如何在Swift同一函数中用双URLSession请求获取Spotify两类数据？

步骤1：定义组合数据结构 #

首先创建一个结构体，用来封装热门歌手（top artists）和热门曲目（top tracks）的数据，让completionHandler可以一次性返回两类结果：

// 假设你已经有解析Spotify返回数据的Artist和Track模型（符合Codable）
struct TopMusicData {
    let artists: [Artist]
    let tracks: [Track]
}

方式一：用Async/Await实现（iOS 15+ / macOS 12+ 推荐） #

如果项目支持Swift并发特性，这种方式代码更简洁易维护，无需手动管理异步任务的同步：

func fetchTopMusicData(timeRange: String = "medium_term", limit: Int = 20) async throws -> TopMusicData {
    let session = URLSession.shared
    let accessToken = "你的Spotify访问令牌" // 需要确保令牌拥有user-top-read权限
    
    // 1. 请求并解析热门歌手数据
    guard let artistsURL = URL(string: "https://api.spotify.com/v1/me/top/artists?time_range=\(timeRange)&limit=\(limit)") else {
        throw URLError(.badURL)
    }
    var artistsRequest = URLRequest(url: artistsURL)
    artistsRequest.setValue("Bearer \(accessToken)", forHTTPHeaderField: "Authorization")
    
    let (artistsData, _) = try await session.data(for: artistsRequest)
    let artistsResponse = try JSONDecoder().decode(TopArtistsResponse.self, from: artistsData)
    let topArtists = artistsResponse.items
    
    // 2. 请求并解析热门曲目数据
    guard let tracksURL = URL(string: "https://api.spotify.com/v1/me/top/tracks?time_range=\(timeRange)&limit=\(limit)") else {
        throw URLError(.badURL)
    }
    var tracksRequest = URLRequest(url: tracksURL)
    tracksRequest.setValue("Bearer \(accessToken)", forHTTPHeaderField: "Authorization")
    
    let (tracksData, _) = try await session.data(for: tracksRequest)
    let tracksResponse = try JSONDecoder().decode(TopTracksResponse.self, from: tracksData)
    let topTracks = tracksResponse.items
    
    // 返回组合数据
    return TopMusicData(artists: topArtists, tracks: topTracks)
}

// 配套的解析模型示例（需符合Codable）
struct TopArtistsResponse: Codable {
    let items: [Artist]
}

struct TopTracksResponse: Codable {
    let items: [Track]
}

struct Artist: Codable {
    let id: String
    let name: String
    let images: [SpotifyImage]?
}

struct Track: Codable {
    let id: String
    let name: String
    let artists: [Artist]
    let album: Album
}

struct SpotifyImage: Codable {
    let url: String
    let height: Int?
    let width: Int?
}

struct Album: Codable {
    let id: String
    let name: String
    let images: [SpotifyImage]?
}

调用示例：

Task {
    do {
        let topMusicData = try await fetchTopMusicData()
        // 处理获取到的歌手和曲目数据
        print("热门歌手：\(topMusicData.artists.map { $0.name })")
        print("热门曲目：\(topMusicData.tracks.map { $0.name })")
    } catch {
        print("请求失败：\(error.localizedDescription)")
    }
}

方式二：用DispatchGroup实现回调式请求（兼容iOS 14及以下） #

如果需要兼容旧系统，可使用DispatchGroup来同步两个异步请求的完成状态：

func fetchTopMusicData(timeRange: String = "medium_term", limit: Int = 20, completion: @escaping (Result<TopMusicData, Error>) -> Void) {
    let session = URLSession.shared
    let accessToken = "你的Spotify访问令牌"
    let dispatchGroup = DispatchGroup()
    
    var topArtists: [Artist]?
    var topTracks: [Track]?
    var requestError: Error?
    
    // 发起热门歌手请求
    dispatchGroup.enter()
    guard let artistsURL = URL(string: "https://api.spotify.com/v1/me/top/artists?time_range=\(timeRange)&limit=\(limit)") else {
        completion(.failure(URLError(.badURL)))
        return
    }
    var artistsRequest = URLRequest(url: artistsURL)
    artistsRequest.setValue("Bearer \(accessToken)", forHTTPHeaderField: "Authorization")
    
    session.dataTask(with: artistsRequest) { data, _, error in
        defer { dispatchGroup.leave() }
        if let error = error {
            requestError = error
            return
        }
        guard let data = data else {
            requestError = URLError(.cannotParseResponse)
            return
        }
        do {
            let response = try JSONDecoder().decode(TopArtistsResponse.self, from: data)
            topArtists = response.items
        } catch {
            requestError = error
        }
    }.resume()
    
    // 发起热门曲目请求
    dispatchGroup.enter()
    guard let tracksURL = URL(string: "https://api.spotify.com/v1/me/top/tracks?time_range=\(timeRange)&limit=\(limit)") else {
        completion(.failure(URLError(.badURL)))
        return
    }
    var tracksRequest = URLRequest(url: tracksURL)
    tracksRequest.setValue("Bearer \(accessToken)", forHTTPHeaderField: "Authorization")
    
    session.dataTask(with: tracksRequest) { data, _, error in
        defer { dispatchGroup.leave() }
        if let error = error {
            requestError = error
            return
        }
        guard let data = data else {
            requestError = URLError(.cannotParseResponse)
            return
        }
        do {
            let response = try JSONDecoder().decode(TopTracksResponse.self, from: data)
            topTracks = response.items
        } catch {
            requestError = error
        }
    }.resume()
    
    // 等待两个请求完成后返回结果
    dispatchGroup.notify(queue: .main) {
        if let error = requestError {
            completion(.failure(error))
            return
        }
        guard let artists = topArtists, let tracks = topTracks else {
            completion(.failure(URLError(.unknown)))
            return
        }
        completion(.success(TopMusicData(artists: artists, tracks: tracks)))
    }
}

调用示例：

fetchTopMusicData { result in
    switch result {
    case .success(let data):
        print("热门歌手：\(data.artists.map { $0.name })")
        print("热门曲目：\(data.tracks.map { $0.name })")
    case .failure(let error):
        print("请求失败：\(error.localizedDescription)")
    }
}

关键注意事项 #

• 权限要求：你的Spotify访问令牌必须拥有user-top-read权限，否则API会返回403错误。
• 令牌有效性：确保访问令牌未过期，可通过Spotify的授权流程刷新令牌。
• 模型适配：根据你需要的字段调整Artist、Track等模型的属性，完全匹配Spotify API返回的JSON结构。

内容的提问来源于stack exchange，提问作者ezhovich