Question

我写了一个类，可以下载网站的app.use(cors()); app.options('*', cors());结构。这很好用，但是有时（我无法弄清楚为什么）方法html返回一个空字符串，这给我带来了很多问题，因为返回的“ html”里面没有文本，然后使用ReadAsStringAsync()的方法将无法对其进行分析。这是我的课程：

HtmlAgilityPack

该类还处理重定向，但是我想将注意力集中在public class NetworkHelper { /// <summary> /// Configure the client to handle web request. /// </summary> static Lazy<HttpClient> httpClient = new Lazy<HttpClient>(() => { var handler = CreateHandler(); return new HttpClient(handler) { Timeout = TimeSpan.FromSeconds(60) }; }); /// <summary> /// Web request handler. /// </summary> /// <returns>Return an object HttpMessageHandler.</returns> static HttpMessageHandler CreateHandler() { var handler = new HttpClientHandler(); //If the framework support it, se a specific redirect. if (handler.SupportsRedirectConfiguration) { handler.AllowAutoRedirect = true; handler.MaxAutomaticRedirections = 5; } //Set page compression. if (handler.SupportsAutomaticDecompression) { handler.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate; } return handler; } /// <summary> /// Get the html from a web page. /// </summary> /// <param name="url">Url of the site.</param> /// <returns>Return a string that contains the html.</returns> public async Task<string> GetHtmlAsync(Uri url, CancellationToken cancellationToken = default(CancellationToken)) { //This protocol is used to exchange the information from client to server. ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls12; //Get web page html. var response = await httpClient.Value.GetAsync(url, cancellationToken); var content = await response.Content.ReadAsStringAsync(); return content; } }上，该方法效果很好，但通常返回一个GetHtmlAsync字符串。我以为这可能是服务器繁忙或类似的情况，在这种情况下，我该如何处理这种情况？

感谢任何提示。

Answer 1

有时服务器正忙，并且不发送任何请求，目前我正在使用以下代码修复此问题：

if (!response.IsSuccessStatusCode)
    content = await new NetworkHelper().GetHtmlAsync(url);
else
    content = await response.Content.ReadAsStringAsync()
return content;

本质上，如果状态代码不成功，则该方法将再次执行，这对我有用，也许有人可以建议其他解决方案

ReadAsStringAsync返回空字符串

1 个答案: