Splitting MBOX Files

Split MBOX Storage/Cancel Splitting Operation

Aspose.Email provides methods for dividing large mailbox files into manageable chunks. This helps improve performance and memory efficiency, especially when working with extensive email archives. The available splitting options vary depending on the .NET version you’re using.

Supported APIs by .NET Version

For .NET Framework 4.5 and .NET Core

You can segment MBOX data using the SplitInto method of the MboxStorageReader class, with the option to include a cancellation token or customize the output file naming:

Parameters:

  • chunkSize: The approximate size of each chunk in bytes.
  • outputPath: The folder path where the chunks will be created.
  • partFileNamePrefix: The prefix to be added to the filename of each part.
  • token: A CancellationToken that allows for the possible cancellation of the operation.

For .NET Versions Below 4.5

Earlier versions support the same SplitInto method but without cancellation tokens:

Code Samples for Controlled Splitting with Cancellation

The following code samples demonstrate how to split an archive into up to 5 parts, automatically cancelling the operation afterward:

.NET 4.5 / .NET Core

int partCount = 0;

var tokenSource = new CancellationTokenSource();

var mbox = new MboxrdStorageReader(fileName, new MboxLoadOptions { LeaveOpen = false });

// Subscribe to events
mbox.MboxFileCreated += (sender, e) =>
{
    partCount++;
    if (partCount >= 5)
        tokenSource.Cancel();
};

System.Threading.Tasks.Task task = mbox.SplitInto(10000000, outputPath, tokenSource.Token);
task.Wait();

Below .NET 4.5

int partCount = 0;
var mbox = new MboxrdStorageReader(fileName, new MboxLoadOptions { LeaveOpen = false });
mbox.SplitInto(10000000, outputPath);

mbox.MboxFileCreated += (sender, e) =>
{
    partCount++;
    if (partCount >= 5)
        mbox.Cancel();
};

Split Large MBOX Files Asynchronously

Working with large email archives can be inefficient and memory-intensive. To improve performance and manageability, Aspose.Email for .NET provides the asynchronous SplitIntoAsync method, which allows you to split large files into smaller chunks - without blocking the main thread. The code sample below shows how to use MboxStorageReader.CreateReaderAsync to open a large MBOX file asynchronously and then call SplitIntoAsync to divide it into smaller files, each with a maximum size of 10 MB. The resulting chunks are saved to the specified output directory using the prefix “chunk_”.

using (var reader = await MboxStorageReader.CreateReaderAsync("input.mbox", new MboxLoadOptions()))
{
    await reader.SplitIntoAsync(10 * 1024 * 1024, "outputDirectory", "chunk_", CancellationToken.None);
}
Convert MBOX to PST with Aspose.Email in C#