@plotdb/pageshot

pageshot

simple express server and APIs powered by puppeteer for following purpose:

• web page screenshot
• web page to pdf
• pdf merge

Security Note

Puppeteer runs headless browser which can access content within intranet, and thus might be vulnerable to SSRF exploit. To accept arbitrary user input, try running pageshot server in a container with proper network configuration.

Usage

install:

npm install --save @plotdb/pageshot

run api server:

npx pageshot -p <port>

this will start a screenshot server listening to specific port.

To take a screenshot, send a POST request to <domain>/api/screenshot with a payload in below format:

{ url: "url-to-screenshot"}

or

{ html: "code-to-render" }

For example:

payload = {url: "https://google.com"}
ld$.fetch "http://localhost:9010/api/", {method: \POST}, {json: payload}
  .then -> it.arrayBuffer!
  .then -> URL.createObjectURL(new Blob([new Uint8Array(it, 0, it.length)], {type: "image/png"}))
  .then (url) ->
    img = new Image!
    img.src = url

There are 3 api curently available:

• POST /api/screenshot - taking screenshot in png format.
• POST /api/print - taking screenshot in pdf format. input similar to /api/screenshot.
• POST /api/merge - merge multiple document into one pdf. payload format:
  • list: a list of documents to merge. Each is an object with following format:
    • html: html code to print and merge.
    • url: url for web page to print and merge. omitted when html is available
    • pdffile: file path for pdf file to merge.
    • pdflink: url for pdf file to merge.
      • note: pdffile and pdflink only work in nodeJS API when calling with trust-input set to true. see API.

API

@plotdb/pageshot also provides JS api for those http api counterpart. To use JS api, first init a pageshot page mananger:

require! <[pageshot]>
ss = new pageshot( opt )

options:

• count - size of page pool. default 4, max 20.

screenshot object API:

• init - initialize page manager. must be called before used.
• shot(payload) - take a screenshot, return Buffer of the image in PNG format.
• get - get a page handler. must free it after using. return an object as:
  • busy - is this page occupied
  • page - the page object. check puppeteer for more information. sample usage:
    • page.setContent "some html code", {waitUntil, "domcontentloaded"}
    • page.goto "some-url"
• free(obj) - free this page.
• print({url, html}): print specific document.
• screenshot({url, html}): screenshot specific document.
• merge(payload, trustInput): merge multiple document.
  • payload: as described in previous section.
  • trustInput: default false. when set to true, pdffile and pdflink options are enabled.

Sample usage:

lc = {}
ps = new pageshot!
ps.init!
  # take a screenshot of google.com through ps.screenshot API
  .then -> ps.screenshot url: "https://google.com"
  .then -> fs.write-file-sync "out.png", it

  # ... or, manually operate the page instance
  .then -> ps.get!
  .then (obj) ->
    lc.obj = obj
    # either one of following
    # obj.page.setContent html, {waitUntil: "domcontentloaded"}
    # obj.page.goto url
  .then -> lc.obj.page.screenshot!
  .then -> ps.free lc.obj

PDF Merge

PDF merging is provided by easy-pdf-merge, which in turn depends on related java package. Java is needed for using this functionality, and can be installed via following commands:

wget -qO - https://adoptopenjdk.jfrog.io/adoptopenjdk/api/gpg/key/public | sudo apt-key add -
sudo apt-get install software-properties-common
sudo add-apt-repository --yes https://adoptopenjdk.jfrog.io/adoptopenjdk/deb/
sudo apt-get update && sudo apt-get install adoptopenjdk-8-hotspot

Font

When generating documents with CJK characters, you may want to install related fonts in your system:

sudo apt-get fonts-noto-cjk

License

MIT