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changedetection.io/changedetectionio/fetch_site_status.py

179 lines
7.3 KiB

import time
from changedetectionio import content_fetcher
import hashlib
from inscriptis import get_text
import urllib3
from . import html_tools
import re
urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)
# Some common stuff here that can be moved to a base class
class perform_site_check():
def __init__(self, *args, datastore, **kwargs):
super().__init__(*args, **kwargs)
self.datastore = datastore
def strip_ignore_text(self, content, list_ignore_text):
import re
ignore = []
ignore_regex = []
for k in list_ignore_text:
# Is it a regex?
if k[0] == '/':
ignore_regex.append(k.strip(" /"))
else:
ignore.append(k)
output = []
for line in content.splitlines():
# Always ignore blank lines in this mode. (when this function gets called)
if len(line.strip()):
regex_matches = False
# if any of these match, skip
for regex in ignore_regex:
try:
if re.search(regex, line, re.IGNORECASE):
regex_matches = True
except Exception as e:
continue
if not regex_matches and not any(skip_text in line for skip_text in ignore):
output.append(line.encode('utf8'))
return "\n".encode('utf8').join(output)
def run(self, uuid):
timestamp = int(time.time()) # used for storage etc too
changed_detected = False
stripped_text_from_html = ""
watch = self.datastore.data['watching'][uuid]
update_obj = {'previous_md5': self.datastore.data['watching'][uuid]['previous_md5'],
'history': {},
"last_checked": timestamp
}
extra_headers = self.datastore.get_val(uuid, 'headers')
# Tweak the base config with the per-watch ones
request_headers = self.datastore.data['settings']['headers'].copy()
request_headers.update(extra_headers)
# https://github.com/psf/requests/issues/4525
# Requests doesnt yet support brotli encoding, so don't put 'br' here, be totally sure that the user cannot
# do this by accident.
if 'Accept-Encoding' in request_headers and "br" in request_headers['Accept-Encoding']:
request_headers['Accept-Encoding'] = request_headers['Accept-Encoding'].replace(', br', '')
# @todo check the failures are really handled how we expect
else:
timeout = self.datastore.data['settings']['requests']['timeout']
url = self.datastore.get_val(uuid, 'url')
# Pluggable content fetcher
prefer_backend = watch['fetch_backend']
if hasattr(content_fetcher, prefer_backend):
klass = getattr(content_fetcher, prefer_backend)
else:
# If the klass doesnt exist, just use a default
klass = getattr(content_fetcher, "html_requests")
fetcher = klass()
fetcher.run(url, timeout, request_headers)
# Fetching complete, now filters
# @todo move to class / maybe inside of fetcher abstract base?
# @note: I feel like the following should be in a more obvious chain system
# - Check filter text
# - Is the checksum different?
# - Do we convert to JSON?
# https://stackoverflow.com/questions/41817578/basic-method-chaining ?
# return content().textfilter().jsonextract().checksumcompare() ?
is_html = True
css_filter_rule = watch['css_filter']
if css_filter_rule and len(css_filter_rule.strip()):
if 'json:' in css_filter_rule:
stripped_text_from_html = html_tools.extract_json_as_string(content=fetcher.content, jsonpath_filter=css_filter_rule)
is_html = False
else:
# CSS Filter, extract the HTML that matches and feed that into the existing inscriptis::get_text
stripped_text_from_html = html_tools.css_filter(css_filter=css_filter_rule, html_content=fetcher.content)
if is_html:
# CSS Filter, extract the HTML that matches and feed that into the existing inscriptis::get_text
html_content = fetcher.content
if css_filter_rule and len(css_filter_rule.strip()):
html_content = html_tools.css_filter(css_filter=css_filter_rule, html_content=fetcher.content)
# get_text() via inscriptis
stripped_text_from_html = get_text(html_content)
# We rely on the actual text in the html output.. many sites have random script vars etc,
# in the future we'll implement other mechanisms.
update_obj["last_check_status"] = fetcher.get_last_status_code()
update_obj["last_error"] = False
# If there's text to skip
# @todo we could abstract out the get_text() to handle this cleaner
if len(watch['ignore_text']):
stripped_text_from_html = self.strip_ignore_text(stripped_text_from_html, watch['ignore_text'])
else:
stripped_text_from_html = stripped_text_from_html.encode('utf8')
fetched_md5 = hashlib.md5(stripped_text_from_html).hexdigest()
blocked_by_not_found_trigger_text = False
if len(watch['trigger_text']):
blocked_by_not_found_trigger_text = True
for line in watch['trigger_text']:
# Because JSON wont serialize a re.compile object
if line[0] == '/' and line[-1] == '/':
regex = re.compile(line.strip('/'), re.IGNORECASE)
# Found it? so we don't wait for it anymore
r = re.search(regex, str(stripped_text_from_html))
if r:
blocked_by_not_found_trigger_text = False
break
elif line.lower() in str(stripped_text_from_html).lower():
# We found it don't wait for it.
blocked_by_not_found_trigger_text = False
break
# could be None or False depending on JSON type
# On the first run of a site, watch['previous_md5'] will be an empty string
if not blocked_by_not_found_trigger_text and watch['previous_md5'] != fetched_md5:
changed_detected = True
# Don't confuse people by updating as last-changed, when it actually just changed from None..
if self.datastore.get_val(uuid, 'previous_md5'):
update_obj["last_changed"] = timestamp
update_obj["previous_md5"] = fetched_md5
# Extract title as title
if is_html and self.datastore.data['settings']['application']['extract_title_as_title']:
if not watch['title'] or not len(watch['title']):
update_obj['title'] = html_tools.extract_element(find='title', html_content=fetcher.content)
return changed_detected, update_obj, stripped_text_from_html