public static async Task <MemoryStream> DownloadImage(string Uri, CancellationToken CancellationToken, ManualResetEvent PauseEvent = null, Func <long, long, Task> ProgressCallback = null)
{
//var Uri = _Uri;
//if (Uri.StartsWith("https"))
//{
// Uri = Uri.Replace("https://", "http://");
//}
var tmpFileName = Uri.Split('/').Last();
var cachedFile = await CacheManager.GetCachedFileAsync(tmpFileName);
if (cachedFile == null)
{
//没有对应的缓存文件
var res = await new PixivAppAPI(GlobalBaseAPI).RequestCall("GET",
Uri, new Dictionary <string, string>()
{
{ "Referer", "https://app-api.pixiv.net/" }
});
//读取长度
var length = res.Content.Headers.ContentLength ?? -1;
using (var resStream = await res.Content.ReadAsStreamAsync())
{
var memStream = new MemoryStream();
memStream.Position = 0;
var bytesCounter = 0L;
int bytesRead;
byte[] buffer = new byte[4096];
try
{
while ((bytesRead = await resStream.ReadAsync(buffer, 0, 4096, CancellationToken)) != 0)
{
PauseEvent?.WaitOne();
bytesCounter += bytesRead;
await memStream.WriteAsync(buffer, 0, bytesRead, CancellationToken);
_ = ProgressCallback?.Invoke(bytesCounter, length);
}
}
catch (TaskCanceledException)
{
memStream.Position = 0;
return(memStream);
}
catch
{
throw;
}
memStream.Position = 0;
var newCachedFile = await CacheManager.CreateCacheFileAsync(tmpFileName);
using (var fileStream = await newCachedFile.Value.File.OpenStreamForWriteAsync())
await memStream.CopyToAsync(fileStream);
await CacheManager.FinishCachedFileAsync(newCachedFile.Value, true);
memStream.Position = 0;
return(memStream);
}
}
else
{
//有缓存文件
using (var fileStream = await cachedFile.OpenStreamForReadAsync())
{
var memStream = new MemoryStream();
await fileStream.CopyToAsync(memStream);
var length = memStream.Length;
_ = ProgressCallback?.Invoke(length, length);
memStream.Position = 0;
return(memStream);
}
}
}
