74 lines
2.4 KiB
Python
74 lines
2.4 KiB
Python
import inspect
|
|
import logging
|
|
|
|
from scrapy.spiders import Spider
|
|
from scrapy.utils.defer import deferred_from_coro
|
|
from scrapy.utils.misc import arg_to_iter
|
|
try:
|
|
from scrapy.utils.py36 import collect_asyncgen
|
|
except SyntaxError:
|
|
collect_asyncgen = None
|
|
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
|
|
def iterate_spider_output(result):
|
|
if collect_asyncgen and hasattr(inspect, 'isasyncgen') and inspect.isasyncgen(result):
|
|
d = deferred_from_coro(collect_asyncgen(result))
|
|
d.addCallback(iterate_spider_output)
|
|
return d
|
|
elif inspect.iscoroutine(result):
|
|
d = deferred_from_coro(result)
|
|
d.addCallback(iterate_spider_output)
|
|
return d
|
|
return arg_to_iter(result)
|
|
|
|
|
|
def iter_spider_classes(module):
|
|
"""Return an iterator over all spider classes defined in the given module
|
|
that can be instantiated (i.e. which have name)
|
|
"""
|
|
# this needs to be imported here until get rid of the spider manager
|
|
# singleton in scrapy.spider.spiders
|
|
from scrapy.spiders import Spider
|
|
|
|
for obj in vars(module).values():
|
|
if (
|
|
inspect.isclass(obj)
|
|
and issubclass(obj, Spider)
|
|
and obj.__module__ == module.__name__
|
|
and getattr(obj, 'name', None)
|
|
):
|
|
yield obj
|
|
|
|
|
|
def spidercls_for_request(spider_loader, request, default_spidercls=None,
|
|
log_none=False, log_multiple=False):
|
|
"""Return a spider class that handles the given Request.
|
|
|
|
This will look for the spiders that can handle the given request (using
|
|
the spider loader) and return a Spider class if (and only if) there is
|
|
only one Spider able to handle the Request.
|
|
|
|
If multiple spiders (or no spider) are found, it will return the
|
|
default_spidercls passed. It can optionally log if multiple or no spiders
|
|
are found.
|
|
"""
|
|
snames = spider_loader.find_by_request(request)
|
|
if len(snames) == 1:
|
|
return spider_loader.load(snames[0])
|
|
|
|
if len(snames) > 1 and log_multiple:
|
|
logger.error('More than one spider can handle: %(request)s - %(snames)s',
|
|
{'request': request, 'snames': ', '.join(snames)})
|
|
|
|
if len(snames) == 0 and log_none:
|
|
logger.error('Unable to find spider that handles: %(request)s',
|
|
{'request': request})
|
|
|
|
return default_spidercls
|
|
|
|
|
|
class DefaultSpider(Spider):
|
|
name = 'default'
|