Module: ChromeAuth

Defined in:
lib/ChromeAuth.rb

Overview

Drive a visible Chrome (via ferrum / CDP) to let the user sign into Medium in a real browser, then read sid/uid/cf_clearance/_cfuvid back out of the session. Used both for first-time setup (no cookies on disk) and as the Cloudflare-block recovery flow (cf_clearance refresh).

“Headless” in the user’s spec is a misnomer — login is interactive, so we launch with headless:false and rely on the user to complete the login in the visible window before pressing Enter.

Constant Summary collapse

TARGET_COOKIES = 
%w[sid uid cf_clearance _cfuvid].freeze
LOGIN_URL = 
'https://medium.com/m/signin'.freeze
REFRESH_URL = 
'https://medium.com'.freeze
@@session = 
nil

Class Method Summary collapse

Class Method Details

.available? ⇒ Boolean

True iff ferrum loads AND a Chrome binary is detectable. Anything else returns false so the caller can fall back to the legacy default-browser flow without aborting.

Returns:

  • (Boolean) 


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# File 'lib/ChromeAuth.rb', line 23

def available?
    require 'ferrum'
    path = Ferrum::Browser::Options::Chrome.options.detect_path
    !path.nil? && !path.empty?
rescue LoadError, StandardError
    false
end

.buildBrowser ⇒ Object

Factory split out so tests can stub it. Tweaking ferrum options globally (window size, timeouts) belongs here too.



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# File 'lib/ChromeAuth.rb', line 110

def buildBrowser
    require 'ferrum'
    Ferrum::Browser.new(
        headless: false,
        window_size: [1280, 900],
        timeout: 60,
        process_timeout: 30
    )
end

.cancelSession! ⇒ Object 



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# File 'lib/ChromeAuth.rb', line 92

def cancelSession!
    return false unless sessionActive?
    browser = @@session[:browser]
    @@session = nil
    begin
        browser&.quit
    rescue StandardError
        # ignore: best-effort shutdown
    end
    true
end

.collectMediumCookies(browser) ⇒ Object

Filter the browser’s cookie jar down to medium.com cookies whose name is one of TARGET_COOKIES. We accept both .medium.com and medium.com because Cloudflare sets _cfuvid on the apex while Medium tends to set sid/uid on the dot-prefixed domain.



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# File 'lib/ChromeAuth.rb', line 124

def collectMediumCookies(browser)
    result = {}
    browser.cookies.each do |cookie|
        next unless TARGET_COOKIES.include?(cookie.name)
        next unless mediumDomain?(cookie.domain)
        result[cookie.name] = cookie.value
    end
    result
rescue StandardError
    {}
end

.finishSession! ⇒ Object 



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# File 'lib/ChromeAuth.rb', line 82

def finishSession!
    raise 'No active ChromeAuth session — call startSession! first.' unless sessionActive?
    browser = @@session[:browser]
    cookies = collectMediumCookies(browser)
    CookieCache.save(CookieCache.load.merge(cookies)) if cookies.any?
    cookies
ensure
    cancelSession!
end

.login!(errput: $stderr, input: $stdin, openURL: LOGIN_URL) ⇒ Object

—- Single-shot CLI flow ————————————— Open Chrome at openURL, wait for the user to press Enter, then collect the four target cookies. Returns hash { ‘sid’ => ‘…’, … } — keys missing from the browser are simply omitted, so callers must check what came back rather than assume completeness.

Raises StandardError on browser launch / navigation failure; callers are expected to rescue and degrade gracefully.



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# File 'lib/ChromeAuth.rb', line 39

def login!(errput: $stderr, input: $stdin, openURL: LOGIN_URL)
    startSession!(openURL: openURL)
    promptUser(errput, input, openURL)
    finishSession!
rescue StandardError
    cancelSession!
    raise
end

.mediumDomain?(domain) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ChromeAuth.rb', line 136

def mediumDomain?(domain)
    return false if domain.nil?
    normalized = domain.start_with?('.') ? domain[1..] : domain
    normalized == 'medium.com' || normalized.end_with?('.medium.com')
end

.promptUser(errput, input, url) ⇒ Object 



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# File 'lib/ChromeAuth.rb', line 142

def promptUser(errput, input, url)
    errput.puts <<~MSG

      ──────────────────────────────────────────────────────────────────────
      🔐 Sign into Medium in the Chrome window that just opened.

      Steps:
        1. Complete login (and any Cloudflare challenge) at #{url}.
        2. Stay on a medium.com page once you're signed in.
        3. Come back here and press Enter — we'll read sid / uid /
           cf_clearance / _cfuvid out of the browser and cache them at
           #{CookieCache.path}.

      (Press Ctrl-D to abort and fall back to manual setup.)
      ──────────────────────────────────────────────────────────────────────
    MSG
    errput.print 'Press Enter when signed in… '
    line = input.gets
    errput.puts
    line
end

.sessionActive? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ChromeAuth.rb', line 104

def sessionActive?
    !@@session.nil?
end

.startSession!(openURL: LOGIN_URL) ⇒ Object

—- Split flow for MCP / other long-lived hosts —————- ‘startSession!` / `finishSession!` / `cancelSession!` let a caller spawn the browser in one tool call and harvest cookies in another, using the host process (e.g. an MCP server) as the place that holds the still-open browser between calls.

Lifecycle:

startSession!  → opens browser, returns immediately. If a session
                 is already alive, that one is force-cancelled
                 first so a stale browser can't strand cookies.
finishSession! → reads cookies from the live browser, writes
                 cache, quits browser, clears session, returns
                 the cookies hash.
cancelSession! → quit + clear; idempotent.

Not thread-safe: assumes a single MCP request handler at a time.



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# File 'lib/ChromeAuth.rb', line 64

def startSession!(openURL: LOGIN_URL)
    cancelSession! if sessionActive?
    browser = buildBrowser
    browser.go_to(openURL)
    @@session = { browser: browser, openURL: openURL, startedAt: Time.now }
    { ok: true, openURL: openURL }
rescue StandardError
    # If go_to or anything else blew up, make sure we don't leave a
    # half-built browser around with no handle.
    begin
        browser&.quit
    rescue StandardError
        # ignore
    end
    @@session = nil
    raise
end