/usr/lib/python3/dist-packages/scrapy/spiderloader.py is in python3-scrapy 1.5.0-1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 | # -*- coding: utf-8 -*-
from __future__ import absolute_import
from collections import defaultdict
import traceback
import warnings
from zope.interface import implementer
from scrapy.interfaces import ISpiderLoader
from scrapy.utils.misc import walk_modules
from scrapy.utils.spider import iter_spider_classes
@implementer(ISpiderLoader)
class SpiderLoader(object):
"""
SpiderLoader is a class which locates and loads spiders
in a Scrapy project.
"""
def __init__(self, settings):
self.spider_modules = settings.getlist('SPIDER_MODULES')
self.warn_only = settings.getbool('SPIDER_LOADER_WARN_ONLY')
self._spiders = {}
self._found = defaultdict(list)
self._load_all_spiders()
def _check_name_duplicates(self):
dupes = ["\n".join(" {cls} named {name!r} (in {module})".format(
module=mod, cls=cls, name=name)
for (mod, cls) in locations)
for name, locations in self._found.items()
if len(locations)>1]
if dupes:
msg = ("There are several spiders with the same name:\n\n"
"{}\n\n This can cause unexpected behavior.".format(
"\n\n".join(dupes)))
warnings.warn(msg, UserWarning)
def _load_spiders(self, module):
for spcls in iter_spider_classes(module):
self._found[spcls.name].append((module.__name__, spcls.__name__))
self._spiders[spcls.name] = spcls
def _load_all_spiders(self):
for name in self.spider_modules:
try:
for module in walk_modules(name):
self._load_spiders(module)
except ImportError as e:
if self.warn_only:
msg = ("\n{tb}Could not load spiders from module '{modname}'. "
"See above traceback for details.".format(
modname=name, tb=traceback.format_exc()))
warnings.warn(msg, RuntimeWarning)
else:
raise
self._check_name_duplicates()
@classmethod
def from_settings(cls, settings):
return cls(settings)
def load(self, spider_name):
"""
Return the Spider class for the given spider name. If the spider
name is not found, raise a KeyError.
"""
try:
return self._spiders[spider_name]
except KeyError:
raise KeyError("Spider not found: {}".format(spider_name))
def find_by_request(self, request):
"""
Return the list of spider names that can handle the given request.
"""
return [name for name, cls in self._spiders.items()
if cls.handles_request(request)]
def list(self):
"""
Return a list with the names of all spiders available in the project.
"""
return list(self._spiders.keys())
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