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