C# 抓取网页类（获取网页中所有信息）

using System;

using System.Data;

using System.Configuration;

using System.Net;

using System.IO;

using System.Text;

using System.Collections.Generic;

using System.Text.RegularExpressions;

using System.Threading;

using System.Web;

using System.Web.UI.MobileControls;

/// <summary>

/// 网页类

/// </summary>

public class WebPage

{

#region 私有成员

private Uri m_uri; //url

private List<Link> m_links; //此网页上的链接

private string m_title; //标题

private string m_html; //HTML代码

private string m_outstr; //网页可输出的纯文本

private bool m_good; //网页是否可用

private int m_pagesize; //网页的大小

private static Dictionary<string, CookieContainer> webcookies = new Dictionary<string, CookieContainer>();//存放所有网页的Cookie

#endregion

#region 属性

/// <summary>

/// 通过此属性可获得本网页的网址，只读

/// </summary>

public string URL

{

get

{

return m_uri.AbsoluteUri;

}

}

/// <summary>

/// 通过此属性可获得本网页的标题，只读

/// </summary>

public string Title

{

get

{

if (m_title == "")

{

Regex reg = new Regex(@"(?m)<title[^>]*>(?<title>(?:\w|\W)*?)</title[^>]*>", RegexOptions.Multiline | RegexOptions.IgnoreCase);

Match mc = reg.Match(m_html);

if (mc.Success)

m_title = mc.Groups["title"].Value.Trim();

}

return m_title;

}

}

public string M_html

{

get

{

if (m_html == null)

{

m_html = "";

}

return m_html;

}

}

/// <summary>

/// 此属性获得本网页的所有链接信息，只读

/// </summary>

public List<Link> Links

{

get

{

if (m_links.Count == 0) getLinks();

return m_links;

}

}

/// <summary>

/// 此属性返回本网页的全部纯文本信息，只读

/// </summary>

public string Context

{

get

{

if (m_outstr == "") getContext(Int16.MaxValue);

return m_outstr;

}

}

/// <summary>

/// 此属性获得本网页的大小

/// </summary>

public int PageSize

{

get

{

return m_pagesize;

}

}

/// <summary>

/// 此属性获得本网页的所有站内链接

/// </summary>

public List<Link> InsiteLinks

{

get

{

return getSpecialLinksByUrl("^http://" + m_uri.Host, Int16.MaxValue);

}

}

/// <summary>

/// 此属性表示本网页是否可用

/// </summary>

public bool IsGood

{

get

{

return m_good;

}

}

/// <summary>

/// 此属性表示网页的所在的网站

/// </summary>

public string Host

{

get

{

return m_uri.Host;

}

}

#endregion

/// <summary>

/// 从HTML代码中分析出链接信息

/// </summary>

/// <returns>List<Link></returns>

private List<Link> getLinks()

{

if (m_links.Count == 0)

{

Regex[] regex = new Regex[2];

regex[0] = new Regex(@"<a\shref\s*=""(?<URL>[^""]*).*?>(?<title>[^<]*)</a>", RegexOptions.IgnoreCase | RegexOptions.Singleline);

regex[1] = new Regex("<[i]*frame[^><]+src=(\"|')?(?<url>([^>\"'\\s)])+)(\"|')?[^>]*>", RegexOptions.IgnoreCase);

for (int i = 0; i < 2; i++)

{

Match match = regex[i].Match(m_html);

while (match.Success)

{

try

{

string url = HttpUtility.UrlDecode(new Uri(m_uri, match.Groups["URL"].Value).AbsoluteUri);

string text = "";

if (i == 0) text = new Regex("(<[^>]+>)|(\\s)|( )|&|\"", RegexOptions.Multiline | RegexOptions.IgnoreCase).Replace(match.Groups["text"].Value, "");

Link link = new Link();

link.Text = text;

link.NavigateUrl = url;

m_links.Add(link);

}

catch (Exception ex) { Console.WriteLine(ex.Message); };

match = match.NextMatch();

}

}

}

return m_links;

}

/// <summary>

/// 此私有方法从一段HTML文本中提取出一定字数的纯文本

/// </summary>

/// <param name="instr">HTML代码</param>

/// <param name="firstN">提取从头数多少个字</param>

/// <param name="withLink">是否要链接里面的字</param>

/// <returns>纯文本</returns>

private string getFirstNchar(string instr, int firstN, bool withLink)

{

if (m_outstr == "")

{

m_outstr = instr.Clone() as string;

m_outstr = new Regex(@"(?m)<script[^>]*>(\w|\W)*?</script[^>]*>", RegexOptions.Multiline | RegexOptions.IgnoreCase).Replace(m_outstr, "");

m_outstr = new Regex(@"(?m)<style[^>]*>(\w|\W)*?</style[^>]*>", RegexOptions.Multiline | RegexOptions.IgnoreCase).Replace(m_outstr, "");

m_outstr = new Regex(@"(?m)<select[^>]*>(\w|\W)*?</select[^>]*>", RegexOptions.Multiline | RegexOptions.IgnoreCase).Replace(m_outstr, "");

if (!withLink) m_outstr = new Regex(@"(?m)<a[^>]*>(\w|\W)*?</a[^>]*>", RegexOptions.Multiline | RegexOptions.IgnoreCase).Replace(m_outstr, "");

Regex objReg = new System.Text.RegularExpressions.Regex("(<[^>]+?>)| ", RegexOptions.Multiline | RegexOptions.IgnoreCase);

m_outstr = objReg.Replace(m_outstr, "");

Regex objReg2 = new System.Text.RegularExpressions.Regex("(\\s)+", RegexOptions.Multiline | RegexOptions.IgnoreCase);

m_outstr = objReg2.Replace(m_outstr, " ");

}

return m_outstr.Length > firstN ? m_outstr.Substring(0, firstN) : m_outstr;

}

#region 公有文法

/// <summary>

/// 此公有方法提取网页中一定字数的纯文本，包括链接文字

/// </summary>

/// <param name="firstN">字数</param>

/// <returns></returns>

public string getContext(int firstN)

{

return getFirstNchar(m_html, firstN, true);

}

/// <summary>

/// 此公有方法从本网页的链接中提取一定数量的链接，该链接的URL满足某正则式

/// </summary>

/// <param name="pattern">正则式</param>

/// <param name="count">返回的链接的个数</param>

/// <returns>List<Link></returns>

public List<Link> getSpecialLinksByUrl(string pattern, int count)

{

if (m_links.Count == 0) getLinks();

List<Link> SpecialLinks = new List<Link>();

List<Link>.Enumerator i;

i = m_links.GetEnumerator();

int cnt = 0;

while (i.MoveNext() && cnt < count)

{

if (new Regex(pattern, RegexOptions.Multiline | RegexOptions.IgnoreCase).Match(i.Current.NavigateUrl).Success)

{

SpecialLinks.Add(i.Current);

cnt++;

}

}

return SpecialLinks;

}

/// <summary>

/// 此公有方法从本网页的链接中提取一定数量的链接，该链接的文字满足某正则式

/// </summary>

/// <param name="pattern">正则式</param>

/// <param name="count">返回的链接的个数</param>

/// <returns>List<Link></returns>

public List<Link> getSpecialLinksByText(string pattern, int count)

{

if (m_links.Count == 0) getLinks();

List<Link> SpecialLinks = new List<Link>();

List<Link>.Enumerator i;

i = m_links.GetEnumerator();

int cnt = 0;

while (i.MoveNext() && cnt < count)

{

if (new Regex(pattern, RegexOptions.Multiline | RegexOptions.IgnoreCase).Match(i.Current.Text).Success)

{

SpecialLinks.Add(i.Current);

cnt++;

}

}

return SpecialLinks;

}

/// <summary>

/// 这公有方法提取本网页的纯文本中满足某正则式的文字

/// </summary>

/// <param name="pattern">正则式</param>

/// <returns>返回文字</returns>

public string getSpecialWords(string pattern)

{

if (m_outstr == "") getContext(Int16.MaxValue);

Regex regex = new Regex(pattern, RegexOptions.Multiline | RegexOptions.IgnoreCase);

Match mc = regex.Match(m_outstr);

if (mc.Success)

return mc.Groups[1].Value;

return string.Empty;

}

#endregion

#region 构造函数

private void Init(string _url)

{

try

{

m_uri = new Uri(_url);

m_links = new List<Link>();

m_html = "";

m_outstr = "";

m_title = "";

m_good = true;

if (_url.EndsWith(".rar") || _url.EndsWith(".dat") || _url.EndsWith(".msi"))

{

m_good = false;

return;

}

HttpWebRequest rqst = (HttpWebRequest)WebRequest.Create(m_uri);

rqst.AllowAutoRedirect = true;

rqst.MaximumAutomaticRedirections = 3;

rqst.UserAgent = "Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)";

rqst.KeepAlive = true;

rqst.Timeout = 10000;

lock (WebPage.webcookies)

{

if (WebPage.webcookies.ContainsKey(m_uri.Host))

rqst.CookieContainer = WebPage.webcookies[m_uri.Host];

else

{

CookieContainer cc = new CookieContainer();

WebPage.webcookies[m_uri.Host] = cc;

rqst.CookieContainer = cc;

}

}

HttpWebResponse rsps = (HttpWebResponse)rqst.GetResponse();

Stream sm = rsps.GetResponseStream();

if (!rsps.ContentType.ToLower().StartsWith("text/") || rsps.ContentLength > 1 << 22)

{

rsps.Close();

m_good = false;

return;

}

Encoding cding = System.Text.Encoding.Default;

string contenttype = rsps.ContentType.ToLower();

int ix = contenttype.IndexOf("charset=");

if (ix != -1)

{

try

{

cding = System.Text.Encoding.GetEncoding(rsps.ContentType.Substring(ix + "charset".Length + 1));

}

catch

{

cding = Encoding.Default;

}

//该处视情况而定 有的需要解码

//m_html = HttpUtility.HtmlDecode(new StreamReader(sm, cding).ReadToEnd());

m_html = new StreamReader(sm, cding).ReadToEnd();

}

else

{

//该处视情况而定 有的需要解码

//m_html = HttpUtility.HtmlDecode(new StreamReader(sm, cding).ReadToEnd());

m_html = new StreamReader(sm, cding).ReadToEnd();

Regex regex = new Regex("charset=(?<cding>[^=]+)?\"", RegexOptions.IgnoreCase);

string strcding = regex.Match(m_html).Groups["cding"].Value;

try

{

cding = Encoding.GetEncoding(strcding);

}

catch

{

cding = Encoding.Default;

}

byte[] bytes = Encoding.Default.GetBytes(m_html.ToCharArray());

m_html = cding.GetString(bytes);

if (m_html.Split('?').Length > 100)

{

m_html = Encoding.Default.GetString(bytes);

}

}

m_pagesize = m_html.Length;

m_uri = rsps.ResponseUri;

rsps.Close();

}

catch (Exception ex)

{

}

}

public WebPage(string _url)

{

string uurl = "";

try

{

uurl = Uri.UnescapeDataString(_url);

_url = uurl;

}

catch { };

Init(_url);

}

#endregion

}

调用

WebPage webInfo = new WebPage("网址");

webInfo.Context;//不包含html标签的所有内容

webInfo.M_html;//包含html标签的内容