PowerPoint to Markdown Converter Implementation Plan

Generated: 2025-01-25 19:30 UTC
Status: Ready for Implementation - Phase 1 Complete
Verified:

Current Progress Status

Completed

1. Implementation Plan - Comprehensive plan documented
2. Research Phase - PowerPoint parsing approaches evaluated
3. Architecture Design - File structure and patterns defined

Next Steps (Ready to Implement)

1. Add Dependencies - Install PowerPoint parsing library
2. Create Converter Module - lib/converters/powerpoint.js
3. Create Route Handler - src/pptxConverterToMD.js
4. Add API Endpoint - Update index.js
5. Local Testing - Create test file and verify functionality

Implementation Checklist

• Install npm dependencies (pptxgenjs or alternative)
• Create PowerPoint converter module
• Create route handler following existing patterns
• Update unified API with new endpoint
• Create test PowerPoint file
• Test locally with curl/test scripts
• Add unit tests
• Update API documentation
• Deploy to production

Overview

This document outlines the implementation plan for adding PowerPoint (.pptx) to Markdown conversion capability to the Convert to Markdown service. The converter will follow existing patterns established by Excel, Word, and PDF converters while addressing PowerPoint-specific challenges such as slide structure and embedded images.

Purpose

Enable users to convert PowerPoint presentations into Markdown format optimized for AI/LLM processing, maintaining slide structure, extracting text content, and handling embedded media appropriately.

Key Requirements

1. Format Support: Initially .pptx only (XML-based format)
2. Content Extraction: Slide titles, text, tables, speaker notes
3. Image Handling: Hybrid approach with size-based decisions
4. API Consistency: Follow existing converter patterns
5. Local Testing: Verify functionality before production deployment

Technical Specifications

Input Format

• File Type: .pptx (Office Open XML Presentation)
• MIME Types:
  • application/vnd.openxmlformats-officedocument.presentationml.presentation
  • application/pptx
• Size Limit: 5MB (configurable, may increase to 50MB for Pro users)

Output Format

Markdown Structure

---
title: Presentation Title
date: 2025-01-25
type: markdown
source: pptx
slideCount: 15
totalImages: 8
hasSpeakerNotes: true
---

## Slide 1: Introduction

Main content from slide...

[Image: Company Logo - centered, 200x100px]

> **Speaker Notes:** These are the speaker notes for this slide explaining key points...

---

## Slide 2: Key Metrics

### Revenue Growth

| Year | Revenue | Growth |
|------|---------|--------|
| 2023 | $1.2M   | 25%    |
| 2024 | $1.5M   | 30%    |

---

Image Handling Strategy

1. Small Images (<50KB)

   • Convert to base64 data URI
   • Embed directly in markdown: ![Alt text](data:image/png;base64,...)
   • Resize to max 800px width maintaining aspect ratio

2. Large Images (≥50KB)

   • Generate descriptive placeholder: [Image: Description - dimensions]
   • Include image metadata (title, alt text if available)
   • Track in statistics for user awareness

3. Charts and Diagrams

   • Extract data tables where possible
   • Provide descriptive text for complex visuals
   • Note chart type in placeholder

Content Extraction Rules

Text Content

• Slide Titles: Convert to H2 headers (## Slide N: Title)
• Text Boxes: Preserve order, merge into paragraphs
• Bullet Points: Convert to markdown lists
• Numbered Lists: Maintain numbering
• Text Formatting: Preserve bold, italic, underline

Tables

• Extract table data maintaining structure
• Convert to markdown table format
• Handle merged cells with notation

Speaker Notes

• Extract if present
• Format as blockquote with label
• Place after slide content

Metadata

{
  title: "Extracted from presentation",
  slideCount: 25,
  totalImages: 12,
  hasSpeakerNotes: true,
  hasAnimations: false,
  presentationSize: "1920x1080",
  theme: "Office Theme",
  author: "If available",
  lastModified: "2025-01-25"
}

Implementation Details

File Structure

unified-api/
├── lib/
│   └── converters/
│       └── powerpoint.js     # Core converter logic
├── src/
│   └── pptxConverterToMD.js  # Route handler
├── test/
│   └── powerpoint.test.js    # Unit tests
└── index.js                   # Add new route

Dependencies to Add

{
  "dependencies": {
    "pptxgenjs": "^3.12.0",  // OR alternative approach
    "sharp": "^0.33.0"       // For image processing
  }
}

Alternative Libraries to Consider:

• node-pptx-parser: Dedicated parser, lightweight
• officegen: General office file handler
• Custom XML parsing with unzipper + xml2js

Code Architecture

1. Converter Module (lib/converters/powerpoint.js)

/**
 * PowerPoint converter functions
 * Handles conversion of PowerPoint files to Markdown format
 */

const PptxGenJS = require('pptxgenjs');
const sharp = require('sharp');
const {
    cleanTextForMarkdown,
    createMetadataHeader,
    calculateStats,
    dataToMarkdownTable
} = require('../utils/common');

/**
 * Converts PowerPoint buffer to Markdown format
 * @param {Buffer} buffer - PowerPoint file buffer
 * @param {Object} options - Conversion options
 * @returns {Promise<Object>} Conversion result
 */
async function convertPowerPointToMarkdown(buffer, options = {}) {
    // Implementation details...
}

module.exports = {
    convertPowerPointToMarkdown
};

2. Route Handler (src/pptxConverterToMD.js)

Follow existing pattern from docxConverterToMD.js:

• Use Busboy for multipart form parsing
• Validate MIME type
• Enforce file size limits
• Handle errors consistently

3. API Route Addition

Add to unified-api/index.js:

// Import handler
const { pptxToMarkdown } = require('./src/pptxConverterToMD');

// Add to API info
endpoints: [
  // ... existing endpoints
  {
    method: 'POST',
    path: '/v1/convert/ppt-to-markdown',
    description: 'Convert PowerPoint presentations to Markdown',
    accepts: '.pptx'
  }
]

// Add route
app.post('/v1/convert/ppt-to-markdown',
  handleFileUpload('file'),
  authenticate,
  trackUsage,
  pptxToMarkdownHandler
);

Error Handling

1. File Validation Errors

   • Invalid format: "Only .pptx files are supported"
   • Corrupted file: "Unable to parse PowerPoint file"
   • File too large: "File size exceeds limit"

2. Content Errors

   • Empty presentation: Return minimal markdown
   • Missing content: Continue with available data
   • Image processing failures: Use placeholders

3. Token Limit Protection

   • Monitor output size during generation
   • Truncate if approaching 50,000 character limit
   • Add truncation notice to output

Testing Strategy

Local Testing Setup

1. Create Test File

   • Save as test-documents/sample-presentation.pptx
   • Include: Multiple slides, images, tables, speaker notes
   • Test edge cases: Empty slides, large images

2. Update Test Script

   // In test-local.js, add:
   const testFiles = {
     // ... existing tests
     'ppt-to-markdown': '../test-documents/sample-presentation.pptx'
   };
   

3. Testing Commands

   # Start local server
   cd unified-api
   npm start
   
   # Run converter test
   curl -X POST http://localhost:8080/v1/convert/ppt-to-markdown \
     -F "file=@../test-documents/sample-presentation.pptx"
   
   # Test with authentication
   curl -X POST http://localhost:8080/v1/convert/ppt-to-markdown \
     -H "X-API-Key: test-key-123" \
     -F "file=@../test-documents/sample-presentation.pptx"
   

Expected Output Validation

1. Structure Verification

   • Metadata header present
   • Slide count matches
   • Slide separators (---) between slides

2. Content Accuracy

   • Text extracted correctly
   • Tables formatted properly
   • Speaker notes included

3. Performance Metrics

   • Processing time < 5 seconds for typical files
   • Memory usage reasonable
   • Token count within limits

Unit Tests

Create test/powerpoint.test.js:

• Test successful conversion
• Test error cases
• Test image handling
• Test metadata extraction

Deployment Plan

Pre-deployment Checklist

• Local testing passes all cases
• Unit tests implemented and passing
• API documentation updated
• Package.json dependencies added
• Error messages user-friendly
• Performance acceptable

Deployment Steps

1. Commit Changes

   git add .
   git commit -m "Add PowerPoint to Markdown converter"
   

2. Deploy to Production

   cd unified-api
   ./deploy.sh
   

3. Post-deployment Verification

   # Test production endpoint
   curl -X POST https://convert-to-markdown.knowcode.tech/v1/convert/ppt-to-markdown \
     -H "X-API-Key: production-key" \
     -F "file=@test.pptx"
   

Documentation Updates

1. API Documentation (docs/api.md)

   • Add PowerPoint endpoint
   • Include example requests/responses
   • Document limitations

2. Pricing Page (docs/pricing.md)

   • Add PowerPoint to supported formats
   • Update feature comparison table

3. README Updates

   • Main README.md
   • unified-api/README.md

Future Enhancements

Phase 2 Features

1. Additional Format Support

   • .ppt (legacy binary format)
   • .ppsx (slideshow format)
   • .potx (template format)

2. Advanced Content Extraction

   • Chart data extraction
   • SmartArt text extraction
   • Animation descriptions
   • Embedded video/audio references

3. Alternative Output Formats

   • /v1/convert/ppt-to-json for structured data
   • Slide-specific conversion options
   • Custom formatting templates

Performance Optimizations

1. Streaming Processing

   • Process slides incrementally
   • Reduce memory footprint
   • Enable larger file support

2. Caching Layer

   • Cache processed images
   • Store conversion results temporarily

3. Parallel Processing

   • Process slides concurrently
   • Optimize for multi-core systems

Risk Mitigation

Technical Risks

1. Library Compatibility

   • Test multiple libraries before final selection
   • Have fallback parsing approach
   • Monitor for security updates

2. Memory Usage

   • Set strict limits
   • Implement streaming where possible
   • Monitor production memory metrics

3. Security Concerns

   • Validate all file inputs
   • Sanitize extracted content
   • Prevent XML bomb attacks

Business Risks

1. User Expectations

   • Clear documentation on limitations
   • Transparent about image handling
   • Set appropriate file size limits

2. Cost Management

   • Monitor processing time
   • Track resource usage
   • Optimize expensive operations

Success Metrics

1. Technical Metrics

   • Conversion success rate > 95%
   • Average processing time < 3 seconds
   • Memory usage < 512MB per conversion

2. User Metrics

   • Adoption rate among existing users
   • Error rate < 5%
   • User feedback positive

3. Business Metrics

   • Increase in Pro subscriptions
   • API usage growth
   • Support ticket volume manageable

Conclusion

This implementation plan provides a comprehensive approach to adding PowerPoint conversion capabilities to the Convert to Markdown service. By following existing patterns and focusing on local testing first, we can ensure a smooth rollout of this frequently requested feature.