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import json
import logging
from itemadapter import is_item, ItemAdapter
from w3lib.url import is_url
from scrapy.commands import BaseRunSpiderCommand
from scrapy.http import Request
from scrapy.utils import display
from scrapy.utils.spider import iterate_spider_output, spidercls_for_request
from scrapy.exceptions import UsageError
logger = logging.getLogger(__name__)
class Command(BaseRunSpiderCommand):
requires_project = True
spider = None
items = {}
requests = {}
first_response = None
def syntax(self):
return "[options] <url>"
def short_desc(self):
return "Parse URL (using its spider) and print the results"
def add_options(self, parser):
BaseRunSpiderCommand.add_options(self, parser)
parser.add_option("--spider", dest="spider", default=None,
help="use this spider without looking for one")
parser.add_option("--pipelines", action="store_true",
help="process items through pipelines")
parser.add_option("--nolinks", dest="nolinks", action="store_true",
help="don't show links to follow (extracted requests)")
parser.add_option("--noitems", dest="noitems", action="store_true",
help="don't show scraped items")
parser.add_option("--nocolour", dest="nocolour", action="store_true",
help="avoid using pygments to colorize the output")
parser.add_option("-r", "--rules", dest="rules", action="store_true",
help="use CrawlSpider rules to discover the callback")
parser.add_option("-c", "--callback", dest="callback",
help="use this callback for parsing, instead looking for a callback")
parser.add_option("-m", "--meta", dest="meta",
help="inject extra meta into the Request, it must be a valid raw json string")
parser.add_option("--cbkwargs", dest="cbkwargs",
help="inject extra callback kwargs into the Request, it must be a valid raw json string")
parser.add_option("-d", "--depth", dest="depth", type="int", default=1,
help="maximum depth for parsing requests [default: %default]")
parser.add_option("-v", "--verbose", dest="verbose", action="store_true",
help="print each depth level one by one")
@property
def max_level(self):
max_items, max_requests = 0, 0
if self.items:
max_items = max(self.items)
if self.requests:
max_requests = max(self.requests)
return max(max_items, max_requests)
def add_items(self, lvl, new_items):
old_items = self.items.get(lvl, [])
self.items[lvl] = old_items + new_items
def add_requests(self, lvl, new_reqs):
old_reqs = self.requests.get(lvl, [])
self.requests[lvl] = old_reqs + new_reqs
def print_items(self, lvl=None, colour=True):
if lvl is None:
items = [item for lst in self.items.values() for item in lst]
else:
items = self.items.get(lvl, [])
print("# Scraped Items ", "-" * 60)
display.pprint([ItemAdapter(x).asdict() for x in items], colorize=colour)
def print_requests(self, lvl=None, colour=True):
if lvl is None:
if self.requests:
requests = self.requests[max(self.requests)]
else:
requests = []
else:
requests = self.requests.get(lvl, [])
print("# Requests ", "-" * 65)
display.pprint(requests, colorize=colour)
def print_results(self, opts):
colour = not opts.nocolour
if opts.verbose:
for level in range(1, self.max_level + 1):
print(f'\n>>> DEPTH LEVEL: {level} <<<')
if not opts.noitems:
self.print_items(level, colour)
if not opts.nolinks:
self.print_requests(level, colour)
else:
print(f'\n>>> STATUS DEPTH LEVEL {self.max_level} <<<')
if not opts.noitems:
self.print_items(colour=colour)
if not opts.nolinks:
self.print_requests(colour=colour)
def run_callback(self, response, callback, cb_kwargs=None):
cb_kwargs = cb_kwargs or {}
items, requests = [], []
for x in iterate_spider_output(callback(response, **cb_kwargs)):
if is_item(x):
items.append(x)
elif isinstance(x, Request):
requests.append(x)
return items, requests
def get_callback_from_rules(self, spider, response):
if getattr(spider, 'rules', None):
for rule in spider.rules:
if rule.link_extractor.matches(response.url):
return rule.callback or "parse"
else:
logger.error('No CrawlSpider rules found in spider %(spider)r, '
'please specify a callback to use for parsing',
{'spider': spider.name})
def set_spidercls(self, url, opts):
spider_loader = self.crawler_process.spider_loader
if opts.spider:
try:
self.spidercls = spider_loader.load(opts.spider)
except KeyError:
logger.error('Unable to find spider: %(spider)s',
{'spider': opts.spider})
else:
self.spidercls = spidercls_for_request(spider_loader, Request(url))
if not self.spidercls:
logger.error('Unable to find spider for: %(url)s', {'url': url})
def _start_requests(spider):
yield self.prepare_request(spider, Request(url), opts)
self.spidercls.start_requests = _start_requests
def start_parsing(self, url, opts):
self.crawler_process.crawl(self.spidercls, **opts.spargs)
self.pcrawler = list(self.crawler_process.crawlers)[0]
self.crawler_process.start()
if not self.first_response:
logger.error('No response downloaded for: %(url)s',
{'url': url})
def prepare_request(self, spider, request, opts):
def callback(response, **cb_kwargs):
# memorize first request
if not self.first_response:
self.first_response = response
# determine real callback
cb = response.meta['_callback']
if not cb:
if opts.callback:
cb = opts.callback
elif opts.rules and self.first_response == response:
cb = self.get_callback_from_rules(spider, response)
if not cb:
logger.error('Cannot find a rule that matches %(url)r in spider: %(spider)s',
{'url': response.url, 'spider': spider.name})
return
else:
cb = 'parse'
if not callable(cb):
cb_method = getattr(spider, cb, None)
if callable(cb_method):
cb = cb_method
else:
logger.error('Cannot find callback %(callback)r in spider: %(spider)s',
{'callback': cb, 'spider': spider.name})
return
# parse items and requests
depth = response.meta['_depth']
items, requests = self.run_callback(response, cb, cb_kwargs)
if opts.pipelines:
itemproc = self.pcrawler.engine.scraper.itemproc
for item in items:
itemproc.process_item(item, spider)
self.add_items(depth, items)
self.add_requests(depth, requests)
scraped_data = items if opts.output else []
if depth < opts.depth:
for req in requests:
req.meta['_depth'] = depth + 1
req.meta['_callback'] = req.callback
req.callback = callback
scraped_data += requests
return scraped_data
# update request meta if any extra meta was passed through the --meta/-m opts.
if opts.meta:
request.meta.update(opts.meta)
# update cb_kwargs if any extra values were was passed through the --cbkwargs option.
if opts.cbkwargs:
request.cb_kwargs.update(opts.cbkwargs)
request.meta['_depth'] = 1
request.meta['_callback'] = request.callback
request.callback = callback
return request
def process_options(self, args, opts):
BaseRunSpiderCommand.process_options(self, args, opts)
self.process_request_meta(opts)
self.process_request_cb_kwargs(opts)
def process_request_meta(self, opts):
if opts.meta:
try:
opts.meta = json.loads(opts.meta)
except ValueError:
raise UsageError("Invalid -m/--meta value, pass a valid json string to -m or --meta. "
"Example: --meta='{\"foo\" : \"bar\"}'", print_help=False)
def process_request_cb_kwargs(self, opts):
if opts.cbkwargs:
try:
opts.cbkwargs = json.loads(opts.cbkwargs)
except ValueError:
raise UsageError("Invalid --cbkwargs value, pass a valid json string to --cbkwargs. "
"Example: --cbkwargs='{\"foo\" : \"bar\"}'", print_help=False)
def run(self, args, opts):
# parse arguments
if not len(args) == 1 or not is_url(args[0]):
raise UsageError()
else:
url = args[0]
# prepare spidercls
self.set_spidercls(url, opts)
if self.spidercls and opts.depth > 0:
self.start_parsing(url, opts)
self.print_results(opts)
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