/// <summary>
/// 下载指定路径的文件
/// </summary>
/// <param name="downloadItem">下载任务信息</param>
/// <returns>下载结果</returns>
public PageRequestResults FileDownload(DownloadMusicTask downloadTask)
{
if (!string.IsNullOrEmpty(downloadTask.DownloadUrl))
{
// 设置请求信息，使用GET方式获得数据
HttpWebRequest musicFileReq = (HttpWebRequest)WebRequest.Create(downloadTask.DownloadUrl);
musicFileReq.AllowAutoRedirect = true;
musicFileReq.Method = "GET";
//设置超时时间
musicFileReq.Timeout = SearchConfig.TIME_OUT;
//获取代理
IWebProxy proxy = SearchConfig.GetConfiguredWebProxy();
//判断代理是否有效
if (proxy != null)
{
//代理有效时设置代理
musicFileReq.Proxy = proxy;
}
// 判断是否断点续传()
FileStream downloadStream,configStream;
if (!File.Exists(downloadTask.MusicSavePath))
{
//不是断点续传时，创建下载文件和配置文件
downloadStream = new FileStream(downloadTask.MusicSavePath, FileMode.Create, FileAccess.Write);
//configStream = new FileStream(downloadTask.MusicConfigPath, FileMode.Create, FileAccess.Write);
downloadTask.DownloadSize = 0;
}
else
{
//断点续传时读入文件，并且从已下载的位置开始下载
downloadStream = System.IO.File.OpenWrite(downloadTask.MusicSavePath);
downloadTask.DownloadSize = downloadStream.Length;
downloadStream.Seek(downloadTask.DownloadSize, SeekOrigin.Current); //移动文件流中的当前指针
musicFileReq.AddRange((int)downloadTask.DownloadSize); //设置请求头的Range值
}
try
{
// 获取HTTP请求响应
using (HttpWebResponse musicFileRes = (HttpWebResponse)musicFileReq.GetResponse())
{
// 如果HTTP返回200--正常，返回206表示是断点续传
//
if (musicFileRes.StatusCode == HttpStatusCode.OK
|| musicFileRes.StatusCode == HttpStatusCode.PartialContent
|| musicFileRes.StatusCode == HttpStatusCode.Moved
|| musicFileRes.StatusCode == HttpStatusCode.MovedPermanently)
{
// 获取响应的页面流
using (Stream remoteStream = musicFileRes.GetResponseStream())
{
using (downloadStream)
{
//设置下载状态和下载大小，状态为准备下载，并汇报进度
downloadTask.DownloadStatus = DownloadStatus.ST_READY_DOWNLOAD;
//此处要加上已下载的大小，因为断线续传时返回的ContentLength是从Range出到结束的大小
downloadTask.FileSize = musicFileRes.ContentLength + downloadTask.DownloadSize;
downloadManager.ReportProgress(downloadTask); //汇报当前下载进度
//用户统计速度
TimeSpan totalTimeSpan = TimeSpan.Zero;
int totalTimeSize = 0;
//开始下载数据，检查是否下载完成
while (downloadTask.DownloadSize < downloadTask.FileSize)
{
// 检查是否被取消
if (downloadManager.TaskCanCancle(downloadTask.DownloadTaskID))
{
//如果任务被取消退出
downloadTask.DownloadStatus = DownloadStatus.ST_CANCEL_DOWNLOAD;
break;
}
// 检查是否被暂停
if (downloadManager.TaskCanStop(downloadTask.DownloadTaskID))
{
//汇报暂停时下载进度
downloadTask.DownloadStatus = DownloadStatus.ST_STOP_DOWNLOAD;
downloadManager.ReportProgress(downloadTask);
break;
}
// 正常下载，从流中读取到文件流中
byte[] buffer = new byte[1024];
TimeSpan readStart = new TimeSpan(DateTime.Now.Ticks);
int readSize = remoteStream.Read(buffer, 0, buffer.Length);
TimeSpan readEnd = new TimeSpan(DateTime.Now.Ticks);
TimeSpan ts = readEnd.Subtract(readStart).Duration();
totalTimeSpan += ts;
totalTimeSize += readSize;
//写入文件
downloadStream.Write(buffer, 0, readSize);
downloadTask.DownloadSize += readSize;
//计算速度，400ms刷新一次
if (totalTimeSpan.Milliseconds > 400)
{
downloadTask.DownloadSpeed = (totalTimeSize / totalTimeSpan.Milliseconds) * 1000;
totalTimeSpan = TimeSpan.Zero;
totalTimeSize = 0;
}
//汇报当前下载进度
downloadTask.DownloadStatus = DownloadStatus.ST_IS_DOWNLOAD;
downloadManager.ReportProgress(downloadTask);
}
// 如果完成，设置状态
if (downloadTask.DownloadSize == downloadTask.FileSize)
{
downloadTask.DownloadStatus = DownloadStatus.ST_OVER_DOWNLOAD;
}
//完成下载，程序退出
return PageRequestResults.Success;
}
}
}
else
{
//汇报下载进度
downloadTask.DownloadStatus = DownloadStatus.ST_ERROR_DOWNLOAD;
downloadManager.ReportProgress(downloadTask);
return PageRequestResults.UnknowException;
}
}
}
catch (WebException webEx)
{
//出错时汇报下载进度和错误信息
downloadTask.Error = webEx;
downloadTask.DownloadStatus = DownloadStatus.ST_ERROR_DOWNLOAD;
downloadManager.ReportProgress(downloadTask);
// 异常时返回异常的原因
if (webEx.Status == WebExceptionStatus.Timeout)
{
return PageRequestResults.TimeOut;
}
else if (webEx.Status == WebExceptionStatus.SendFailure)
{
return PageRequestResults.SendFailure;
}
else if (webEx.Status == WebExceptionStatus.ConnectFailure)
{
return PageRequestResults.ConnectFailure;
}
else if (webEx.Status == WebExceptionStatus.ReceiveFailure)
{
return PageRequestResults.ReceiveFailure;
}
else if (webEx.Status == WebExceptionStatus.NameResolutionFailure)
{
return PageRequestResults.DNSFailure;
}
else if (webEx.Status == WebExceptionStatus.RequestProhibitedByProxy)
{
return PageRequestResults.ProxyFailure;
}
else
{
return PageRequestResults.UnknowException;
}
}
catch (Exception ex)
{
//出错时汇报下载进度和错误信息
downloadTask.Error = ex;
downloadTask.DownloadStatus = DownloadStatus.ST_ERROR_DOWNLOAD;
downloadManager.ReportProgress(downloadTask);
return PageRequestResults.UnknowException;
}
finally
{
downloadStream.Close();
//configStream.Close();
}
}
return PageRequestResults.UrlIsNull;
}
/// <summary>
/// 开始下载
/// </summary>
/// <param name="argument">要下载的音乐信息</param>
public void RunWorkerAsync(DownloadMusicTask downloadItem)
{
//如果目前下载数量小于5条，则通过委托启动新的下载任务
//设置下载状态
downloadItem.IsStop = false;
downloadItem.DownloadStatus = DownloadStatus.ST_READY_DOWNLOAD;
// 对于新增的任务，添加到同步管理表
if (!asyncOperationtTable.ContainsKey(downloadItem.DownloadTaskID))
{
AsyncOperation asyncOperation = AsyncOperationManager.CreateOperation(downloadItem.DownloadTaskID);
lock (asyncOperationLock)
{
asyncOperationtTable.Add(downloadItem.DownloadTaskID, asyncOperation);
}
}
if (downloadTable.Count < 5)
{
// 如果开始的是等待任务，则从等待列表删除
if (waitDownloadTable.ContainsKey(downloadItem.DownloadTaskID))
{
lock (waitTableLock)
{
waitDownloadTable.Remove(downloadItem.DownloadTaskID);
}
}
//加入到下载列表
lock (downloadTableLock)
{
downloadTable.Add(downloadItem.DownloadTaskID, downloadItem);
}
//新启一个线程开始下载
this.threadStart.BeginInvoke(downloadItem, null, null);
}
else //如果目前下载数量大于5则进入等待下载队列
{
//设置下载状态
downloadItem.IsStop = true;
downloadItem.DownloadStatus = DownloadStatus.ST_WAIT_DOWNLOAD;
//添加到等待列表
lock (waitTableLock)
{
waitDownloadTable.Add(downloadItem.DownloadTaskID, downloadItem);
}
ReportProgress(downloadItem); //报道下载进度
}
}
/// <summary>
/// 提交下载歌曲任务
/// </summary>
private void btnDownload_Click(object sender, EventArgs e)
{
if (searchSelectIndex != -1)
{
//设置下载任务
DownloadMusicTask task = new DownloadMusicTask();
task.DownloadUrl = dataGridView1["MusicUrl", searchSelectIndex].Value.ToString();
task.MusicName = dataGridView1["MusicName", searchSelectIndex].Value.ToString();
task.MusicSavePath = FileManager.GetSavaPath(task.MusicName, dataGridView1["MusicFormat", searchSelectIndex].Value.ToString());
if (string.IsNullOrEmpty(task.MusicSavePath))
{
task = null;
MessageBox.Show("无法保存文件");
}
task.DownloadTaskID = Guid.NewGuid();
//添加到下载列表
DataRow row = downListTable.NewRow();
row["name"] = task.MusicName;
row["size"] = string.Empty;
row["status"] = string.Empty;
row["process"] = 0;
row["speed"] = string.Empty;
row["link"] = task.DownloadUrl;
row["GUID"] = task.DownloadTaskID;
row["task"] = task;
downListTable.Rows.Add(row);
//开始下载
downloadManager.RunWorkerAsync(task);
}
}