Implement custom logger c# in GroupDocs.Redaction for .NET

Managing document redactions efficiently is critical, especially when handling sensitive information. In this guide you’ll learn how to implement a custom logger c# with GroupDocs.Redaction for .NET, giving you full control over logging, error handling, and audit trails. By the end of the tutorial you’ll be able to capture warnings, errors, and informational messages, integrate the logger with existing .NET logging frameworks, and save the redacted document without rasterization.

Quick answers

  • What does a custom logger c# do? It captures errors, warnings, and informational messages during redaction, giving you a searchable audit trail.
  • Which library provides the ILogger interface? GroupDocs.Redaction for .NET supplies the ILogger interface.
  • Can I save the redacted document without rasterization? Yes – call redactor.Save(..., new Options.RasterizationOptions { Enabled = false }).
  • Do I need a license for production use? A full license is required for production; a trial license is available for evaluation.
  • Is this approach compatible with .NET Core / .NET 6+? Absolutely – the same API works across .NET Framework, .NET Core, .NET 5, and .NET 6.

What is a custom logger c#?

A custom logger c# is a class that implements the ILogger interface supplied by GroupDocs.Redaction. It lets you route log messages wherever you need—console, file, database, or external monitoring systems—while giving you a clear view of the redaction workflow overall.

Why use custom logging .net with GroupDocs.Redaction?

Load your redaction process with detailed, searchable logs that satisfy regulatory audits and speed up troubleshooting. GroupDocs.Redaction supports 70+ input and output formats and can process documents up to 500 pages without loading the entire file into memory, so a well‑designed logger adds negligible overhead while providing priceless visibility.

Prerequisites

  • GroupDocs.Redaction for .NET installed (see the Installation section below).
  • A .NET development environment (Visual Studio, VS Code, or the .NET CLI).
  • Basic C# knowledge and familiarity with file streams.

Installation

.NET CLI

dotnet add package GroupDocs.Redaction

Package Manager

Install-Package GroupDocs.Redaction

NuGet Package Manager UI
Search for “GroupDocs.Redaction” and install the latest version.

License acquisition

  • Free trial: Test the API with a temporary license.
  • Temporary license: Get full feature access for a limited period.
  • Purchase: Obtain a perpetual license for production deployments.

Step‑by‑step guide

How to implement custom logger in .NET Core?

Load the CustomLogger class into your .NET Core project and wire it to the RedactorSettings. The logger works the same way on .NET Framework, .NET 5, and .NET 6, so you can share the same code across all platforms.

Step 1: Define a custom logger class (log warnings c#)

The CustomLogger class implements ILogger.
CustomLogger is a user‑defined class that implements the ILogger interface to capture redaction events.

using System;
using GroupDocs.Redaction;

class CustomLogger : ILogger
{
    public bool HasErrors { get; private set; }

    // Log errors encountered during processing.
    public void LogError(string message)
    {
        Console.WriteLine("Error: " + message);
        HasErrors = true;
    }

    // Log warnings that may not be critical but need attention.
    public void LogWarning(string message)
    {
        Console.WriteLine("Warning: " + message);
    }

    // Log informational messages for tracking normal operations.
    public void LogInfo(string message)
    {
        Console.WriteLine("Info: " + message);
    }
}

Definition anchor: CustomLogger is a user‑defined implementation of the ILogger interface that records redaction events.
Explanation: The HasErrors flag helps you decide whether to continue processing. The three methods correspond to the three log levels you’ll need in most redaction scenarios.

Step 2: Prepare file paths and open the source document

string sourceFile = Utils.PrepareOutputDirectory("YOUR_DOCUMENT_DIRECTORY");
string outputFile = Utils.GetOutputFile(sourceFile);

Definition anchor: Redactor is the primary class in GroupDocs.Redaction that performs redaction operations on a PDF document.
Why this matters: Using utility methods keeps your code clean and guarantees the output folder exists before you attempt to save redacted document.

Step 3: Apply redactions while using the custom logger

using (Stream stream = File.Open(sourceFile, FileMode.Open, FileAccess.ReadWrite))
{
    var logger = new CustomLogger();
    
    using (Redactor redactor = new Redactor(stream, new LoadOptions(), new RedactorSettings(logger)))
    {
        // Apply a redaction to the document.
        redactor.Apply(new DeleteAnnotationRedaction());
        
        if (!logger.HasErrors)
        {
            using (Stream streamOut = File.Open(outputFile, FileMode.OpenOrCreate, FileAccess.ReadWrite))
            {
                // Save changes without rasterizing the output.
                redactor.Save(streamOut, new Options.RasterizationOptions { Enabled = false });
            }
        }
    }
}

Direct answer: The redaction workflow starts by creating a Redactor instance with RedactorSettings(logger), then applying redaction objects, checking logger.HasErrors, and finally calling redactor.Save with rasterization disabled. This pattern ensures every step is logged and that you only persist a clean document when no errors occurred.

Explanation:

  1. The Redactor is instantiated with RedactorSettings(logger), linking your CustomLogger.
  2. After applying a redaction, the code checks logger.HasErrors. If no errors occurred, the document is saved—demonstrating save redacted document logic without rasterization.

Common pitfalls & troubleshooting

  • Missing log output: Verify that each Log* method is correctly overridden.
  • File access exceptions: Ensure the application has read/write permissions for both source and output paths.
  • Logger not wired: The RedactorSettings(logger) parameter is essential; omitting it disables custom logging.

Practical applications

  1. Compliance reporting: Export log entries to a CSV or database for audit trails.
  2. Error tracking: Quickly locate problematic files by scanning LogError output.
  3. Workflow automation: Trigger downstream processes (e.g., notifying a compliance officer) when LogWarning is invoked.

Performance considerations

  • Dispose streams promptly to free memory, especially when processing large batches.
  • Monitor CPU & memory during bulk redactions; consider processing documents in parallel with careful logger synchronization.
  • Stay updated: Newer versions of GroupDocs.Redaction often include performance optimizations and additional logging hooks.

Conclusion

By implementing a custom logger c#, you gain granular insight into every step of the redaction pipeline, making it easier to meet compliance standards and debug issues. The approach shown here works seamlessly with GroupDocs.Redaction for .NET and can be extended to integrate with any .NET logging framework you already use.

Frequently asked questions

Q: What is the purpose of custom logging with GroupDocs.Redaction?
A: Custom logging captures detailed redaction events, satisfies audit requirements, and simplifies troubleshooting by exposing errors and warnings in real time.

Q: How do I handle errors using a custom logger?
A: Implement LogError in your CustomLogger class; the HasErrors flag lets you abort processing if a critical issue is detected.

Q: Can custom logging be integrated with other systems?
A: Yes—you can forward log messages to CRM, ERP, or centralized monitoring tools by extending the logger methods.

Q: What are common pitfalls when implementing custom logging?
A: Missing method overrides, forgetting to pass RedactorSettings(logger), and insufficient file permissions are the most frequent issues.

Q: How does custom logging improve document redaction workflows?
A: Detailed logs provide real‑time visibility, streamline debugging, and generate the audit trails required by regulations such as GDPR and HIPAA.

Resources

Last updated: 2026-10-01
Tested with: GroupDocs.Redaction 23.11 for .NET
Author: GroupDocs