PDF plugin for express-dom
Optionally converts pdf using ghostscript with presets.
See express-dom documentation about how web pages are prerendered.
const dom = require('express-dom');
const pdf = require('express-dom-pdf');
const express = require('express');
const app = express();
// unconditionally outputs a pdf
app.get('*.html', dom(pdf({
presets: {
// merged with pdf.presets
},
policies: {
// merged with pdf.policies
}
plugins: ['custom'] // these plugins are added before 'pdf' plugin
})).route((phase, req, res) => {
if (phase.visible) {
phase.settings.pdf(req.query.pdf);
// no need to keep the parameter during prerendering
phase.location.searchParams.delete('pdf');
} else {
res.set('Content-Security-Policy', "default 'self' data:");
}
}), express.static('public/'));It is also possible to get a response stream directly without express, in scenarios where pdf generation takes a long time:
// res: { statusCode, headers } is a passthrough stream
const res = dom(pdf(opts))({
url: 'http://localhost/custom.html',
body: '<html>...</html>'
});Depends on the value of the phase.settings.preset parameter.
If not set, the "default" preset is used.
If a preset is unknown, an error with error.statusCode of 400 is thrown.
- default: the pdf as produced by browser (without ghostscript conversion)
- screen, ebook, printer, prepress: See ghostscript pdf outputs
Ghostscript can produce a pdf/x-3 using this kind of preset:
pdf.presets.fogra39l = {
quality: 'printer',
scale: 4,
icc: 'ISOcoated_v2_300_eci.icc',
condition: 'FOGRA39L',
others: [ "-dColorImageResolution=600" ]
};See also pdflib documentation.
These settings can be changed globally, or for each instance.
- timeout: max time to wait for page load to finish (default 30000)
- parallel: number of parts to process pdf in parallel (default 1, experimental)
- pdfx: file path for the pdfx postscript template
- iccdir: dir path for the icc profiles (icc-profiles debian package installs /usr/share/color/icc)
- presets: map of presets
- plugins: load these dom plugins before media and pdf plugins
- policies: the csp for express-dom online phase
Presets accept these options:
- quality: false (boolean) or screen|ebook|prepress|printer (string)
- scale: device scale factor, changes value of window.devicePixelRatio
- icc: relative file path found in iccdir (required for pdf/x-3)
- condition: output condition identifier (required for pdf/x-3)
- others: additional gs arguments, see ghostscript.
- pageCount: boolean, sets X-Page-Count HTTP response header. defaults to true for printer preset.
A minimal stylesheet:
@media only print {
@page {
size: 210mm 297mm;
margin:1cm;
}
html, body {
padding: 0;
margin: 0;
}
body > .page {
page-break-inside: avoid;
page-break-after: always;
}
}Sample code of how to break pages at the DOM level, before printing, is available in test/public/autobreak.html (to actually see the result, just serve test/public and open autobreak.html).
This is more powerful than print breaks, because it allows one to style the resulting layout.
On Debian, install "fonts-recommended" package.
System fonts rendering can have some bugs, especially regarding emojis or color fonts.