URL to PDF Microservice
Web page PDF rendering done right. Microservice for rendering receipts, invoices, or any content. Packaged to an easy API.
⚠️ WARNING ⚠️ Don't serve this API publicly to the internet unless you are aware of the
risks. It allows API users to run any JavaScript code inside a Chrome session on the server.
It's fairly easy to expose the contents of files on the server. You have been warned!. See https://github.com/alvarcarto/url-to-pdf-api/issues/12 for background.
⭐️ Features:
- Converts any URL or HTML content to a PDF file or an image (PNG/JPEG)
- Rendered with Headless Chrome, using Puppeteer. The PDFs should match to the ones generated with a desktop Chrome.
- Sensible defaults but everything is configurable.
- Single-page app (SPA) support. Waits until all network requests are finished before rendering.
- Easy deployment to Heroku. We love Lambda but...Deploy to Heroku button.
- Renders lazy loaded elements. (scrollPage option)
- Supports optional
x-api-keyauthentication. (API_TOKENSenv var)
Usage is as simple as https://url-to-pdf-api.herokuapp.com/api/render?url=http://google.com. There's also a POST /api/render if you prefer to send options in the body.
? Why?
This microservice is useful when you need to automatically produce PDF files
for whatever reason. The files could be receipts, weekly reports, invoices,
or any content.
PDFs can be generated in many ways, but one of them is to convert HTML+CSS
content to a PDF. This API does just that.
? Shortcuts:
How it works
Local setup is identical except Express API is running on your machine
and requests are direct connections to it.
Good to know
-
By default, page's
@media printCSS rules are ignored. We set Chrome to emulate@media screento make the default PDFs look more like actual sites. To get results closer to desktop Chrome, add&emulateScreenMedia=falsequery parameter. See more at Puppeteer API docs. -
Chrome is launched with
--no-sandbox --disable-setuid-sandboxflags to fix usage in Heroku. See this issue. -
Heavy pages may cause Chrome to crash if the server doesn't have enough RAM.
-
Docker image for this can be found here: https://github.com/restorecommerce/pdf-rendering-srv
Examples
Note: the demo Heroku app runs on a free dyno which sleep after idle.
A request to sleeping dyno may take even 30 seconds.
The most minimal example, render google.com
https://url-to-pdf-api.herokuapp.com/api/render?url=http://google.com
The most minimal example, render google.com as PNG image
https://url-to-pdf-api.herokuapp.com/api/render?output=screenshot&url=http://google.com
Use the default @media print instead of @media screen.
https://url-to-pdf-api.herokuapp.com/api/render?url=http://google.com&emulateScreenMedia=false
Use scrollPage=true which tries to reveal all lazy loaded elements. Not perfect but better than without.
Render only the first page.
Render A5-sized PDF in landscape.
Add 2cm margins to the PDF.
Wait for extra 1000ms before render.
https://url-to-pdf-api.herokuapp.com/api/render?url=http://google.com&waitFor=1000
Download the PDF with a given attachment name
https://url-to-pdf-api.herokuapp.com/api/render?url=http://google.com&attachmentName=google.pdf
Wait for an element matching the selector input appears.
https://url-to-pdf-api.herokuapp.com/api/render?url=http://google.com&waitFor=input
Render HTML sent in JSON body
curl -o html.pdf -XPOST -d'{"html": "<body>test</body>"}' -H"content-type: application/json" https://url-to-pdf-api.herokuapp.com/api/render
Render HTML sent as text body
curl -o html.pdf -XPOST -d@page.html -H"content-type: text/html" https://url-to-pdf-api.herokuapp.com/api/render
API
To understand the API options, it's useful to know how Puppeteer
is internally used by this API. The render code
is quite simple, check it out. Render flow:
-
page.setViewport(options)where options matchesviewport.*. -
Possibly
page.emulateMedia('screen')ifemulateScreenMedia=trueis set. -
Render url or html.
If
urlis defined,page.goto(url, options)is called and options matchgoto.*.
Otherwisepage.setContent(html, options)is called where html is taken from request body, and options matchgoto.*. -
Possibly
page.waitFor(numOrStr)if e.g.waitFor=1000is set. -
Possibly Scroll the whole page to the end before rendering if e.g.
scrollPage=trueis set.Useful if you want to render a page which lazy loads elements.
-
Render the output
- If output is
pdfrendering is done withpage.pdf(options)where options matchespdf.*. - Else if output is
screenshotrendering is done withpage.screenshot(options)where options matchesscreenshot.*.
GET /api/render
All options are passed as query parameters.
Parameter names match Puppeteer options.
These options are exactly the same as its POST counterpart, but options are
expressed with the dot notation. E.g. ?pdf.scale=2 instead of { pdf: { scale: 2 }}.
The only required parameter is url.
Parameter, Type, Default, Description
----------, ------, ---------, ------------
url, string, -, URL to render as PDF. (required)
output, string, pdf, Specify the output format. Possible values: pdf or screenshot.
emulateScreenMedia, boolean, true, Emulates @media screen when rendering the PDF.
ignoreHttpsErrors, boolean, false, Ignores possible HTTPS errors when navigating to a page.
scrollPage, boolean, false, Scroll page down before rendering to trigger lazy loading elements.
waitFor, number or string, -, Number in ms to wait before render or selector element to wait before render.
attachmentName, string, -, When set, the content-disposition headers are set and browser will download the PDF instead of showing inline. The given string will be used as the name for the file.
viewport.width, number, 1600, Viewport width.
viewport.height, number, 1200, Viewport height.
viewport.deviceScaleFactor, number, 1, Device scale factor (could be thought of as dpr).
viewport.isMobile, boolean, false, Whether the meta viewport tag is taken into account.
viewport.hasTouch, boolean, false, Specifies if viewport supports touch events.
viewport.isLandscape, boolean, false, Specifies if viewport is in landscape mode.
cookies[0][name], string, -, Cookie name (required)
cookies[0][value], string, -, Cookie value (required)
cookies[0][url], string, -, Cookie url
cookies[0][domain], string, -, Cookie domain
cookies[0][path], string, -, Cookie path
cookies[0][expires], number, -, Cookie expiry in unix time
cookies[0][httpOnly], boolean, -, Cookie httpOnly
cookies[0][secure], boolean, -, Cookie secure
cookies[0][sameSite], string, -, Strict or Lax
goto.timeout, number, 30000, Maximum navigation time in milliseconds, defaults to 30 seconds, pass 0 to disable timeout.
goto.waitUntil, string, networkidle, When to consider navigation succeeded. Options: load, networkidle. load = consider navigation to be finished when the load event is fired. networkidle = consider navigation to be finished when the network activity stays "idle" for at least goto.networkIdleTimeout ms.
goto.networkIdleInflight, number, 2, Maximum amount of inflight requests which are considered "idle". Takes effect only with goto.waitUntil: 'networkidle' parameter.
goto.networkIdleTimeout, number, 2000, A timeout to wait before completing navigation. Takes effect only with waitUntil: 'networkidle' parameter.
pdf.scale, number, 1, Scale of the webpage rendering.
pdf.printBackground, boolean, false, Print background graphics.
pdf.displayHeaderFooter, boolean, false, Display header and footer.
pdf.headerTemplate, string, -, HTML template to use as the header of each page in the PDF. Currently Puppeteer basically only supports a single line of text and you must use pdf.margins+CSS to make the header appear! See https://github.com/alvarcarto/url-to-pdf-api/issues/77.
pdf.footerTemplate, string, -, HTML template to use as the footer of each page in the PDF. Currently Puppeteer basically only supports a single line of text and you must use pdf.margins+CSS to make the footer appear! See https://github.com/alvarcarto/url-to-pdf-api/issues/77.
pdf.landscape, boolean, false, Paper orientation.
pdf.pageRanges, string, -, Paper ranges to print, e.g., '1-5, 8, 11-13'. Defaults to the empty string, which means print all pages.
pdf.format, string, A4, Paper format. If set, takes priority over width or height options.
pdf.width, string, -, Paper width, accepts values labeled with units.
pdf.height, string, -, Paper height, accepts values labeled with units.
pdf.margin.top, string, -, Top margin, accepts values labeled with units.
pdf.margin.right, string, -, Right margin, accepts values labeled with units.
pdf.margin.bottom, string, -, Bottom margin, accepts values labeled with units.
pdf.margin.left, string, -, Left margin, accepts values labeled with units.
screenshot.fullPage, boolean, true, When true, takes a screenshot of the full scrollable page.
screenshot.type, string, png, Screenshot image type. Possible values: png, jpeg
screenshot.quality, number, -, The quality of the JPEG image, between 0-100. Only applies when screenshot.type is jpeg.
screenshot.omitBackground, boolean, false, Hides default white background and allows capturing screenshots with transparency.
screenshot.clip.x, number, -, Specifies x-coordinate of top-left corner of clipping region of the page.
screenshot.clip.y, number, -, Specifies y-coordinate of top-left corner of clipping region of the page.
screenshot.clip.width, number, -, Specifies width of clipping region of the page.
screenshot.clip.height, number, -, Specifies height of clipping region of the page.
Example:
curl -o google.pdf https://url-to-pdf-api.herokuapp.com/api/render?url=http://google.com
POST /api/render - (JSON)
All options are passed in a JSON body object.
Parameter names match Puppeteer options.
These options are exactly the same as its GET counterpart.
Body
The only required parameter is url.
{
// Url to render. Either url or html is required
url: "https://google.com",
// Either "pdf" or "screenshot"
output: "pdf",
// HTML content to render. Either url or html is required
html: "<html><head></head><body>Your content</body></html>",
// If we should emulate @media screen instead of print
emulateScreenMedia: true,
// If we should ignore HTTPS errors
ignoreHttpsErrors: false,
// If true, page is scrolled to the end before rendering
// Note: this makes rendering a bit slower
scrollPage: false,
// Passed to Puppeteer page.waitFor()
waitFor: null,
// Passsed to Puppeteer page.setCookies()
cookies: [{ ... }]
// Passed to Puppeteer page.setViewport()
viewport: { ... },
// Passed to Puppeteer page.goto() as the second argument after url
goto: { ... },
// Passed to Puppeteer page.pdf()
pdf: { ... },
// Passed to Puppeteer page.screenshot()
screenshot: { ... },
}
Example:
curl -o google.pdf -XPOST -d'{"url": "http://google.com"}' -H"content-type: application/json" https://url-to-pdf-api.herokuapp.com/api/render
curl -o html.pdf -XPOST -d'{"html": "<body>test</body>"}' -H"content-type: application/json" https://url-to-pdf-api.herokuapp.com/api/render
POST /api/render - (HTML)
HTML to render is sent in body. All options are passed in query parameters.
Supports exactly the same query parameters as GET /api/render, except url
paremeter.
Remember that relative links do not work.
Example:
curl -o receipt.html https://rawgit.com/wildbit/postmark-templates/master/templates_inlined/receipt.html
curl -o html.pdf -XPOST -d@receipt.html -H"content-type: text/html" https://url-to-pdf-api.herokuapp.com/api/render?pdf.scale=1
Development
To get this thing running, you have two options: run it in Heroku, or locally.
The code requires Node 8+ (async, await).
1. Heroku deployment
Scroll this readme up to the Deploy to Heroku -button. Click it and follow
instructions.
WARNING: Heroku dynos have a very low amount of RAM. Rendering heavy pages
may cause Chrome instance to crash inside Heroku dyno. 512MB should be
enough for most real-life use cases such as receipts. Some news sites may need
even 2GB of RAM.
2. Local development
First, clone the repository and cd into it.
-
cp .env.sample .env -
Fill in the blanks in
.env -
npm install -
npm startStart express server locally -
Server runs at http://localhost:9000 or what
$PORTenv defines
Techstack
- Node 8+ (async, await), written in ES7
- Express.js app with a nice internal architecture, based on these conventions.
- Hapi-style Joi validation with express-validation
- Heroku + Puppeteer buildpack
- Puppeteer to control Chrome
