scrapy.logformatter 源代码

import os
import logging

from twisted.python.failure import Failure

from scrapy.utils.request import referer_str

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"

[文档]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 <>`_ : ``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, } } """
[文档] def crawled(self, request, response, spider): """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 } }
[文档] def scraped(self, item, response, spider): """Logs a message when an item is scraped by a spider.""" if isinstance(response, Failure): src = response.getErrorMessage() else: src = response return { 'level': logging.DEBUG, 'msg': SCRAPEDMSG, 'args': { 'src': src, 'item': item, } }
[文档] def dropped(self, item, exception, response, spider): """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, } }
[文档] def item_error(self, item, exception, response, spider): """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, } }
[文档] def spider_error(self, failure, request, response, spider): """Logs an error message from a spider. .. versionadded:: 2.0 """ return { 'level': logging.ERROR, 'msg': SPIDERERRORMSG, 'args': { 'request': request, 'referer': referer_str(request), } }
[文档] def download_error(self, failure, request, spider, errmsg=None): """Logs a download error message from a spider (typically coming from the engine). .. versionadded:: 2.0 """ args = {'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): return cls()