Add web service, PDF export, and Docker support

- Refactor conversion logic into reusable convert.js module
- Add HTTP server with upload UI, HTML/PDF download, and live preview
- Dockerfile with Chromium for server-side PDF rendering
- Local mermaid.min.js injection for offline diagram rendering

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-04-10 11:15:08 -07:00
parent c38d60e34c
commit 9c5046de7b
5 changed files with 546 additions and 3 deletions

3
.dockerignore Normal file
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node_modules
*.html
*.pdf

6
.gitignore vendored Normal file
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node_modules/
*.html
*.pdf
!server.js
!convert.js
!md2html.js

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FROM node:22-slim
# Install Chrome dependencies
RUN apt-get update && apt-get install -y --no-install-recommends \
chromium \
fonts-freefont-ttf \
@@ -12,8 +11,14 @@ WORKDIR /app
COPY package.json package-lock.json ./
RUN npm ci --omit=dev
COPY md2html.js mermaid.min.js ./
COPY convert.js server.js md2html.js mermaid.min.js ./
ENV CHROME_PATH=/usr/bin/chromium
ENV PORT=3000
ENTRYPOINT ["node", "md2html.js"]
EXPOSE 3000
HEALTHCHECK --interval=30s --timeout=5s --retries=3 \
CMD node -e "require('http').get('http://localhost:3000/health', r => process.exit(r.statusCode === 200 ? 0 : 1))"
CMD ["node", "server.js"]

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const fs = require("fs");
const path = require("path");
const { marked } = require("marked");
function escapeHtml(s) {
return s
.replace(/&/g, "&amp;")
.replace(/</g, "&lt;")
.replace(/>/g, "&gt;")
.replace(/"/g, "&quot;");
}
function stripHtml(s) {
return s.replace(/<[^>]*>/g, "");
}
function buildToc(items) {
if (items.length === 0) return "";
let html = "";
let prevDepth = 0;
for (const item of items) {
if (item.depth > prevDepth) {
for (let i = prevDepth; i < item.depth; i++) html += "<ul>";
} else if (item.depth < prevDepth) {
for (let i = item.depth; i < prevDepth; i++) html += "</ul>";
}
html += `<li><a href="#${item.slug}">${escapeHtml(item.text)}</a></li>\n`;
prevDepth = item.depth;
}
for (let i = 0; i < prevDepth; i++) html += "</ul>";
return html;
}
function markdownToHtml(md) {
const renderer = new marked.Renderer();
const defaultCode = renderer.code.bind(renderer);
renderer.code = function ({ text, lang }) {
if (lang === "mermaid") {
return `<pre class="mermaid">${escapeHtml(text)}</pre>\n`;
}
return defaultCode({ text, lang });
};
const tocItems = [];
renderer.heading = function ({ text, depth }) {
const slug = text
.toLowerCase()
.replace(/<[^>]*>/g, "")
.replace(/[^\w\s-]/g, "")
.replace(/\s+/g, "-")
.replace(/-+/g, "-")
.trim();
tocItems.push({ text: stripHtml(text), depth, slug });
return `<h${depth} id="${slug}">${text}</h${depth}>\n`;
};
marked.setOptions({ renderer, gfm: true, breaks: false });
const bodyHtml = marked.parse(md);
const tocHtml = buildToc(tocItems);
const docTitle = tocItems.length > 0 ? tocItems[0].text : "Document";
return `<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>${escapeHtml(docTitle)}</title>
<style>
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
color: #24292f;
background: #ffffff;
line-height: 1.6;
display: flex;
min-height: 100vh;
}
#toc-sidebar {
position: fixed;
top: 0; left: 0;
width: 280px;
height: 100vh;
overflow-y: auto;
background: #f6f8fa;
border-right: 1px solid #d0d7de;
padding: 20px 16px;
font-size: 0.85rem;
z-index: 10;
}
#toc-sidebar ul { list-style: none; padding-left: 0; }
#toc-sidebar ul ul { padding-left: 16px; }
#toc-sidebar li { margin: 3px 0; }
#toc-sidebar a {
color: #0969da;
text-decoration: none;
display: block;
padding: 2px 6px;
border-radius: 4px;
overflow: hidden;
text-overflow: ellipsis;
white-space: nowrap;
}
#toc-sidebar a:hover { background: #ddf4ff; }
#toc-sidebar a.active { background: #0969da; color: #fff; }
#toc-toggle {
display: none;
position: fixed;
top: 12px; left: 12px;
z-index: 20;
background: #f6f8fa;
border: 1px solid #d0d7de;
border-radius: 6px;
padding: 6px 10px;
cursor: pointer;
font-size: 1.1rem;
}
#content {
margin-left: 280px;
max-width: 920px;
padding: 40px 48px 80px;
width: 100%;
}
h1, h2, h3, h4, h5, h6 {
margin-top: 1.8em;
margin-bottom: 0.6em;
font-weight: 600;
line-height: 1.25;
color: #1f2328;
}
h1 { font-size: 2em; border-bottom: 1px solid #d0d7de; padding-bottom: 0.3em; }
h2 { font-size: 1.5em; border-bottom: 1px solid #d0d7de; padding-bottom: 0.3em; }
h3 { font-size: 1.25em; }
h1:first-child { margin-top: 0; }
p { margin: 0 0 1em; }
a { color: #0969da; text-decoration: none; }
a:hover { text-decoration: underline; }
strong { font-weight: 600; }
hr { border: none; border-top: 1px solid #d0d7de; margin: 2em 0; }
ul, ol { margin: 0 0 1em 2em; }
li + li { margin-top: 0.25em; }
table {
border-collapse: collapse;
width: 100%;
margin: 0 0 1em;
font-size: 0.9rem;
}
th, td { border: 1px solid #d0d7de; padding: 8px 12px; text-align: left; }
th { background: #f6f8fa; font-weight: 600; }
tr:nth-child(even) { background: #f6f8fa; }
code {
font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
font-size: 0.875em;
background: #f6f8fa;
padding: 0.2em 0.4em;
border-radius: 4px;
}
pre {
background: #f6f8fa;
border: 1px solid #d0d7de;
border-radius: 6px;
padding: 16px;
overflow-x: auto;
margin: 0 0 1em;
line-height: 1.45;
}
pre code { background: none; padding: 0; font-size: 0.85rem; }
pre.mermaid {
background: #fff;
border: 1px solid #d0d7de;
text-align: center;
padding: 20px;
}
@media (max-width: 900px) {
#toc-sidebar { transform: translateX(-100%); transition: transform 0.25s; }
#toc-sidebar.open { transform: translateX(0); }
#toc-toggle { display: block; }
#content { margin-left: 0; padding: 40px 24px 80px; }
}
@media print {
#toc-sidebar, #toc-toggle { display: none; }
#content { margin-left: 0; max-width: 100%; padding: 0; }
pre.mermaid { border: none; }
h1, h2 { break-after: avoid; }
table { break-inside: avoid; }
}
</style>
</head>
<body>
<button id="toc-toggle" onclick="document.getElementById('toc-sidebar').classList.toggle('open')" aria-label="Toggle table of contents">&#9776;</button>
<nav id="toc-sidebar">
${tocHtml}
</nav>
<main id="content">
${bodyHtml}
</main>
<script src="https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.min.js"></script>
<script>
mermaid.initialize({
startOnLoad: true,
theme: "default",
flowchart: { useMaxWidth: true, htmlLabels: true, curve: "basis" },
securityLevel: "loose"
});
</script>
<script>
(function () {
const links = document.querySelectorAll("#toc-sidebar a");
const headings = [];
links.forEach(function (a) {
const id = a.getAttribute("href").slice(1);
const el = document.getElementById(id);
if (el) headings.push({ el: el, a: a });
});
if (headings.length === 0) return;
function onScroll() {
let current = headings[0];
for (const h of headings) {
if (h.el.getBoundingClientRect().top <= 80) current = h;
}
links.forEach(function (a) { a.classList.remove("active"); });
current.a.classList.add("active");
}
window.addEventListener("scroll", onScroll, { passive: true });
onScroll();
})();
</script>
</body>
</html>`;
}
async function htmlToPdf(html) {
const puppeteer = require("puppeteer-core");
const browser = await puppeteer.launch({
executablePath: process.env.CHROME_PATH || "/usr/bin/google-chrome-stable",
args: ["--no-sandbox", "--disable-setuid-sandbox"],
});
const page = await browser.newPage();
const htmlForPdf = html.replace(
/<script src="https:\/\/cdn\.jsdelivr\.net\/npm\/mermaid@[^"]*"><\/script>/,
""
);
await page.setContent(htmlForPdf, { waitUntil: "domcontentloaded" });
const hasMermaid = await page.evaluate(
() => document.querySelectorAll("pre.mermaid").length > 0
);
if (hasMermaid) {
const mermaidJs = fs.readFileSync(
path.join(__dirname, "mermaid.min.js"),
"utf-8"
);
await page.addScriptTag({ content: mermaidJs });
await page.evaluate(() => {
mermaid.initialize({
startOnLoad: false,
theme: "default",
flowchart: { useMaxWidth: true, htmlLabels: true, curve: "basis" },
securityLevel: "loose",
});
return mermaid.run({ querySelector: "pre.mermaid" });
});
}
const pdfBuffer = await page.pdf({
format: "A4",
printBackground: true,
margin: { top: "20mm", bottom: "20mm", left: "15mm", right: "15mm" },
});
await browser.close();
return pdfBuffer;
}
module.exports = { markdownToHtml, htmlToPdf };

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const http = require("http");
const { markdownToHtml, htmlToPdf } = require("./convert");
const PORT = process.env.PORT || 3000;
const UPLOAD_PAGE = `<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Markdown Converter</title>
<style>
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
body {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
background: #f6f8fa;
color: #24292f;
display: flex;
justify-content: center;
padding: 40px 20px;
min-height: 100vh;
}
.container { max-width: 800px; width: 100%; }
h1 { font-size: 1.8em; margin-bottom: 8px; }
p.sub { color: #656d76; margin-bottom: 24px; }
.card {
background: #fff;
border: 1px solid #d0d7de;
border-radius: 8px;
padding: 24px;
margin-bottom: 16px;
}
label { display: block; font-weight: 600; margin-bottom: 8px; }
textarea {
width: 100%;
height: 300px;
font-family: "SFMono-Regular", Consolas, monospace;
font-size: 0.9rem;
padding: 12px;
border: 1px solid #d0d7de;
border-radius: 6px;
resize: vertical;
}
.actions { display: flex; gap: 12px; margin-top: 16px; flex-wrap: wrap; }
.btn {
padding: 10px 20px;
border: none;
border-radius: 6px;
font-size: 0.95rem;
font-weight: 600;
cursor: pointer;
text-decoration: none;
display: inline-flex;
align-items: center;
gap: 6px;
}
.btn-primary { background: #0969da; color: #fff; }
.btn-primary:hover { background: #0860ca; }
.btn-secondary { background: #24292f; color: #fff; }
.btn-secondary:hover { background: #32383f; }
.btn-outline { background: #fff; color: #24292f; border: 1px solid #d0d7de; }
.btn-outline:hover { background: #f6f8fa; }
.or { color: #656d76; padding: 0 4px; font-size: 0.85rem; }
.drop-zone {
border: 2px dashed #d0d7de;
border-radius: 6px;
padding: 24px;
text-align: center;
color: #656d76;
margin-bottom: 16px;
cursor: pointer;
transition: border-color 0.2s, background 0.2s;
}
.drop-zone.over { border-color: #0969da; background: #ddf4ff; }
.drop-zone input { display: none; }
.status { margin-top: 12px; font-size: 0.85rem; color: #656d76; }
</style>
</head>
<body>
<div class="container">
<h1>Markdown Converter</h1>
<p class="sub">Convert Markdown to styled HTML or PDF with TOC and Mermaid diagrams</p>
<div class="card">
<label>Upload a .md file</label>
<div class="drop-zone" id="dropZone">
<p>Drag & drop a .md file here, or click to browse</p>
<input type="file" id="fileInput" accept=".md,.markdown,.txt">
</div>
<label>Or paste Markdown</label>
<textarea id="mdInput" placeholder="# Hello World&#10;&#10;Your markdown here..."></textarea>
<div class="actions">
<button class="btn btn-primary" onclick="convert('html')">Convert to HTML</button>
<button class="btn btn-secondary" onclick="convert('pdf')">Convert to PDF</button>
<button class="btn btn-outline" onclick="preview()">Preview</button>
</div>
<div class="status" id="status"></div>
</div>
</div>
<script>
const dropZone = document.getElementById('dropZone');
const fileInput = document.getElementById('fileInput');
const mdInput = document.getElementById('mdInput');
const status = document.getElementById('status');
dropZone.addEventListener('click', () => fileInput.click());
dropZone.addEventListener('dragover', (e) => { e.preventDefault(); dropZone.classList.add('over'); });
dropZone.addEventListener('dragleave', () => dropZone.classList.remove('over'));
dropZone.addEventListener('drop', (e) => {
e.preventDefault();
dropZone.classList.remove('over');
const file = e.dataTransfer.files[0];
if (file) readFile(file);
});
fileInput.addEventListener('change', () => {
if (fileInput.files[0]) readFile(fileInput.files[0]);
});
function readFile(file) {
const reader = new FileReader();
reader.onload = (e) => {
mdInput.value = e.target.result;
status.textContent = 'Loaded: ' + file.name;
};
reader.readAsText(file);
}
async function convert(format) {
const md = mdInput.value.trim();
if (!md) { status.textContent = 'Please enter some markdown first.'; return; }
status.textContent = 'Converting to ' + format.toUpperCase() + '...';
try {
const res = await fetch('/convert', {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify({ markdown: md, format })
});
if (!res.ok) throw new Error(await res.text());
const blob = await res.blob();
const url = URL.createObjectURL(blob);
const a = document.createElement('a');
a.href = url;
a.download = 'output.' + (format === 'pdf' ? 'pdf' : 'html');
a.click();
URL.revokeObjectURL(url);
status.textContent = 'Done!';
} catch (err) {
status.textContent = 'Error: ' + err.message;
}
}
async function preview() {
const md = mdInput.value.trim();
if (!md) { status.textContent = 'Please enter some markdown first.'; return; }
status.textContent = 'Generating preview...';
try {
const res = await fetch('/convert', {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify({ markdown: md, format: 'html' })
});
if (!res.ok) throw new Error(await res.text());
const html = await res.text();
const w = window.open('', '_blank');
w.document.write(html);
w.document.close();
status.textContent = 'Preview opened in new tab.';
} catch (err) {
status.textContent = 'Error: ' + err.message;
}
}
</script>
</body>
</html>`;
function parseBody(req) {
return new Promise((resolve, reject) => {
const chunks = [];
let size = 0;
const limit = 10 * 1024 * 1024; // 10MB
req.on("data", (chunk) => {
size += chunk.length;
if (size > limit) {
reject(new Error("Request body too large"));
req.destroy();
return;
}
chunks.push(chunk);
});
req.on("end", () => resolve(Buffer.concat(chunks).toString()));
req.on("error", reject);
});
}
const server = http.createServer(async (req, res) => {
if (req.method === "GET" && (req.url === "/" || req.url === "")) {
res.writeHead(200, { "Content-Type": "text/html" });
res.end(UPLOAD_PAGE);
return;
}
if (req.method === "POST" && req.url === "/convert") {
try {
const body = JSON.parse(await parseBody(req));
const { markdown, format } = body;
if (!markdown) {
res.writeHead(400, { "Content-Type": "text/plain" });
res.end("Missing 'markdown' field");
return;
}
const html = markdownToHtml(markdown);
if (format === "pdf") {
const pdfBuffer = await htmlToPdf(html);
res.writeHead(200, {
"Content-Type": "application/pdf",
"Content-Disposition": "attachment; filename=output.pdf",
});
res.end(pdfBuffer);
} else {
res.writeHead(200, { "Content-Type": "text/html; charset=utf-8" });
res.end(html);
}
} catch (err) {
console.error("Convert error:", err);
res.writeHead(500, { "Content-Type": "text/plain" });
res.end("Conversion failed: " + err.message);
}
return;
}
if (req.method === "GET" && req.url === "/health") {
res.writeHead(200, { "Content-Type": "application/json" });
res.end(JSON.stringify({ status: "ok" }));
return;
}
res.writeHead(404, { "Content-Type": "text/plain" });
res.end("Not found");
});
server.listen(PORT, () => {
console.log(`md2html server listening on http://0.0.0.0:${PORT}`);
});