/// <summary>
/// Creates a transfer object for a given requested resource.
/// </summary>
/// <param name="submittedResourceFilePath">The resource identifier as submitted.</param>
/// <param name="fileItem">Represents the requested file resource.</param>
/// <param name="token">The token that is being issued for the transfer.</param>
/// <param name="claims">The access rights for the resource.</param>
/// <param name="lockGuard">File locks, if necessary. Can be a null reference
/// if no locking takes place.</param>
/// <param name="expirationJob">A scheduled job that invokes the
/// <see cref="TransferHandlerBase{TFile,TToken,TTransfer}.OnTransferExpiration"/>
/// method once the transfer expires. May be null if the token does not expire.</param>
/// <returns>A transfer object which encapsulates the information required to perform
/// the transfer.</returns>
protected abstract TTransfer CreateTransfer(string submittedResourceFilePath, TFile fileItem, DownloadToken token,
FileClaims claims, ResourceLockGuard lockGuard,
Job <DownloadToken> expirationJob);
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);
}