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changedetection.io/changedetectionio/fetch_site_status.py

227 lines
9.8 KiB

import hashlib
import os
import re
import time
import urllib3
from changedetectionio import content_fetcher, html_tools
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
# If there was a proxy list enabled, figure out what proxy_args/which proxy to use
# if watch.proxy use that
# fetcher.proxy_override = watch.proxy or main config proxy
# Allows override the proxy on a per-request basis
# ALWAYS use the first one is nothing selected
def set_proxy_from_list(self, watch):
proxy_args = None
if self.datastore.proxy_list is None:
return None
# If its a valid one
if any([watch['proxy'] in p for p in self.datastore.proxy_list]):
proxy_args = watch['proxy']
# not valid (including None), try the system one
else:
system_proxy = self.datastore.data['settings']['requests']['proxy']
# Is not None and exists
if any([system_proxy in p for p in self.datastore.proxy_list]):
proxy_args = system_proxy
# Fallback - Did not resolve anything, use the first available
if proxy_args is None:
proxy_args = self.datastore.proxy_list[0][0]
return proxy_args
def run(self, uuid):
timestamp = int(time.time()) # used for storage etc too
changed_detected = False
screenshot = False # as bytes
stripped_text_from_html = ""
watch = self.datastore.data['watching'][uuid]
# Protect against file:// access
if re.search(r'^file', watch['url'], re.IGNORECASE) and not os.getenv('ALLOW_FILE_URI', False):
raise Exception(
"file:// type access is denied for security reasons."
)
# 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', '')
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')
ignore_status_code = self.datastore.get_val(uuid, 'ignore_status_codes')
# source: support
is_source = False
if url.startswith('source:'):
url = url.replace('source:', '')
is_source = True
# 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")
proxy_args = self.set_proxy_from_list(watch)
fetcher = klass(proxy_override=proxy_args)
# Proxy List support
fetcher.run(url, timeout, request_headers, request_body, request_method, ignore_status_code)
# 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
# source: support, basically treat it as plaintext
if is_source:
is_html = False
is_json = False
css_filter_rule = watch['css_filter']
subtractive_selectors = watch.get(
"subtractive_selectors", []
) + self.datastore.data["settings"]["application"].get(
"global_subtractive_selectors", []
)
has_filter_rule = css_filter_rule and len(css_filter_rule.strip())
has_subtractive_selectors = subtractive_selectors and len(subtractive_selectors[0].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 or is_source:
# 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)
if has_subtractive_selectors:
html_content = html_tools.element_removal(subtractive_selectors, html_content)
if not is_source:
# extract text
stripped_text_from_html = \
html_tools.html_to_text(
html_content,
render_anchor_tag_content=self.datastore.data["settings"][
"application"].get(
"render_anchor_tag_content", False)
)
elif is_source:
stripped_text_from_html = 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')
# 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 None, set it the current one.
if not watch.get('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, fetcher.screenshot