readme.md for @push.rocks/smartpdf

Transform HTML, websites, and PDFs into beautiful documents and images with just a few lines of code.
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🚀 Why SmartPDF?
SmartPDF is your Swiss Army knife for PDF operations in Node.js. Whether you're generating invoices from HTML, snapshotting web pages, merging documents, or converting PDF pages to images — SmartPDF handles it all through a clean, async-first TypeScript API backed by headless Chromium.
✨ Features at a Glance
Feature
Description
📝 HTML → PDF
Render any HTML string (with full CSS) into an A4-sized PDF
🌐 Website → PDF
Capture a live URL as a PDF — either A4 or full-page scroll
🔀 PDF Merging
Combine multiple PDF buffers into a single document
🖼️ PDF → Images
Convert PDF pages to PNG, WebP, or progressive JPEG
📑 Text Extraction
Pull raw text content from any PDF buffer
🔌 Smart Port Management
Automatic port allocation so multiple instances never collide
🎛️ DPI Control
Built-in scale constants for screen, high-quality, and print resolutions
🌐 BYO Browser
Optionally pass your own Puppeteer 
Browser instance
📦 Installation
pnpm add @push.rocks/smartpdf
Prerequisites: SmartPDF uses headless Chromium via Puppeteer under the hood. On most systems this is handled automatically. If you run into browser-launch issues (CI, Docker, etc.), make sure the required system libraries are installed — see the Puppeteer troubleshooting guide.
🎯 Quick Start
import { SmartPdf } from '@push.rocks/smartpdf';
import * as fs from 'fs';
// 1. Create and start
const smartPdf = await SmartPdf.create();
await smartPdf.start();
// 2. Generate a PDF from HTML
const pdf = await smartPdf.getA4PdfResultForHtmlString(`
  <h1>Hello, PDF World! 🌍</h1>
  <p>Generated with SmartPDF.</p>
`);
// 3. Write to disk
fs.writeFileSync('my-first.pdf', pdf.buffer);
// 4. Clean up
await smartPdf.stop();
Every method returns an 
IPdf object:
interface IPdf {
  id: string | null;        // Unique identifier
  name: string;             // Filename
  buffer: Buffer;           // Raw PDF bytes
  metadata?: {
    textExtraction?: string; // Extracted text (when available)
  };
}
📚 How It Works
SmartPDF spins up a lightweight HTTP server (via 
@push.rocks/smartserve) bound to 
localhost and a headless Chromium browser. When you call a generation method:
Your HTML is registered internally and served at 
http://localhost:{port}/{id}
Puppeteer navigates to that URL, waits for the page to fully render, and captures a PDF
A header-based security check ensures only the correct content is captured
The server and browser are torn down when you call 
stop()
This architecture means you get pixel-perfect CSS rendering, web font support, and full JavaScript execution — the same rendering engine that powers Chrome.
🏗️ Instance Management
const smartPdf = await SmartPdf.create();
await smartPdf.start();
// ... your operations ...
await smartPdf.stop();
For production use, wrap in try/finally:
const smartPdf = await SmartPdf.create();
try {
  await smartPdf.start();
  // ... generate PDFs ...
} finally {
  await smartPdf.stop();
}
🔌 Smart Port Allocation
Run multiple instances without conflicts:
// Each instance auto-selects a free port (default range: 20000–30000)
const instance1 = new SmartPdf();
const instance2 = new SmartPdf();
await instance1.start(); // e.g. port 20000
await instance2.start(); // e.g. port 20001
console.log(instance1.serverPort); // 20000
console.log(instance2.serverPort); // 20001
// Custom range
const custom = new SmartPdf({ portRangeStart: 4000, portRangeEnd: 5000 });
// Or pin a specific port
const pinned = new SmartPdf({ port: 3000 });
If a specific port is already in use, 
start() throws an error immediately instead of silently failing.
🌐 Bring Your Own Browser
Pass an existing Puppeteer 
Browser instance — SmartPDF won't close it when you call 
stop():
import puppeteer from 'puppeteer';
const browser = await puppeteer.launch({
  headless: 'new',
  args: ['--no-sandbox'],
});
const smartPdf = await SmartPdf.create();
await smartPdf.start(browser); // uses your browser
await smartPdf.stop();      // server stops, browser stays open
await browser.close();       // you manage browser lifecycle
🎨 PDF Generation
📝 HTML → A4 PDF
Renders at a 794×1122 viewport (A4 at 96 DPI) with full CSS support:
const pdf = await smartPdf.getA4PdfResultForHtmlString(`
  <style>
    body { font-family: 'Helvetica', sans-serif; margin: 40px; }
    .header {
      background: linear-gradient(135deg, #667eea, #764ba2);
      color: white; padding: 30px; border-radius: 10px; text-align: center;
    }
    table { width: 100%; border-collapse: collapse; margin-top: 20px; }
    th, td { border: 1px solid #ddd; padding: 8px; text-align: left; }
    th { background: #f5f5f5; }
  </style>
  <div class="header">
    <h1>Invoice #2024-001</h1>
  </div>
  <table>
    <tr><th>Item</th><th>Qty</th><th>Price</th></tr>
    <tr><td>Widget Pro</td><td>5</td><td>$49.99</td></tr>
    <tr><td>Gizmo Ultra</td><td>2</td><td>$129.99</td></tr>
  </table>
`);
fs.writeFileSync('invoice.pdf', pdf.buffer);
🌐 Website → PDF
Two methods depending on your needs:
// Standard capture — uses the document's own dimensions
const pdf = await smartPdf.getPdfResultForWebsite('https://example.com');
// Full-page capture — scrolls to bottom, captures everything as a single page
const fullPdf = await smartPdf.getFullWebsiteAsSinglePdf('https://example.com');
getPdfResultForWebsite uses a 1980×1200 viewport and respects the page's own width/height. 
getFullWebsiteAsSinglePdf uses a 1920px-wide viewport and measures the full scroll height, producing a single tall page.
🔀 Merge Multiple PDFs
Combine any number of PDF buffers into one document using 
pdf-lib:
const invoice = await smartPdf.readFileToPdfObject('./invoice.pdf');
const terms = await smartPdf.readFileToPdfObject('./terms.pdf');
const appendix = await smartPdf.getA4PdfResultForHtmlString('<h1>Appendix</h1>...');
const merged = await smartPdf.mergePdfs([
  invoice.buffer,
  terms.buffer,
  appendix.buffer,
]);
fs.writeFileSync('complete-package.pdf', merged);
📑 Read a PDF from Disk
const pdfObject = await smartPdf.readFileToPdfObject('./document.pdf');
console.log(pdfObject.name);   // "document.pdf"
console.log(pdfObject.buffer); // <Buffer ...>
📖 Extract Text
Pull raw text from any PDF buffer:
const text = await smartPdf.extractTextFromPdfBuffer(pdf.buffer);
console.log(text);
Uses pdf2json under the hood. Works best with text-based PDFs; scanned documents may return limited results.
🖼️ PDF → Image Conversion
Convert PDF pages to raster images using Puppeteer + PDF.js. Each page becomes a separate image buffer.
PNG — Lossless Quality
const pngPages = await smartPdf.convertPDFToPngBytes(pdf.buffer, {
  scale: SmartPdf.SCALE_HIGH, // 3.0 = ~216 DPI (default)
});
pngPages.forEach((png, i) => {
  fs.writeFileSync(`page-${i + 1}.png`, Buffer.from(png));
});
WebP — Modern & Efficient
25–60% smaller than PNG at similar visual quality:
const webpPages = await smartPdf.convertPDFToWebpBytes(pdf.buffer, {
  scale: 2.0,     // ~144 DPI
  quality: 90,    // 0–100 (default: 85)
});
JPEG — Progressive Loading
Generates true progressive JPEGs (multi-pass rendering) via sharp:
const jpegPages = await smartPdf.convertPDFToJpegBytes(pdf.buffer, {
  scale: SmartPdf.SCALE_HIGH,
  quality: 85,       // 0–100 (default: 85)
  maxWidth: 1920,    // optional dimension constraints
  maxHeight: 1080,
});
📏 DPI & Scale Reference
All image methods accept a 
scale parameter. PDF.js renders at 72 DPI by default, so 
scale is a multiplier:
Constant
Value
DPI
Use Case
SmartPdf.SCALE_SCREEN
2.0
~144
Web display, thumbnails
SmartPdf.SCALE_HIGH
3.0
~216
General purpose (default)
SmartPdf.SCALE_PRINT
6.0
~432
Print-quality output
Or calculate a custom scale:
const scale = SmartPdf.getScaleForDPI(300); // → 4.167
🖼️ Dimension Constraints
All image methods support 
maxWidth and 
maxHeight to cap output size while preserving aspect ratio:
// High-res render, but capped at 800×1000 px
const constrained = await smartPdf.convertPDFToWebpBytes(pdf.buffer, {
  scale: SmartPdf.SCALE_HIGH,
  quality: 90,
  maxWidth: 800,
  maxHeight: 1000,
});
📊 Format Comparison
Format
Typical Size vs PNG
Lossy?
Transparency
Progressive
Best For
PNG
baseline
No
✅
—
Screenshots, diagrams, text-heavy docs
WebP
40–75%
Yes
✅
—
Modern web apps, thumbnails
JPEG
50–70%
Yes
❌
✅
Photos, complex graphics, email
⚡ Parallel Processing
Process multiple URLs concurrently with separate instances:
const urls = [
  'https://example.com/page1',
  'https://example.com/page2',
  'https://example.com/page3',
];
// Spin up parallel instances
const instances = await Promise.all(
  urls.map(() => SmartPdf.create())
);
await Promise.all(instances.map(i => i.start()));
// Generate in parallel
const pdfs = await Promise.all(
  urls.map((url, i) => instances[i].getFullWebsiteAsSinglePdf(url))
);
// Merge all results
const merged = await instances[0].mergePdfs(pdfs.map(p => p.buffer));
fs.writeFileSync('all-pages.pdf', merged);
// Clean up
await Promise.all(instances.map(i => i.stop()));
📝 Full API Reference
SmartPdf Class
Static Properties
Property
Type
Value
Description
SCALE_SCREEN
number
2.0
~144 DPI scale factor
SCALE_HIGH
number
3.0
~216 DPI scale factor (default)
SCALE_PRINT
number
6.0
~432 DPI scale factor
Static Methods
Method
Returns
Description
create(options?)
Promise<SmartPdf>
Factory method to create an instance
getScaleForDPI(dpi)
number
Converts a DPI value to a scale factor (
dpi / 72)
Instance Properties
Property
Type
Description
serverPort
number
The port the internal HTTP server is listening on
Instance Methods
Method
Returns
Description
start(browser?)
Promise<void>
Starts internal server + browser. Optionally accepts an existing Puppeteer 
Browser.
stop()
Promise<void>
Shuts down server and browser (unless external browser was provided).
getA4PdfResultForHtmlString(html)
Promise<IPdf>
Renders HTML at 794×1122 viewport → A4 PDF
getPdfResultForWebsite(url)
Promise<IPdf>
Captures website at 1980×1200 viewport → PDF
getFullWebsiteAsSinglePdf(url)
Promise<IPdf>
Captures full scrollable page at 1920px wide → single-page PDF
mergePdfs(buffers)
Promise<Uint8Array>
Merges an array of PDF 
Uint8Array buffers
readFileToPdfObject(path)
Promise<IPdf>
Reads a PDF file from disk into an 
IPdf object
extractTextFromPdfBuffer(buffer)
Promise<string>
Extracts raw text from a PDF buffer
convertPDFToPngBytes(buffer, opts?)
Promise<Uint8Array[]>
Converts each PDF page to a PNG buffer
convertPDFToWebpBytes(buffer, opts?)
Promise<Uint8Array[]>
Converts each PDF page to a WebP buffer
convertPDFToJpegBytes(buffer, opts?)
Promise<Uint8Array[]>
Converts each PDF page to a progressive JPEG buffer
Image Conversion Options
{
  scale?: number;      // DPI multiplier (default: 3.0)
  quality?: number;    // 0–100, WebP/JPEG only (default: 85)
  maxWidth?: number;   // Max output width in pixels
  maxHeight?: number;  // Max output height in pixels
}
ISmartPdfOptions Interface
{
  port?: number;           // Use a specific port
  portRangeStart?: number; // Auto-allocation range start (default: 20000)
  portRangeEnd?: number;   // Auto-allocation range end (default: 30000)
}
License and Legal Information
This repository contains open-source code licensed under the MIT License. A copy of the license can be found in the LICENSE file.
Please note: The MIT License does not grant permission to use the trade names, trademarks, service marks, or product names of the project, except as required for reasonable and customary use in describing the origin of the work and reproducing the content of the NOTICE file.
Trademarks
This project is owned and maintained by Task Venture Capital GmbH. The names and logos associated with Task Venture Capital GmbH and any related products or services are trademarks of Task Venture Capital GmbH or third parties, and are not included within the scope of the MIT license granted herein.
Use of these trademarks must comply with Task Venture Capital GmbH's Trademark Guidelines or the guidelines of the respective third-party owners, and any usage must be approved in writing. Third-party trademarks used herein are the property of their respective owners and used only in a descriptive manner, e.g. for an implementation of an API or similar.
Company Information
Task Venture Capital GmbH
Registered at District Court Bremen HRB 35230 HB, Germany
For any legal inquiries or further information, please contact us via email at hello@task.vc.
By using this repository, you acknowledge that you have read this section, agree to comply with its terms, and understand that the licensing of the code does not imply endorsement by Task Venture Capital GmbH of any derivative works.