Facebook Groups — Scrape Posts

Input: Facebook group URL + sort order + desired count → Output: post list with full metadata (JSON).

Language

Objective

Prerequisites

• Target group page is already open in the browser: https://www.facebook.com/groups/{group_slug_or_id}
• Already logged into Facebook (user avatar, Messenger icon, and notification bell visible in the top-right corner)

Pre-execution Checks

1. Tool Readiness

2. Login Verification

browser-act navigate 'https://www.facebook.com/'
browser-act wait stable --timeout 15000
browser-act eval "JSON.stringify({user_id: document.cookie.match(/c_user=(\d+)/)?.[1] || '0', USER_ID: (()=>{try{return require('CurrentUserInitialData').USER_ID;}catch(e){return '0';}})()})"

• user_id is a non-empty numeric string (e.g., "61560817072276"), or USER_ID !== "0" → logged in, continue
• user_id === null or USER_ID === "0" → not logged in; assist user: run browser-act browser open {browser_id} https://www.facebook.com/login --headed to open a headed window so the user can sign in manually (Stealth normal mode persists cookies — one login is reusable)

Capability Components

This Skill's operational boundary = what the user can manually do in their browser. It only reads data already displayed to the authenticated user, never bypassing authentication or access controls — equivalent to copy-pasting on the user's behalf. JS code is encapsulated in Python files under the scripts/ directory, invoked via eval "$(python scripts/xxx.py {params})". $(...) is bash syntax; use the bash tool for execution.

API: Scrape group posts (with auto-pagination)

browser-act navigate 'https://www.facebook.com/groups/{group_slug_or_id}'
browser-act wait stable --timeout 20000
browser-act eval "$(python scripts/scrape-posts.py --sort CHRONOLOGICAL --count 20)"

• --sort: Sort order, default CHRONOLOGICAL. See "Enum Parameters" below
• --count: Desired number of posts, default 20. Script auto-paginates until count is met or feed is exhausted
• --max-pages: Pagination safety cap, default 100
• --doc-id: GraphQL persisted query doc_id for GroupsCometFeedRegularStoriesPaginationQuery, default 26577462205242925. Update via this flag if Facebook rotates the version (see "Known Limitations")

{
  "ok": true,
  "group_id": "2580640642080467",
  "group_name": "Programmer Humor",
  "sort": "CHRONOLOGICAL",
  "total": 20,
  "posts": [
    {
      "post_id": "4052937798184070",
      "cache_id": "6790541484885792441",
      "id": "UzpfSTEwMDA4ODY4MzIx...",
      "permalink_url": "https://www.facebook.com/groups/programmerhumor/posts/4052937798184070/",
      "creation_time": 1772941518,
      "message": "Those were the days my friend ...",
      "author": {
        "id": "100088683215191",
        "name": "Jeff Bramlett",
        "profile_picture": null,
        "url": "https://www.facebook.com/JeffieB56"
      },
      "group": {
        "id": "2580640642080467",
        "name": "Programmer Humor",
        "url": "https://www.facebook.com/groups/programmerhumor/"
      },
      "reactions": {
        "total": 1,
        "total_formatted": "1",
        "breakdown": [
          { "name": "Haha", "reaction_id": "115940658764963", "count": 1 }
        ]
      },
      "share_count": 0,
      "share_count_formatted": "0",
      "comment_count": 0,
      "media": [
        {
          "__typename": "Photo",
          "id": "938454962453936",
          "photo_image": "https://scontent-...fbcdn.net/v/t39...jpg"
        }
      ]
    }
  ],
  "diagnostics": {
    "pages": [
      { "pageIdx": 0, "httpStatus": 200, "edgeCount": 4, "err": null, "hasNext": true }
    ]
  }
}

Enum Parameters

• TOP_POSTS — most relevant (default web sort)
• CHRONOLOGICAL — newest first (reverse chronological by post time)
• RECENT_ACTIVITY — most recently active (reverse chronological by latest comment/reaction time)

Pagination

• Pagination parameter: cursor (embedded in GraphQL variables)
• Type: opaque cursor (server-side state, base64-encoded)
• Initial value: null (first request)
• Next page value: data.node.group_feed.page_info.end_cursor
• Each response returns 3 edges (FB streaming mode ignores client-provided count)
• Termination: has_next_page === false, or --count / --max-pages limit reached

Success Criteria

• ok === true and total >= 1
• posts[*].post_id non-null rate = 100% (non-post units such as Section Headers are filtered out by the script)
• posts[*].permalink_url and posts[*].creation_time non-null rate = 100%
• When using CHRONOLOGICAL sort, creation_time is strictly monotonically decreasing

Known Limitations

• Public groups only: private groups require membership; returns empty or permission error when not a member
• No comment body: comment_count returns total count but the group feed GraphQL does not include top_comments content or authors. Facebook places comment data in a separate CommentsRenderer query triggered only when the user clicks "Comments" — fetching comment bodies requires additional per-post_id GraphQL requests (out of scope)
• doc_id rotates with Facebook frontend versions: when the default 26577462205242925 expires (PersistedQueryNotFound or HTTP 404), retrieve a fresh one:
  1. Open any group page while logged in
  2. Scroll down to trigger a new batch of posts
  3. browser-act network requests --filter api/graphql --method POST
  4. Check X-FB-Friendly-Name header on each request; find GroupsCometFeedRegularStoriesPaginationQuery
  5. Extract doc_id from that request's POST body and pass it via --doc-id
• group_name can be null: parsed from page HTML via heuristic regex; prefer posts[*].group.name (more reliable)
• Localized count fields: reactions.total_formatted and share_count_formatted format depends on Facebook's UI language (e.g., non-English Facebook UI may return locale-specific number abbreviations instead of "12K")
• Rapid requests trigger temporary throttling: paginating too fast or calling multiple groups concurrently may return empty responses or temporary bans. Serialize group requests with a 2–5 s sleep between each
• GraphQL field_exception / partial edges + errors: almost always caused by session cookie being cleared. Check c_user cookie and require('CurrentUserInitialData').USER_ID — if 0 / null, return to "Login Verification" and re-login; do not attempt to extract data from error responses
• Author avatar often null: author.profile_picture is frequently unloaded in the group feed default response (Facebook lazy-loads avatars); a separate query is required if avatars are needed

Execution Efficiency

• Batch orchestration: for small counts, call each group directly; for large counts, write a bash script to loop serially — do not parallelize (prone to anti-scraping triggers). Test with a minimal sample before running the full batch. Add appropriate intervals per rate guidance in "Known Limitations" above
• Test before batch execution: always test with 1–2 items to verify the script runs correctly before running the full batch
• Reduce redundant pre-operations: when multiple steps share the same prerequisite state, complete them in batch under that state to avoid repeatedly re-establishing it
• Error resumption: save results item by item during batch processing; resume from the breakpoint on failure rather than starting over

Experience Notes