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Goodbye F12: session-capture — One Command to Grab Any Website's Auth Session

#opensource #python #ai

Goodbye F12: session-capture — One Command to Grab Any Website's Auth Session

Tired of F12 → Application → Cookies → copy-paste-repeat? This open-source CLI tool captures your entire auth session — cookies, localStorage, CSRF tokens, and request headers — in a single command.

The Pain Every Developer Knows

Writing a scraper or automation script? You know the drill:

  1. Open DevTools (F12)
  2. Application tab → Cookies → find session_id
  3. Application tab → Local Storage → find token
  4. Network tab → dig through headers for x-csrf-token
  5. Copy referer, user-agent...
  6. Format, paste into .env, pray you didn't miss anything

Five platforms = repeat five times. Cookie expires = repeat everything.

Existing tools don't help much:

Tool Cookies localStorage CSRF Headers CLI pipe Persistent
session-capture ✅ ✅ ✅ ✅ ✅ ✅
EditThisCookie ✅ ❌ ❌ ❌ ❌ ❌
browser_cookie3 ✅ ❌ ❌ ❌ ✅ ❌
Manual DevTools ✅ Separate Separate Separate ❌ ❌

The real killer: many platforms (CSDN, Xiaohongshu, SegmentFault) need x-csrf-token, x-requested-with, and referer headers on top of cookies. Cookie-only tools are useless there.

session-capture: Full Auth Session, One Command

session-capture is an open-source CLI tool + Chrome extension that captures the entire authentication session state — everything a backend needs to authenticate a request.

pip install session-capture
playwright install chromium   # one-time setup

capture capture https://dev.to
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Here's what happens:

  1. A real browser window opens to dev.to
  2. You log in manually (secure — your password never touches the tool)
  3. Press Enter in your terminal
  4. Full session data captured: 
{
  "cookies": [
    {"name": "session_id", "value": "abc123", "domain": ".dev.to"}
  ],
  "localStorage": {
    "token": "eyJhbG...",
    "refresh": "xyz789"
  },
  "meta_csrf_token": "abc123def456",
  "headers": {
    "x-requested-with": "XMLHttpRequest",
    "referer": "https://dev.to/settings",
    "user-agent": "Mozilla/5.0 ..."
  }
}
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No more clicking through 4 DevTools tabs. One command, everything at once.

Four Output Formats for Every Workflow 

# JSON — for programmatic use
capture capture https://dev.to

# Env — pipe straight to .env
capture capture https://dev.to --format env >> .env
# DEV_COOKIE="session_id=abc123;csrf=xyz"
# DEV_HEADERS="x-csrf-token:abc\nx-requested-with:XMLHttpRequest"
# DEV_LOCALSTORAGE='{"token":"abc"}'
# DEV_CSRF_TOKEN=abc123

# Netscape — for curl/wget
capture capture https://httpbin.org --format netscape > cookies.txt
curl -b cookies.txt https://httpbin.org/cookies

# Curl — single-line header
capture capture https://example.com --format curl
# → Cookie: name=value; name2=value2
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Persistent Sessions: Login Once, Reuse Forever

This is where session-capture really shines. Every capture capture saves Playwright's storage_state — the full browser context including cookies, localStorage, sessionStorage, and IndexedDB.

Later:

# List saved sessions
capture list
# ┌──────────┬──────────────────────────────────────────────┐
# │ Name     │ Storage Path                                 │
# ├──────────┼──────────────────────────────────────────────┤
# │ dev_to   │ ~/.session-capture/sessions/dev_to           │
# │ juejin_cn│ ~/.session-capture/sessions/juejin_cn        │
# └──────────┴──────────────────────────────────────────────┘

# Refresh without re-login
capture refresh dev_to --format env >> .env
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Cookie expired? Just re-run refresh — your login state is still intact.

Chrome Extension Included

A companion Chrome extension is also available (pending Chrome Web Store review, can be loaded in dev mode):

  • One-click export: cookies + localStorage + CSRF tokens from the current tab
  • Format switching: JSON / Env / Netscape / Curl
  • Copy to clipboard or download as file

Tech Stack

Component Tech Why
CLI Typer + Rich Modern Python CLI, type-safe, beautiful output
Browser Playwright Context persistence, multi-engine (Chromium/Firefox)
Config TOML Human-readable, stdlib tomllib — zero extra deps
Extension Chrome Manifest V3 Web Store requirement
Testing pytest 49 tests, 90% coverage

Key design decisions:

  • Headed browser, manual login — no touching encrypted cookie files, no fragile browser_cookie3 hacks. You log in. Secure.
  • capture_session() as Python API — importable by other projects. No subprocess, no pipe parsing. agentcrew-mcn integrates it this way.
  • Single repo, dual component — CLI (Python) + extension (JS/HTML), zero coupling, CI with path filters.
  • Cross-platform — macOS, Windows, Linux. Chromium and Firefox engines.

Comparison

Feature session-capture EditThisCookie browser_cookie3
CLI pipe output ✅ ❌ ✅
Full session (cookies + localStorage + CSRF + headers) ✅ ❌ ❌
Persistent sessions ✅ ❌ ❌
Multi-format (JSON / env / Netscape / curl) ✅ JSON only Custom
Cross-platform ✅ ✅ ❌ (fragile)
Chrome extension ✅ ✅ ❌
No local cookie files ✅ N/A ❌
Python API (direct import) ✅ ❌ ❌
CI tested (49 tests) ✅ ❌ ❌

Install & Links 

pip install session-capture
# or with pipx:
pipx install session-capture

playwright install chromium
capture capture https://dev.to
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MIT license. Stars, issues, and PRs welcome.

If you've ever cursed at F12 → Application → Cookies, try capture capture.

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