Web 服务调用花费的时间太长

Question

我用 C# 创建了一个客户端 Web 服务，以便能够检索有关我从服务器获得的书籍的信息。

当我打电话从 bookId 获取我在 paremeter 中传递的书籍信息时，有时调用很快，有时需要 1 分钟，有时需要很长时间。我只将 bookId 存储在我的数据库中，所以当我需要有关书籍的更多信息(标题、出版日期等(时，我会联系网络服务以获取它们。我正在使用chrome调试器，在"网络"选项卡下，我只有"警告;请求尚未完成">...没有其他信息可以帮助我了解到底发生了什么！–

我调用的函数是getBooksByAuthor(authorId)的，我应该只有 8 个与 authorId 相关的结果，所以它应该不会花那么长时间！这是我的所有代码：

public async Task<T> GetObject<T>(string uriActionString)
        {
            T wsObject =
                default(T);
            try
            {
                using (var client = new HttpClient())
                {
                    client.BaseAddress = new Uri(@"https://books.server.net");
                    client.DefaultRequestHeaders.Accept.Clear();
                    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                    // connect to the server
                    var byteArray = Encoding.ASCII.GetBytes("NXXXXX:Passxxxx");
                    client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", Convert.ToBase64String(byteArray));
                    HttpResponseMessage response = await client.GetAsync(uriActionString);
                    response.EnsureSuccessStatusCode();
                    wsObject = JsonConvert.DeserializeObject<T>(await((HttpResponseMessage)response).Content.ReadAsStringAsync());
                }
                return wsObject;
            }
            catch (Exception e)
            {
                throw (e);
            }
        }
        public async Task<Book> viewBook(int id)
        {
            Book book = new Book();
            string urlAction = String.Format("api/book/{0}", id);
            book = await GetWSObject<Book>(urlAction);
            return book;
        }
        public string getBooksByAuthor (int authorId) {
            string result = "";
            var books = from a in db.Authors
                        where a.id == authorId
                        select new
                        {
                            id = a.id
                        };
            foreach (var book in books.ToList())
            {
                var bookdata = await ws.viewBook(book .id);
                result += this.getBookObject(book.id).name + ", ";   
            }
            return result;
        }
     /* How to return a string from a task ? */  
    foreach (var author in listOfAuthors)
      {
      booksFromAuthors.Add(new { id = author.id, book = getBooksByAuthor(author.id) // ? how convert it to a string ?  });
      }

Answer 1

失去getBookObject函数，你只是通过在那里启动一个新任务使事情复杂化。

你可以简单地等待getBooksByAuthor的结果，如果你使该函数异步。

public async Task<Book> getBook(int id)
{
    string urlAction = String.Format("api/book/{0}", id);
    return await GetWSObject<Book>(urlAction);
}
public async Task<string> getBooksByAuthor (int authorId) 
{
    string result = "";
    var books = from a in db.Authors
                where a.id == authorId
                select new
                {
                    id = a.id
                };
    foreach (var book in books.ToList())
    {
        var bookdata = await this.getBook(book.id);
        result += bookdata.name + ", ";   
    }
    return result; 
}

如果你想发出并发的http请求，你可以创建一些任务并使用Task.WhenAll，例如

https://stackoverflow.com/a/30668277/1538039