express-dom-pdf
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PDF plugin for express-dom
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Markdown
PDF plugin for express-dom
Optionally converts pdf using ghostscript with presets.
See express-dom documentation about how web pages are prerendered.
```js
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:
```js
// 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](https://www.ghostscript.com/doc/current/VectorDevices.htm)
Ghostscript can produce a pdf/x-3 using this kind of preset:
```js
pdf.presets.fogra39l = {
quality: 'printer',
devicePixelRatio: 4,
pdfx: true,
icc: 'ISOcoated_v2_300_eci.icc',
condition: 'FOGRA39L',
others: [ "-dColorImageResolution=600" ]
};
```
[](https://www.pdflib.com/pdf-knowledge-base/pdfx-output-intents/).
For pdf/a-2 output, a icc profile may be specified.
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)
- iccdir: dir path for the icc profiles (on Debian, install `icc-profiles` to get some common profiles in `/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)
- devicePixelRatio: changes value of window.devicePixelRatio
- compatibilityLevel: "1.3", "1.5", "1.7"
- format: "a4", "a3", "letter", ...
- browser: which browser to use, see express-dom browser option
- pdfa: boolean
- pdfx: boolean
- icc: profile path relative to iccdir (for pdfa, pdfx)
defaults to `ghostscript/default_cmyk.icc`
- condition: output condition identifier (for pdfa, pdfx, can be left empty)
See [Registered CMYK characterization data sets](https://www.color.org/chardata/drsection1.xalter).
- others: additional gs arguments, see [ghostscript](https://ghostscript.readthedocs.io/en/latest/VectorDevices.html).
- pageCount: boolean, sets X-Page-Count HTTP response header.
defaults to true for printer preset.
## Styling
A minimal stylesheet:
```css
@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.