def start_requests(self):
for url_id, raw in self.url_tuples:
purl = get_parsed_url(raw)
status_code = None
if purl is None or purl.hostname is None:
status_code = U_HTML_ERROR_INVALID_URL
logger.debug('Invalide url %r', raw)
elif is_home_url(purl.path) is True:
status_code = U_HTML_ERROR_HOME_URL
logger.debug('Ignore home kind url %r', raw)
elif belongs_to_domain(purl.hostname,
self.excluded_domains) is not None:
status_code = U_HTML_ERROR_EXCLUDED_DOMAIN
logger.debug('Ignore excluded domain %r', raw)
else:
try:
yield scrapy.Request(
raw,
callback=self.parse,
meta=dict(url_id=url_id, raw=raw),
errback=self.errback_request)
except Exception as e:
logger.error('Error when sending request %r: %s', raw, e)
status_code = U_HTML_ERROR_INVALID_URL
# when error happends, update url status_code
if status_code is not None:
try:
self.session.query(Url).filter_by(id=url_id)\
.update(dict(status_code=status_code),
synchronize_session=False)
self.session.commit()
except SQLAlchemyError as e:
logger.error('Error when update url status_code: %s', e)
self.session.rollback()
def process_item(self, item, spider):
"""Main function that process URL item (second phase)."""
# canonicalize expanded URL without considering the status_code
# because scrapy crawling not ganrantee the success
# we still try to canonicalize the URL
if len(item['expanded']) > MAX_URL_LEN:
item['expanded'] = item['expanded'][:MAX_URL_LEN]
logger.error('Expanded URL too long, trucate it! %r', item['raw'])
item['canonical'] = canonicalize(item['expanded'])
if item['canonical'] is None:
item['status_code'] = U_HTML_ERROR_INVALID_URL
# if url could be canonicalized and if site_id is not determined
# we infer it from the expanded url
if item['status_code'] != U_HTML_ERROR_INVALID_URL\
and item.get('site_id', None) is None:
purl = get_parsed_url(item['expanded'])
if purl is not None and purl.hostname is not None:
if belongs_to_domain(purl.hostname, spider.excluded_domains)\
is not None:
item['status_code'] = U_HTML_ERROR_EXCLUDED_DOMAIN
else:
item['site_id'] = belongs_to_site(purl.hostname,
self.site_tuples)
else:
item['status_code'] = U_HTML_ERROR_INVALID_URL
# remove potential NUL byte \x00 in the HTML
if 'html' in item:
item['html'] = item['html'].replace(b'\x00', '')
try:
# update database of url table
spider.session.query(Url).filter_by(id=item['id'])\
.update(dict(item), synchronize_session=False)
spider.session.commit()
logger.debug('Fetched html of url %r with status %i', item['raw'],
item['status_code'])
except SQLAlchemyError as e:
logger.error(e)
spider.session.rollback()
raise DropItem('Fail to update database of url: %s', item)
return item