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Cookie Sessions

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How SameSession reads pages behind a login by decrypting cookies from your local Chrome profile and injecting them into a throwaway browser.

Usage

result, err := browser.Fetch(ctx, "https://example.com/profile", 60*time.Second, &browser.Option{
    SameSession: true,
    Profile:     "Default",
})

Your own Chrome is never touched: the cookie database is copied to a temporary directory and read from there, and the page loads in a fresh Chrome on an empty temporary profile with the decrypted cookies injected over CDP. Profile names a subdirectory of the Chrome profile root (Default, Profile 1, ...).

Flow

graph TB
    A[launchWithSnapshot] --> B[Copy Cookies / -wal / -shm to temp dir]
    B --> C[Read Chrome Safe Storage password]
    C --> D[Derive 16-byte key with PBKDF2-SHA1]
    D --> E[Read cookies through sqlite3]
    E --> F[AES-128-CBC decrypt v10 values]
    F --> G[Launch Chrome on the temp profile]
    G --> H[SetCookies injection]

Decryption and injection

Parameter Value
Password source (macOS) security find-generic-password -w -s "Chrome Safe Storage" -a Chrome
Password source (Linux) secret-tool lookup application chrome, then application chromium
Key derivation PBKDF2-SHA1, salt saltysalt, 1003 iterations, 16-byte key
Cipher AES-128-CBC, IV of 16 space characters, PKCS#7 padding
Encrypted marker v10 prefix; values without it are used as stored
Plaintext prefix The first 32 bytes after decryption are stripped when the plaintext is longer than 32 bytes

Each row of the cookies table becomes a CDP cookie with domain, path, expiry (converted from the WebKit epoch), Secure, HTTPOnly and SameSite. Rows that fail to decode are skipped.

Injection

Cookies without a domain or name are dropped, and an empty path becomes /. If the batch injection fails, cookies are injected one by one and the run continues as long as at least one lands; zero successes returns inject cookies (0/N).

Failure behavior

Situation Result
Profile root unknown (not macOS/Linux) or Profile directory missing Falls back to a regular cached browser without cookies
Keychain, secret-tool, sqlite3 or launch failure The error is returned; no fallback
Session ends Browser closed and temporary directory removed, even on error

Routing still applies: a SameSession call can be retried headed when blocked, and each attempt builds its own temporary profile. See Fetch Routing.

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