remote-pdf-printer

Converts a URL or HTML into PDF via Headless Google Chrome instance

End Points

PDF

• /pdf [POST]
• /pdf/:file [GET]
• /preview [POST]
• /preview/:file [GET]
• /png [POST]
• /png/:file [GET]

All endpoints accepting a POST request can handle json, form-data and xml request formats.

/pdf and /preview

Both these endpoints convert the requested page(s) or url(s) to PDFs. The /preview endpoint returns an image per page, and /pdf returns the actual pdf.

Request Options

{
    "data": [...], // array of strings, submit HTML this way though nothing stops you from submitting an external URL
    "url": [...], // array of urls
    "download": boolean, // default false - return the file directly if true
    "header": string, // header content - if set marginTop is required
    "footer": string, // footer content - if set marginBottom is required
    "marginTop": float,
    "marginBottom": float,
    "marginLeft": float,
    "marginRight": float,
    "paperSize": [float,float] // [width,height]
}

/pdf

When download is set to false the return value is json

{
    "components": [
        "http://localhost:8080/pdfs/0-793062911.pdf",
        "http://localhost:8080/pdfs/1-1442655579.pdf"
    ],
    "pdf": "2844005942-combined.pdf",
    "url": "http://localhost:8080/pdfs/2844005942-combined.pdf"
}

/preview

The return value

{
    "basename": "2378371505-combined",
    "images": [
        "http://localhost:8080/preview/2378371505-combined-1.jpg",
        "http://localhost:8080/preview/2378371505-combined-2.jpg"
    ],
    "pages": 2,
    "success": true
}

/png

If none of x,y,width,height are provided the screenshot will be of the entire page

{
    "data": '', // HTML or a URL
    "download": boolean, // default false - return the file directly if true
    "x": float, // Default 0, the x coordinate for the area being screenshot
    "y": float, // Default 0, the y coordinate for the area being screenshot
    "width": float, // Default 1024 if any x, y or height are provided and this is left empty
    "height": float, // Default 150 if any x, y or width are provided and this is left empty
    "scale": float, // Default 1 if any x, y, width or height are provided and this is left empty
}

The response

{
    "png": "2363534771.png",
    "url": "http://localhost:8080/png/2363534771.png"
}

Service Configuration

There are a number of environment variables that can be set to control the service

Environment Variable	Default Value
REMOTE_PDF_ROOT_DIRECTORY	$CWD
REMOTE_PDF_DEBUG_HEADER_STYLE_TEMPLATE	css/default-header.css.txt
REMOTE_PDF_PORT	3000
REMOTE_PDF_LISTEN	127.0.0.1
REMOTE_PDF_CHROME_URI	127.0.0.1:1337
REMOTE_PDF_TLS_ENABLE	true
REMOTE_PDF_TLS_CERT_DIR	$CWD/certs
REMOTE_PDF_TLS_CERT_PATH	nil - required if TLS is true
REMOTE_PDF_TLS_KEY_PATH	nil - required if TLS is true
REMOTE_PDF_LOG_PATH	/var/log
REMOTE_PDF_DEBUG	false
REMOTE_PDF_DEBUG_SOURCES	false - if true save the submitted data

Docker Container

A Dockerfile is provided that builds a container to use.

Running podman build . -t localhost/remote-pdf-printer:latest will build and tag the container

It is ideal to use a storage volume for the files

To run it with a local chrome instance

You'll need a headless chrome instance running and listening on port 1337

podman run -name remote-pdf-printer -e REMOTE_PDF_LISTEN=0.0.0.0 -e REMOTE_PDF_CHROME_URI="host.containers.internal:1337" -e REMOTE_PDF_TLS_ENABLE=false -p 8080:3000 -v ./files:/app/files:z localhost/remote-pdf-printer:latest

Will start the container

Chrome Headless

The remote PDF service depends on a headless chrome instance. A dockerfile is provided in the chrome-headless directory that is known to work

podman build chrome-headless/ -t localhost/chromium-headless:testing will build it. If you require additional repos or packages you can pass additional build args. The defaults are

APP_DNF_PACKAGES="chromium-headless socat"
APP_DNF_REPOS=""

Chromedp Examples

Run git clone https://github.com/chromedp/examples.git chromedp-examples to checkout samples on how to use the go chrome remote protocol. The directory chromedp-examples is ignored by git.