selenium爬取动态网页的步骤（用CSelenium）

火客 2023-06-09 10:40:42 606

selenium爬取动态网页的步骤（用CSelenium）3.对html数据进行解析2.确定数据源，从driver.PageSource读取数据 private void crawlingWebFunc { SetText("\r\n开始尝试..."); List<testfold> surls = new List<testfold>; string path = System.Environment.CurrentDirectory "\\图片url\\"; DirectoryInfo root = new DirectoryInfo(path); DirectoryInfo dics = root.GetDirectories; foreach (var itemdic in dics) { string txt = ""; StreamReader sr = new StreamReader(itemdic.F

背景

Selenium是一个用于Web应用程序测试的工具。Selenium测试直接运行在浏览器中，就像真正的用户在操作一样。而对于爬虫来说，使用Selenium操控浏览器来爬取网上的数据那么肯定是爬虫中的杀手武器。这里，我将介绍selenium 谷歌浏览器的一般使用。

需求

在平常的爬虫开发中，有时候网页是一堆js堆起来的代码，涉及很多异步计算，如果是普通的http 控制台请求，那么得到的源文件是一堆js ，需要自己在去组装数据，很费力；但是采用Selenium chromeDriver可以达到所见即所得的完美效果。

实现方式

项目结构：为了方便使用，用的winform程序，附nuget包

selenium爬取动态网页的步骤（用CSelenium）(1)

以下是form1.cs的代码，这里就只放关键方法代码了。需要安装最新的chrome浏览器代码中使用的chromedriver是 v2.9.248315

private void crawlingWebFunc { SetText("\r\n开始尝试..."); List<testfold> surls = new List<testfold>; string path = System.Environment.CurrentDirectory "\\图片url\\"; DirectoryInfo root = new DirectoryInfo(path); DirectoryInfo dics = root.GetDirectories; foreach (var itemdic in dics) { string txt = ""; StreamReader sr = new StreamReader(itemdic.FullName "\\data.txt"); while (!sr.EndOfStream) { string str = sr.ReadLine; txt = str;// "\n"; } sr.Close; surls.Add(new testfold { key = itemdic.FullName picurl = txt }); }
ChromeDriverService service = ChromeDriverService.CreateDefaultService(System.Environment.CurrentDirectory); // service.HideCommandPromptWindow = true;
ChromeOptions options = new ChromeOptions; options.AddArguments("--test-type" "--ignore-certificate-errors"); options.AddArgument("enable-automation"); // options.AddArgument("headless"); // options.AddArguments("--proxy-server=http://user:password@yourProxyServer.com:8080");
using (IWebDriver driver = new OpenQA.Selenium.Chrome.ChromeDriver(service options TimeSpan.FromSeconds(120))) { driver.Url = "https://www.1688.com/"; Thread.Sleep(200); try { int a = 1; foreach (var itemsurls in surls) { SetText("\r\n第" a.ToString "个"); driver.Navigate.GoToUrl(itemsurls.picurl); //登录 if (driver.Url.Contains("login.1688.com")) { SetText("\r\n需要登录，开始尝试..."); trylogin(driver); //尝试登录完成 //再试试 driver.Navigate.GoToUrl("https://s.1688.com/youyuan/index.htm?tab=imageSearch&imageType=oss&imageAddress=cbuimgsearch/eWXC7XHHPN1607529600000&spm=");
if (driver.Url.Contains("login.1688.com")) { //没办法退出 SetText("\r\n退出，换ip重试..."); return; } }
//鼠标放上去的内容因为页面自带只能显示一个的原因没办法做到全部显示然后在下载只能是其他方式下载 // var elements = document.getElementsByClassName('hover-container'); // Array.prototype.forEach.call(elements function(element) { // element.style.display = "block"; // console.log(element); // });
// IJavaScriptExecutor js = (IJavaScriptExecutor)driver;
// var sss = js.ExecuteScript(" var elements = document.getElementsByClassName('hover-container'); Array.prototype.forEach.call(elements function(element) { console.log(element); element.setAttribute(\"class\" \"测试title\"); element.style.display = \"block\"; console.log(element); });");
Thread.Sleep(500); var responseModel = Write(itemsurls.key driver.PageSource Pagetypeenum.列表); Thread.Sleep(500); int i = 1; foreach (var offer in responseModel?.data?.offerList ?? new List<OfferItemModel>) { driver.Navigate.GoToUrl(offer.information.detailUrl); string responseDatadetail = driver.PageSource; Write(itemsurls.key driver.PageSource Pagetypeenum.详情); SetText("\r\n第" a.ToString "-" i.ToString "个"); Thread.Sleep(500); i ; } } } catch (Exception ex) { CloseChromeDriver(driver); throw; } } }

#region 异常退出chromedriver
[DllImport("user32.dll" EntryPoint = "FindWindow")] private extern static IntPtr FindWindow(string lpClassName string lpWindowName);
[DllImport("user32.dll" EntryPoint = "SendMessage")] public static extern int SendMessage(IntPtr hWnd int Msg int wParam int lParam);
public const int SW_HIDE = 0; public const int SW_SHOW = 5;
[DllImport("user32.dll" EntryPoint = "ShowWindow")] public static extern int ShowWindow(IntPtr hwnd int nCmdShow);
/// <summary> /// 获取窗口句柄 /// </summary> /// <returns></returns> public IntPtr GetWindowHandle { string name = (Environment.CurrentDirectory "\\chromedriver.exe"); IntPtr hwd = FindWindow( name); return hwd; }
/// <summary> /// 关闭chromedriver窗口 /// </summary> public void CloseWindow { try { IntPtr hwd = GetWindowHandle; SendMessage(hwd 0x10 0 0); } catch { } }
/// <summary> /// 退出chromedriver /// </summary> /// <param name="driver"></param> public void CloseChromeDriver(IWebDriver driver) { try { driver.Quit; driver.Dispose; } catch { } CloseWindow; }
#endregion 异常退出chromedriver