private async Task <(byte[], CacheControlHeaderValue)> CreateDownloadTask(ILoadingContext <TSource> context, Uri uri, CancellationToken cancellationToken)
{
var client = _httpClientFactory.CreateClient(Constants.HttpClientName);
using var response = await client.GetAsync(uri, HttpCompletionOption.ResponseHeadersRead, cancellationToken);
response.EnsureSuccessStatusCode();
var cacheControl = response.Headers.CacheControl;
var contentLength = response.Content.Headers.ContentLength;
using var stream = await response.Content.ReadAsStreamAsync();
var buffer = new byte[BufferSize];
int bytesRead;
var bytes = new List <byte>();
var downloadProgress = new HttpDownloadProgress();
if (contentLength.HasValue)
{
downloadProgress.TotalBytesToReceive = (ulong)contentLength.Value;
}
context.RaiseDownloadProgressChanged(downloadProgress);
while ((bytesRead = await stream.ReadAsync(buffer, 0, BufferSize, cancellationToken)) > 0)
{
bytes.AddRange(buffer.Take(bytesRead));
downloadProgress.BytesReceived += (ulong)bytesRead;
context.RaiseDownloadProgressChanged(downloadProgress);
}
return(bytes.ToArray(), cacheControl);
}
/// <summary>
/// HTTP下载性能优先
/// </summary>
/// <param name="url">下载地址</param>
/// <param name="fileName">保存本地路劲</param>
/// <param name="progress">进度的委托事件</param>
public void Download(string url, string fileName, HttpDownloadProgress progress)
{
RequestBuilder request = Http.Get(url).DownloadTo(fileName, onProgressChanged: (bytesCopied, totalBytes) => {
progress(bytesCopied, totalBytes, HttpDownloadState.Loading, null);
},
onSuccess: (headers) => {
progress(0, 0, HttpDownloadState.Success, null);
});
request.OnFail(action => {
progress(0, 0, HttpDownloadState.ERROR, action.Message);//这里发生错误异常
}).Go();
}
/// <summary>
/// HTTP多线程下载,急速提升下载速度,但很消耗性能
/// </summary>
/// <param name="url">下载地址</param>
/// <param name="fileName">保存本地路劲</param>
/// <param name="ThreadNum">线程数量(建议6个)</param>
/// <param name="progress"></param>
public void DownloadMutilThread(string url, string fileName, int threadNum, int bufSize, HttpDownloadProgress progress)
{
HttpMutilThreadDownload httpMTD = new HttpMutilThreadDownload(url, fileName, threadNum, bufSize, progress);
httpMTD.StartDownload();
}
