wait.py

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import time
from typing import Callable, Generic, Literal, Optional, TypeVar, Union

from selenium.common.exceptions import NoSuchElementException, TimeoutException
from selenium.types import WaitExcTypes
from selenium.webdriver.remote.webdriver import WebDriver
from selenium.webdriver.remote.webelement import WebElement

POLL_FREQUENCY: float = 0.5  # How long to sleep in between calls to the method
IGNORED_EXCEPTIONS: tuple[type[Exception]] = (NoSuchElementException,)  # default to be ignored.

D = TypeVar("D", bound=Union[WebDriver, WebElement])
T = TypeVar("T")


class WebDriverWait(Generic[D]):
    def __init__(
        self,
        driver: D,
        timeout: float,
        poll_frequency: float = POLL_FREQUENCY,
        ignored_exceptions: Optional[WaitExcTypes] = None,
    ):
        """Constructor, takes a WebDriver instance and timeout in seconds.

        Attributes:
        -----------
        driver
            - Instance of WebDriver (Ie, Firefox, Chrome or Remote) or
            a WebElement

        timeout
            - Number of seconds before timing out

        poll_frequency
            - Sleep interval between calls
            - By default, it is 0.5 second.

        ignored_exceptions
            - Iterable structure of exception classes ignored during calls.
            - By default, it contains NoSuchElementException only.

        Example:
        --------
        >>> from selenium.webdriver.common.by import By
        >>> from selenium.webdriver.support.wait import WebDriverWait
        >>> from selenium.common.exceptions import ElementNotVisibleException
        >>>
        >>> # Wait until the element is no longer visible
        >>> is_disappeared = WebDriverWait(driver, 30, 1, (ElementNotVisibleException))
        ...     .until_not(lambda x: x.find_element(By.ID, "someId").is_displayed())
        """
        self._driver = driver
        self._timeout = float(timeout)
        self._poll = poll_frequency
        # avoid the divide by zero
        if self._poll == 0:
            self._poll = POLL_FREQUENCY
        exceptions: list = list(IGNORED_EXCEPTIONS)
        if ignored_exceptions:
            try:
                exceptions.extend(iter(ignored_exceptions))
            except TypeError:  # ignored_exceptions is not iterable
                exceptions.append(ignored_exceptions)
        self._ignored_exceptions = tuple(exceptions)

    def __repr__(self) -> str:
        return f'<{type(self).__module__}.{type(self).__name__} (session="{self._driver.session_id}")>'

    def until(self, method: Callable[[D], Union[Literal[False], T]], message: str = "") -> T:
        """Wait until the method returns a value that is not False.

        Calls the method provided with the driver as an argument until the
        return value does not evaluate to ``False``.

        Parameters:
        -----------
        method: callable(WebDriver)
            - A callable object that takes a WebDriver instance as an argument.

        message: str
            - Optional message for :exc:`TimeoutException`

        Return:
        -------
        object: T
            - The result of the last call to `method`

        Raises:
        -------
        TimeoutException
            - If 'method' does not return a truthy value within the WebDriverWait
            object's timeout

        Example:
        --------
        >>> from selenium.webdriver.common.by import By
        >>> from selenium.webdriver.support.ui import WebDriverWait
        >>> from selenium.webdriver.support import expected_conditions as EC

        # Wait until an element is visible on the page
        >>> wait = WebDriverWait(driver, 10)
        >>> element = wait.until(EC.visibility_of_element_located((By.ID, "exampleId")))
        >>> print(element.text)
        """
        screen = None
        stacktrace = None

        end_time = time.monotonic() + self._timeout
        while True:
            try:
                value = method(self._driver)
                if value:
                    return value
            except self._ignored_exceptions as exc:
                screen = getattr(exc, "screen", None)
                stacktrace = getattr(exc, "stacktrace", None)
            if time.monotonic() > end_time:
                break
            time.sleep(self._poll)
        raise TimeoutException(message, screen, stacktrace)

    def until_not(self, method: Callable[[D], T], message: str = "") -> Union[T, Literal[True]]:
        """Wait until the method returns a value that is not False.

        Calls the method provided with the driver as an argument until the
        return value does not evaluate to ``False``.

        Parameters:
        -----------
        method: callable(WebDriver)
            - A callable object that takes a WebDriver instance as an argument.

        message: str
            - Optional message for :exc:`TimeoutException`

        Return:
        -------
        object: T
            - The result of the last call to `method`

        Raises:
        -------
        TimeoutException
            - If 'method' does not return False within the WebDriverWait
            object's timeout

        Example:
        --------
        >>> from selenium.webdriver.common.by import By
        >>> from selenium.webdriver.support.ui import WebDriverWait
        >>> from selenium.webdriver.support import expected_conditions as EC

        # Wait until an element is visible on the page
        >>> wait = WebDriverWait(driver, 10)
        >>> is_disappeared = wait.until_not(EC.visibility_of_element_located((By.ID, "exampleId")))
        """
        end_time = time.monotonic() + self._timeout
        while True:
            try:
                value = method(self._driver)
                if not value:
                    return value
            except self._ignored_exceptions:
                return True
            if time.monotonic() > end_time:
                break
            time.sleep(self._poll)
        raise TimeoutException(message)