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changedetection.io/changedetectionio/fetch_site_status.py

162 lines
7.4 KiB

import time
from changedetectionio import content_fetcher
from changedetectionio import html_tools
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 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]
# Unset any existing notification error
update_obj = {'last_notification_error': False, 'last_error': False}
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')
request_body = self.datastore.get_val(uuid, 'body')
request_method = self.datastore.get_val(uuid, 'method')
# 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, request_body, request_method)
# 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_json = 'application/json' in fetcher.headers.get('Content-Type', '')
is_html = not is_json
css_filter_rule = watch['css_filter']
has_filter_rule = css_filter_rule and len(css_filter_rule.strip())
if is_json and not has_filter_rule:
css_filter_rule = "json:$"
has_filter_rule = True
if has_filter_rule:
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
if is_html:
# CSS Filter, extract the HTML that matches and feed that into the existing inscriptis::get_text
html_content = fetcher.content
# If not JSON, and if it's not text/plain..
if 'text/plain' in fetcher.headers.get('Content-Type', '').lower():
# Don't run get_text or xpath/css filters on plaintext
stripped_text_from_html = html_content
else:
# Then we assume HTML
if has_filter_rule:
# For HTML/XML we offer xpath as an option, just start a regular xPath "/.."
if css_filter_rule[0] == '/':
html_content = html_tools.xpath_filter(xpath_filter=css_filter_rule, html_content=fetcher.content)
else:
# CSS Filter, extract the HTML that matches and feed that into the existing inscriptis::get_text
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)
# Re #340 - return the content before the 'ignore text' was applied
text_content_before_ignored_filter = stripped_text_from_html.encode('utf-8')
# 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()
# If there's text to skip
# @todo we could abstract out the get_text() to handle this cleaner
text_to_ignore = watch.get('ignore_text', []) + self.datastore.data['settings']['application'].get('global_ignore_text', [])
if len(text_to_ignore):
stripped_text_from_html = html_tools.strip_ignore_text(stripped_text_from_html, text_to_ignore)
else:
stripped_text_from_html = stripped_text_from_html.encode('utf8')
# Re #133 - if we should strip whitespaces from triggering the change detected comparison
if self.datastore.data['settings']['application'].get('ignore_whitespace', False):
fetched_md5 = hashlib.md5(stripped_text_from_html.translate(None, b'\r\n\t ')).hexdigest()
else:
fetched_md5 = hashlib.md5(stripped_text_from_html).hexdigest()
# On the first run of a site, watch['previous_md5'] will be an empty string, set it the current one.
if not len(watch['previous_md5']):
watch['previous_md5'] = fetched_md5
update_obj["previous_md5"] = fetched_md5
blocked_by_not_found_trigger_text = False
if len(watch['trigger_text']):
# Yeah, lets block first until something matches
blocked_by_not_found_trigger_text = True
# Filter and trigger works the same, so reuse it
result = html_tools.strip_ignore_text(content=str(stripped_text_from_html),
wordlist=watch['trigger_text'],
mode="line numbers")
if result:
blocked_by_not_found_trigger_text = False
if not blocked_by_not_found_trigger_text and watch['previous_md5'] != fetched_md5:
changed_detected = True
update_obj["previous_md5"] = fetched_md5
update_obj["last_changed"] = timestamp
# Extract title as title
if is_html:
if self.datastore.data['settings']['application']['extract_title_as_title'] or watch['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, text_content_before_ignored_filter