from .processors.exceptions import ProcessorException
import changedetectionio.content_fetchers.exceptions as content_fetchers_exceptions
from changedetectionio.processors.text_json_diff.processor import FilterNotFoundInResponse
from changedetectionio import html_tools
import importlib
import os
import queue
import threading
import time
# A single update worker
#
# Requests for checking on a single site(watch) from a queue of watches
# (another process inserts watches into the queue that are time-ready for checking)
from loguru import logger
class update_worker(threading.Thread):
current_uuid = None
def __init__(self, app, *args, **kwargs):
self.app = app
super().__init__(*args, **kwargs)
def queue_notification_for_watch(self, notification_q, n_object, watch):
from changedetectionio import diff
dates = []
trigger_text = ''
now = time.time()
if watch:
watch_history = watch.history
dates = list(watch_history.keys())
trigger_text = watch.get('trigger_text', [])
# Add text that was triggered
if len(dates):
snapshot_contents = watch.get_history_snapshot(dates[-1])
else:
snapshot_contents = "No snapshot/history available, the watch should fetch atleast once."
# HTML needs linebreak, but MarkDown and Text can use a linefeed
if n_object.get('notification_format') == 'HTML':
line_feed_sep = "
"
# Snapshot will be plaintext on the disk, convert to some kind of HTML
snapshot_contents = snapshot_contents.replace('\n', line_feed_sep)
else:
line_feed_sep = "\n"
triggered_text = ''
if len(trigger_text):
from . import html_tools
triggered_text = html_tools.get_triggered_text(content=snapshot_contents, trigger_text=trigger_text)
if triggered_text:
triggered_text = line_feed_sep.join(triggered_text)
# Could be called as a 'test notification' with only 1 snapshot available
prev_snapshot = "Example text: example test\nExample text: change detection is cool\nExample text: some more examples\n"
current_snapshot = "Example text: example test\nExample text: change detection is fantastic\nExample text: even more examples\nExample text: a lot more examples"
if len(dates) > 1:
prev_snapshot = watch.get_history_snapshot(dates[-2])
current_snapshot = watch.get_history_snapshot(dates[-1])
n_object.update({
'current_snapshot': snapshot_contents,
'diff': diff.render_diff(prev_snapshot, current_snapshot, line_feed_sep=line_feed_sep),
'diff_added': diff.render_diff(prev_snapshot, current_snapshot, include_removed=False, line_feed_sep=line_feed_sep),
'diff_full': diff.render_diff(prev_snapshot, current_snapshot, include_equal=True, line_feed_sep=line_feed_sep),
'diff_patch': diff.render_diff(prev_snapshot, current_snapshot, line_feed_sep=line_feed_sep, patch_format=True),
'diff_removed': diff.render_diff(prev_snapshot, current_snapshot, include_added=False, line_feed_sep=line_feed_sep),
'notification_timestamp': now,
'screenshot': watch.get_screenshot() if watch and watch.get('notification_screenshot') else None,
'triggered_text': triggered_text,
'uuid': watch.get('uuid') if watch else None,
'watch_url': watch.get('url') if watch else None,
})
if watch:
n_object.update(watch.extra_notification_token_values())
logger.trace(f"Main rendered notification placeholders (diff_added etc) calculated in {time.time()-now:.3f}s")
logger.debug("Queued notification for sending")
notification_q.put(n_object)
# Prefer - Individual watch settings > Tag settings > Global settings (in that order)
def _check_cascading_vars(self, var_name, watch):
from changedetectionio.notification import (
default_notification_format_for_watch,
default_notification_body,
default_notification_title
)
# Would be better if this was some kind of Object where Watch can reference the parent datastore etc
v = watch.get(var_name)
if v and not watch.get('notification_muted'):
if var_name == 'notification_format' and v == default_notification_format_for_watch:
return self.app.datastore.data['settings']['application'].get('notification_format')
return v
tags = self.app.datastore.get_all_tags_for_watch(uuid=watch.get('uuid'))
if tags:
for tag_uuid, tag in tags.items():
v = tag.get(var_name)
if v and not tag.get('notification_muted'):
return v
if self.app.datastore.data['settings']['application'].get(var_name):
return self.app.datastore.data['settings']['application'].get(var_name)
# Otherwise could be defaults
if var_name == 'notification_format':
return default_notification_format_for_watch
if var_name == 'notification_body':
return default_notification_body
if var_name == 'notification_title':
return default_notification_title
return None
def send_content_changed_notification(self, watch_uuid):
n_object = {}
watch = self.app.datastore.data['watching'].get(watch_uuid)
if not watch:
return
watch_history = watch.history
dates = list(watch_history.keys())
# Theoretically it's possible that this could be just 1 long,
# - In the case that the timestamp key was not unique
if len(dates) == 1:
raise ValueError(
"History index had 2 or more, but only 1 date loaded, timestamps were not unique? maybe two of the same timestamps got written, needs more delay?"
)
# Should be a better parent getter in the model object
# Prefer - Individual watch settings > Tag settings > Global settings (in that order)
n_object['notification_urls'] = self._check_cascading_vars('notification_urls', watch)
n_object['notification_title'] = self._check_cascading_vars('notification_title', watch)
n_object['notification_body'] = self._check_cascading_vars('notification_body', watch)
n_object['notification_format'] = self._check_cascading_vars('notification_format', watch)
# (Individual watch) Only prepare to notify if the rules above matched
queued = False
if n_object and n_object.get('notification_urls'):
queued = True
count = watch.get('notification_alert_count', 0) + 1
self.app.datastore.update_watch(uuid=watch_uuid, update_obj={'notification_alert_count': count})
self.queue_notification_for_watch(notification_q=self.app.notification_q, n_object=n_object, watch=watch)
return queued
def send_filter_failure_notification(self, watch_uuid):
threshold = self.app.datastore.data['settings']['application'].get('filter_failure_notification_threshold_attempts')
watch = self.app.datastore.data['watching'].get(watch_uuid)
if not watch:
return
n_object = {'notification_title': 'Changedetection.io - Alert - CSS/xPath filter was not present in the page',
'notification_body': "Your configured CSS/xPath filters of '{}' for {{{{watch_url}}}} did not appear on the page after {} attempts, did the page change layout?\n\nLink: {{{{base_url}}}}/edit/{{{{watch_uuid}}}}\n\nThanks - Your omniscient changedetection.io installation :)\n".format(
", ".join(watch['include_filters']),
threshold),
'notification_format': 'text'}
if len(watch['notification_urls']):
n_object['notification_urls'] = watch['notification_urls']
elif len(self.app.datastore.data['settings']['application']['notification_urls']):
n_object['notification_urls'] = self.app.datastore.data['settings']['application']['notification_urls']
# Only prepare to notify if the rules above matched
if 'notification_urls' in n_object:
n_object.update({
'watch_url': watch['url'],
'uuid': watch_uuid,
'screenshot': None
})
self.app.notification_q.put(n_object)
logger.debug(f"Sent filter not found notification for {watch_uuid}")
else:
logger.debug(f"NOT sending filter not found notification for {watch_uuid} - no notification URLs")
def send_step_failure_notification(self, watch_uuid, step_n):
watch = self.app.datastore.data['watching'].get(watch_uuid, False)
if not watch:
return
threshold = self.app.datastore.data['settings']['application'].get('filter_failure_notification_threshold_attempts')
n_object = {'notification_title': "Changedetection.io - Alert - Browser step at position {} could not be run".format(step_n+1),
'notification_body': "Your configured browser step at position {} for {{{{watch_url}}}} "
"did not appear on the page after {} attempts, did the page change layout? "
"Does it need a delay added?\n\nLink: {{{{base_url}}}}/edit/{{{{watch_uuid}}}}\n\n"
"Thanks - Your omniscient changedetection.io installation :)\n".format(step_n+1, threshold),
'notification_format': 'text'}
if len(watch['notification_urls']):
n_object['notification_urls'] = watch['notification_urls']
elif len(self.app.datastore.data['settings']['application']['notification_urls']):
n_object['notification_urls'] = self.app.datastore.data['settings']['application']['notification_urls']
# Only prepare to notify if the rules above matched
if 'notification_urls' in n_object:
n_object.update({
'watch_url': watch['url'],
'uuid': watch_uuid
})
self.app.notification_q.put(n_object)
logger.error(f"Sent step not found notification for {watch_uuid}")
def cleanup_error_artifacts(self, uuid):
# All went fine, remove error artifacts
cleanup_files = ["last-error-screenshot.png", "last-error.txt"]
for f in cleanup_files:
full_path = os.path.join(self.app.datastore.datastore_path, uuid, f)
if os.path.isfile(full_path):
os.unlink(full_path)
def run(self):
now = time.time()
while not self.app.config.exit.is_set():
update_handler = None
try:
queued_item_data = self.app.update_q.get(block=False)
except queue.Empty:
pass
else:
uuid = queued_item_data.item.get('uuid')
self.current_uuid = uuid
if uuid in list(self.app.datastore.data['watching'].keys()) and self.app.datastore.data['watching'][uuid].get('url'):
changed_detected = False
contents = b''
process_changedetection_results = True
update_obj = {}
# Clear last errors (move to preflight func?)
self.app.datastore.data['watching'][uuid]['browser_steps_last_error_step'] = None
watch = self.app.datastore.data['watching'].get(uuid)
logger.info(f"Processing watch UUID {uuid} Priority {queued_item_data.priority} URL {watch['url']}")
now = time.time()
try:
# Processor is what we are using for detecting the "Change"
processor = watch.get('processor', 'text_json_diff')
# Init a new 'difference_detection_processor', first look in processors
processor_module_name = f"changedetectionio.processors.{processor}.processor"
try:
processor_module = importlib.import_module(processor_module_name)
except ModuleNotFoundError as e:
print(f"Processor module '{processor}' not found.")
raise e
update_handler = processor_module.perform_site_check(datastore=self.app.datastore,
watch_uuid=uuid
)
update_handler.call_browser()
changed_detected, update_obj, contents = update_handler.run_changedetection(watch=watch)
# Re #342
# In Python 3, all strings are sequences of Unicode characters. There is a bytes type that holds raw bytes.
# We then convert/.decode('utf-8') for the notification etc
# if not isinstance(contents, (bytes, bytearray)):
# raise Exception("Error - returned data from the fetch handler SHOULD be bytes")
except PermissionError as e:
logger.critical(f"File permission error updating file, watch: {uuid}")
logger.critical(str(e))
process_changedetection_results = False
# A generic other-exception thrown by processors
except ProcessorException as e:
if e.screenshot:
watch.save_screenshot(screenshot=e.screenshot)
if e.xpath_data:
watch.save_xpath_data(data=e.xpath_data)
self.app.datastore.update_watch(uuid=uuid, update_obj={'last_error': e.message})
process_changedetection_results = False
except content_fetchers_exceptions.ReplyWithContentButNoText as e:
# Totally fine, it's by choice - just continue on, nothing more to care about
# Page had elements/content but no renderable text
# Backend (not filters) gave zero output
extra_help = ""
if e.has_filters:
# Maybe it contains an image? offer a more helpful link
has_img = html_tools.include_filters(include_filters='img',
html_content=e.html_content)
if has_img:
extra_help = ", it's possible that the filters you have give an empty result or contain only an image."
else:
extra_help = ", it's possible that the filters were found, but contained no usable text."
self.app.datastore.update_watch(uuid=uuid, update_obj={
'last_error': f"Got HTML content but no text found (With {e.status_code} reply code){extra_help}"
})
if e.screenshot:
watch.save_screenshot(screenshot=e.screenshot, as_error=True)
if e.xpath_data:
watch.save_xpath_data(data=e.xpath_data)
process_changedetection_results = False
except content_fetchers_exceptions.Non200ErrorCodeReceived as e:
if e.status_code == 403:
err_text = "Error - 403 (Access denied) received"
elif e.status_code == 404:
err_text = "Error - 404 (Page not found) received"
elif e.status_code == 407:
err_text = "Error - 407 (Proxy authentication required) received, did you need a username and password for the proxy?"
elif e.status_code == 500:
err_text = "Error - 500 (Internal server error) received from the web site"
else:
extra = ' (Access denied or blocked)' if str(e.status_code).startswith('4') else ''
err_text = f"Error - Request returned a HTTP error code {e.status_code}{extra}"
if e.screenshot:
watch.save_screenshot(screenshot=e.screenshot, as_error=True)
if e.xpath_data:
watch.save_xpath_data(data=e.xpath_data, as_error=True)
if e.page_text:
watch.save_error_text(contents=e.page_text)
self.app.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text})
process_changedetection_results = False
except FilterNotFoundInResponse as e:
if not self.app.datastore.data['watching'].get(uuid):
continue
err_text = "Warning, no filters were found, no change detection ran - Did the page change layout? update your Visual Filter if necessary."
self.app.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text})
# Filter wasnt found, but we should still update the visual selector so that they can have a chance to set it up again
if e.screenshot:
watch.save_screenshot(screenshot=e.screenshot)
if e.xpath_data:
watch.save_xpath_data(data=e.xpath_data)
# Only when enabled, send the notification
if watch.get('filter_failure_notification_send', False):
c = watch.get('consecutive_filter_failures', 0)
c += 1
# Send notification if we reached the threshold?
threshold = self.app.datastore.data['settings']['application'].get('filter_failure_notification_threshold_attempts', 0)
logger.debug(f"Filter for {uuid} not found, consecutive_filter_failures: {c} of threshold {threshold}")
if c >= threshold:
if not watch.get('notification_muted'):
logger.debug(f"Sending filter failed notification for {uuid}")
self.send_filter_failure_notification(uuid)
c = 0
logger.debug(f"Reset filter failure count back to zero")
self.app.datastore.update_watch(uuid=uuid, update_obj={'consecutive_filter_failures': c})
else:
logger.trace(f"{uuid} - filter_failure_notification_send not enabled, skipping")
process_changedetection_results = False
except content_fetchers_exceptions.checksumFromPreviousCheckWasTheSame as e:
# Yes fine, so nothing todo, don't continue to process.
process_changedetection_results = False
changed_detected = False
except content_fetchers_exceptions.BrowserConnectError as e:
self.app.datastore.update_watch(uuid=uuid,
update_obj={'last_error': e.msg
}
)
process_changedetection_results = False
except content_fetchers_exceptions.BrowserFetchTimedOut as e:
self.app.datastore.update_watch(uuid=uuid,
update_obj={'last_error': e.msg
}
)
process_changedetection_results = False
except content_fetchers_exceptions.BrowserStepsStepException as e:
if not self.app.datastore.data['watching'].get(uuid):
continue
error_step = e.step_n + 1
from playwright._impl._errors import TimeoutError, Error
# Generally enough info for TimeoutError (couldnt locate the element after default seconds)
err_text = f"Browser step at position {error_step} could not run, check the watch, add a delay if necessary, view Browser Steps to see screenshot at that step."
if e.original_e.name == "TimeoutError":
# Just the first line is enough, the rest is the stack trace
err_text += " Could not find the target."
else:
# Other Error, more info is good.
err_text += " " + str(e.original_e).splitlines()[0]
logger.debug(f"BrowserSteps exception at step {error_step} {str(e.original_e)}")
self.app.datastore.update_watch(uuid=uuid,
update_obj={'last_error': err_text,
'browser_steps_last_error_step': error_step
}
)
if watch.get('filter_failure_notification_send', False):
c = watch.get('consecutive_filter_failures', 0)
c += 1
# Send notification if we reached the threshold?
threshold = self.app.datastore.data['settings']['application'].get('filter_failure_notification_threshold_attempts',
0)
logger.error(f"Step for {uuid} not found, consecutive_filter_failures: {c}")
if threshold > 0 and c >= threshold:
if not watch.get('notification_muted'):
self.send_step_failure_notification(watch_uuid=uuid, step_n=e.step_n)
c = 0
self.app.datastore.update_watch(uuid=uuid, update_obj={'consecutive_filter_failures': c})
process_changedetection_results = False
except content_fetchers_exceptions.EmptyReply as e:
# Some kind of custom to-str handler in the exception handler that does this?
err_text = "EmptyReply - try increasing 'Wait seconds before extracting text', Status Code {}".format(e.status_code)
self.app.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text,
'last_check_status': e.status_code})
process_changedetection_results = False
except content_fetchers_exceptions.ScreenshotUnavailable as e:
err_text = "Screenshot unavailable, page did not render fully in the expected time or page was too long - try increasing 'Wait seconds before extracting text'"
self.app.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text,
'last_check_status': e.status_code})
process_changedetection_results = False
except content_fetchers_exceptions.JSActionExceptions as e:
err_text = "Error running JS Actions - Page request - "+e.message
if e.screenshot:
watch.save_screenshot(screenshot=e.screenshot, as_error=True)
self.app.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text,
'last_check_status': e.status_code})
process_changedetection_results = False
except content_fetchers_exceptions.PageUnloadable as e:
err_text = "Page request from server didnt respond correctly"
if e.message:
err_text = "{} - {}".format(err_text, e.message)
if e.screenshot:
watch.save_screenshot(screenshot=e.screenshot, as_error=True)
self.app.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text,
'last_check_status': e.status_code,
'has_ldjson_price_data': None})
process_changedetection_results = False
except content_fetchers_exceptions.BrowserStepsInUnsupportedFetcher as e:
err_text = "This watch has Browser Steps configured and so it cannot run with the 'Basic fast Plaintext/HTTP Client', either remove the Browser Steps or select a Chrome fetcher."
self.app.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text})
process_changedetection_results = False
logger.error(f"Exception (BrowserStepsInUnsupportedFetcher) reached processing watch UUID: {uuid}")
except Exception as e:
logger.error(f"Exception reached processing watch UUID: {uuid}")
logger.error(str(e))
self.app.datastore.update_watch(uuid=uuid, update_obj={'last_error': "Exception: " + str(e)})
# Other serious error
process_changedetection_results = False
else:
# Crash protection, the watch entry could have been removed by this point (during a slow chrome fetch etc)
if not self.app.datastore.data['watching'].get(uuid):
continue
update_obj['content-type'] = update_handler.fetcher.get_all_headers().get('content-type', '').lower()
# Mark that we never had any failures
if not watch.get('ignore_status_codes'):
update_obj['consecutive_filter_failures'] = 0
# Everything ran OK, clean off any previous error
update_obj['last_error'] = False
self.cleanup_error_artifacts(uuid)
if not self.app.datastore.data['watching'].get(uuid):
continue
#
# Different exceptions mean that we may or may not want to bump the snapshot, trigger notifications etc
if process_changedetection_results:
# Extract as title if possible/requested.
if self.app.datastore.data['settings']['application'].get('extract_title_as_title') or watch['extract_title_as_title']:
if not watch['title'] or not len(watch['title']):
try:
update_obj['title'] = html_tools.extract_element(find='title', html_content=update_handler.fetcher.content)
logger.info(f"UUID: {uuid} Extract <title> updated title to '{update_obj['title']}")
except Exception as e:
logger.warning(f"UUID: {uuid} Extract <title> as watch title was enabled, but couldn't find a <title>.")
# Now update after running everything
timestamp = round(time.time())
try:
self.app.datastore.update_watch(uuid=uuid, update_obj=update_obj)
# Also save the snapshot on the first time checked, "last checked" will always be updated, so we just check history length.
if changed_detected or not watch.history_n:
if update_handler.screenshot:
watch.save_screenshot(screenshot=update_handler.screenshot)
if update_handler.xpath_data:
watch.save_xpath_data(data=update_handler.xpath_data)
# Small hack so that we sleep just enough to allow 1 second between history snapshots
# this is because history.txt indexes/keys snapshots by epoch seconds and we dont want dupe keys
if watch.newest_history_key and int(timestamp) == int(watch.newest_history_key):
logger.warning(
f"Timestamp {timestamp} already exists, waiting 1 seconds so we have a unique key in history.txt")
timestamp = str(int(timestamp) + 1)
time.sleep(1)
watch.save_history_text(contents=contents,
timestamp=timestamp,
snapshot_id=update_obj.get('previous_md5', 'none'))
if update_handler.fetcher.content:
watch.save_last_fetched_html(contents=update_handler.fetcher.content, timestamp=timestamp)
# Notifications should only trigger on the second time (first time, we gather the initial snapshot)
if watch.history_n >= 2:
logger.info(f"Change detected in UUID {uuid} - {watch['url']}")
if not watch.get('notification_muted'):
self.send_content_changed_notification(watch_uuid=uuid)
except Exception as e:
# Catch everything possible here, so that if a worker crashes, we don't lose it until restart!
logger.critical("!!!! Exception in update_worker while processing process_changedetection_results !!!")
logger.critical(str(e))
self.app.datastore.update_watch(uuid=uuid, update_obj={'last_error': str(e)})
# Always record that we atleast tried
count = watch.get('check_count', 0) + 1
# Record the 'server' header reply, can be used for actions in the future like cloudflare/akamai workarounds
try:
server_header = update_handler.fetcher.headers.get('server', '').strip().lower()[:255]
self.app.datastore.update_watch(uuid=uuid,
update_obj={'remote_server_reply': server_header}
)
except Exception as e:
pass
self.app.datastore.update_watch(uuid=uuid, update_obj={'fetch_time': round(time.time() - now, 3),
'last_checked': round(time.time()),
'check_count': count
})
self.current_uuid = None # Done
self.q.task_done()
logger.debug(f"Watch {uuid} done in {time.time()-now:.2f}s")
# Give the CPU time to interrupt
time.sleep(0.1)
self.app.config.exit.wait(1)