/// <summary>
/// 暂停下载.
/// </summary>
public void Pause()
{
// 只有正在下载的情况下才能暂停。
if (this.Status != HttpDownloadClientStatus.Downloading)
{
throw new ApplicationException("只有正在下载的客户端才能暂停。");
}
// 主线程会检查状态。如果暂停了，下载将会被暂停，并且状态会变成暂停状态。
this.Status = HttpDownloadClientStatus.Pausing;
}
/// <summary>
/// Pause the download.
/// </summary>
public void Pause()
{
// Only downloading client can be paused.
if (this.Status != HttpDownloadClientStatus.Downloading)
{
throw new ApplicationException("Only downloading client can be paused.");
}
// The backgound thread will check the status. If it is Pausing, the download
// will be paused and the status will be changed to Paused.
this.Status = HttpDownloadClientStatus.Pausing;
}
/// <summary>
/// 暂停下载
/// </summary>
public void Pause()
{
// 只有正在下载的客户端才能暂停.
if (this.Status != HttpDownloadClientStatus.Downloading)
{
throw new ApplicationException("只有正在下载的客户端才能暂停.");
}
// 后台线程会查看状态，如果状态时暂停的，
// 下载将会被暂停并且状态将随之改为暂停.
this.Status = HttpDownloadClientStatus.Pausing;
}
/// <summary>
/// 取消下载。
/// </summary>
public void Cancel()
{
// 只有正在下载或者暂停的情况下才能被取消。
if (this.Status != HttpDownloadClientStatus.Paused &&
this.Status != HttpDownloadClientStatus.Downloading)
{
throw new ApplicationException("只有正在下载或者暂停的情况下才能被取消");
}
// 主线程会检查状态，如果是取消，下载将会取消，状态同时改变成取消状态。
this.Status = HttpDownloadClientStatus.Canceling;
}
/// <summary>
/// 取消下载
/// </summary>
public void Cancel()
{
// 只有正在下载的或者是暂停的客户端才能被取消.
if (this.Status != HttpDownloadClientStatus.Paused &&
this.Status != HttpDownloadClientStatus.Downloading)
{
throw new ApplicationException("只有正在下载的或者是暂停的客户端"
+ "才能被取消.");
}
// 后台线程将查看状态.如果是正在取消，
// 那么下载将被取消并且状态将改成已取消.
this.Status = HttpDownloadClientStatus.Canceling;
}
/// <summary>
/// Cancel the download
/// </summary>
public void Cancel()
{
// Only a downloading or paused client can be canceled.
if (this.Status != HttpDownloadClientStatus.Paused &&
this.Status != HttpDownloadClientStatus.Downloading)
{
throw new ApplicationException("Only a downloading or paused client"
+ " can be canceled.");
}
// The backgound thread will check the status. If it is Canceling, the download
// will be canceled and the status will be changed to Canceled.
this.Status = HttpDownloadClientStatus.Canceling;
}
public HttpDownloadClient(int index, string url, string downloadPath, int startPoint,
int endPoint, int bufferSize, int cacheSize, int bufferCountPerNotification)
{
if (startPoint < 0)
{
throw new ArgumentOutOfRangeException(
"StartPoint cannot be less then 0. ");
}
if (endPoint < startPoint)
{
throw new ArgumentOutOfRangeException(
"EndPoint cannot be less then StartPoint ");
}
if (bufferSize < 0)
{
throw new ArgumentOutOfRangeException(
"BufferSize cannot be less then 0. ");
}
if (cacheSize < bufferSize)
{
throw new ArgumentOutOfRangeException(
"MaxCacheSize cannot be less then BufferSize ");
}
if (bufferCountPerNotification <= 0)
{
throw new ArgumentOutOfRangeException(
"BufferCountPerNotification cannot be less then 0. ");
}
this.StartPoint = startPoint;
this.EndPoint = endPoint;
this.BufferSize = bufferSize;
this.MaxCacheSize = cacheSize;
this.BufferCountPerNotification = bufferCountPerNotification;
this.Url = new Uri(url, UriKind.Absolute);
this.DownloadPath = downloadPath;
// Set the idle status.
this.status = HttpDownloadClientStatus.Idle;
Index = index;
}
public HttpDownloadClient(string url, string downloadPath, int startPoint,
int endPoint, int bufferSize, int cacheSize, int bufferCountPerNotification)
{
if (startPoint < 0)
{
throw new ArgumentOutOfRangeException(
"StartPoint不能小于0.");
}
if (endPoint < startPoint)
{
throw new ArgumentOutOfRangeException(
"EndPoint不能小于StartPoint. ");
}
if (bufferSize < 0)
{
throw new ArgumentOutOfRangeException(
"BufferSize不能小于0.");
}
if (cacheSize < bufferSize)
{
throw new ArgumentOutOfRangeException(
"MaxCacheSize不能小于BufferSize.");
}
if (bufferCountPerNotification <= 0)
{
throw new ArgumentOutOfRangeException(
"BufferCountPerNotification不能小于0. ");
}
this.StartPoint = startPoint;
this.EndPoint = endPoint;
this.BufferSize = bufferSize;
this.MaxCacheSize = cacheSize;
this.BufferCountPerNotification = bufferCountPerNotification;
this.Url = new Uri(url, UriKind.Absolute);
this.DownloadPath = downloadPath;
// 设定空闲的状态
this.status = HttpDownloadClientStatus.Idle;
}
public HttpDownloadClient(Uri url, string downloadPath, long startPoint,
long endPoint, int bufferSize, int cacheSize)
{
if (startPoint < 0)
{
throw new ArgumentOutOfRangeException(
"StartPoint cannot be less than 0. ");
}
if (endPoint < startPoint)
{
throw new ArgumentOutOfRangeException(
"EndPoint cannot be less than StartPoint ");
}
if (bufferSize < 0)
{
throw new ArgumentOutOfRangeException(
"BufferSize cannot be less than 0. ");
}
if (cacheSize < bufferSize)
{
throw new ArgumentOutOfRangeException(
"MaxCacheSize cannot be less than BufferSize ");
}
this.StartPoint = startPoint;
this.EndPoint = endPoint;
this.BufferSize = bufferSize;
this.MaxCacheSize = cacheSize;
this.Url = url;
this.DownloadPath = downloadPath;
// Set the idle status.
this.status = HttpDownloadClientStatus.Idle;
}
/// <summary>
/// Cancel the download
/// </summary>
public void Cancel()
{
// Only a downloading or paused client can be canceled.
if (this.Status != HttpDownloadClientStatus.Paused
&& this.Status != HttpDownloadClientStatus.Downloading)
{
throw new ApplicationException("Only a downloading or paused client"
+ " can be canceled.");
}
// The backgound thread will check the status. If it is Canceling, the download
// will be canceled and the status will be changed to Canceled.
this.Status = HttpDownloadClientStatus.Canceling;
}
/// <summary>
/// 用 HttpWebRequest下载数据. 它从响应流中读取缓冲区的数据。
/// 并且先把数据存储在内存缓存中。
/// 如果缓存满了，或者下载被暂停，取消或者完成，就将缓存中的数据写成本地文件。
/// </summary>
void Download()
{
HttpWebRequest webRequest = null;
HttpWebResponse webResponse = null;
Stream responseStream = null;
MemoryStream downloadCache = null;
// 设置状态。
this.Status = HttpDownloadClientStatus.Downloading;
try
{
// 创建一个下载的请求。
webRequest = (HttpWebRequest)WebRequest.Create(Url);
webRequest.Method = "GET";
webRequest.Credentials = CredentialCache.DefaultCredentials;
// 指定下载的模块。
if (EndPoint != long.MaxValue)
{
webRequest.AddRange(StartPoint + DownloadedSize, EndPoint);
}
else
{
webRequest.AddRange(StartPoint + DownloadedSize);
}
// 设置 proxy.
if (Proxy != null)
{
webRequest.Proxy = Proxy;
}
// 得到从服务器中的响应和响应流。
webResponse = (HttpWebResponse)webRequest.GetResponse();
responseStream = webResponse.GetResponseStream();
// 在内存中缓存数据。
downloadCache = new MemoryStream(this.MaxCacheSize);
byte[] downloadBuffer = new byte[this.BufferSize];
int bytesSize = 0;
int cachedSize = 0;
// 下载文件，知道被取消，暂停或者完成。
while (true)
{
// 从响应流中读取缓冲数据。
bytesSize = responseStream.Read(downloadBuffer, 0, downloadBuffer.Length);
// 如果缓存满了，或者下载被暂停，取消，或者完成了，将缓存数据写成本地文件。
if (this.Status != HttpDownloadClientStatus.Downloading ||
bytesSize == 0 ||
this.MaxCacheSize < cachedSize + bytesSize)
{
try
{
// 将缓存数据写成本地文件。
WriteCacheToFile(downloadCache, cachedSize);
this.DownloadedSize += cachedSize;
// 停止下载文件，如果下载被暂停，取消，或者完成。
if (this.Status != HttpDownloadClientStatus.Downloading ||
bytesSize == 0)
{
break;
}
// 重新设置缓存。
downloadCache.Seek(0, SeekOrigin.Begin);
cachedSize = 0;
}
catch (Exception ex)
{
//触发 DownloadCompleted事件。
this.OnError(new ErrorEventArgs {
Error = ex
});
return;
}
}
// 从缓冲区写入数据到内存中的缓存。
downloadCache.Write(downloadBuffer, 0, bytesSize);
cachedSize += bytesSize;
// 触发DownloadProgressChanged事件。
OnDownloadProgressChanged(
new HttpDownloadClientProgressChangedEventArgs
{
Size = bytesSize
});
}
// 更新状态。当状态是暂停，取消，完成时，上面的循环将会停止。
if (this.Status == HttpDownloadClientStatus.Pausing)
{
this.Status = HttpDownloadClientStatus.Paused;
}
else if (this.Status == HttpDownloadClientStatus.Canceling)
{
this.Status = HttpDownloadClientStatus.Canceled;
Exception ex = new Exception("下载被用户取消 ");
this.OnError(new ErrorEventArgs {
Error = ex
});
}
else
{
this.Status = HttpDownloadClientStatus.Completed;
return;
}
}
finally
{
// 当以上代码执行结束时，关闭流。
if (responseStream != null)
{
responseStream.Close();
}
if (webResponse != null)
{
webResponse.Close();
}
if (downloadCache != null)
{
downloadCache.Close();
}
}
}
/// <summary>
/// Download the data using HttpWebRequest. It will read a buffer of bytes from the
/// response stream, and store the buffer to a MemoryStream cache first.
/// If the cache is full, or the download is paused, canceled or completed, write
/// the data in cache to local file.
/// </summary>
void Download()
{
HttpWebRequest webRequest = null;
HttpWebResponse webResponse = null;
Stream responseStream = null;
MemoryStream downloadCache = null;
lastStartTime = DateTime.Now;
// Set the status.
this.Status = HttpDownloadClientStatus.Downloading;
try
{
// Create a request to the file to be downloaded.
webRequest = (HttpWebRequest)WebRequest.Create(Url);
webRequest.Method = "GET";
webRequest.Credentials = CredentialCache.DefaultCredentials;
// Specify the block to download.
if (EndPoint != int.MaxValue)
{
webRequest.AddRange(StartPoint + DownloadedSize, EndPoint);
}
else
{
webRequest.AddRange(StartPoint + DownloadedSize);
}
// Retrieve the response from the server and get the response stream.
webResponse = (HttpWebResponse)webRequest.GetResponse();
responseStream = webResponse.GetResponseStream();
// Cache data in memory.
downloadCache = new MemoryStream(this.MaxCacheSize);
byte[] downloadBuffer = new byte[this.BufferSize];
int bytesSize = 0;
int cachedSize = 0;
int receivedBufferCount = 0;
// Download the file until the download is paused, canceled or completed.
while (true)
{
// Read a buffer of data from the stream.
bytesSize = responseStream.Read(downloadBuffer, 0, downloadBuffer.Length);
// If the cache is full, or the download is paused, canceled or
// completed, write the data in cache to local file.
if (this.Status != HttpDownloadClientStatus.Downloading ||
bytesSize == 0 ||
this.MaxCacheSize < cachedSize + bytesSize)
{
try
{
// Write the data in cache to local file.
WriteCacheToFile(downloadCache, cachedSize);
this.DownloadedSize += cachedSize;
// Stop downloading the file if the download is paused,
// canceled or completed.
if (this.Status != HttpDownloadClientStatus.Downloading ||
bytesSize == 0)
{
break;
}
// Reset cache.
downloadCache.Seek(0, SeekOrigin.Begin);
cachedSize = 0;
}
catch (Exception ex)
{
// Fire the DownloadCompleted event with the error.
this.OnDownloadCompleted(new HttpDownloadCompletedEventArgs(
this.DownloadedSize, this.TotalSize,
this.TotalUsedTime, ex));
return;
}
}
// Write the data from the buffer to the cache in memory.
downloadCache.Write(downloadBuffer, 0, bytesSize);
cachedSize += bytesSize;
receivedBufferCount++;
// Fire the DownloadProgressChanged event.
if (receivedBufferCount == this.BufferCountPerNotification)
{
InternalDownloadProgressChanged(cachedSize);
receivedBufferCount = 0;
}
}
// Update the used time when the current doanload is stopped.
usedTime = usedTime.Add(DateTime.Now - lastStartTime);
// Update the status of the client. Above loop will be stopped when the
// status of the client is pausing, canceling or completed.
if (this.Status == HttpDownloadClientStatus.Pausing)
{
this.Status = HttpDownloadClientStatus.Paused;
}
else if (this.Status == HttpDownloadClientStatus.Canceling)
{
this.Status = HttpDownloadClientStatus.Canceled;
Exception ex = new Exception("Downloading is canceled by user's request. ");
this.OnDownloadCompleted(new HttpDownloadCompletedEventArgs(
this.DownloadedSize, this.TotalSize, this.TotalUsedTime, ex));
}
else
{
this.Status = HttpDownloadClientStatus.Completed;
this.OnDownloadCompleted(new HttpDownloadCompletedEventArgs(
this.DownloadedSize, this.TotalSize, this.TotalUsedTime, null));
return;
}
}
finally
{
// When the above code has ended, close the streams.
if (responseStream != null)
{
responseStream.Close();
}
if (webResponse != null)
{
webResponse.Close();
}
if (downloadCache != null)
{
downloadCache.Close();
}
}
}
public void CheckUrl(out string fileName)
{
fileName = string.Empty;
// The file could be checked only in Idle status.
if (this.status != HttpDownloadClientStatus.Idle)
{
throw new ApplicationException(
"The file could be checked only in Idle status.");
}
// Check the file information on the remote server.
var webRequest = (HttpWebRequest)WebRequest.Create(Url);
webRequest.Credentials = CredentialCache.DefaultCredentials;
using (var response = webRequest.GetResponse())
{
foreach (var header in response.Headers.AllKeys)
{
if (header.Equals("Accept-Ranges", StringComparison.OrdinalIgnoreCase))
{
this.IsRangeSupported = true;
}
if (header.Equals("Content-Disposition", StringComparison.OrdinalIgnoreCase))
{
string contentDisposition = response.Headers[header];
string pattern = ".[^;]*;\\s+filename=\"(?<file>.*)\"";
Regex r = new Regex(pattern);
Match m = r.Match(contentDisposition);
if (m.Success)
{
fileName = m.Groups["file"].Value;
}
}
}
this.TotalSize = response.ContentLength;
if (TotalSize <= 0)
{
throw new ApplicationException(
"The file to download does not exist!");
}
if (!IsRangeSupported)
{
this.StartPoint = 0;
this.EndPoint = int.MaxValue;
}
}
if (this.IsRangeSupported &&
(this.StartPoint != 0 || this.EndPoint != int.MaxValue))
{
webRequest = (HttpWebRequest)WebRequest.Create(Url);
if (EndPoint != int.MaxValue)
{
webRequest.AddRange(StartPoint, EndPoint);
}
else
{
webRequest.AddRange(StartPoint);
}
using (var response = webRequest.GetResponse())
{
this.TotalSize = response.ContentLength;
}
}
// Set the checked status.
this.Status = HttpDownloadClientStatus.Checked;
}
/// <summary>
/// 通过HttpWebRequest线程来下载数据.它会从响应流中读取一个字节的缓冲区，
/// 并把它先储存在一个MemoryStream的缓存中。
/// 如果缓存没有空间或者下载暂停、取消或完成了，就将缓存中的数据写入本地文件中。
/// </summary>
void Download()
{
HttpWebRequest webRequest = null;
HttpWebResponse webResponse = null;
Stream responseStream = null;
MemoryStream downloadCache = null;
lastStartTime = DateTime.Now;
// 设定状态.
this.Status = HttpDownloadClientStatus.Downloading;
try
{
// 为需要下载的文件创建一个请求.
webRequest = (HttpWebRequest)WebRequest.Create(Url);
webRequest.Method = "GET";
webRequest.Credentials = CredentialCache.DefaultCredentials;
// 指定块下载
if (EndPoint != int.MaxValue)
{
webRequest.AddRange(StartPoint + DownloadedSize, EndPoint);
}
else
{
webRequest.AddRange(StartPoint + DownloadedSize);
}
// 接受服务器端的响应并得到响应流.
webResponse = (HttpWebResponse)webRequest.GetResponse();
responseStream = webResponse.GetResponseStream();
// 内存中的缓存数据.
downloadCache = new MemoryStream(this.MaxCacheSize);
byte[] downloadBuffer = new byte[this.BufferSize];
int bytesSize = 0;
int cachedSize = 0;
int receivedBufferCount = 0;
// 下载文件直到下载被暂停、取消或完成.
while (true)
{
// 从流中读取缓冲区的数据.
bytesSize = responseStream.Read(downloadBuffer, 0, downloadBuffer.Length);
// 如果缓存是满的，或者下载被暂停、取消或完成，
// 就把缓存中的数据写入本地文件.
if (this.Status != HttpDownloadClientStatus.Downloading ||
bytesSize == 0 ||
this.MaxCacheSize < cachedSize + bytesSize)
{
try
{
// 把缓存中的数据写入本地文件.
WriteCacheToFile(downloadCache, cachedSize);
this.DownloadedSize += cachedSize;
// 如果下载被暂停、取消或完成了，
// 就停止下载文件.
if (this.Status != HttpDownloadClientStatus.Downloading ||
bytesSize == 0)
{
break;
}
// 读取缓存.
downloadCache.Seek(0, SeekOrigin.Begin);
cachedSize = 0;
}
catch (Exception ex)
{
// 如果错误，触发DownloadCompleted事件.
this.OnDownloadCompleted(new HttpDownloadCompletedEventArgs(
this.DownloadedSize, this.TotalSize,
this.TotalUsedTime, ex));
return;
}
}
// 将数据从缓冲区写入内存的缓存中.
downloadCache.Write(downloadBuffer, 0, bytesSize);
cachedSize += bytesSize;
receivedBufferCount++;
// 触发DownloadProgressChanged事件.
if (receivedBufferCount == this.BufferCountPerNotification)
{
InternalDownloadProgressChanged(cachedSize);
receivedBufferCount = 0;
}
}
// 如果当前下载被停止了，更新所用的时间.
usedTime = usedTime.Add(DateTime.Now - lastStartTime);
// 更新客户端的状态. 在客户端的状态为暂停、取消或完成时，
// 以上的循环将被终止.
if (this.Status == HttpDownloadClientStatus.Pausing)
{
this.Status = HttpDownloadClientStatus.Paused;
}
else if (this.Status == HttpDownloadClientStatus.Canceling)
{
this.Status = HttpDownloadClientStatus.Canceled;
Exception ex = new Exception("由于用户的需求下载已被取消. ");
this.OnDownloadCompleted(new HttpDownloadCompletedEventArgs(
this.DownloadedSize, this.TotalSize, this.TotalUsedTime, ex));
}
else
{
this.Status = HttpDownloadClientStatus.Completed;
this.OnDownloadCompleted(new HttpDownloadCompletedEventArgs(
this.DownloadedSize, this.TotalSize, this.TotalUsedTime, null));
return;
}
}
finally
{
// 当以上的代码执行完毕，关闭流.
if (responseStream != null)
{
responseStream.Close();
}
if (webResponse != null)
{
webResponse.Close();
}
if (downloadCache != null)
{
downloadCache.Close();
}
}
}
/// <summary>
/// Pause the download.
/// </summary>
public void Pause()
{
// Only downloading client can be paused.
if (this.Status != HttpDownloadClientStatus.Downloading)
{
throw new ApplicationException("Only downloading client can be paused.");
}
// The backgound thread will check the status. If it is Pausing, the download
// will be paused and the status will be changed to Paused.
this.Status = HttpDownloadClientStatus.Pausing;
}
public void CheckUrl(out string fileName)
{
fileName = string.Empty;
// The file could be checked only in Idle status.
if (this.status != HttpDownloadClientStatus.Idle)
{
throw new ApplicationException(
"The file could be checked only in Idle status.");
}
// Check the file information on the remote server.
var webRequest = (HttpWebRequest)WebRequest.Create(Url);
webRequest.Credentials = CredentialCache.DefaultCredentials;
using (var response = webRequest.GetResponse())
{
foreach (var header in response.Headers.AllKeys)
{
if (header.Equals("Accept-Ranges", StringComparison.OrdinalIgnoreCase))
{
this.IsRangeSupported = true;
}
if (header.Equals("Content-Disposition", StringComparison.OrdinalIgnoreCase))
{
string contentDisposition = response.Headers[header];
string pattern = ".[^;]*;\\s+filename=\"(?<file>.*)\"";
Regex r = new Regex(pattern);
Match m = r.Match(contentDisposition);
if (m.Success)
{
fileName = m.Groups["file"].Value;
}
}
}
this.TotalSize = response.ContentLength;
if (TotalSize <= 0)
{
throw new ApplicationException(
"The file to download does not exist!");
}
if (!IsRangeSupported)
{
this.StartPoint = 0;
this.EndPoint = int.MaxValue;
}
}
if (this.IsRangeSupported &&
(this.StartPoint != 0 || this.EndPoint != int.MaxValue))
{
webRequest = (HttpWebRequest)WebRequest.Create(Url);
if (EndPoint != int.MaxValue)
{
webRequest.AddRange(StartPoint, EndPoint);
}
else
{
webRequest.AddRange(StartPoint);
}
using (var response = webRequest.GetResponse())
{
this.TotalSize = response.ContentLength;
}
}
// Set the checked status.
this.Status = HttpDownloadClientStatus.Checked;
}
public HttpDownloadClient(string url, int startPoint,
int endPoint, int bufferSize, int cacheSize, int bufferCountPerNotification)
{
if (startPoint < 0)
{
throw new ArgumentOutOfRangeException(
"StartPoint cannot be less then 0. ");
}
if (endPoint < startPoint)
{
throw new ArgumentOutOfRangeException(
"EndPoint cannot be less then StartPoint ");
}
if (bufferSize < 0)
{
throw new ArgumentOutOfRangeException(
"BufferSize cannot be less then 0. ");
}
if (cacheSize < bufferSize)
{
throw new ArgumentOutOfRangeException(
"MaxCacheSize cannot be less then BufferSize ");
}
if (bufferCountPerNotification <= 0)
{
throw new ArgumentOutOfRangeException(
"BufferCountPerNotification cannot be less then 0. ");
}
this.StartPoint = startPoint;
this.EndPoint = endPoint;
this.BufferSize = bufferSize;
this.MaxCacheSize = cacheSize;
this.BufferCountPerNotification = bufferCountPerNotification;
this.Url = new Uri(url, UriKind.Absolute);
// Set the idle status.
this.status = HttpDownloadClientStatus.Idle;
}
public HttpDownloadClient(Uri url, string downloadPath, long startPoint,
long endPoint, int bufferSize, int cacheSize)
{
if (startPoint < 0)
{
throw new ArgumentOutOfRangeException(
"StartPoint cannot be less than 0. ");
}
if (endPoint < startPoint)
{
throw new ArgumentOutOfRangeException(
"EndPoint cannot be less than StartPoint ");
}
if (bufferSize < 0)
{
throw new ArgumentOutOfRangeException(
"BufferSize cannot be less than 0. ");
}
if (cacheSize < bufferSize)
{
throw new ArgumentOutOfRangeException(
"MaxCacheSize cannot be less than BufferSize ");
}
this.StartPoint = startPoint;
this.EndPoint = endPoint;
this.BufferSize = bufferSize;
this.MaxCacheSize = cacheSize;
this.Url = url;
this.DownloadPath = downloadPath;
// Set the idle status.
this.status = HttpDownloadClientStatus.Idle;
}
public HttpDownloadClient(string url, string downloadPath, int startPoint,
int endPoint, int bufferSize, int cacheSize, int bufferCountPerNotification)
{
if (startPoint < 0)
{
throw new ArgumentOutOfRangeException(
"StartPoint不能小于0.");
}
if (endPoint < startPoint)
{
throw new ArgumentOutOfRangeException(
"EndPoint不能小于StartPoint. ");
}
if (bufferSize < 0)
{
throw new ArgumentOutOfRangeException(
"BufferSize不能小于0.");
}
if (cacheSize < bufferSize)
{
throw new ArgumentOutOfRangeException(
"MaxCacheSize不能小于BufferSize.");
}
if (bufferCountPerNotification <= 0)
{
throw new ArgumentOutOfRangeException(
"BufferCountPerNotification不能小于0. ");
}
this.StartPoint = startPoint;
this.EndPoint = endPoint;
this.BufferSize = bufferSize;
this.MaxCacheSize = cacheSize;
this.BufferCountPerNotification = bufferCountPerNotification;
this.Url = new Uri(url, UriKind.Absolute);
this.DownloadPath = downloadPath;
// 设定空闲的状态
this.status = HttpDownloadClientStatus.Idle;
}
/// <summary>
/// Download the data using HttpWebRequest. It will read a buffer of bytes from the
/// response stream, and store the buffer to a MemoryStream cache first.
/// If the cache is full, or the download is paused, canceled or completed, write
/// the data in cache to local file.
/// </summary>
void Download()
{
HttpWebRequest webRequest = null;
HttpWebResponse webResponse = null;
Stream responseStream = null;
MemoryStream downloadCache = null;
lastStartTime = DateTime.Now;
// Set the status.
this.Status = HttpDownloadClientStatus.Downloading;
try
{
// Create a request to the file to be downloaded.
webRequest = (HttpWebRequest)WebRequest.Create(Url);
webRequest.Method = "GET";
webRequest.Credentials = CredentialCache.DefaultCredentials;
// Specify the block to download.
if (EndPoint != int.MaxValue)
{
webRequest.AddRange(StartPoint + DownloadedSize, EndPoint);
}
else
{
webRequest.AddRange(StartPoint + DownloadedSize);
}
// Retrieve the response from the server and get the response stream.
webResponse = (HttpWebResponse)webRequest.GetResponse();
responseStream = webResponse.GetResponseStream();
// Cache data in memory.
downloadCache = new MemoryStream(this.MaxCacheSize);
byte[] downloadBuffer = new byte[this.BufferSize];
int bytesSize = 0;
int cachedSize = 0;
int receivedBufferCount = 0;
// Download the file until the download is paused, canceled or completed.
while (true)
{
// Read a buffer of data from the stream.
bytesSize = responseStream.Read(downloadBuffer, 0, downloadBuffer.Length);
// If the cache is full, or the download is paused, canceled or
// completed, write the data in cache to local file.
if (this.Status != HttpDownloadClientStatus.Downloading
|| bytesSize == 0
|| this.MaxCacheSize < cachedSize + bytesSize)
{
try
{
// Write the data in cache to local file.
WriteCacheToFile(downloadCache, cachedSize);
this.DownloadedSize += cachedSize;
// Stop downloading the file if the download is paused,
// canceled or completed.
if (this.Status != HttpDownloadClientStatus.Downloading
|| bytesSize == 0)
{
break;
}
// Reset cache.
downloadCache.Seek(0, SeekOrigin.Begin);
cachedSize = 0;
}
catch (Exception ex)
{
// Fire the DownloadCompleted event with the error.
this.OnDownloadCompleted(new HttpDownloadCompletedEventArgs(
this.DownloadedSize, this.TotalSize,
this.TotalUsedTime, ex));
return;
}
}
// Write the data from the buffer to the cache in memory.
downloadCache.Write(downloadBuffer, 0, bytesSize);
cachedSize += bytesSize;
receivedBufferCount++;
// Fire the DownloadProgressChanged event.
if (receivedBufferCount == this.BufferCountPerNotification)
{
InternalDownloadProgressChanged(cachedSize);
receivedBufferCount = 0;
}
}
// Update the used time when the current doanload is stopped.
usedTime = usedTime.Add(DateTime.Now - lastStartTime);
// Update the status of the client. Above loop will be stopped when the
// status of the client is pausing, canceling or completed.
if (this.Status == HttpDownloadClientStatus.Pausing)
{
this.Status = HttpDownloadClientStatus.Paused;
}
else if (this.Status == HttpDownloadClientStatus.Canceling)
{
this.Status = HttpDownloadClientStatus.Canceled;
Exception ex = new Exception("Downloading is canceled by user's request. ");
this.OnDownloadCompleted(new HttpDownloadCompletedEventArgs(
this.DownloadedSize, this.TotalSize, this.TotalUsedTime, ex));
}
else
{
this.Status = HttpDownloadClientStatus.Completed;
this.OnDownloadCompleted(new HttpDownloadCompletedEventArgs(
this.DownloadedSize, this.TotalSize, this.TotalUsedTime, null));
return;
}
}
finally
{
// When the above code has ended, close the streams.
if (responseStream != null)
{
responseStream.Close();
}
if (webResponse != null)
{
webResponse.Close();
}
if (downloadCache != null)
{
downloadCache.Close();
}
}
}
