Scrape facebook group post permalinks

...with puppeteer and MutationObserver

This is a one (now three) night hack that I used to scrape 8K+ permalink ids from a secret facebook group we use to share photos with family. It became an annoyance that there was no way to search posts by date and manually scrolling back over 2-3 years is not an option.

UPDATE: this is much easier via the Graph API

See api.js that I'm yet to document here but pretty straightforward. You just need the numeric group id and an access token. (See also Graph API Explorer here)

The API also supports specifying date ranges as UNIX timestamps (e.g. ?since=1420070400&until=1430070400) so there's no need to paginate through the whole feed to get to dates years ago.

Requirements

• MacOS
• Google Chrome installed (and logged in to facebook)
• PUPPETEER_SKIP_CHROMIUM_DOWNLOAD=true yarn

PUPPETEER_SKIP_CHROMIUM_DOWNLOAD to skip downloading Chromium since we'll use your default Chrome anyway

Usage

1. Quit Google Chrome (if you have it running)

• This is required to start a new Chrome instance with remote debugging enabled to allow Puppeteer to connect to it.
• This Chrome instance will use your default profile that's assumed to be logged in to facebook.

2. Start the script

node index.js <groupid> | tee permalinks.csv

• Output is simply CSV: <ISO date>, <facebook post URL> (one per line).
• ...that post from 2014 is available to you again if you were patient enough.

How

This script:

• starts up Chrome with your default profile (and remote debugging enabled)
• connects to Chrome with Puppeteer
• goes to your facebook group page
• registers a MutationObserver and starts scrolling
• for each node (post) added tries to grab the permalink id

Caveats

• it's just a one (OK, now three) night hack, quality is like that :D
• permalinks for posts on the first page are not captured