# Source code for scrapy.logformatter

    from __future__ import annotations

    import logging
    import os
    from typing import TYPE_CHECKING, Any, TypedDict

    from twisted.python.failure import Failure

    # working around https://github.com/sphinx-doc/sphinx/issues/10400
    from scrapy import Request, Spider  # noqa: TC001
    from scrapy.http import Response  # noqa: TC001
    from scrapy.utils.python import global_object_name
    from scrapy.utils.request import referer_str

    if TYPE_CHECKING:
        # typing.Self requires Python 3.11
        from typing_extensions import Self

        from scrapy.crawler import Crawler

    SCRAPEDMSG = "Scraped from %(src)s" + os.linesep + "%(item)s"
    DROPPEDMSG = "Dropped: %(exception)s" + os.linesep + "%(item)s"
    CRAWLEDMSG = "Crawled (%(status)s) %(request)s%(request_flags)s (referer: %(referer)s)%(response_flags)s"
    ITEMERRORMSG = "Error processing %(item)s"
    SPIDERERRORMSG = "Spider error processing %(request)s (referer: %(referer)s)"
    DOWNLOADERRORMSG_SHORT = "Error downloading %(request)s"
    DOWNLOADERRORMSG_LONG = "Error downloading %(request)s: %(errmsg)s"

    class LogFormatterResult(TypedDict):
        level: int
        msg: str
        args: dict[str, Any] | tuple[Any, ...]

    class LogFormatter:
        """Class for generating log messages for different actions.

        All methods must return a dictionary listing the parameters ``level``, ``msg``
        and ``args`` which are going to be used for constructing the log message when
        calling ``logging.log``.

        Dictionary keys for the method outputs:

        *   ``level`` is the log level for that action, you can use those from the
            `python logging library <https://docs.python.org/3/library/logging.html>`_ :
            ``logging.DEBUG``, ``logging.INFO``, ``logging.WARNING``, ``logging.ERROR``
            and ``logging.CRITICAL``.
        *   ``msg`` should be a string that can contain different formatting placeholders.
            This string, formatted with the provided ``args``, is going to be the long message
            for that action.
        *   ``args`` should be a tuple or dict with the formatting placeholders for ``msg``.
            The final log message is computed as ``msg % args``.

        Users can define their own ``LogFormatter`` class if they want to customize how
        each action is logged or if they want to omit it entirely. In order to omit
        logging an action the method must return ``None``.

        Here is an example on how to create a custom log formatter to lower the severity level of
        the log message when an item is dropped from the pipeline::

                class PoliteLogFormatter(logformatter.LogFormatter):
                    def dropped(self, item, exception, response, spider):
                        return {
                            'level': logging.INFO, # lowering the level from logging.WARNING
                            'msg': "Dropped: %(exception)s" + os.linesep + "%(item)s",
                            'args': {
                                'exception': exception,
                                'item': item,
                            }
                        }
        """

        def crawled(
            self, request: Request, response: Response, spider: Spider
        ) -> LogFormatterResult:
            """Logs a message when the crawler finds a webpage."""
            request_flags = f" {str(request.flags)}" if request.flags else ""
            response_flags = f" {str(response.flags)}" if response.flags else ""
            return {
                "level": logging.DEBUG,
                "msg": CRAWLEDMSG,
                "args": {
                    "status": response.status,
                    "request": request,
                    "request_flags": request_flags,
                    "referer": referer_str(request),
                    "response_flags": response_flags,
                    # backward compatibility with Scrapy logformatter below 1.4 version
                    "flags": response_flags,
                },
            }

        def scraped(
            self, item: Any, response: Response | Failure | None, spider: Spider
        ) -> LogFormatterResult:
            """Logs a message when an item is scraped by a spider."""
            src: Any
            if response is None:
                src = f"{global_object_name(spider.__class__)}.start_requests"
            elif isinstance(response, Failure):
                src = response.getErrorMessage()
            else:
                src = response
            return {
                "level": logging.DEBUG,
                "msg": SCRAPEDMSG,
                "args": {
                    "src": src,
                    "item": item,
                },
            }

        def dropped(
            self,
            item: Any,
            exception: BaseException,
            response: Response | None,
            spider: Spider,
        ) -> LogFormatterResult:
            """Logs a message when an item is dropped while it is passing through the item pipeline."""
            return {
                "level": logging.WARNING,
                "msg": DROPPEDMSG,
                "args": {
                    "exception": exception,
                    "item": item,
                },
            }

        def item_error(
            self,
            item: Any,
            exception: BaseException,
            response: Response | None,
            spider: Spider,
        ) -> LogFormatterResult:
            """Logs a message when an item causes an error while it is passing
            through the item pipeline.

            .. versionadded:: 2.0
            """
            return {
                "level": logging.ERROR,
                "msg": ITEMERRORMSG,
                "args": {
                    "item": item,
                },
            }

        def spider_error(
            self,
            failure: Failure,
            request: Request,
            response: Response | Failure,
            spider: Spider,
        ) -> LogFormatterResult:
            """Logs an error message from a spider.

            .. versionadded:: 2.0
            """
            return {
                "level": logging.ERROR,
                "msg": SPIDERERRORMSG,
                "args": {
                    "request": request,
                    "referer": referer_str(request),
                },
            }

        def download_error(
            self,
            failure: Failure,
            request: Request,
            spider: Spider,
            errmsg: str | None = None,
        ) -> LogFormatterResult:
            """Logs a download error message from a spider (typically coming from
            the engine).

            .. versionadded:: 2.0
            """
            args: dict[str, Any] = {"request": request}
            if errmsg:
                msg = DOWNLOADERRORMSG_LONG
                args["errmsg"] = errmsg
            else:
                msg = DOWNLOADERRORMSG_SHORT
            return {
                "level": logging.ERROR,
                "msg": msg,
                "args": args,
            }

        @classmethod
        def from_crawler(cls, crawler: Crawler) -> Self:
            return cls()