m3uhandler.cs

c#的小例子:用到的知识点： * c#编程基础 * IO流 * 读取HTTP响应 * 多线程异步GUI的使用 * 使用“委派”实现“监听-观察者”模式

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Text.RegularExpressions;
using System.Net;
using System.Threading;

namespace M3UDownloader
{
    public class m3uHandler
    {
        struct Song
        {
            public String name;
            public String url;
        }

        StreamReader m3ufile;
        List<Song> mp3FileList = new List<Song>();
        Song song;

        // Define the delegate and event
        public delegate void DownloadHandler(String name, int TotalSize, int Downloaded);
        public event DownloadHandler CompleteEvent;

        public m3uHandler(String m3uName)
        {

            m3ufile = new StreamReader(m3uName, Encoding.GetEncoding("gb2312"));
        }

        public void parse()
        {
            String str;
            Regex srhMp3 = new Regex(@"mp3$");
            Regex srhTitle = new Regex(@"^#EXTINF:");
            Match match;

            // Read m3u header tag
            if ((str = m3ufile.ReadLine()) != null)
            {
                if (!str.Equals("#EXTM3U"))
                    return;
            }

            while ((str = m3ufile.ReadLine()) != null)
            {
                match = srhTitle.Match(str);
                if (match.Success)
                {
                    song.name = str.Substring(match.Length);
                }

                match = srhMp3.Match(str);
                if (match.Success)
                {
                    song.url = str;
                    mp3FileList.Add(song);
                }
            }
        }

        public void download()
        {
            int count = mp3FileList.Count;
            int index = 0;

            do
            {
                saveToFile(mp3FileList[index].url, mp3FileList[index].name);
                index = index + 1;
            } while (index < count);
        }

        private void saveToFile(String mp3, string title)
        {
            // prepare the web page we will be asking for
            HttpWebRequest request = (HttpWebRequest)
                WebRequest.Create(mp3);

            // execute the request
            HttpWebResponse response = (HttpWebResponse)
                request.GetResponse();

            // we will read data via the response stream
            Stream resStream = response.GetResponseStream();

            // Open a file to write
            FileStream SaveStream = new FileStream(title + ".MP3", FileMode.OpenOrCreate, FileAccess.Write);

            byte[] ByteArray = new byte[102400];

            int bytes;
            int Downloaded=0;
            while ((bytes = resStream.Read(ByteArray, 0, ByteArray.Length)) > 0) // any data read?
            {
                // write in a file
                SaveStream.Write(ByteArray, 0, bytes);
                Downloaded += bytes;
                Notify(title,(int) response.ContentLength,Downloaded);
            }
            resStream.Close();
            SaveStream.Close();
        }

        public void Notify(String Mp3Name, int TotalSize, int Downloaded)
        {
            if (CompleteEvent != null)
            {
                CompleteEvent(Mp3Name,TotalSize,Downloaded);
            }
        }
    }
}