Optimizer Plugin for Aspose.PDF
How to Automate Batch PDF Compression for Storage in .NET

How to Automate Batch PDF Compression for Storage in .NET

Handling thousands of large PDFs is a major challenge for IT, legal, and enterprise operations. The Aspose.PDF.Optimizer Plugin for .NET lets you automate compression across entire repositories, reducing file sizes for archiving, digital delivery, or email attachments.

Batch Job Setup: Preparing Your Compression Pipeline

  1. Organize Input Files: Gather all target PDFs in a designated input folder (e.g., /Documents/ToCompress).
  2. Designate Output Folder: Set an output directory for compressed PDFs (e.g., /Documents/Compressed).
  3. Initialize the Optimizer Plugin: Set up your batch process using the Aspose.PDF.Plugin API.

File Input/Output: Compression in Action 

using Aspose.Pdf.Plugins;
using System.IO;

string inputDir = @"C:\Documents\ToCompress";
string outputDir = @"C:\Documents\Compressed";
Directory.CreateDirectory(outputDir);

string[] pdfFiles = Directory.GetFiles(inputDir, "*.pdf");
int processed = 0;

foreach (var pdfFile in pdfFiles)
{
    string fileName = Path.GetFileName(pdfFile);
    string outputFile = Path.Combine(outputDir, fileName);

    var optimizer = new Optimizer();
    var options = new OptimizeOptions();
    options.AddInput(new FileDataSource(pdfFile));
    options.AddOutput(new FileDataSource(outputFile));

    optimizer.Process(options);
    processed++;
    Console.WriteLine($"Compressed: {fileName}");
}

Console.WriteLine($"Total PDFs compressed: {processed}");

Logging and Reporting

  • Log every input and output file for traceability (CSV, database, or simple text log)
  • Capture compression stats (original size vs. compressed size)
  • Report failures or skipped files for review

Example Logging:

long originalSize = new FileInfo(pdfFile).Length;
long compressedSize = new FileInfo(outputFile).Length;
Console.WriteLine($"{fileName},Original: {originalSize},Compressed: {compressedSize}");

Advanced Tips

  • Combine with Merger: Compress individual PDFs, then merge into a single file using the Merger plugin for easier distribution.
  • Automate for Email: Integrate into email sending workflows so PDFs are compressed before sending as attachments.
  • Optimize Only Changed Files: Use timestamps to only compress files that are new or updated.

Use Cases

  • Bulk legal discovery/document production
  • Enterprise document retention/archiving
  • IT workflows for onboarding, HR, or digital signature pipelines

Frequently Asked Questions

Q: Is there a limit to how many PDFs can be processed in a batch? A: No hard limit—Aspose.PDF.Plugin can process thousands of files. For very large jobs, split inputs into manageable batches to avoid memory or timeout issues.

Q: Can I compress and merge PDFs in one workflow? A: Yes! Compress PDFs first, then use the Merger plugin to combine them into a single optimized file.

Q: What kind of compression is performed? A: Image downsampling, metadata cleanup, font optimization, and more, as supported by the plugin’s options.

Pro Tip: Automate your compression workflow as a nightly/weekly batch job and monitor logs for any files skipped or failed due to errors or corruption.

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