ZDDC/pandoc

ZDDC Pandoc Tools

A collection of tools for converting Markdown documents to HTML with a professional viewer interface, optimized for technical documentation and engineering documents.

Server-side conversion (zddc-server)

The shell scripts in this folder are standalone CLI/batch tools. zddc-server implements its own on-demand conversion (Go package zddc/internal/convert) and does not call these scripts. It does, however, reuse the same viewer-template.html and custom.css (embedded at build time). See AGENTS.md → "Server-side document conversion" for the authoritative reference.

zddc-server can render any served .md on demand: requesting the sibling URL <path>/foo.docx (or .html / .pdf) returns the converted bytes — no query string. A real on-disk file of that name always wins; the virtual conversion only fires when the requested file doesn't exist but foo.md does. The browse app's markdown editor surfaces these as DOCX/HTML/PDF download links (auto-saving a dirty buffer first so the output matches what's on screen).

Architecture. The Go code does the minimum — it execs pandoc and chromium-browser directly. The sandbox and resource caps live in the runtime image, where /usr/local/bin/{pandoc,chromium-browser} are wrapper scripts that run the real binary inside a per-conversion bubblewrap sandbox (--unshare-all, read-only binds, --tmpfs /tmp, --clearenv) under cgroup v2 memory/PID caps. I/O is via stdin/stdout plus a per-call scratch dir. There is no container runtime and no image pulling at request time.

The PDF flow is two-stage: pandoc renders the markdown through viewer-template.html to standalone HTML, then headless Chromium prints that HTML to PDF — preserving the viewer template's print-media CSS rather than going through pandoc's LaTeX template.

Converted bytes are cached at <dir>/.zddc.d/converted/<base>.<ext> with mtime synced to the source, so a fresh cache hit is a stat-and-serve with no exec. A PUT/DELETE/MOVE on the source .md purges the sidecars. Per-project header metadata (client/project/contractor/project_number) comes from the .zddc convert: cascade; title/tracking_number/revision/status are derived from the filename via zddc.ParseFilename.

Relevant flags (defaults in parens):

• --convert-pandoc-binary (pandoc) / --convert-chromium-binary (chromium-browser; chromium on Debian) — PATH-resolved name or absolute path
• --convert-scratch-dir ($TMPDIR) — host scratch root for template + intermediates
• --convert-mem-mib (1024) — per-conversion memory cap (cgroup memory.max)
• --convert-pids (256) — per-conversion PID cap (cgroup pids.max)
• --convert-timeout (60s) — per-conversion wall clock (Go context.WithTimeout)

If pandoc/chromium aren't on PATH (e.g. running zddc-server outside the runtime image) the endpoint serves 503 with a Retry-After; the rest of the server keeps working. Running against raw pandoc/chromium with no wrapper gives a working but unsandboxed endpoint — fine for dev iteration.

Features

Document Conversion (convert)

• Batch processing: Convert multiple Markdown files at once
• Force overwrite: -f flag to overwrite existing output files
• Custom output directory: -o flag to specify output location
• Configuration-driven: Uses zddc.conf for project-specific settings
• Template integration: Automatically applies the viewer template
• Progress tracking: Real-time conversion status and summary

Professional Viewer Template (viewer-template.html)

• Modern responsive design: Works on desktop, tablet, and mobile
• Table of Contents (TOC): Auto-generated sidebar navigation with smooth scrolling
• Print optimization: Professional formatting for PDF generation
  • Page break controls for tables
  • Repeating table headers
  • Proper page numbering
  • Clean print layout
• URL hash navigation: Shareable links to specific document sections
• Mobile-friendly: Collapsible sidebar and touch-optimized interface
• Professional styling: Clean typography optimized for technical documents

Usage

Basic Conversion

# Convert all Markdown files in current directory
./convert *.md

# Convert with force overwrite
./convert -f *.md

# Convert to specific output directory
./convert -o rendered/ *.md

# Combine flags
./convert -f -o rendered/ *.md

Configuration (zddc.conf)

Create a zddc.conf file in your project directory. It is sourced as shell, so use var="value" syntax (no spaces around =). Only these four variables are read; all are optional and feed the document header via pandoc --variable:

contractor="Contractor Name"   # contracting organization (header)
client="Client Name"           # client org (header, paired with project)
project="Project Name"         # full project name
project_number="AR 28088"      # shown in parentheses after the project name

The template path is discovered automatically (input dir → script dir → symlink target) or set per-run with -T; the output directory is set with -o. They are not zddc.conf keys.

Directory Structure

your-project/
├── zddc.conf              # Configuration file
├── document1.md           # Source Markdown files
├── document2.md
└── rendered/              # Generated HTML files
    ├── document1.html
    └── document2.html

Template Features

Navigation

• TOC Generation: Automatically creates navigation from document headings
• Smooth Scrolling: Click TOC items for smooth navigation to sections
• Hash URLs: Address bar updates with section anchors for sharing
• Mobile Menu: Collapsible sidebar for mobile devices

Print Styling

• Page Breaks: Tables won't split across pages
• Header Repetition: Table headers repeat on each page
• Professional Layout: Optimized margins and typography
• Page Numbers: Sequential page numbering in footer

Responsive Design

• Desktop: Full sidebar with TOC always visible
• Tablet: Collapsible sidebar with overlay
• Mobile: Hamburger menu with full-screen TOC overlay

File Types Supported

• Input: Markdown (.md), DOCX (.docx), and HTML (.html/.htm) files (auto-detected: DOCX→MD, MD→HTML, HTML→MD; override with -t md|html|docx). Direct DOCX→HTML is not supported — convert to MD first.
• Output: HTML files with embedded CSS and JavaScript (plus MD and DOCX targets)
• Images: Supports embedded images and diagrams
• Tables: Full table support with print optimization
• Code: Syntax highlighting for code blocks

Dependencies

• pandoc: Document conversion engine
• Modern browser: For viewing generated HTML files
• Optional: Web server for serving files (prevents CORS issues)

Troubleshooting

Common Issues

1. Template not found: Keep viewer-template.html beside the script (or input), or pass -T /path/to/template.html
2. Permission errors: Make sure convert script is executable (chmod +x convert)
3. Missing output: Check that output directory exists or use -o to create it
4. Print issues: Use "Print to PDF" in browser for best results