pageRequest, completionHandler: {data, _, _ -> Void in
 111
 112             // If the response is parseable JSON, and has a url, we'll look for
 113             // the lyrics in there
 114
 115             if let data = data {
 116                 if let htmlBody = String(data: data, encoding: String.Encoding.utf8) {
 117                     self.parseHtmlBody(htmlBody, completionHandler: completionHandler)
 118                     return
 119                 }
 120             }
 121
 122             completionHandler(nil)
 123         })
 124         task.resume()
 125     }
 126
 127     // Parses the wiki to find the lyrics, decodes the lyrics object
 128     private func parseHtmlBody(_ body: String, completionHandler: @escaping (String?) -> Void) {
 129
 130         do {
 131             let document: Document = try SwiftSoup.parse(body)
 132             let lyricsBox = try document.select("div[data-lyrics-container=\"true\"]")
 133             try lyricsBox.select("br").after("\\n")
 134             let lyrics = try lyricsBox.text()
 135             completionHandler(lyrics.replacingOccurrences(of: "\\n", with: "\r\n"))
 136         } catch {
 137             completionHandler(nil)
 138         }
 139     }
 140 }