/// <summary>
/// Orchestrates common block reading procedures for the <see cref="ReadBlock"/> and
/// <see cref="ReadBlockStreamed"/> methods.
/// </summary>
protected virtual T OrchestrateBlockReading <T>(TTransfer transfer, long blockNumber,
Func <TTransfer, long, DataBlockInfo, T> readerImplFunc) where T : IDataBlock
{
const FileSystemTask context = FileSystemTask.DataBlockDownloadRequest;
if (blockNumber < 0)
{
string msg = "Invalid block number [{0}] requested - block numbers cannot be negative.";
msg = String.Format(msg, blockNumber);
throw new DataBlockException(msg);
}
if (blockNumber >= transfer.Token.TotalBlockCount)
{
string msg = "Invalid block number [{0}] requested - the total number of blocks is [{1}].";
msg = String.Format(msg, blockNumber, transfer.Token.TotalBlockCount);
throw new DataBlockException(msg);
}
//make sure the file still exists
if (!transfer.FileItem.Exists)
{
Auditor.AuditRequestedFileNotFound(transfer.FileItem, context);
string msg = "Resource [{0}] of transfer [{1}] was not found.";
msg = String.Format(msg, transfer.Token.ResourceName, transfer.TransferId);
throw new VirtualResourceNotFoundException(msg)
{
IsAudited = true
};
}
lock (transfer.SyncRoot)
{
//make sure the transfer is active
if (!transfer.Status.Is(TransferStatus.Starting, TransferStatus.Running, TransferStatus.Paused))
{
string msg = String.Format("Transfer [{0}] is not active anymore - status is [{1}].", transfer.TransferId,
transfer.Status);
if (transfer.AbortReason.HasValue)
{
msg += String.Format(" Transfer abort reason: [{0}].", transfer.AbortReason);
}
Auditor.AuditDeniedOperation(context, AuditEvent.DownloadNoLongerActive, transfer.FileItem, msg);
throw new TransferStatusException(msg)
{
IsAudited = true, EventId = (int)AuditEvent.DownloadNoLongerActive
};
}
//check whether we already transferred this block once
DataBlockInfo transferredBlock = transfer.TryGetTransferredBlock(blockNumber);
T dataBlock = readerImplFunc(transfer, blockNumber, transferredBlock);
//update status
transfer.Status = TransferStatus.Running;
//store copy of the downloaded block that doesn't contain any data
transfer.RegisterBlock(DataBlockInfo.FromDataBlock(dataBlock));
//audit download
Auditor.AuditTransferOperation(context, AuditEvent.FileBlockDownloaded, transfer.TransferId, transfer.FileItem);
return(dataBlock);
}
}
private TTransfer InitTransferImpl(string submittedResourceFilePath, int?clientMaxBlockSize, bool includeFileHash)
{
const FileSystemTask context = FileSystemTask.DownloadTokenRequest;
TFile fileItem = CreateFileItemImpl(submittedResourceFilePath, false, context);
if (!fileItem.Exists)
{
Auditor.AuditRequestedFileNotFound(fileItem, context);
string msg = String.Format("Resource [{0}] not found.", submittedResourceFilePath);
throw new VirtualResourceNotFoundException(msg)
{
IsAudited = true
};
}
//get authorization
FileClaims claims = GetFileClaims(fileItem);
if (!claims.AllowReadData)
{
Auditor.AuditDeniedOperation(context, AuditEvent.FileDataDownloadDenied, fileItem);
string msg = "Read request for file [{0}] was denied - you are not authorized to read the resource.";
msg = String.Format(msg, submittedResourceFilePath);
throw new ResourceAccessException(msg)
{
IsAudited = true
};
}
//try to get lock
ResourceLockGuard readLock = LockResourceForDownload(fileItem, claims);
if (readLock != null && !readLock.IsLockEnabled)
{
Auditor.AuditDeniedOperation(context, AuditEvent.FileReadLockDenied, fileItem);
string msg = "The requested file [{0}] is currently locked and thus cannot be accessed.";
msg = String.Format(msg, submittedResourceFilePath);
throw new ResourceLockedException(msg)
{
IsAudited = true
};
}
//create download token
DownloadToken token = CreateDownloadToken(submittedResourceFilePath, fileItem, clientMaxBlockSize, includeFileHash);
//create expiration job if we have an expiration time
Job <DownloadToken> job = null;
if (token.ExpirationTime.HasValue)
{
job = ScheduleExpiration(token);
}
//create transfer instance
TTransfer transfer = CreateTransfer(submittedResourceFilePath, fileItem, token, claims, readLock, job);
//cache transfer
TransferStore.AddTransfer(transfer);
//audit issued token
Auditor.AuditResourceOperation(context, AuditEvent.DownloadTokenIssued, fileItem);
return(transfer);
}