Add Firefox support via firefox_cookies()

Add a new `firefox_cookies()`, similar to `chrome_cookies()`. The
arguments are slightly different:

  - `profile_name` instead of `cookie_file`, since Firefox supports
    multiple profiles in the default config directory. `profile_name`
    may be a glob pattern because Firefox profiles have a random
    prefix that's not directly user-visible or -maintained.
  - No `password` argument, since Firefox doesn't encrypt its cookies.

Firefox stores its cookies in an SQLite3 database file. While Firefox
is running, the database is locked, so the code makes a temporary
copy of it before reading cookies from it.

If no `profile_name` is given the default profile will be returned, by
parsing the `profiles.ini` file in the Firefox config directory. This
can be overridden by passing a profile name or pattern to
`profile_name`.

A note on the unit tests: They don't test the scenario where Firefox
is running while getting the cookies. This is because the synchronous
playwright API doesn't support yielding from inside the running `with`
context manager. The asynchronous API probably does, but I haven't
looked into using that. Nonetheless the code supports retrieving
cookies while Firefox is running.

Closes #48.

src/pycookiecheat/__init__.py

@@ -1,11 +1,13 @@
 """__init__.py :: Exposes chrome_cookies function."""
 
 from pycookiecheat.pycookiecheat import chrome_cookies
+from pycookiecheat.firefox import firefox_cookies
 
 __author__ = "Nathan Henrie"
 __email__ = "nate@n8henrie.com"
 __version__ = "v0.5.0"
 
 __all__ = [
     "chrome_cookies",
+    "firefox_cookies",
 ]

src/pycookiecheat/firefox.py

@@ -0,0 +1,211 @@
+import configparser
+from pathlib import Path
+import shutil
+import sqlite3
+import sys
+import tempfile
+from typing import Dict
+from typing import List
+from typing import Optional
+import urllib
+import urllib.error
+import urllib.parse
+
+FIREFOX_COOKIE_SELECT_SQL = """
+    SELECT name, value, `path`, isSecure, expiry
+    FROM moz_cookies
+    WHERE host = ?;
+"""
+
+FIREFOX_OS_PROFILE_DIRS: Dict[str, Dict[str, str]] = {
+    "linux": {
+        "Firefox": "~/.mozilla/firefox",
+    },
+    "osx": {
+        "Firefox": "~/Library/Application Support/Firefox/Profiles",
+    },
+    "windows": {
+        "Firefox": "~/AppData/Roaming/Mozilla/Firefox/Profiles",
+    },
+}
+
+
+class FirefoxProfileNotPopulatedError(Exception):
+    """Raised when the Firefox profile has never been used."""
+
+    pass
+
+
+def _get_profiles_dir_for_os(os: str, browser: str = "Firefox") -> Path:
+    """Retrieve the default directory containing the user profiles."""
+    browser = browser.title()
+    try:
+        os_config = FIREFOX_OS_PROFILE_DIRS[os]
+    except KeyError:
+        raise ValueError(
+            f"OS must be one of {list(FIREFOX_OS_PROFILE_DIRS.keys())}"
+        )
+    try:
+        return Path(os_config[browser]).expanduser()
+    except KeyError:
+        raise ValueError(f"Browser must be one of {list(os_config.keys())}")
+
+
+def _find_firefox_default_profile(firefox_dir: Path) -> str:
+    """
+    Return the name of the default Firefox profile.
+
+    Args:
+        firefox_dir: Path to the Firefox config directory
+    Returns:
+        Name of the default profile
+
+    Firefox' profiles.ini file in the Firefox config directory that lists all
+    available profiles.
+
+    In Firefox versions 66 and below the default profile is simply marked with
+    `Default=1` in the profile section. Firefox 67 started to support multiple
+    installs of Firefox on the same machine and the default profile is now set
+    in `Install...` sections. The install section contains the name of its
+    default profile in the `Default` key.
+
+    https://support.mozilla.org/en-US/kb/understanding-depth-profile-installation
+    """
+    profiles_ini = configparser.ConfigParser()
+    profiles_ini.read(firefox_dir / "profiles.ini")
+    installs = [s for s in profiles_ini.sections() if s.startswith("Install")]
+    if installs:  # Firefox >= 67
+        # Heuristic: Take the first install, that's probably the system install
+        return profiles_ini[installs[0]]["Default"]
+    else:  # Firefox < 67
+        profiles = [
+            s for s in profiles_ini.sections() if s.startswith("Profile")
+        ]
+        for profile in profiles:
+            if profiles_ini[profile].get("Default") == "1":
+                return profiles_ini[profile]["Path"]
+        if profiles:
+            return profiles_ini[profiles[0]]["Path"]
+        raise Exception("no profiles found at {}".format(firefox_dir))
+
+
+def _copy_if_exists(src: List[Path], dest: Path):
+    for file in src:
+        try:
+            shutil.copy2(file, dest)
+        except FileNotFoundError:
+            pass
+
+
+def _load_firefox_cookie_db(
+    profiles_dir: Path,
+    tmp_dir: Path,
+    profile_name: Optional[str] = None,
+) -> Path:
+    """
+    Return a file path to the selected browser profile's cookie database.
+
+    Args:
+        profiles_dir: Browser+OS paths profiles_dir path
+        tmp_dir: A temporary directory to copy the DB file(s) into
+        profile_name: Name (or glob pattern) of the Firefox profile to search
+                      for cookies -- if none given it will find the configured
+                      default profile
+    Returns:
+        Path to the "deWAL'ed" temporary copy of cookies.sqlite
+
+    Firefox stores its cookies in an SQLite3 database file. While Firefox is
+    running it has an exclusive lock on this file and other processes can't
+    read from it. To circumvent this, copy the cookies file to the given
+    temporary directory and read it from there.
+
+    The SQLite database uses a feature called WAL ("write-ahead logging") that
+    writes transactions for the database into a second file _prior_ to writing
+    it to the actual DB. When copying the database this method also copies the
+    WAL file and then merges any outstanding writes, to make sure the cookies
+    DB has the most recent data.
+    """
+    if not profile_name:
+        profile_name = _find_firefox_default_profile(profiles_dir)
+    for profile_dir in profiles_dir.glob(profile_name):
+        if (profile_dir / "cookies.sqlite").exists():
+            break
+    else:
+        raise FirefoxProfileNotPopulatedError(profiles_dir / profile_name)
+    cookies_db = profile_dir / "cookies.sqlite"
+    cookies_wal = profile_dir / "cookies.sqlite-wal"
+    _copy_if_exists([cookies_db, cookies_wal], tmp_dir)
+    db_file = tmp_dir / "cookies.sqlite"
+    if not db_file.exists():
+        raise FileNotFoundError(f"no Firefox cookies DB in temp dir {tmp_dir}")
+    with sqlite3.connect(db_file) as con:
+        con.execute("PRAGMA journal_mode=OFF;")  # merge WAL
+    return db_file
+
+
+def firefox_cookies(
+    url: str,
+    profile_name: Optional[str] = None,
+    browser: str = "Firefox",
+    curl_cookie_file: Optional[str] = None,
+) -> Dict[str, str]:
+    """Retrieve cookies from Chrome/Chromium on OSX or Linux.
+
+    Args:
+        url: Domain from which to retrieve cookies, starting with http(s)
+        profile_name: Name (or glob pattern) of the Firefox profile to search
+                      for cookies -- if none given it will find the configured
+                      default profile
+        browser: Name of the browser's cookies to read (must be 'Firefox')
+        curl_cookie_file: Path to save the cookie file to be used with cURL
+    Returns:
+        Dictionary of cookie values for URL
+    """
+    parsed_url = urllib.parse.urlparse(url)
+    if parsed_url.scheme:
+        domain = parsed_url.netloc
+    else:
+        raise urllib.error.URLError("You must include a scheme with your URL.")
+
+    if sys.platform.startswith("linux"):
+        os = "linux"
+    elif sys.platform == "darwin":
+        os = "osx"
+    elif sys.platform == "win32":
+        os = "windows"
+    else:
+        raise OSError(
+            "This script only works on "
+            + ", ".join(FIREFOX_OS_PROFILE_DIRS.keys())
+        )
+    profiles_dir = _get_profiles_dir_for_os(os, browser)
+
+    cookies = {}
+    curl_cookies = []
+    with tempfile.TemporaryDirectory() as tmp_dir:
+        db_file = _load_firefox_cookie_db(
+            profiles_dir, Path(tmp_dir), profile_name
+        )
+        with sqlite3.connect(db_file) as con:
+            res = con.execute(FIREFOX_COOKIE_SELECT_SQL, (domain,))
+            for key, value, path, is_secure, expiry in res.fetchall():
+                cookies[key] = value
+                if curl_cookie_file:
+                    # http://www.cookiecentral.com/faq/#3.5
+                    curl_cookies.append(
+                        "\t".join(
+                            [
+                                domain,
+                                "TRUE",
+                                path,
+                                "TRUE" if is_secure else "FALSE",
+                                str(expiry),
+                                key,
+                                value,
+                            ]
+                        )
+                    )
+    if curl_cookie_file:
+        with open(curl_cookie_file, "w") as text_file:
+            text_file.write("\n".join(curl_cookies) + "\n")
+    return cookies