/// <summary>
/// Downloads a file from the specified address and returns the file.
/// </summary>
/// <param name="fileUri">The URI of the file.</param>
/// <param name="folder">The folder to save the file to.</param>
/// <param name="fileName">The file name to save the file as.</param>
/// <param name="option">
/// A value that indicates what to do
/// if the filename already exists in the current folder.
/// </param>
/// <remarks>
/// If no file name is given - the method will try to find
/// the suggested file name in the HTTP response
/// based on the Content-Disposition HTTP header.
/// </remarks>
/// <returns></returns>
public async Task <StorageFile> SaveAsyncWithBackgroundDownloaderAndProgress(
Uri fileUri,
IProgress <DownloadOperation> ProgressCallBack,
StorageFolder folder = null,
string fileName = null,
NameCollisionOption option = NameCollisionOption.GenerateUniqueName)
{
if (folder == null)
{
folder = ApplicationData.Current.LocalFolder;
}
var file = await folder.CreateTempFileAsync();
var downloader = new BackgroundDownloader();
var download = downloader.CreateDownload(
fileUri,
file);
var res = await download.StartAsync().AsTask(ProgressCallBack);
if (string.IsNullOrEmpty(fileName))
{
// Use temp file name by default
fileName = file.Name;
// Try to find a suggested file name in the http response headers
// and rename the temp file before returning if the name is found.
var info = res.GetResponseInformation();
if (info.Headers.ContainsKey("Content-Disposition"))
{
var cd = info.Headers["Content-Disposition"];
var regEx = new Regex("filename=\"(?<fileNameGroup>.+?)\"");
var match = regEx.Match(cd);
if (match.Success)
{
fileName = match.Groups["fileNameGroup"].Value;
await file.RenameAsync(fileName, option);
return(file);
}
}
}
await file.RenameAsync(fileName, option);
return(file);
}
/// <summary>
/// Downloads a file from the specified address and returns the file.
/// </summary>
/// <param name="fileUri">The URI of the file.</param>
/// <param name="folder">The folder to save the file to.</param>
/// <param name="fileName">The file name to save the file as.</param>
/// <param name="option">
/// A value that indicates what to do
/// if the filename already exists in the current folder.
/// </param>
/// <remarks>
/// If no file name is given - the method will try to find
/// the suggested file name in the HTTP response
/// based on the Content-Disposition HTTP header.
/// </remarks>
/// <returns></returns>
public async Task <StorageFile> SaveAsyncWithBackgroundDownloaderAndProgress(
Uri fileUri,
IProgress <DownloadOperation> ProgressCallBack,
StorageFolder folder = null,
string fileName = null,
NameCollisionOption option = NameCollisionOption.GenerateUniqueName)
{
Uri uri = new Uri("...");
try
{
Windows.Web.Http.HttpClient client = new Windows.Web.Http.HttpClient();
var downloadTask = client.GetAsync(uri);
downloadTask.Progress = (result, progress) =>
{
Debug.WriteLine("===start===");
Debug.WriteLine(progress.BytesReceived);
Debug.WriteLine(progress.TotalBytesToReceive);
Debug.WriteLine("===end===");
};
var Downloadresult = await downloadTask;
Debug.WriteLine("Done: " + Downloadresult.StatusCode.ToString());
}
catch (Exception ex)
{
}
if (folder == null)
{
folder = ApplicationData.Current.LocalFolder;
}
var file = await folder.CreateTempFileAsync();
var downloader = new BackgroundDownloader();
var download = downloader.CreateDownload(
fileUri,
file);
var res = await download.StartAsync().AsTask(ProgressCallBack);
if (string.IsNullOrEmpty(fileName))
{
// Use temp file name by default
fileName = file.Name;
// Try to find a suggested file name in the http response headers
// and rename the temp file before returning if the name is found.
var info = res.GetResponseInformation();
if (info.Headers.ContainsKey("Content-Disposition"))
{
var cd = info.Headers["Content-Disposition"];
var regEx = new Regex("filename=\"(?<fileNameGroup>.+?)\"");
var match = regEx.Match(cd);
if (match.Success)
{
fileName = match.Groups["fileNameGroup"].Value;
await file.RenameAsync(fileName, option);
return(file);
}
}
}
await file.RenameAsync(fileName, option);
return(file);
}
/// <summary>
/// Downloads a file from the specified address and returns the file.
/// </summary>
/// <param name="fileUri">The URI of the file.</param>
/// <param name="folder">The folder to save the file to.</param>
/// <param name="fileName">The file name to save the file as.</param>
/// <param name="option">
/// A value that indicates what to do
/// if the filename already exists in the current folder.
/// </param>
/// <remarks>
/// If no file name is given - the method will try to find
/// the suggested file name in the HTTP response
/// based on the Content-Disposition HTTP header.
/// </remarks>
/// <returns></returns>
public async Task <StorageFile> SaveAsyncWithBackgroundDownloader(
Uri fileUri,
StorageFolder folder = null,
string fileName = null,
NameCollisionOption option = NameCollisionOption.ReplaceExisting)
{
//将要下载的文件标记记录到下载队列标识集合里面
var fileUniqueMark = folder + fileName;
if (!downloadList.Contains(fileUniqueMark))
{
downloadList.Add(fileUniqueMark);
}
else
{
return(null);
}
if (folder == null)
{
folder = ApplicationData.Current.LocalFolder;
}
//首先以reationCollisionOption.GenerateUniqueName的方式创建一个临时文件
var file = await folder.CreateTempFileAsync();
//创建BackgroundDownloader任务
var downloader = new BackgroundDownloader();
var download = downloader.CreateDownload(
fileUri,
file);
#region 之前的代码
//var res = await download.StartAsync();
//var ss = download.GetResponseInformation();
//if (string.IsNullOrEmpty(fileName))
//{
// // Use temp file name by default
// fileName = file.Name;
// // Try to find a suggested file name in the http response headers
// // and rename the temp file before returning if the name is found.
// var info = res.GetResponseInformation();
// if (info.Headers.ContainsKey("Content-Disposition"))
// {
// var cd = info.Headers["Content-Disposition"];
// var regEx = new Regex("filename=\"(?<fileNameGroup>.+?)\"");
// var match = regEx.Match(cd);
// if (match.Success)
// {
// fileName = match.Groups["fileNameGroup"].Value;
// await file.RenameAsync(fileName, option);
// return file;
// }
// }
//}
#endregion
try
{
//开始下载
await download.StartAsync();
//下载成功则重命名之前已经创建的文件为目标文件名
await file.RenameAsync(fileName, option);
}
catch (Exception ex)
{
//如果下载或者重命名失败则立刻删除之前的临时文件
file.DeleteAsync(StorageDeleteOption.PermanentDelete);
//及时从下载队列标识中移除标记
if (downloadList.Contains(fileUniqueMark))
{
downloadList.Remove(fileUniqueMark);
}
//抛出异常以便外部调用的方法能够处理
throw ex;
}
//var ri = download.GetResponseInformation();
////如果返回的是404，说明网络上没有此资源，则应立刻删除.tmp临时文件
//if (ri.StatusCode == 404)
//{
// await
// throw new FileNotFoundException();
//}
//else
//{
// await file.RenameAsync(fileName, option);
//}
//及时从下载队列标识中移除标记
if (downloadList.Contains(fileUniqueMark))
{
downloadList.Remove(fileUniqueMark);
}
return(file);
}
