Source code for web_poet.exceptions.core

"""
Core Exceptions
~~~~~~~~~~~~~~~

These exceptions are tied to how **web-poet** operates.
"""

from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from web_poet import HttpRequest


__all__ = [
    "RequestDownloaderVarError",
    "PageObjectAction",
    "Retry",
    "UseFallback",
    "NoSavedHttpResponse",
]


[docs]class RequestDownloaderVarError(Exception): """The ``web_poet.request_downloader_var`` had its contents accessed but there wasn't any value set during the time requests are executed. See the documentation section about :ref:`setting up the contextvars <setup-contextvars>` to learn more about this. """
[docs]class PageObjectAction(ValueError): """Base class for exceptions that can be raised from a page object to indicate something to be done about that page object."""
[docs]class Retry(PageObjectAction): """The page object found that the input data is partial or empty, and a request retry may provide better input."""
[docs]class UseFallback(PageObjectAction): """The page object cannot extract data from the input, but the input seems valid, so an alternative data extraction implementation for the same item type may succeed."""
[docs]class NoSavedHttpResponse(AssertionError): """Indicates that there is no saved response for this request. Can only be raised when a :class:`~.HttpClient` instance is used to get saved responses. :param request: The :class:`~.HttpRequest` instance that was used. :type request: HttpRequest """ def __init__(self, msg: str = None, request: "HttpRequest" = None): self.request = request if msg is None: msg = f"There is no saved response available for this HTTP Request: {self.request}" super().__init__(msg)