C#备份博客园随笔文章和图片----使用HtmlAgilityPack解析html

之前用.NET做网页采集实现采用正则表达式去匹配解析，比较繁琐，花费时间较多，若是Html复杂的话真是欲哭无泪。

很早就听过包HtmlAgilityPack，其是在.NET下用XPath来解析的HTML的一个类库（包）。但是一直没时间尝试，简单了解了下HtmlAgilityPack的API后，发现真是HTML解析利器，于是花些时间做一个例子记录下。

 

本次是以下载博客园随笔分类文章为例，采用两部分实现，第一部分是将采集到的文章放到集合变量中，第二部分是通过操作集合变量将文章下载到本地，

这样做效率较低，因为可以直接边采集文章边下载。暂时没有考虑效率问题，仅仅只是实现功能。下面简单阐述下。

 

获取随笔分类

 

根据输入的博客名取得对应的随笔分类。

 

   /// <summary>
        /// 获取博客分类
        /// </summary>
        /// <param name=" uname"></param>
        /// <returns></returns>
        private static List< BlogType> GettBlogTypeList(string uname)
        {
            string url = "http://www.cnblogs.com/" + uname + "/mvc/blog/sidecolumn.aspx?blogApp=" + uname;
            string htmlStr = CommonHelper .GetRequestStr(url);
            HtmlDocument doc = new HtmlDocument();
            doc.LoadHtml(htmlStr);
            var nodes = doc.DocumentNode.SelectNodes("//div[@id='sidebar_postcategory']//a"); //随笔分类
            if (nodes == null || nodes.Count <= 0)
                return null ;

            List<BlogType > list = new List< BlogType>();
            for (int i = 0; i < nodes.Count; i++)
            {
                var aUrl = nodes[i].Attributes["href" ].Value;
                var name = nodes[i].InnerText;
                list.Add( new BlogType () { BlogTypeUrl = aUrl, BlogTypeName = name.Contains( "(") ? name.Split('(')[0] : name,BlogTypeNameShow=name });
            }
            return list;
        }

 

  public class BlogType
    {
        public string BlogTypeUrl { get; set; }
        public string BlogTypeName { get; set; }
        public string BlogTypeNameShow { get; set; }
    }

View Code

 

 如获取到的随笔分类如下：

 

 

采集分类的文章

 

采用两步实现，第一步获取只包含标题和url的文章，第二步再获取文章内容。

     

 /// <summary>
        /// 根据分类获取博客
        /// </summary>
        /// <param name=" blogTypes"></param>
        /// <param name=" useTime"></param>
        /// <returns></returns>
        public static Dictionary< BlogType,List <BlogInfo>> GetBlogsByType( List<BlogType > blogTypes,out long useTime)
        {
            Stopwatch sw = new Stopwatch();
            sw.Start();
            Dictionary<BlogType , List< BlogInfo>> dic = new Dictionary< BlogType, List <BlogInfo>>();          
            foreach (var blogType in blogTypes)
            {
                List<BlogInfo > list = new List< BlogInfo>();
                HtmlDocument doc = new HtmlDocument();
                doc.LoadHtml( CommonHelper.GetRequestStr(blogType.BlogTypeUrl));
                var typeNameNode = doc.DocumentNode.SelectSingleNode("//div[@class='entrylist']/h1");
                string typeName = typeNameNode.InnerText;
                var listPosttitleNodes = doc.DocumentNode.SelectNodes("//div[@class='entrylistPosttitle']/a");
                if (listPosttitleNodes != null && listPosttitleNodes.Count > 0)
                {
                    for (int i = 0; i < listPosttitleNodes.Count; i++)
                    {
                        Console.WriteLine("正在爬取文章【{0}】..." , listPosttitleNodes[i].InnerText);
                        list.Add( new BlogInfo ()
                        {
                            BlogUrl = listPosttitleNodes[i].Attributes[ "href"].Value,
                            BlogTitle = listPosttitleNodes[i].InnerText,
                            BlogTypeName = typeName
                        });
                    }
                }

                dic.Add(blogType,list);

            }

            sw.Stop();
            useTime = sw.ElapsedMilliseconds;
            return dic;
        }

 

 

     /// <summary>
        /// 获取详细的博客信息
        /// </summary>
        /// <param name=" dic"></param>
        /// <param name=" useTime"></param>
        /// <returns></returns>
        public static Dictionary< BlogType, List <BlogInfo>> GetBlogDetail( Dictionary<BlogType , List<BlogInfo >> dic, out long useTime)
        {
            Stopwatch sw = new Stopwatch();
            sw.Start();
            HtmlDocument doc = new HtmlDocument();
            for(int k=0;k<dic.Keys.Count;k++)
            {
                var blogType = dic.Keys.ElementAt(k);
                var list = dic[blogType];
                for (int i = 0; i < list.Count; i++)
                {
                    Console.WriteLine("正在获取文章【{0}】内容..." , list[i].BlogTitle);
                    doc.LoadHtml( CommonHelper.GetRequestStr(list[i].BlogUrl));
                    var bodyNode = doc.DocumentNode.SelectSingleNode("//div[@id='likecs_post_body']");
                    var dateNode = doc.DocumentNode.SelectSingleNode("//span[@id='post-date']");
                    var userNode = doc.DocumentNode.SelectSingleNode("//div[@class='postDesc']/a[1]");
                    list[i].BlogContent = bodyNode == null ? "内容获取失败" : bodyNode.InnerHtml;
                    list[i].BlogPostTime = dateNode == null ? "发布时间获取失败" : dateNode.InnerText;
                    list[i].BlogName = userNode == null ? "用户获取失败" : userNode.InnerText;
                }
                dic[blogType] = list;
            }
            sw.Stop();
            useTime = sw.ElapsedMilliseconds;
            return dic;
        }

 

    public class BlogInfo
    {
        public string BlogUrl { get; set; }
        public string BlogName { get; set; }
        public string BlogTitle { get; set; }
        public string BlogContent { get; set; }
        public string BlogTypeName { get; set; }
        public string BlogPostTime { get; set; }
    }

View Code

 

 下载到本地

 

根据上面采集到的文章再一步步下载到本地，期间分两步，第一步下载图片，第二步下载文章内容。

 

 /// <summary>

        /// 下载

        /// </summary>

        /// <param name=" dic"></param>

        /// <param name=" uname"></param>

        /// <param name=" useTime"></param>

        /// <returns></returns>

        public static string DowanloadBlog( Dictionary<BlogType , List< BlogInfo>> dic, string uname,out long useTime)

        {

            Stopwatch sw = new Stopwatch();

            sw.Start();

            int countFlag = 0;

            for (int i = 0; i < dic.Keys.Count; i++)

            {

                var blogType = dic.Keys.ElementAt(i);

                var blogList = dic[blogType];

                var dicPath = AppDomain .CurrentDomain.BaseDirectory +"BlogFiles\\" + uname + "\\" + blogType.BlogTypeName;

                Console.WriteLine("<<开始处理分类【{0}】<<" , blogType.BlogTypeName);

                FileHelper.CreatePath(dicPath);

                var blogModel = new BlogInfo();

                for (int j = 0; j < blogList.Count; j++)

                {

                    countFlag++;

                    try

                    {

                        Console.WriteLine("~~~~开始处理文章{0}【{1}】~~~~" , countFlag,blogModel.BlogTitle);

                        blogModel = blogList[j];

                        var filePath = dicPath + "\\" + FileHelper.FilterInvalidChar(blogModel.BlogTitle, "_") + ".html" ;

                        HtmlDocument doc = new HtmlDocument();

                        doc.DocumentNode.InnerHtml = blogModel.BlogContent;

 

                        //处理图片

                        Console.WriteLine("~~开始处理图片" );

                        var imgPath = dicPath + "\\images" ;

                        FileHelper.CreatePath(imgPath);

                        SaveImage(doc, imgPath);

                        Console.WriteLine("~~处理图片完成" );

 

                        //去掉a标签

                        var aNodes = doc.DocumentNode.SelectNodes("//a");

                        if (aNodes != null && aNodes.Count > 0)

                        {

                            for (int a = 0; a < aNodes.Count; a++)

                            {

                                if (aNodes[a].Attributes["href" ] != null && aNodes[a].Attributes[ "href"].Value != "#" )

                                {

                                    aNodes[a].Attributes[ "href"].Value = "javascript:void()" ;

                                }

                            }

                        }

                        doc.DocumentNode.InnerHtml = "<div id='div_head'>" + uname + " " + blogType.BlogTypeName + "</div><div id='div_title'>" + blogModel.BlogTitle + "<div><div id='div_body'>" + doc.DocumentNode.InnerHtml + "</div>";

                        doc.Save(filePath, Encoding.UTF8);

                        Console.WriteLine("~~~~处理文章{0}【{1}】完毕~~~~" ,countFlag,blogModel.BlogTitle);

                    }

                    catch (Exception ex)

                    {

                        string errorMsg = DateTime .Now.ToString("yyyyMMdd HH:mm:ss") + "\r\n" + "url=" + blogModel.BlogUrl + "\r\n" + "title=" + blogModel.BlogTitle + "\r\n" + "errorMsg=" + ex.Message + "\r\n" + "stackTrace=" + ex.StackTrace + "\r\n\r\n\r\n";

                        Console.WriteLine("error>>处理文章【{0}】出现错误，开始记录错误信息~~" , blogModel.BlogTitle);

                        FileHelper.SaveTxtFile(dicPath, "errorLog.txt" , errorMsg, false);

                        Console.WriteLine("error>>处理文章【{0}】出现错误，记录错误信息完成~~" , blogModel.BlogTitle);

                    }

                }

                Console.WriteLine("<<处理分类【{0}】完成<<" , blogType.BlogTypeName);

 

            }

            sw.Start();

            useTime = sw.ElapsedMilliseconds;

            return AppDomain .CurrentDomain.BaseDirectory + "BlogFiles\\" + uname;

        }

 

 /// <summary>

        /// 保存图片

        /// </summary>

        /// <param name=" doc"></param>

        /// <param name=" filePath"></param>

        public static void SaveImage( HtmlDocument doc, string filePath)

        {

            var imgNodes = doc.DocumentNode.SelectNodes("//img");

            if (imgNodes != null && imgNodes.Count > 0)

            {

                for (int i = 0; i < imgNodes.Count; i++)

                {

                    try

                    {                     

                        string src = imgNodes[i].Attributes["src" ].Value;

                        string fileName = "" ;

                        if (src != null && src.Contains("/"))

                        {

                            fileName = src.Substring(src.LastIndexOf( "/") + 1);

                            Console.WriteLine("~~开始下载图片【{0}】~~" , fileName);

                            string imgPath = filePath + "\\" + fileName;

                            imgNodes[i].Attributes[ "src"].Value = imgPath;

                            byte[] imgByte = CommonHelper .GetRequestByteArr(src);

                            if (imgByte != null )

                            {

                                FileHelper.SaveImage(imgPath, imgByte);

                                Console.WriteLine("~~下载图片【{0}】完成~~" , fileName);

                            }

                            else

                            {

                                Console.WriteLine("~~下载图片【{0}】失败~~" , fileName);

                            }

                        }

                    }

                    catch (Exception ex)

                    {

                        throw new Exception( "SaveImage_Error:" + ex.Message);

                    }

 

                }

            }

        }

View Code