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from __future__ import print_function
from w3lib.url import is_url
from scrapy.command import ScrapyCommand
from scrapy.http import Request
from scrapy.item import BaseItem
from scrapy.utils import display
from scrapy.utils.conf import arglist_to_dict
from scrapy.utils.spider import iterate_spider_output, create_spider_for_request
from scrapy.exceptions import UsageError
from scrapy import log
class Command(ScrapyCommand):
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):
ScrapyCommand.add_options(self, parser)
parser.add_option("--spider", dest="spider", default=None, \
help="use this spider without looking for one")
parser.add_option("-a", dest="spargs", action="append", default=[], metavar="NAME=VALUE", \
help="set spider argument (may be repeated)")
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("-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):
levels = self.items.keys() + self.requests.keys()
if levels: return max(levels)
else: return 0
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([dict(x) for x in items], colorize=colour)
def print_requests(self, lvl=None, colour=True):
if lvl is None:
levels = self.requests.keys()
if levels:
requests = self.requests[max(levels)]
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 xrange(1, self.max_level+1):
print('\n>>> DEPTH LEVEL: %s <<<' % level)
if not opts.noitems:
self.print_items(level, colour)
if not opts.nolinks:
self.print_requests(level, colour)
else:
print('\n>>> STATUS DEPTH LEVEL %s <<<' % 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, cb):
items, requests = [], []
for x in iterate_spider_output(cb(response)):
if isinstance(x, BaseItem):
items.append(x)
elif isinstance(x, Request):
requests.append(x)
return items, requests
def get_callback_from_rules(self, response):
if getattr(self.spider, 'rules', None):
for rule in self.spider.rules:
if rule.link_extractor.matches(response.url) and rule.callback:
return rule.callback
else:
log.msg(format='No CrawlSpider rules found in spider %(spider)r, '
'please specify a callback to use for parsing',
level=log.ERROR, spider=self.spider.name)
def set_spider(self, url, opts):
if opts.spider:
try:
self.spider = self.pcrawler.spiders.create(opts.spider, **opts.spargs)
except KeyError:
log.msg(format='Unable to find spider: %(spider)s',
level=log.ERROR, spider=opts.spider)
else:
self.spider = create_spider_for_request(self.pcrawler.spiders, Request(url), **opts.spargs)
if not self.spider:
log.msg(format='Unable to find spider for: %(url)s',
level=log.ERROR, url=url)
def start_parsing(self, url, opts):
request = Request(url, opts.callback)
request = self.prepare_request(request, opts)
self.pcrawler.crawl(self.spider, [request])
self.crawler_process.start()
if not self.first_response:
log.msg(format='No response downloaded for: %(request)s',
level=log.ERROR, request=request)
def prepare_request(self, request, opts):
def callback(response):
# memorize first request
if not self.first_response:
self.first_response = response
# determine real callback
cb = response.meta['_callback']
if not cb:
if opts.rules and self.first_response == response:
cb = self.get_callback_from_rules(response)
else:
cb = 'parse'
if not callable(cb):
cb_method = getattr(self.spider, cb, None)
if callable(cb_method):
cb = cb_method
else:
log.msg(format='Cannot find callback %(callback)r in spider: %(spider)s',
callback=callback, spider=self.spider.name, level=log.ERROR)
return
# parse items and requests
depth = response.meta['_depth']
items, requests = self.run_callback(response, cb)
if opts.pipelines:
itemproc = self.pcrawler.engine.scraper.itemproc
for item in items:
itemproc.process_item(item, self.spider)
self.add_items(depth, items)
self.add_requests(depth, requests)
if depth < opts.depth:
for req in requests:
req.meta['_depth'] = depth + 1
req.meta['_callback'] = req.callback
req.callback = callback
return requests
request.meta['_depth'] = 1
request.meta['_callback'] = request.callback
request.callback = callback
return request
def process_options(self, args, opts):
ScrapyCommand.process_options(self, args, opts)
try:
opts.spargs = arglist_to_dict(opts.spargs)
except ValueError:
raise UsageError("Invalid -a value, use -a NAME=VALUE", 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 spider
self.pcrawler = self.crawler_process.create_crawler()
self.set_spider(url, opts)
if self.spider and opts.depth > 0:
self.start_parsing(url, opts)
self.print_results(opts)
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