Auto-install chromedriver from start_chrome(...)

helium/__init__.py

@@ -38,10 +38,6 @@ def start_chrome(
 
  start_chrome()
 
- If this doesn't work for you, then it may be that Helium's copy of
- ChromeDriver is not compatible with your version of Chrome. To fix this,
- place a copy of ChromeDriver on your `PATH`.
-
  You can optionally open a URL::
 
  start_chrome("google.com")
@@ -66,10 +62,16 @@ def start_chrome(
  capabilities["goog:loggingPrefs"] = {'performance': 'ALL'}
  start_chrome(capabilities=capabilities)
 
- On shutdown of the Python interpreter, Helium cleans up all resources used
- for controlling the browser (such as the ChromeDriver process), but does
- not close the browser itself. If you want to terminate the browser at the
- end of your script, use the following command::
+ When no compatible ChromeDriver is found on your `PATH`, then `start_chrome`
+ automatically downloads it into the following directories::
+
+ * Windows: `%LOCALAPPDATA%\Cache\Helium`
+ * macOS: `~/Library/Caches/Helium`
+ * Linux: `$XDG_CACHE_HOME/helium` or `~/.cache/Helium`
+
+ On shutdown of the Python interpreter, Helium terminates the ChromeDriver
+ process but does not close the browser itself. If you want to close the
+ browser at the end of your script, use the following command::
 
  kill_browser()
  """

helium/_impl/__init__.py

@@ -1,4 +1,5 @@
 from copy import copy
+from helium._impl.chromedriver import install_matching_chromedriver
 from helium._impl.match_type import PREFIX_IGNORE_CASE
 from helium._impl.selenium_wrappers import WebElementWrapper, \
  WebDriverWrapper, FrameIterator, FramesChangedWhileIterating
@@ -16,7 +17,8 @@
 from selenium.webdriver.remote.webelement import WebElement
 from selenium.webdriver.support.wait import WebDriverWait
 from selenium.webdriver.support.ui import Select
-from selenium.webdriver import Chrome, ChromeOptions, Firefox, FirefoxOptions, FirefoxProfile
+from selenium.webdriver import Chrome, ChromeOptions, Firefox, FirefoxOptions, \
+ FirefoxProfile
 from time import sleep, time
 
 import atexit
@@ -74,7 +76,9 @@ class APIImpl:
  " * set_driver(...)"
  def __init__(self):
  self.driver = None
- def start_firefox_impl(self, url=None, headless=False, options=None, profile=None):
+ def start_firefox_impl(
+ self, url=None, headless=False, options=None, profile=None
+ ):
  firefox_driver = self._start_firefox_driver(headless, options, profile)
  return self._start(firefox_driver, url)
  def _start_firefox_driver(self, headless, options, profile):
@@ -105,10 +109,12 @@ def start_chrome_impl(
  def _start_chrome_driver(self, headless, maximize, options, capabilities):
  chrome_options = self._get_chrome_options(headless, maximize, options)
  try:
- result = Chrome(options=chrome_options, desired_capabilities=capabilities)
+ result = Chrome(
+ options=chrome_options, desired_capabilities=capabilities
+ )
  except WebDriverException:
  # This usually happens when chromedriver is not on the PATH.
- driver_path = self._use_included_web_driver('chromedriver')
+ driver_path = install_matching_chromedriver()
  result = Chrome(
  options=chrome_options, desired_capabilities=capabilities,
  executable_path=driver_path

helium/_impl/chromedriver.py

@@ -0,0 +1,42 @@
+from get_chrome_driver import GetChromeDriver
+from os.path import join, expanduser
+
+import os
+import platform
+
+def install_matching_chromedriver():
+ get_driver = GetChromeDriver()
+ chrome_version = get_driver._GetChromeDriver__get_installed_chrome_version()
+ cache_directory = _get_cache_directory()
+ cached_chrome_version = \
+ StringStoredInFile(join(cache_directory, 'chrome.version'))
+ if chrome_version != cached_chrome_version.read():
+ get_driver.auto_download(cache_directory, True)
+ cached_chrome_version.write(chrome_version)
+ return join(
+ cache_directory,
+ 'chromedriver' + '.exe' if platform.system() == 'Windows' else ''
+ )
+
+def _get_cache_directory():
+ system = platform.system()
+ if system == 'Windows':
+ return join(os.getenv('LOCALAPPDATA'), 'Cache', 'Helium')
+ elif system == 'Darwin':
+ return expanduser('~/Library/Caches/Helium')
+ else:
+ cache_home = os.getenv('XDG_CACHE_HOME', expanduser('~/.cache'))
+ return join(cache_home, 'helium')
+
+class StringStoredInFile:
+ def __init__(self, path):
+ self.path = path
+ def read(self):
+ try:
+ with open(self.path) as f:
+ return f.read()
+ except FileNotFoundError:
+ return None
+ def write(self, value):
+ with open(self.path, 'w') as f:
+ f.write(value)

requirements/base.txt

@@ -3,4 +3,6 @@
 selenium==3.141.0
 
 # Selenium 3 is incompatible with urllib3 >= 2:
-urllib3<2
+urllib3<2
+
+get-chrome-driver==1.3.12

setup.py

@@ -15,7 +15,8 @@
  # Also update requirements/base.txt when you make changes here.
  'selenium==3.141.0',
  # Selenium 3 is incompatible with urllib3 >= 2:
- 'urllib3<2'
+ 'urllib3<2',
+ 'get-chrome-driver==1.3.12'
  ],
  package_data = {
  'helium._impl': ['webdrivers/**/*']

tests/unit/test__impl/test_chromedriver.py

@@ -0,0 +1,24 @@
+from helium._impl import chromedriver
+from helium._impl.chromedriver import install_matching_chromedriver
+from os import access, X_OK
+from os.path import getctime
+from tempfile import TemporaryDirectory
+from unittest import TestCase
+
+
+class InstallMatchingChromeDriverTest(TestCase):
+ def test_install_matching_chromedriver(self):
+ driver_path = install_matching_chromedriver()
+ self.assertTrue(access(driver_path, X_OK))
+ def test_caching(self):
+ driver_path = install_matching_chromedriver()
+ ctime = getctime(driver_path)
+ self.assertEqual(install_matching_chromedriver(), driver_path)
+ self.assertEqual(ctime, getctime(driver_path))
+ def setUp(self):
+ self.temp_dir = TemporaryDirectory()
+ self._original_get_cache_directory = chromedriver._get_cache_directory
+ chromedriver._get_cache_directory = lambda: self.temp_dir.name
+ def tearDown(self):
+ chromedriver._get_cache_directory = self._original_get_cache_directory
+ self.temp_dir.cleanup()