/// <inheritdoc />
public List <StoredFrame> ReadBetween(
DateTime inclusiveFrom,
DateTime exclusiveTo
)
{
var frames = ReadFramesFromDb(inclusiveFrom, exclusiveTo);
var frameGroups = (
from frame in frames
group frame by frame.FilePath into frameGroup
select frameGroup
).ToList();
foreach (var frameGroup in frameGroups)
{
lock (TargetFileLocker.GetFileLocker(frameGroup.Key))
{
using (var fs = File.OpenRead(frameGroup.Key))
{
foreach (var frame in frameGroup.OrderBy(f => f.Offset))
{
fs.Position = frame.Offset;
var compressedBody = new byte[frame.Length];
fs.Read(compressedBody, 0, compressedBody.Length);
using (var targetStream = new MemoryStream(compressedBody))
{
using (var decompressionStream = new GZipStream(targetStream, CompressionMode.Decompress))
{
using (var sr = new StreamReader(decompressionStream, Encoding.UTF8))
{
var body = sr.ReadToEnd();
frame.AppendBody(body);
}
}
}
}
}
}
}
return(frames);
}
/// <inheritdoc />
protected override void LogCompleteMessage(
string message
)
{
//zip message...
byte[] zippedMessage;
using (var targetStream = new MemoryStream())
{
using (var compressionStream = new GZipStream(targetStream, CompressionMode.Compress))
{
using (var sw = new StreamWriter(compressionStream, Encoding.UTF8))
{
sw.Write(message);
}
}
zippedMessage = targetStream.ToArray();
}
//determine target file...
var(targetFilePath, targetFolderPath, targetFileName) = _targetController.GetTargetFile();
//append data
var offset = 0L;
lock (TargetFileLocker.GetFileLocker(targetFilePath))
{
using (var fs = new FileStream(targetFilePath, FileMode.Append, FileAccess.Write))
{
offset = fs.Position;
fs.Write(zippedMessage, 0, zippedMessage.Length);
fs.Flush();
}
//we should still hold the file lock here for the case of revert
//otherwise different thread (different SqlServerCollectionSaver)
//can append their data between append ours and revert ours
//in that case we will truncate both records and DB-metadata will be completely invalid
//save metadata to DB
try
{
_command.Parameters["fileName"].Value = targetFileName.GetFromLast(261);
_command.Parameters["offset"].Value = offset;
_command.Parameters["length"].Value = zippedMessage.Length;
_command.ExecuteNonQuery();
}
catch (Exception firstException)
{
//shit happens...
//try to revert the file to its original state
try
{
using (var fs = new FileStream(targetFilePath, FileMode.Open, FileAccess.ReadWrite))
{
fs.SetLength(offset);
}
}
catch (Exception secondException)
{
//reverting fails, this file is unrecoverable
//force to switch the file!
_targetController.SwitchTargetFile();
throw new AggregateException(firstException, secondException);
}
throw;
}
}
//success
}
