markdown.ts•5.99 kB
/**
* @fileoverview Markdown file renderer.
* Converts markdown files to PDF using crossnote.
* Provides beautiful Markdown Preview Enhanced-quality output with Mermaid diagram support.
* Automatically adds page numbering to all rendered PDFs.
*/
import { basename, join } from "path"
import { readFileSync, writeFileSync, mkdtempSync, unlinkSync } from "fs"
import { tmpdir } from "os"
import matter from "gray-matter"
import he from "he"
import { findChrome } from "../utils.js"
import { validateFilePath } from "../file-security.js"
import { config } from "../config.js"
import { Notebook } from "crossnote"
/**
* Page numbering configuration function for Puppeteer PDF generation.
* Generates header/footer templates with inline styles (required by Puppeteer).
* Filename is HTML-escaped to prevent XSS and rendering issues.
*
* @param filename - The name of the file being rendered (displayed in footer)
* @returns Configuration object with header/footer templates
*/
function getPageNumberConfig(filename: string) {
// Puppeteer PDF headers/footers require inline styles (no external CSS support)
const footerStyles = {
container: [
"font-size: 9px",
"width: 100%",
"margin: 0",
"padding: 0 1cm",
"font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji'",
"display: flex",
"justify-content: space-between",
"align-items: center",
].join("; "),
filename: "font-size: 8px; color: #666;",
}
return {
displayHeaderFooter: true,
headerTemplate: "<div></div>",
footerTemplate: `
<div style="${footerStyles.container}">
<span style="${footerStyles.filename}">${he.encode(filename)}</span>
<span><span class="pageNumber"></span> / <span class="totalPages"></span></span>
</div>
`,
margin: {
top: "1cm",
bottom: "1.5cm",
left: "1cm",
right: "1cm",
},
}
}
/**
* Injects page numbering configuration into markdown content.
* Properly merges with existing front-matter if present.
* Uses gray-matter's stringify for robust formatting.
* @param content - Original markdown content
* @param filename - Name of the file being rendered (displayed in footer)
* @returns Markdown content with page numbering front-matter added/merged
*/
function injectPageNumbering(content: string, filename: string): string {
const { data, content: body } = matter(content)
// Check if user already has chrome or puppeteer config in their frontmatter -
// respect their settings
if (data.chrome || data.puppeteer) {
return content // Don't modify user's existing config
}
// Merge in the chrome config with existing front-matter (even if empty)
const mergedFrontMatter = {
...data,
chrome: getPageNumberConfig(filename),
}
// Use gray-matter's stringify to properly format the document
return matter.stringify(body, mergedFrontMatter)
}
/**
* Renders a markdown file to PDF using crossnote.
* Provides beautiful Markdown Preview Enhanced-quality output with
* comprehensive diagram support. Automatically adds page numbering (Page X /
* Y) to the footer of each page.
*
* @param filePath - Path to the markdown file to render
* @returns Path to the generated temporary PDF file
* @throws {Error} If Chrome is not found or rendering fails
*/
export async function renderMarkdownToPdf(filePath: string): Promise<string> {
// Validate file path security
validateFilePath(filePath)
// Read the original markdown content
const originalContent = readFileSync(filePath, "utf-8")
// Inject page numbering configuration if not already present
const contentWithPageNumbers = injectPageNumbering(originalContent, basename(filePath))
// Create a temporary directory for the modified markdown file
const tempDir = mkdtempSync(join(tmpdir(), "mcp-printer-markdown-"))
const tempFileName = basename(filePath)
const tempFilePath = join(tempDir, tempFileName)
// Write the modified content to temp file
writeFileSync(tempFilePath, contentWithPageNumbers, "utf-8")
// Find Chrome executable (required by crossnote/puppeteer)
const chromePath = config.chromePath || (await findChrome())
let outputPath: string
try {
// Initialize crossnote notebook with configuration, pointing to temp directory
const notebook = await Notebook.init({
notebookPath: tempDir,
config: {
// Hardcoded themes optimized for printing (light background, clean styling)
previewTheme: "github-light.css",
codeBlockTheme: "github.css",
mermaidTheme: "default",
// Math rendering
mathRenderingOption: "KaTeX",
// Rendering options
printBackground: true,
breakOnSingleNewLine: true,
enableEmojiSyntax: true,
enableWikiLinkSyntax: false,
enableExtendedTableSyntax: false,
// Chrome configuration
chromePath,
// Security: disable script execution
enableScriptExecution: false,
},
})
// Get the markdown engine for the temp file
const engine = notebook.getNoteMarkdownEngine(tempFileName)
// Export to PDF using Chrome/Puppeteer
// crossnote returns the path to the generated PDF
outputPath = await engine.chromeExport({
fileType: "pdf",
runAllCodeChunks: false, // Don't execute code chunks for security
})
} catch (error: unknown) {
// Clean up temp file before throwing
try {
unlinkSync(tempFilePath)
} catch {
// Ignore cleanup errors
}
throw new Error(
`Failed to render markdown with crossnote: ${error instanceof Error ? error.message : String(error)}`
)
}
// Clean up temp markdown file (PDF is in a different location)
try {
unlinkSync(tempFilePath)
} catch {
// Ignore cleanup errors - temp files will be cleaned up by OS eventually
}
return outputPath
}