markitect-main/docs/advanced_packaging.md

Advanced Packaging Features

Issue #150 Implementation: Complete support for advanced packaging formats including .mdz (Markdown Zip) and transclusion engine for .mdt (Markdown Transcluded) formats.

Overview

MarkiTect's advanced packaging system provides sophisticated document packaging capabilities built on the solid foundation of the explode-implode variant system (Issues #148-149). The system supports:

• 📦 MDZ Format: Self-contained markdown packages with embedded assets
• 🔗 Transclusion Engine: Template-based documents with dynamic content inclusion
• 🔧 Asset Management: Automated asset discovery, embedding, and path rewriting
• ✅ Integrity Validation: Checksum verification and cross-platform compatibility

Package Formats

MDZ (Markdown Zip) Format

MDZ packages are self-contained ZIP archives that include markdown content, embedded assets, and metadata.

Structure

document.mdz
├── content.md          # Main markdown content with rewritten asset paths
├── assets/             # Embedded assets directory
│   ├── image1.png
│   ├── style.css
│   └── ...
└── package.json        # Package metadata and manifest

Creating MDZ Packages

from markitect.packaging.mdz_variant import MdzVariant

# Create MDZ variant
mdz = MdzVariant()

# Package a markdown file with assets
result = mdz.create_package(
    source_path=Path("document.md"),
    options={
        'output_path': Path("document.mdz"),
        'compression_level': 6  # Optional: ZIP compression level
    }
)

print(f"Package created: {result['package_path']}")
print(f"Assets embedded: {result['assets_embedded']}")

Extracting MDZ Packages

# Extract package contents
result = mdz.extract_package(
    package_path=Path("document.mdz"),
    options={
        'output_dir': Path("extracted_content/")
    }
)

print(f"Files extracted: {result['files_extracted']}")

MDT (Markdown Transcluded) Format

MDT format uses the transclusion engine to create template-based documents with dynamic content inclusion.

Transclusion Directives

File Inclusion

# My Document

{{include "header.md"}}

## Main Content

{{include "sections/introduction.md"}}

{{include "footer.md"}}

Variable Substitution

# {{title}}

Author: {{author}}
Version: {{version}}

{{include "content.md" title="Advanced Guide" author="MarkiTect"}}

Conditional Content

{{if debug}}
**Debug Mode**: This content only appears when debug=true
{{endif}}

Using the Transclusion Engine

from markitect.packaging.transclusion import TransclusionEngine

# Create engine with base path and variables
engine = TransclusionEngine(
    base_path=Path("templates/"),
    variables={
        'title': 'Advanced Guide',
        'author': 'MarkiTect Team',
        'version': '2.0',
        'debug': True
    }
)

# Process a template file
result = engine.process_file(Path("document.mdt"))
print(result)  # Fully processed content with includes resolved

Asset Management

Automatic Asset Discovery

The system automatically discovers assets referenced in markdown content:

from markitect.packaging.asset_utils import discover_assets

# Discover assets in a directory
assets = discover_assets(Path("project/"))

# Discover assets from content
content = "![Image](./images/photo.jpg) [Link](./docs/readme.md)"
referenced_assets = discover_assets(content)

Asset Metadata and Validation

from markitect.packaging.asset_utils import AssetUtils

# Create asset metadata with checksum
metadata = AssetUtils.create_asset_metadata(
    file_path=Path("image.png"),
    package_path="assets/image.png"
)

print(f"Size: {metadata.size} bytes")
print(f"Checksum: {metadata.checksum}")
print(f"MIME Type: {metadata.mime_type}")

# Validate asset integrity
is_valid = AssetUtils.validate_asset_integrity(
    Path("image.png"),
    expected_checksum=metadata.checksum
)

Path Rewriting

Automatic path rewriting ensures assets work correctly within packages:

from markitect.packaging.path_utils import PathUtils

content = """
# My Document
![Logo](./assets/logo.png)
[Documentation](./docs/guide.md)
"""

asset_map = {
    './assets/logo.png': 'assets/logo.png',
    './docs/guide.md': 'assets/guide.md'
}

rewritten = PathUtils.rewrite_asset_paths(content, asset_map)
# Result: paths updated to package-internal locations

Integration with Variant System

The packaging system seamlessly integrates with MarkiTect's existing variant architecture:

Variant Factory Integration

from markitect.explode_variants import get_variant_factory, ExplodeVariant

factory = get_variant_factory()

# Create MDZ variant
mdz_variant = factory.create_variant(ExplodeVariant.MDZ)

# Auto-detect package format
detection_result = factory.detect_variant(Path("document.mdz"))
print(f"Detected format: {detection_result.variant}")

CLI Integration

# Create MDZ package
markitect md-package create document.md --format mdz --output document.mdz

# Extract MDZ package
markitect md-package extract document.mdz --output extracted/

# Process MDT template
markitect md-transclude process template.mdt --variables config.json

Error Handling

Comprehensive error handling with specialized exception types:

from markitect.packaging.errors import (
    PackagingError, AssetError, TransclusionError,
    CircularReferenceError, DepthLimitError
)

try:
    result = engine.process_file(Path("template.mdt"))
except CircularReferenceError as e:
    print(f"Circular reference detected: {e}")
except DepthLimitError as e:
    print(f"Inclusion depth exceeded: {e}")
except AssetError as e:
    print(f"Asset processing error: {e}")

Advanced Features

Circular Reference Detection

The transclusion engine automatically detects and prevents circular references:

# This will raise CircularReferenceError
# file1.md: {{include "file2.md"}}
# file2.md: {{include "file1.md"}}

engine = TransclusionEngine(max_depth=10)
try:
    result = engine.process_file(Path("file1.md"))
except CircularReferenceError as e:
    print(f"Cycle detected: {e}")

Depth Limiting

Control inclusion depth to prevent infinite recursion:

engine = TransclusionEngine(max_depth=5)  # Limit to 5 levels deep

Cross-Platform Compatibility

Path handling ensures compatibility across operating systems:

from markitect.packaging.path_utils import PathUtils

# Handles Windows, macOS, and Linux path conventions automatically
normalized = PathUtils.normalize_path("./assets\\image.png")
# Result: "./assets/image.png" (normalized to POSIX format)

Performance Considerations

Asset Processing

• Lazy Loading: Assets are processed only when needed
• Checksum Caching: Asset checksums are cached for performance
• Compression: ZIP compression reduces package size

Memory Usage

• Streaming Processing: Large files are processed in chunks
• Context Management: Transclusion contexts are properly cleaned up
• Resource Cleanup: File handles and temporary files are automatically cleaned

Best Practices

Package Organization

project/
├── content.md          # Main content
├── assets/             # All assets in dedicated directory
│   ├── images/
│   ├── stylesheets/
│   └── documents/
├── templates/          # Transclusion templates
│   ├── header.md
│   ├── footer.md
│   └── sections/
└── variables.json      # Template variables

Asset Management

1. Use relative paths in markdown content
2. Organize assets in dedicated directories
3. Validate checksums for integrity verification
4. Optimize file sizes before packaging

Transclusion Templates

1. Keep templates focused on single concerns
2. Use meaningful variable names
3. Document template requirements
4. Test with various variable combinations

Migration Guide

From Legacy Exploded Structures

Existing exploded structures can be migrated to packaging formats:

# Convert exploded directory to MDZ package
from markitect.packaging.mdz_variant import MdzVariant

mdz = MdzVariant()
result = mdz.create_package(
    source_path=Path("document.mdd/"),  # Existing exploded directory
    options={'output_path': Path("document.mdz")}
)

From Traditional Markdown

# Package existing markdown with assets
result = mdz.create_package(
    source_path=Path("README.md"),
    options={
        'output_path': Path("README.mdz"),
        'include_assets': True  # Auto-discover and include assets
    }
)

API Reference

Core Classes

• PackagingVariant: Abstract base class for packaging variants
• MdzVariant: MDZ format implementation
• TransclusionEngine: Template processing engine
• TransclusionContext: Processing context with variable management
• DirectiveParser: Parses transclusion directives

Utility Classes

• AssetUtils: Asset discovery and metadata management
• PathUtils: Path rewriting and normalization
• PackageMetadata: Package metadata representation
• AssetMetadata: Individual asset metadata

Error Types

• PackagingError: Base packaging exception
• PackageFormatError: Package format issues
• AssetError: Asset handling problems
• TransclusionError: Transclusion processing errors
• CircularReferenceError: Circular inclusion detection
• DepthLimitError: Inclusion depth exceeded

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Implementation Status: ✅ Complete (Issue #150) Test Coverage: 53/53 tests passing (100%) Documentation: Comprehensive API and usage documentation Integration: Full integration with existing variant system