ChatGPT Plugin for Aspose.PDF
How to Process PDF Text with ChatGPT in .NET

How to Process PDF Text with ChatGPT in .NET

This article demonstrates how to integrate ChatGPT with PDF workflows in .NET using the Aspose.PDF ChatGPT Plugin. You’ll learn to extract text from PDFs, process it through ChatGPT, and write responses to new or existing PDF files—ideal for document summarization, auto-commenting, or AI-driven content enrichment.

Real-World Problem

Extracting meaningful insights, summaries, or answers from PDF files manually is time-consuming. Developers need a streamlined way to connect PDF content with ChatGPT for automated processing and feedback, saving time and boosting productivity.

Solution Overview

Aspose.PDF ChatGPT Plugin for .NET lets you send PDF content to ChatGPT, receive completions or summaries, and save responses as new PDFs—all with minimal code. The plugin provides async operations, flexible request options, and easy PDF input/output management.

Prerequisites

  • Visual Studio 2019 or later
  • .NET 6.0 or later
  • Aspose.PDF for .NET installed via NuGet
  • OpenAI API Key for ChatGPT
PM> Install-Package Aspose.PDF

Step-by-Step Implementation

Step 1: Install and Configure Aspose.PDF

Add the required namespaces:

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

Step 2: Prepare PDF Text or File

Specify your input PDF and desired output PDF file:

string inputPdfPath = @"C:\Samples\source.pdf";
string outputPdfPath = @"C:\Samples\ChatGPT_output.pdf";

Step 3: Configure ChatGPT Request Options

Set up your API key, prompt, and output path. You can extract text from PDF manually, or let the plugin use the whole PDF file as input:

using (var plugin = new PdfChatGpt())
{
    var options = new PdfChatGptRequestOptions();
    options.AddInput(new FileDataSource(inputPdfPath));    // Use full PDF text as message
    options.AddOutput(new FileDataSource(outputPdfPath));   // Path for the output PDF
    
    options.ApiKey = "Your-OpenAI-API-Key";                // REQUIRED: Your API key for ChatGPT
    options.MaxTokens = 1000;                              // Limit response size
    options.Query = "Summarize the contents of this document."; // Or ask any question about the PDF

You can also add custom conversation messages (system/user roles):

    options.Messages.Add(new Message
    {
        Content = "You are a document assistant. Summarize the provided PDF text.",
        Role = Role.System
    });
    options.Messages.Add(new Message
    {
        Content = "What are the main topics covered in this PDF?",
        Role = Role.User
    });

Step 4: Send Request to ChatGPT and Save Result

Process the request asynchronously, receive both the new PDF file path and the ChatGPT response:

    // Process the request and await the result
    var result = await plugin.ProcessAsync(options);
    var fileResultPath = result.ResultCollection[0].Data; // Path to the output PDF
    var chatCompletion = result.ResultCollection[1].Data as ChatCompletion; // ChatGPT API object

    // Access the generated response text if needed:
    var firstChoice = chatCompletion?.Choices?.FirstOrDefault();
    var responseText = firstChoice?.Message?.Content;

    Console.WriteLine($"PDF generated at: {fileResultPath}");
    Console.WriteLine("ChatGPT response:");
    Console.WriteLine(responseText);
}

Step 5: Error Handling and Async Usage

Always wrap async calls and handle API/network errors:

try
{
    // (Code above)
}
catch (Exception ex)
{
    Console.WriteLine($"Error during ChatGPT PDF processing: {ex.Message}");
}

Complete Implementation Example 

using Aspose.Pdf.Plugins;
using System;
using System.IO;
using System.Linq;
using System.Threading.Tasks;

class Program
{
    static async Task Main()
    {
        string inputPdfPath = @"C:\Samples\source.pdf";
        string outputPdfPath = @"C:\Samples\ChatGPT_output.pdf";

        using (var plugin = new PdfChatGpt())
        {
            var options = new PdfChatGptRequestOptions();
            options.AddInput(new FileDataSource(inputPdfPath));
            options.AddOutput(new FileDataSource(outputPdfPath));
            options.ApiKey = "Your-OpenAI-API-Key";
            options.MaxTokens = 1000;
            options.Query = "Summarize the content of this PDF document.";

            try
            {
                var result = await plugin.ProcessAsync(options);
                var fileResultPath = result.ResultCollection[0].Data;
                var chatCompletion = result.ResultCollection[1].Data as ChatCompletion;
                var firstChoice = chatCompletion?.Choices?.FirstOrDefault();
                var responseText = firstChoice?.Message?.Content;

                Console.WriteLine($"PDF generated at: {fileResultPath}");
                Console.WriteLine("ChatGPT response:");
                Console.WriteLine(responseText);
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error: {ex.Message}");
            }
        }
    }
}

Use Cases and Applications

PDF Summarization and AI-Generated Comments

Automatically summarize contracts, reports, or research papers using ChatGPT and save responses in PDFs.

Automated Q&A or Insights Extraction

Send custom prompts to ChatGPT for extracting answers, tables, or key data from PDF files.

Batch Document Enrichment

Integrate into workflows to process many PDFs, generating chat-based responses or auto-annotations.

Common Challenges and Solutions

Challenge: API Limits or Response Truncation

Solution: Adjust MaxTokens and Query for optimal results; split large PDFs into chunks if needed.

Challenge: Secure API Key Management

Solution: Store API keys securely (environment variables, vaults) and avoid hardcoding in production.

Performance Considerations

  • Batch PDF inputs and prompts to minimize API calls.
  • Use async workflows to keep your application responsive.
  • Tune token limits to manage API costs.

Best Practices

  1. Always check PDF output and ChatGPT responses for accuracy.
  2. Customize prompts and message roles for targeted results.
  3. Securely manage API credentials.
  4. Log and handle errors gracefully in async operations.

Advanced Scenarios

  • Use multiple PDFs or prompt variations in a loop.
  • Combine system/user messages for complex context or tasks.
  • Leverage output PDF for downstream processing or workflows.

Conclusion

Aspose.PDF ChatGPT Plugin for .NET empowers developers to automate document analysis, summarization, and interactive PDF processing using the power of ChatGPT—directly within their .NET applications. Streamline your AI document workflows, from extraction to enrichment, with just a few lines of code.

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