/// <summary>
/// Reads this file content from the remote storage.
/// </summary>
/// <param name="offset">File content offset, in bytes, to start reading from.</param>
/// <param name="length">Data length to read, in bytes.</param>
/// <param name="fileSize">Total file size, in bytes.</param>
/// <param name="resultContext">
/// You will use this parameter to return file content by
/// calling <see cref="ITransferDataResultContext.ReturnData(byte[], long, long)"/>
/// </param>
public async Task ReadAsync(long offset, long length, long fileSize, ITransferDataResultContext resultContext)
{
// On Windows this method has a 60 sec timeout.
// To process longer requests and reset the timout timer call the resultContext.ReportProgress() or resultContext.ReturnData() method.
IFileAsync file = await Program.DavClient.OpenFileAsync(RemoteStorageUri);
using (Stream stream = await file.GetReadStreamAsync(offset, fileSize))
{
const long MAX_CHUNK_SIZE = 0x500000; //5Mb
long chunkSize = Math.Min(MAX_CHUNK_SIZE, length);
stream.Seek(offset, SeekOrigin.Begin);
long total = offset + length;
byte[] buffer = new byte[chunkSize];
long bytesRead;
while ((bytesRead = await stream.ReadAsync(buffer, 0, (int)chunkSize)) > 0)
{
resultContext.ReturnData(buffer, offset, bytesRead);
offset += bytesRead;
length -= bytesRead;
chunkSize = Math.Min(MAX_CHUNK_SIZE, length);
if (offset >= total)
{
return;
}
}
}
}
/// <inheritdoc/>
public async Task ReadAsync(Stream output, long offset, long length, ITransferDataOperationContext operationContext, ITransferDataResultContext resultContext)
{
// On Windows this method has a 60 sec timeout.
// To process longer requests and reset the timout timer call the resultContext.ReportProgress() or resultContext.ReturnData() method.
Logger.LogMessage($"{nameof(IFile)}.{nameof(ReadAsync)}({offset}, {length})", UserFileSystemPath);
SimulateNetworkDelay(length, resultContext);
IFileAsync file = await Program.DavClient.OpenFileAsync(RemoteStoragePath);
using (Stream stream = await file.GetReadStreamAsync(offset, length))
{
const int bufferSize = 0x500000; // 5Mb. Buffer size must be multiple of 4096 bytes for optimal performance.
await stream.CopyToAsync(output, bufferSize, length);
}
}
/// <summary>
/// Reads file content from the remote storage.
/// </summary>
/// <param name="offset">Offset in bytes in file content to start reading from.</param>
/// <param name="length">Lenth in bytes of the file content to read.</param>
/// <returns>File content that corresponds to the provided offset and length.</returns>
public async Task <byte[]> ReadAsync(long offset, long length)
{
// This method has a 60 sec timeout.
// To process longer requests modify the IFolder.TransferDataAsync() implementation.
IFileAsync file = await Program.DavClient.OpenFileAsync(RemoteStorageUri);
using (Stream stream = await file.GetReadStreamAsync(offset, length))
{
byte[] buffer = new byte[length];
int bufferPos = 0;
int bytesRead = 0;
while ((bytesRead = await stream.ReadAsync(buffer, bufferPos, (int)length)) > 0)
{
bufferPos += bytesRead;
length -= bytesRead;
}
return(buffer);
}
}